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"Archea" redirects here. For the geologic eon, see Archean. For the spider family, see Archaeidae.
Archaea
Fossil range: Paleoarchean - Recent
Halobacteria sp. strain .NRC-1, each cell about 5 μm long.^ The cells are very small, roughly the size of an animal mitochondrion (about 1-2μm in diameter and 10 μm long).

 ^ Pyrobaculum aerophilum cells were usually found to be 3 to 8 μm long and 0.6 μm wide.
Scientific classification
Domain: Archaea
Woese, Kandler & Wheelis, 1990
Kingdoms and phyla
.The Archaea /ɑrˈkiːə/  ( listen) are a group of single-celled microorganisms.^ They are archaea , single-celled microbes similar to, but not quite, bacteria.
  • NSF - OLPA - PR 03-84: MICROBE FROM DEPTHS TAKES LIFE TO HOTTEST KNOWN LIMIT 19 January 2010 9:52 UTC www.nsf.gov [Source type: FILTERED WITH BAYES]

 ^ Archaea are single celled, lacking a nuclear membrane and having a low deoxyribonucleic acid content.
  • Di- and tetra-alkyl ether lipids of the Archaea 19 January 2010 9:52 UTC lipidlibrary.aocs.org [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 .A single individual or species from this domain is called an archaeon (sometimes spelled "archeon").^ A single individual or species from this domain is called an archaeon (sometimes spelled "archeon").
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ A single organism from this domain has been called an " archaean ."
  • Archaea - Hwiki 19 January 2010 9:52 UTC hwiki.fzk.de [Source type: Academic]

 ^ A single organism from this domain is called an archaeon .

 .They have no cell nucleus or any other organelles within their cells.^ There is no cell nucleus in procaryote cells .
  • Biosphere Bacteria and Archaea, the Procaryote Domain 19 January 2010 9:52 UTC www.morning-earth.org [Source type: FILTERED WITH BAYES]

 ^ They have no cell nucleus or any other organelles within their cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Their cells contain no cell nucleus or other organelles.

 .In the past they were viewed as an unusual group of bacteria and named archaebacteria but since the Archaea have an independent evolutionary history and show many differences in their biochemistry from other forms of life, they are now classified as a separate domain in the three-domain system.^ They have significant differences in their cell walls and biochemistry when compared to the bacteria.

 ^ There are three main groups which the Archaea have been separated into.

 ^ Under the three domain model, they are the taxonomic equivalents of the other bacteria and the eukaryotes.

 .In this system the three main branches of evolutionary descent are the Archaea, Eukarya and Bacteria.^ The three domains are bacteria, archaea and eukarya.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ Archaea can cluster with eukarya, or archaea can cluster with bacteria, or bacteria can cluster with eukarya.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ In this system the three main branches of evolutionary descent are the Archaea, Eukarya and Bacteria .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Archaea are further divided into four recognized phyla, but many more phyla may exist.^ Archaea may exist.
  • Chapter 6 Notes: Diversification of Bacteria and Archaea. I: Phylogeny and Biology 19 January 2010 9:52 UTC evolution-textbook.org [Source type: Academic]

 ^ Archaea are further divided into four recognized phyla, but many more phyla may exist.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The discovery of the relationship of the Archaea to the Eucarya revealed that prokaryotes do not comprise a monophyletic group since they can be divided into two distinct lineages.
  • What is Archaebacteria? - A definition of Archaebacteria from the ecomii science encyclopedia 19 January 2010 9:52 UTC www.ecomii.com [Source type: General]

 .Of these groups the Crenarchaeota and the Euryarchaeota are most intensively studied.^ Of these groups the Crenarchaeota and the Euryarchaeota are most intensively studied.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea In Hot Springs Use Ammonia For Energy: May Shed Light On Early Evolution (May 25, 2007) — One of the most common groups of archaea (Crenarchaeota) and a group that includes members that live in hot springs, use ammonia as their energy source, according to a new study.
  • New Group Of Microorganisms Discovered In The Open Sea 19 January 2010 9:52 UTC www.sciencedaily.com [Source type: News]

 ^ Cultivated crenarchaea are all thermophilic, and most are extremely thermophilic, with optimal growth temperatures above 80°C. As a group, these are the most thermophilic organisms known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .Classifying the Archaea is still difficult, since the vast majority have never been studied in the laboratory and have only been detected by analysis of their nucleic acids in samples from the environment.^ Classifying the Archaea is still difficult, since the vast majority have never been studied in the laboratory and have only been detected by analysis of their nucleic acids in samples from the environment.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ He does agree with Thomas on one point, though: studying archaea is tough, and was harder still when he started his work without the benefit of the technology available today.
  • Making the Case Against Archaea » Scienceline 19 January 2010 9:52 UTC www.scienceline.org [Source type: FILTERED WITH BAYES]

 ^ The first prokaryotes to be classified in domain Archaea are species that can live in environments so extreme that few other organisms can survive there.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 .Although archaea have, in the past, been classed with bacteria as prokaryotes, this classification has been described as outdated, since it fails to distinguish between the three very distinct domains of life.^ The three domains are bacteria, archaea and eukarya.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ Archaea are prokaryotes, just like bacteria are.

 ^ The two prokaryotic domains are Eubacteria (bacteria) and Archaea .

 [1]
.Generally, archaea and bacteria are quite similar in size and shape, although a few archaea have very unusual shapes, such as the flat and square-shaped cells of Haloquadra walsbyi.^ They are archaea , single-celled microbes similar to, but not quite, bacteria.
  • NSF - OLPA - PR 03-84: MICROBE FROM DEPTHS TAKES LIFE TO HOTTEST KNOWN LIMIT 19 January 2010 9:52 UTC www.nsf.gov [Source type: FILTERED WITH BAYES]

 ^ Archaea have different cell walls to bacteria.

 ^ They tend to be very similar in shape to bacteria , although they have been seen to have very strange shapes.

 .Despite this visual similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes: notably the enzymes involved in transcription and translation.^ Archaea, like Bacteria, are prokaryotic in organization, but show similarities to several components of the eukaryotic replication, transcription and translation systems.
  • Research 19 January 2010 9:52 UTC www.siumed.edu [Source type: Academic]

 ^ About 75% of all eukaryote genes are more closely related to genes found in bacteria than ones in archaea.
  • CarlZimmer.com: Articles 19 January 2010 9:52 UTC carlzimmer.com [Source type: FILTERED WITH BAYES]

 ^ These bacteria are very closely related to eukaryotic mitochondria.
  • The 3 domains of life 11 September 2009 0:44 UTC www.biology.iupui.edu [Source type: FILTERED WITH BAYES]

 .Other aspects of archaean biochemistry are unique, such as their reliance on ether lipids in their cell membranes.^ The Archaea, or Archaebacteria have cell membrane of prenyl ether lipids.
  • Palaeos Bacteria: Bacteria 19 January 2010 9:52 UTC www.palaeos.com [Source type: FILTERED WITH BAYES]

 ^ Other aspects of archaean biochemistry are unique, such as their reliance on ether lipids in their cell membranes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In addition, many morphological or physiological characteristics such as the presence of branched-chain ether-linked lipids in their cell membrane, lack of peptidoglycan in their cell wall, characteristic subunit pattern of RNA polymerase, presence of modified bases in tRNA, presence of a unique form of DNA polymerase, have been previously indicated as defining characteristics of archaea [ 1 , 15 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .The archaea exploit a much greater variety of sources of energy than eukaryotes: ranging from familiar organic compounds such as sugars, to using ammonia, metal ions or even hydrogen gas as nutrients.^ Sunlight can also be used as a source of energy for the Archaea.

 ^ Some Archaea use ammonia or sulfur.

 ^ The bacteria use the archaea’s waste products, such as organic compounds and hydrogen.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 .Salt-tolerant archaea (the Halobacteria) use sunlight as a source of energy, and other species of archaea fix carbon; however, unlike plants and cyanobacteria, no species of archaea is known to do both.^ The Archaea used for this treatment is the methanogenic species.

 ^ However, in other incubation studies, pelagic archaea also were capable of using organic carbon (e.g., 2).
  • Archaea in the Earth System I Posters - Biogeosciences [B] 19 January 2010 9:52 UTC www.agu.org [Source type: Academic]

 ^ Salt-tolerant archaea (the Halobacteria ) use sunlight as a source of energy, and other species of archaea fix carbon ; however, unlike plants and cyanobacteria , no species of archaea is known to do both.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Archaea reproduce asexually and divide by binary fission, fragmentation, or budding; in contrast to bacteria and eukaryotes, no species of archaea are known that form spores.^ In contrast, no known eukaryote can survive over 60C (140F).
  • The Three Domains of Life 19 January 2010 9:52 UTC www.spacedaily.com [Source type: FILTERED WITH BAYES]
  • NAI: News Stories 19 January 2010 9:52 UTC nai.arc.nasa.gov [Source type: FILTERED WITH BAYES]

 ^ Archaea reproduce asexually and divide by binary fission , fragmentation, or budding; in contrast to bacteria and eukaryotes, no species of archaea are known that form spores .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Bacteria and archaea reproduce by doubling in an asexual (non-sexual) process called binary fission.
  • Biosphere Bacteria and Archaea, the Procaryote Domain 19 January 2010 9:52 UTC www.morning-earth.org [Source type: FILTERED WITH BAYES]
.Initially, archaea were seen as extremophiles that lived in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats, such as soils, oceans, and marshlands.^ Archaea were first detected in extreme environments, such as volcanic hot springs .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Other archaea do not live in extreme environments.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Initially, archaea were seen as extremophiles that lived in harsh environments, such as hot springs and salt lakes , but they have since been found in a broad range of habitats , such as soils , oceans , and marshlands .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Archaea are particularly numerous in the oceans, and the archaea in plankton may be one of the most abundant groups of organisms on the planet.^ Archaea are particularly numerous in the oceans, and the archaea in plankton may be one of the most abundant groups of organisms on the planet.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea , one of the three domains of life, is a highly diverse and abundant group of prokaryotes, and includes a number of "extremophiles" that thrive in such environments as hot springs, salt lakes, and submarine volcanic habitats ( 33 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 .Archaea are now recognized as a major part of life on Earth and may play an important role in both the carbon cycle and nitrogen cycle.^ Archaea are now recognized as a major part of life on Earth and may play an important role in both the carbon cycle and nitrogen cycle .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are important for earth's nitrogen and methane cycles.

 ^ Nitrate reduction and the nitrogen cycle in archaea ".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .No clear examples of archaeal pathogens or parasites are known, but they are often mutualists or commensals.^ As of 2007, no clear examples of archaeal pathogens or parasites are known.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ No clear examples of archaeal pathogens or parasites are known, but they are often mutualists or commensals .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ This raises the interesting question as to whether some archaea can be considered potential human pathogens; that is, do they have features or strategies that characteristically distinguish pathogenic bacteria from commensals?
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 .One example are the methanogenic archaea that inhabit the gut of humans and ruminants, where they are present in vast numbers and aid in the digestion of food.^ Methanogenic archaea and human periodontal disease.
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 ^ Methanogenic Archaea and human periodontal disease.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ "Methanogenic Archaea and human periodontal disease".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Archaea have some importance in technology, with methanogens used to produce biogas and as part of sewage treatment, and enzymes from extremophile archaea that can resist high temperatures and organic solvents are exploited in biotechnology.^ The Archaea used for this treatment is the methanogenic species.

 ^ Such 'thermophiles' produce enzymes that are stable at high temperatures.
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 ^ Some Archaea use ammonia or sulfur.

Contents

Classification

A new domain

.Early in the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry, morphology and metabolism.^ Early in the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry , morphology and metabolism .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Prokaryotes are a very diverse group of organisms that are believed to have evolved early.
  • Microbiology - The Prokaryotes: Domains Bacteria and Archaea 19 January 2010 9:52 UTC www.rapidlearningcenter.com [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 .For example, microbiologists tried to classify microorganisms based on the structures of their cell walls, their shapes, and the substances they consume.^ For ex ample, microbiologists tried to classify microorganisms based on the structures of their cell walls , their shapes, and the substances they consume.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Structure of the cell wall of mycobacteria.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 ^ Most fungal species are filamentous and possess cell walls made of chitin, the same substance that is found in insect exoskeletons.
  • Plant Physiology Online: The Plant Kingdom 19 January 2010 9:52 UTC 4e.plantphys.net [Source type: Academic]

 [2] .However, a new approach was proposed in 1965,[3] using the sequences of the genes in these organisms to work out which prokaryotes are genuinely related to each other.^ A new proposal for the classification of prokaryotic organisms.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ The use of ribosomal RNA sequences as molecular chronometers has led to the recognition of a group of prokaryotes, the Archaea, that are phylogenetically distinct from both bacteria and eukaryotes.
  • Archaea: A Laboratory Manual 19 January 2010 9:52 UTC www.cshlpress.com [Source type: Academic]

 ^ However, became obvious from biochemical characteristics and DNA sequence analysis that there were numerous differences between these archaebacteria and other bacteria.
  • The 3 domains of life 11 September 2009 0:44 UTC www.biology.iupui.edu [Source type: FILTERED WITH BAYES]

 .This approach, known as phylogenetics, is the main method used today.^ This approach, known as phylogenetics , is the main method used today.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ A third classification method is the cladistic approach, which strives to classify organisms by natural evolutionary relationships, known as phylogeny.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ As a result, the entire second edition of Bergey's Manual of Systematic Bacteriology uses the phylogenetic approach for classifying Bacteria and Archaea (www.bergeys .org).
  • The Phylogenomic Species Concept for Bacteria and Archaea 19 January 2010 9:52 UTC www.microbemagazine.org [Source type: Academic]
Archaea were first detected in extreme environments, such as volcanic hot springs.
.Archaea were first classified as a separate group of prokaryotes in 1977 by Carl Woese and George E. Fox in phylogenetic trees based on the sequences of ribosomal RNA (rRNA) genes.^ Schematic based on Woese's Tree of Life, which is based upon studies of 16s ribosomal RNA .

 ^ In 1977, Woese and Fox discovered the Archaea based upon their phylogenetic relationships to the Bacteria and the Eucarya.

 ^ Woese CR, Fox GE (1977).
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 [4] .These two groups were originally named the Archaebacteria and Eubacteria and treated as kingdoms or subkingdoms, which Woese and Fox termed Urkingdoms.^ These two groups were originally named the Archaebacteria and Eubacteria, treated as kingdoms or subkingdoms, which Woese and Fox termed Urkingdoms.

 ^ Archaebacteria Ancient (over 3.5 billion years old) group of prokaryotes; some biologists want to place this group into a separate Kingdom, the Archaea.

 ^ In 1977 Carl Woese and George Fox proposed that archaea are different enough to have their own kingdom.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]

 .Woese argued that this group of prokaryotes is a fundamentally different sort of life.^ Woese and his colleagues argued that there were three major groups of living things: eukaryotes, bacteria, and a group they dubbed archaea.
  • CarlZimmer.com: Articles 19 January 2010 9:52 UTC carlzimmer.com [Source type: FILTERED WITH BAYES]

 ^ He argues that the fundamental division in life is the prokaryote eukaryote division and that the archaea are just another group of bacteria that do not deserve domain status.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ The cellular and genomic organization of prokaryotes is fundamentally different from that of eukaryotes.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 .To emphasize this difference, these two domains were later renamed Archaea and Bacteria.^ The three domains are bacteria, archaea and eukarya.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ The two prokaryotic domains are Eubacteria (bacteria) and Archaea .

 ^ The Tree shows the procaryotes in two Domains, Archaea and Bacteria.

 [5] The word archaea comes from the Ancient Greek ἀρχαῖα, meaning "ancient things".[6]
.At first, only the methanogens were placed in this new domain, and the archaea were seen as extremophiles that exist only in habitats such as hot springs and salt lakes.^ Archaea were first detected in extreme environments, such as volcanic hot springs .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Thermophiles live in places that have high temperatures, such as hot springs.
  • Archaea - encyclopedia article - Citizendium 19 January 2010 9:52 UTC locke.citizendium.org:8080 [Source type: Academic]
  • Archaea - Hwiki 19 January 2010 9:52 UTC hwiki.fzk.de [Source type: Academic]

 ^ At first, only the methanogens were placed in this new domain, and the archaea were seen as extremophiles that exist only in habitats such as hot springs and salt lakes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .By the end of the 20th century, microbiologists realized that the archaea are a large and diverse group of organisms that are widely distributed in nature and are common in much less extreme habitats, such as soils and oceans.^ Of course, generalizations about a group of organisms as diverse as archaea are problematic.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Researchers are identifying a great diversity of archaea in extreme environments and in the oceans.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Actinomycetes such as Streptomyces have a world-wide distribution in soils.

 [7] .This new appreciation of the importance and ubiquity of archaea came from using the polymerase chain reaction to detect prokaryotes in samples of water or soil from their nucleic acids alone.^ This new appreciation of the importance and ubiquity of archaea came from using the polymerase chain reaction to detect prokaryotes in samples of water or soil from their nucleic acids alone.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, like all Archaea, Crenarchaeota are prokaryotic, and are bounded by ether-linked lipid membranes which contain isoprinoid side chains instead of fatty acids.
  • Crenarchaeota 19 January 2010 9:52 UTC tolweb.org [Source type: Academic]

 ^ The use of ribosomal RNA sequences as molecular chronometers has led to the recognition of a group of prokaryotes, the Archaea, that are phylogenetically distinct from both bacteria and eukaryotes.
  • Archaea: A Laboratory Manual 19 January 2010 9:52 UTC www.cshlpress.com [Source type: Academic]

 .This allows the detection and identification of organisms that cannot be cultured in the laboratory, which is often difficult.^ This allows the detection and identification of organisms that cannot be cultured in the laboratory, which is often difficult.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The majority of archaea cannot be cultured within the laboratory setting, and their ubiquitous presence in global habitats has been realized through the use of culture-independent techniques.
  • archaea (bacteria) -- Britannica Online Encyclopedia 19 January 2010 9:52 UTC www.britannica.com [Source type: Reference]

 ^ Members of the Korarchaeota and Nanoarchaeota have not been detected in pure culture ; rather, they have been detected only in mixed laboratory cultures.
  • archaea (bacteria) -- Britannica Online Encyclopedia 19 January 2010 9:52 UTC www.britannica.com [Source type: Reference]

 [8][9]

Current classification

Further information: Biological classification and Systematics
.The classification of archaea, and of prokaryotes in general, is a rapidly moving and contentious field.^ Further information: Biological classification and Systematics The classification of archaea, and of prokaryotes in general, is a rapidly moving and contentious field.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Our results indicate that polyploidy might be more widespread in archaea (or even prokaryotes in general) than previously assumed.
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 ^ Although archaea have, in the past, been classed with bacteria as prokaryotes , this classification may be outdated, since it fails to distinguish between the three very distinct domains of life.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Current classification systems aim to organize archaea into groups of organisms that share structural features and common ancestors.^ Current classification systems aim to organize archaea into groups of organisms that share structural features and common ancestors.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The classification of archaea into species is also controversial.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Scientists now believe that the archaea and the bacteria evolved separately from a common ancestor, and that the eukarya branched off from archaea at a later point.
  • Pathways for Life 19 January 2010 9:52 UTC www.rps.psu.edu [Source type: FILTERED WITH BAYES]

 [10] .These classifications rely heavily on the use of the sequence of ribosomal RNA genes to reveal relationships between organisms (molecular phylogenetics).^ These classifications rely heavily on the use of the sequence of ribosomal RNA genes to reveal relationships between organisms (molecular phylogenetics ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The relationships between organisms can be graphed in this way.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ These developments, which are attributable to rapid advances in molecular sequencing of highly conserved regions of the procaryotic genome, most notably genes coding for the RNA of the small ribosomal subunit, have lead to a natural classification that reflects the evolutionary history of Bacteria and Archaea, and to the development of new, universally applicable methods of identifying these organisms.

 [11] .Most of the culturable and well-investigated species of archaea are members of two main phyla, the Euryarchaeota and Crenarchaeota.^ Most of the culturable and well-investigated species of archaea are members of two main phyla , the Euryarchaeota and Crenarchaeota .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Still, it is clear that very early in the history of life on Earth, prokaryotes diverged into two main lineages: bacteria and archaea.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Within the archaea, there are two main divisions called crenarchaeota (4 complete genomes) and euryarchaeota (12 complete genomes).
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 .Other groups have been tentatively created.^ Other groups have been tentatively created.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .For example, the peculiar species Nanoarchaeum equitans, which was discovered in 2003, has been given its own phylum, the Nanoarchaeota.^ For example, the peculiar species Nanoarchaeum equitans , which was discovered in 2003, has been given its own phylum, the Nanoarchaeota .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Two other groups have been tentatively created for certain environmental samples and the peculiar species Nanoarchaeum equitans , discovered in 2002 by Karl Stetter , but their affinities are uncertain.

 [12] .A new phylum Korarchaeota has also been proposed.^ A new phylum Korarchaeota has also been proposed, it contains a small group of unusual thermophilic species that shares features of both of the main phyla, but is most closely related to the Crenarchaeota.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .It contains a small group of unusual thermophilic species that shares features of both of the main phyla, but is most closely related to the Crenarchaeota.^ A new phylum Korarchaeota has also been proposed, it contains a small group of unusual thermophilic species that shares features of both of the main phyla, but is most closely related to the Crenarchaeota.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Most thermophilic species belong to a second clade, Crenarchaeota.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ In biology, a species is a group of related organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [13][14] Other recently detected species of archaea are only distantly related to any of these groups, such as the Archaeal Richmond Mine Acidophilic Nanoorganisms (ARMAN), which were discovered in 2006.[15]
The ARMAN are a new group of archaea recently discovered in acid mine drainage.
.The classification of archaea into species is also controversial.^ The classification of archaea into species is also controversial.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The archaea, as representatives of one of the deepest lineages, offer special insights into the origin of cellular life and the ancestry of eukaryotes.
  • What Archaea Have to Tell Biologists -- Whitman et al. 152 (4): 1245 -- Genetics 19 January 2010 9:52 UTC www.genetics.org [Source type: Academic]

 ^ From this perspective, transcriptional regulation in archaea is of special interest because it may provide insight into the natures of the last common ancestors with the bacteria as well as the eukaryotes.
  • What Archaea Have to Tell Biologists -- Whitman et al. 152 (4): 1245 -- Genetics 19 January 2010 9:52 UTC www.genetics.org [Source type: Academic]

 .In biology, a species is a group of related organisms.^ In biology, a species is a group of related organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ More generally, "species" is often defined as a "group of organisms capable of interbreeding and producing fertile offspring."
  • An Exercise in Species Barcoding 19 January 2010 9:52 UTC norvig.com [Source type: Original source]

 ^ Several groups commented on the conservation of CoA biosynthetic enzymes among distantly related species.
  • Coenzyme A Biosynthesis: Reconstruction of the Pathway in Archaea and an Evolutionary Scenario Based on Comparative Genomics -- Genschel 21 (7): 1242 -- Molecular Biology and Evolution 19 January 2010 9:52 UTC mbe.oxfordjournals.org [Source type: Academic]

 .A popular definition of a species in animals is a set of organisms that can breed with each other and are reproductively isolated from other groups of organisms (i.e. they cannot breed with other species).^ However, we have also retained a few proteins where 1 or 2 isolated species from other groups (e.g.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ A popular definition of a species in animals is a set of organisms that can breed with each other and are reproductively isolated from other groups of organisms ( i.e.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In this regard, they are priceless to other organisms.

 [16] .However, efforts to classify prokaryotes such as archaea into species are complicated by the fact that they are asexual and show high levels of horizontal gene transfer between lineages.^ Gene transfer in archaea.
  • Paul Blum - Associate Professor - University of Nebraska,Lincoln 19 January 2010 9:52 UTC www.biosci.unl.edu [Source type: Academic]

 ^ The classification of archaea into species is also controversial.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These genes can spread to other species by horizontal gene transfer.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 .The area is contentious; with, for example, some data suggesting that in archaea such as the genus Ferroplasma, individual cells can be grouped into populations that have highly similar genomes and rarely transfer genes with more divergent groups of cells.^ Gene transfer in archaea.
  • Paul Blum - Associate Professor - University of Nebraska,Lincoln 19 January 2010 9:52 UTC www.biosci.unl.edu [Source type: Academic]

 ^ The area is contentious; with, for example, some data suggesting that in archaea such as the genus Ferroplasma , individual cells can be grouped into populations that have highly similar genomes and rarely transfer genes with more divergent groups of cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea , one of the three domains of life, is a highly diverse and abundant group of prokaryotes, and includes a number of "extremophiles" that thrive in such environments as hot springs, salt lakes, and submarine volcanic habitats ( 33 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [17] .These groups of cells are argued to be analogous to species.^ These groups of cells are argued to be analogous to species.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These results can again be explained by either selective loss of these genes from these particular groups or deeper branching of these lineages within the Euryarchaeota species.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ The species from both these groups, particularly Euryarchaeota, are highly diverse in terms of their metabolism and physiology.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .On the other hand, studies in Halorubrum found significant genetic exchange between such populations.^ On the other hand, studies in Halorubrum found significant genetic exchange between such populations.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Although this four-kingdom system advocated herein has the greatest advantage, the differences between it and some other systems, such as a five kingdom system recognizing Protistia, are not significant."
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ LIBSHUFF analysis displayed the significant dissimilarity of archaeal diversity between two studied samples.
  • Archaea in the Earth System I Posters - Biogeosciences [B] 19 January 2010 9:52 UTC www.agu.org [Source type: Academic]

 [18] .Such results have led to the argument that classifying these groups of organisms as species would have little practical meaning.^ Such results have led to the argument that classifying these groups of organisms as species would have little practical meaning.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In biology, a species is a group of related organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Biomolecules from these organisms are active at temperatures that generally degrade normal cellular molecules (or membranes), such as enzymes, lipids, and nucleic acids.

 [19]
.Current knowledge on the diversity of archaea is fragmentary and the total number of archaean species cannot be estimated with any accuracy.^ Current knowledge on the diversity of archaea is fragmentary and the total number of archaean species cannot be estimated with any accuracy.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Genome copiy numbers were also determined for several species from the third domain of life, the archaea.
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 ^ This review covers the current knowledge on the nitrate reduction processes and other pathways of the N-cycle in archaea.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [11] .Even estimates of the total number of phyla in the archaea range from 18 to 23, of which only 8 phyla have representatives that have been grown in culture and studied directly.^ Even estimates of the total number of phyla in the archaea range from 18 to 23, of which only 8 phyla have representatives that have been grown in culture and studied directly.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Some archaea also form symbiotic relationships with sponges ; in fact, Cenarchaeum symbiosum was grown in the laboratory with its host sponge and was the first nonthermophilic Crenarchaeota to be cultured and described.
  • archaea (bacteria) -- Britannica Online Encyclopedia 19 January 2010 9:52 UTC www.britannica.com [Source type: Reference]

 ^ Borrelia hermsii , a spirochete that causes relapsing fever, harbors about 16 genome copies if it is grown in mice but only 1/4 to 1/2 of this number if it is grown axenically in batch culture [22] .
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 .Many of these hypothetical groups are known from only a single rRNA sequence, indicating that the vast majority of the diversity among these organisms remains completely unknown.^ Many of these hypothetical groups are known from only a single rRNA sequence, indicating that the vast majority of the diversity among these organisms remains completely unknown.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Therefore, the phylogenetic and phenotypic diversity of this group remains largely unknown.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ These names were subsequently changed to bacteria and archaea (the archaea being distinctly different from bacteria), but Woese’s splitting of the prokaryotes into two groups has remained, and all living organisms are now considered by many biologists to fall into one of three great domains: Archaea, Bacteria, and Eukarya.
  • archaea (bacteria) -- Britannica Online Encyclopedia 19 January 2010 9:52 UTC www.britannica.com [Source type: Reference]

 [20] .The problem of how to study and classify uncultured microbes is also encountered in the Bacteria.^ The problem of how to study and classify uncultured microbes is also encountered in the Bacteria.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Cross-fertilization between research with archaea and research with bacteria and eukaryotes is highlighted to show how the study of archaea has contributed, and will continue to contribute, to other fields, both basic and applied.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [21]

Origin and evolution

Further information: Timeline of evolution
.Although probable fossils of prokaryotic cells have been dated to almost 3.5 billion years ago, most prokaryotes do not have distinctive morphologies and the shapes of fossils cannot be used to identify them as Archaea.^ Sometime after 3.85 billion years, but before 3.7 billion years: prokaryotes diverge from archaea.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ Back to top ] Further information: Timeline of evolution Although probable fo ssils of prokaryotic cells have been dated to almost 3.5 billion years ago , most prokaryotes do not have distinctive morphologies and the shapes of fossils cannot be used to identify them as Archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ What was Earth like 3 to 4 billion years ago?

 [22] .Instead, chemical fossils, in the form of the unique lipids found in archaea, are more informative because such compounds do not occur in other groups of organisms.^ Instead, chemical fossils, in the form of the unique lipids found in archaea, are more informative because such compounds do not occur in other groups of organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Secondly, archaeal lipids are unique because the stereochemistry of the glycerol group is the reverse of that found in other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Thirdly, the lipid tails of the phospholipids of archaea are chemically different from those in other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [23] .Some publications have suggested that the remains of lipids that may be either archaean or eukaryotic were present in shales dating from 2.7 billion years ago;[24] these data have since been questioned.^ What was Earth like 3 to 4 billion years ago?

 ^ Some publications have suggested that the remains of lipids that may be either archaean or eukaryotic were present in shales dating from 2.7 billion years ago, [24 ] these data have since been questioned.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The oldest known traces of these isoprene lipids come from the Isua district of west Greenland , which include sediments formed 3.8 billion years ago and are the oldest on Earth.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [25] .Such lipids have also been detected in rocks dating back to the Precambrian.^ Such lipids have also been detected in rocks dating back to the Precambrian .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .The oldest known traces of these isoprene lipids come from the Isua district of west Greenland, which include sediments formed 3.8 billion years ago and are the oldest on Earth.^ The oldest known traces of these isoprene lipids come from the Isua district of west Greenland , which include sediments formed 3.8 billion years ago and are the oldest on Earth.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The oldest known rocks on Earth are 3.96 billion years old and are from Arctic Canada.

 ^ Archaea is one of the oldest life forms on Earth, and is estimated to be 35% or more of the Earths biomass.
  • FREQUENTLY ASKED QUESTIONS 19 January 2010 9:52 UTC ges-biosys.com [Source type: FILTERED WITH BAYES]

 [26] .The origin of Archaea appears very old indeed and the archaeal lineage may be the most ancient that exists on earth.^ The origin of Archaea appears very old indeed and the archaeal lineage may be the most ancient that exists on earth.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea may exist.
  • Chapter 6 Notes: Diversification of Bacteria and Archaea. I: Phylogeny and Biology 19 January 2010 9:52 UTC evolution-textbook.org [Source type: Academic]

 ^ Archaebacteria Ancient (over 3.5 billion years old) group of prokaryotes; some biologists want to place this group into a separate Kingdom, the Archaea.

 [27]
Euryarchaeota Nanoarchaeota Crenarchaeota Protozoa Algae Plantae Slime molds Animal Fungus Gram-positive bacteria Chlamydiae Chloroflexi Actinobacteria Planctomycetes Spirochaetes Fusobacteria Cyanobacteria Thermophiles Acidobacteria Proteobacteria
.
Phylogenetic tree showing the relationship between the archaea and other forms of life.^ Phylogenetic tree of Archaea .

 ^ Archaea is one of the oldest life forms on Earth, and is estimated to be 35% or more of the Earths biomass.
  • FREQUENTLY ASKED QUESTIONS 19 January 2010 9:52 UTC ges-biosys.com [Source type: FILTERED WITH BAYES]

 ^ In addition, in many of these trees, M. kandleri branches distinctly from all other methanogenic archaea [ 13 , 34 , 48 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .Eukaryotes are colored red, archaea green and bacteria blue.^ Eukaryotes are colored red, archaea green and bacteria blue.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The use of ribosomal RNA sequences as molecular chronometers has led to the recognition of a group of prokaryotes, the Archaea, that are phylogenetically distinct from both bacteria and eukaryotes.
  • Archaea: A Laboratory Manual 19 January 2010 9:52 UTC www.cshlpress.com [Source type: Academic]

 ^ Origin of eukaryotic cell nuclei by symbiosis of Archaea and Bacteria is revealed by homology-hit analysis.
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 Adapted from Ciccarelli et al.[28]
.Woese argued that the bacteria, archaea, and eukaryotes each represent a separate line of descent that diverged early on from an ancestral colony of organisms.^ Woese argued that the bacteria, archaea, and eukaryotes each represent a separate line of descent that diverged early on from an ancestral colony of organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ As explained early in this chapter, it has become evident that eukaryotes arose when certain bacteria became engulfed in archaeal cells, eventually becoming organelles.
  • The Microbial World :: A look at all things small 19 January 2010 9:52 UTC www.microbiologytext.com [Source type: General]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 [29][30] .A few biologists, however, have argued that the Archaea and Eukaryota arose from a group of bacteria.^ A few biologists, however, have argued that the Archaea and Eukaryota arose from a group of bacteria.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, nitrogen metabolism is much less known in archaea than in bacteria.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ This revolution is the subject of later chapters, but here we will discuss the structural differences between this new group, the Archaea , and the Bacteria .
  • The Microbial World :: A look at all things small 19 January 2010 9:52 UTC www.microbiologytext.com [Source type: General]

 [31] .It is possible that the last common ancestor of the bacteria and archaea was a thermophile, which raises the possibility that lower temperatures are "extreme environments" in archaeal terms, and organisms that live in cooler environments appeared later in the history of life on Earth.^ Were bacteria the first forms of life on Earth?
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 ^ Respiratory chains in the last common ancestor of living organisms.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ It is possible that the last common ancestor of the bacteria and archaea was a thermophile, which raises the possibility that lower temperatures are "extreme environments" in archaeal terms, and organisms that live in cooler environments appeared later in the history of life on Earth.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [32] .Since the Archaea and Bacteria are no more related to each other than they are to eukaryotes, this has led to the argument that the term prokaryote has no real evolutionary meaning and should be discarded entirely.^ Archaea share certain traits with bacteria and other traits with eukaryotes.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Since the Archaea and Bacteria are no more related to each other than they are to eukaryotes, this has led to the argument that the term prokaryote has no real evolutionary meaning and should be discarded entirely.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea They look very much like bacteria, but they are no more closely related to bacteria than we are to bacteria.

 [33]
.The relationship between archaea and eukaryotes remains an important problem.^ The relationship between archaea and eukaryotes remains an important problem.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Similarities between Archaea and Eukaryotes .

 ^ Evolutionary relationship of Archaea, Bacteria, and eukaryotes inferred from phylogenetic trees of duplicated genes.
  • Discontinuous Occurrence of the hsp70 (dnaK) Gene among Archaea and Sequence Features of HSP70 Suggest a Novel Outlook on Phylogenies Inferred from This Protein -- Gribaldo et al. 181 (2): 434 -- The Journal of Bacteriology 19 January 2010 9:52 UTC jb.asm.org [Source type: Academic]

 .Aside from the similarities in cell structure and function that are discussed below, many genetic trees group the two together.^ Aside from the similarities in cell structure and function that are discussed below, many genetic trees group the two together.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Some have suggested that eukaryotes arose through fusion of an archaean and eubacterium, which became the nucleus and cytoplasm ; this accounts for various genetic similarities but runs into difficulties explaining cell structure.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Such an approach generates the Phylogenetic Tree of Life (below) that lands the procaryotes in two Domains, Archaea and Bacteria.

 .Some early analyses even suggested that the relationship between eukaryotes and the archaeal phylum Euryarchaeota is closer than the relationship between the Euryarchaeota and the phylum Crenarchaeota.^ Some early analyses even suggested that the relationship between eukaryotes and the archaeal phylum Euryarchaeota is closer than the relationship between the Euryarchaeota and the phylum Crenarchaeota .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ As explained early in this chapter, it has become evident that eukaryotes arose when certain bacteria became engulfed in archaeal cells, eventually becoming organelles.
  • The Microbial World :: A look at all things small 19 January 2010 9:52 UTC www.microbiologytext.com [Source type: General]

 ^ Gene promoter structure in archaea is also more similar to that of eukaryotes than eubacteria, although, like the eubacteria, archaea have operons and transcribe these to polycistronic mRNA. Similarity also exists between the protein synthesis factors of archaea and eukaryotes suggesting that the overall protein synthesis mechanisms of eukaryotes and archaea may be similar.

 [34] .However, it is now considered more likely that the ancestor of the eukaryotes diverged early from the Archaea.^ However, it is now considered more likely that the ancestor of the eukaryotes diverged early from the Archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Gene promoter structure in archaea is also more similar to that of eukaryotes than eubacteria, although, like the eubacteria, archaea have operons and transcribe these to polycistronic mRNA. Similarity also exists between the protein synthesis factors of archaea and eukaryotes suggesting that the overall protein synthesis mechanisms of eukaryotes and archaea may be similar.

 ^ Still, it is clear that very early in the history of life on Earth, prokaryotes diverged into two main lineages: bacteria and archaea.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [35][36] .The discovery of archaean-like genes in certain bacteria, such as Thermotoga maritima, makes these relationships difficult to determine, since horizontal gene transfer has occurred.^ The discovery of archaean-like genes in certain bacteria, such as Thermotoga maritima , makes these relationships difficult to determine, since horizontal gene transfer has occurred.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ They can do horizontal gene transfer .
  • Biosphere Bacteria and Archaea, the Procaryote Domain 19 January 2010 9:52 UTC www.morning-earth.org [Source type: FILTERED WITH BAYES]

 ^ These genes can spread to other species by horizontal gene transfer.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [37] .Some have suggested that eukaryotes arose through fusion of an archaean and eubacterium, which became the nucleus and cytoplasm; this accounts for various genetic similarities but runs into difficulties explaining cell structure.^ Some have suggested that eukaryotes arose through fusion of an archaean and eubacterium, which became the nucleus and cytoplasm ; this accounts for various genetic similarities but runs into difficulties explaining cell structure.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ As explained early in this chapter, it has become evident that eukaryotes arose when certain bacteria became engulfed in archaeal cells, eventually becoming organelles.
  • The Microbial World :: A look at all things small 19 January 2010 9:52 UTC www.microbiologytext.com [Source type: General]

 ^ Way to add to that confusion…bacteria are not “more complicated” than archaea, and only a rare few groups of bacteria have what could be termed a ‘nucleus’- which isn’t at all the same as the structure found in eukaryotic cells.
  • Extreme Life Thrives Where the Livin’ Ain’t Easy | Wired Science | Wired.com 19 January 2010 9:52 UTC www.wired.com [Source type: General]

 [38]

Morphology

The sizes of prokaryotic cells relative to other cells and biomolecules.
.Individual archaeans range from 0.1 micrometers (μm) to over 15 μm in diameter, and occur in various shapes, commonly as spheres, rods, spirals or plates.^ Individual archaeans range from 0.1 micrometers (m) to over 15 m in diameter, and occur in various shapes, commonly as spheres, rods, spirals or plates.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Other morphologies i n the Crenarchaeota include irregularly shaped lobed cells in Sulfolobus , thin needle-like filaments that are less than half a micrometer in diameter in Thermofilum , and almost perfectly rectangular rods in Thermoproteus and Pyrobaculum .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Members of the methanomicrobia are usually nonmotile, and come in various shapes - rods, cocci, spirals, pleomorphs.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [39] .Other morphologies in the Crenarchaeota include irregularly shaped lobed cells in Sulfolobus, thin needle-like filaments that are less than half a micrometer in diameter in Thermofilum, and almost perfectly rectangular rods in Thermoproteus and Pyrobaculum.^ Species display a wide range of cell shapes, including regular cocci clustered in grape-like aggregates (Staphylothermus), irregular, lobed cells (Sulfolobus), discs (Thermodiscus), very thin filaments ( <0.5m diameter; Thermofilum), and almost rectangular rods (Thermoproteus, Pyrobaculum).
  • Crenarchaeota 19 January 2010 9:52 UTC tolweb.org [Source type: Academic]

 ^ Cells are rod-shaped, ca.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Pyrobaculum, a rod-shaped organism with flagella.
  • Crenarchaeota 19 January 2010 9:52 UTC tolweb.org [Source type: Academic]

 [40] .There is even a species of flat, square archaea called Haloquadra walsbyi that lives in hypersaline pools.^ There is even a species of flat, square archaea called Haloquadra walsbyi that lives in hypersaline pools.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ It has also a cylindrical shape like the GroEL/S bacterial complex, but both ends are flat; there is no equivalent of GroES in archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ The first prokaryotes to be classified in domain Archaea are species that can live in environments so extreme that few other organisms can survive there.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [41] .These unusual shapes are probably maintained both by their cell walls and a prokaryotic cytoskeleton.^ These unusual shapes are probably maintained both by their cell walls and a prokaryotic cytoskeleton .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Which of these is not a typical shape for a bacterial cell?

 ^ Regular crystalline surface layers ( S-layers ) are widespread among prokaryotes and probably represent the earliest cell wall structures.

 .Proteins related to the cytoskeleton components of other organisms exist in the archaea,[42] and filaments are formed within their cells,[43] but in contrast to other organisms, these cellular structures are poorly understood in archaea.^ Proteins related to the cytoskeleton components of other organisms exist in the archaea, [42 ] and filaments are formed within their cells, [43 ] but in contrast to other organisms, these cellular structures are poorly understood in archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ A diverse array of living organisms (life forms) can be found in the biosphere on Earth, and properties common to these organisms—plants, animals, fungi, protists, archaea, and bacteria — are a carbon- and water-based cellular form with complex organization and heritable genetic information.
  • I can't tell the difference (subjectively) between life and death - Philosophy, Sociology & Psychology - Shroomery Message Board 19 January 2010 9:52 UTC www.shroomery.org [Source type: FILTERED WITH BAYES]

 [44] .In Thermoplasma and Ferroplasma the lack of a cell wall means that the cells have irregular shapes, and can resemble amoebae.^ Thermoplasma resembles the bacterial mycoplasmas in that it lacks a cell wall.

 ^ Mycoplasma-like Thermoplasma cells lack a cell wall.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]

 ^ In Thermoplasma and Ferroplasma the lack of a cell wall means that the cells have irregular shapes, and can resemble amoebae .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [45]
.Some species of archaea form aggregates or filaments of cells up to 200 μm long,[39] and these organisms can be prominent members of the communities of microbes that make up biofilms.^ Some species of archaea form aggregates or filaments of cells up to 200 m long, [39 ] and these organisms can be prominent members of the communities of microbes that make up biofilms .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In some aggregates/colonies there is specialization among the cells of the colony.

 ^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [46] .An extreme example is Thermococcus coalescens, as aggregates of these cells fuse together in culture, forming single giant cells.^ An extreme example is Thermococcus coalescens , as aggregates of these cells fuse together in culture, forming single giant cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ Branched forms superficially resemble molds and are a striking example of convergent evolution of a procaryote and a eucaryote together in the soil habitat.

 [47] .A particularly elaborate form of multicellular colony is produced by archaea in the genus Pyrodictium.^ A particularly elaborate form of multicellular colony is produced by archaea in the genus Pyrodictium .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ It resembles a biofilm formed by many bacteria and some archaea, as discussed above (see "Multicellular structures").
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 .Here, the cells produce arrays of long, thin hollow tubes called cannulae that stick out from the cells' surfaces and connect them together into a dense bush-like colony.^ The capsule is also an adhesive surface to hold colonies together and hold the cells to surfaces and their host.

 ^ Here, the cells produce arrays of long, thin hollow tubes called cannulae that stick out from the cells' surfaces and connect them together into a dense bush-like colony.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ It is a flat irregular coccus (think of the body of a prickly-pear cactus) with a network of tubular fibriles that connect cells together.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [48] .The function of these cannulae is not known, but they may allow the cells to communicate or exchange nutrients with their neighbors.^ The function of these cannulae is not known, but they may allow the cells to communicate or exchange nutrients with their neighbors.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These solutes balance osmotic pressure and allow the cell to function using normal enzymes and proteins that would otherwise be dysfunctional at such a high salinity.
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ Of these proteins only about 1/3 are indicated to be directly involved in methanogenesis and the cellular functions of others are presently not known.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [49] .Colonies can also be produced by an association between different species.^ Colonies can also be produced by an association between different species.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ A number of proteins in this group are present in a limited number (between 3 to 6) of archaeal species belonging to different groups.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .For example, in the "string-of-pearls" community that was discovered in 2001 in a German swamp, round whitish colonies of a novel species of archaea in the phylum Euryarchaeota are spaced along thin filaments that can be up to 15 centimetres (5.9 in) long; these filaments are made of a particular species of bacteria.^ For example, in the "string-of-pearls" community that was discovered in 2001 in a German swamp, round whitish colonies of a novel species of archaea in the phylum Euryarchaeota are spaced along thin filaments that can be up to 15 centimetres (5.9 in) long; these filaments are made of a particular species of bacteria.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Another group of microbes, the archaea, meet these criteria but are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life.
  • Bacteria 11 September 2009 0:44 UTC users.rcn.com [Source type: FILTERED WITH BAYES]

 [50]

Cell structure

.Archaea are similar to bacteria in their general cell structure, but the composition and organization of some of these structures set the archaea apart.^ In some respects, Archaea do resemble Bacteria.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Back to top ] Archaea are similar to bacteria in their general cell structure, but the composition and organization of some of these structures set the archaea apart.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 .Like bacteria, archaea lack interior membranes so their cells do not contain organelles.^ Photosynthetic bacteria (cyanobacteria) have chlorophyl organelles surrounded by a cell membrane .
  • Biosphere Bacteria and Archaea, the Procaryote Domain 19 January 2010 9:52 UTC www.morning-earth.org [Source type: FILTERED WITH BAYES]

 ^ The cell walls of archaea contain polysaccharides and proteins, but lack peptidoglycan.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Like bacteria, archaea lack interior membranes so their cells do not contain organelles .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [33] .They also resemble bacteria in that their cell membrane is usually bounded by a cell wall and they swim by the use of one or more flagella.^ They have significant differences in their cell walls and biochemistry when compared to the bacteria.

 ^ Inside the procaryote cell wall there are usually no membranes.
  • Biosphere Bacteria and Archaea, the Procaryote Domain 19 January 2010 9:52 UTC www.morning-earth.org [Source type: FILTERED WITH BAYES]

 ^ All bacteria also have a cell membrane, as well as a cell wall, as shown in Figure 4.

 [51] .In overall structure the archaea are most similar to gram-positive bacteria, as most have a single plasma membrane and cell wall, and lack a periplasmic space; the exception to this general rule is the archaean Ignicoccus, which possess a particularly large periplasm that contains membrane-bound vesicles and is enclosed by an outer membrane.^ As true Bacteria, cyanobacteria contain peptidoglycan or murein in their cell walls.

 ^ Further information: Cell wall Most archaea possess a cell wallthe exceptions being Thermoplasma and Ferroplasma .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ PMID: 11092967 Anionic polymers in cell walls of gram-positive bacteria.

 [52]

Cell membranes

Membrane structures. .Top: an archaeal phospholipid, 1 isoprene sidechain, 2 ether linkage, 3 L-glycerol, 4 phosphate moieties.^ Top : an archaeal phospholipid, 1 isoprene sidechain, 2 ether linkage, 3 L-glycerol, 4 phosphate moieties.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Middle : a bacterial and eukaryotic phospholipid: 5 fatty acid, 6 ester linkage, 7 D-glycerol, 8 phosphate moieties.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ What would be a fatty acid in our cells, is a hydrocarbon in archaea, so they are liked by an ether link rather than the ester linkage to the glycerol.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]

 .Middle: a bacterial and eukaryotic phospholipid: 5 fatty acid, 6 ester linkage, 7 D-glycerol, 8 phosphate moieties.^ The two attachments to the glycerol are long-chain branched hydrocarbons rather than fatty acids.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]

 ^ What would be a fatty acid in our cells, is a hydrocarbon in archaea, so they are liked by an ether link rather than the ester linkage to the glycerol.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]

 ^ The second glucosamine residue also contains two β-hydroxymyristic acids, in ester linkage at C-3′ and amide linkage at C-2′, with additional lauroyl groups on the β-hydroxyls (which resemble waxes).
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 Bottom: 9 lipid bilayer of bacteria and eukaryotes, 10 lipid monolayer of some archaea.
.Archaeal membranes are made of molecules that differ strongly from those in other forms of life, which is evidence that archaea are related only distantly to bacteria and eukaryotes.^ Were bacteria the first forms of life on Earth?
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 ^ Archaea share certain traits with bacteria and other traits with eukaryotes.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Spores are made by both bacteria and eukaryotes, but are not formed in any of the known archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [53] .In all organisms cell membranes are made of molecules known as phospholipids.^ In all organisms cell membranes are made of molecules known as phospholipids .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The suggestion has been made that the common ancestor of all three domains was not yet a properly developed, integrated cell, but a ‘progenote.’ Woese (2002) .
  • Palaeos Bacteria: Bacteria 19 January 2010 9:52 UTC www.palaeos.com [Source type: FILTERED WITH BAYES]

 ^ Cultivated crenarchaea are all thermophilic, and most are extremely thermophilic, with optimal growth temperatures above 80°C. As a group, these are the most thermophilic organisms known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .These molecules possess both a polar part that will dissolve in water (the phosphate "head"), and a "greasy" non-polar part that will not dissolve in water (the lipid tail).^ These molecules possess both a polar part that will dissolve in water (the phosphate "head"), and a "greasy" non-polar part that will not dissolve in water (the lipid tail).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In water, phospholipids cluster together, with the polar phosphate heads facing the water and the non-polar lipid tails facing away from the water.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Bacteria and eukaryotes do contain some ether lipids, but in contrast to archaea these lipids are not a major part of their membranes.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .These dissimilar parts are connected by a glycerol group.^ These dissimilar parts are connected by a glycerol group.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The glycerol group can occur in two forms that are mirror images of one another, which may be called the right-handed and left-handed forms; in chemical terms these forms are called enantiomers .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The difference between these two types of phospholipid is the type of bond that joins the lipids to the glycerol group; these two types of bonds are shown in yellow in the Figure at the right.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .In water, phospholipids cluster together, with the polar phosphate heads facing the water and the non-polar lipid tails facing away from the water.^ These molecules possess both a polar part that will dissolve in water (the phosphate "head"), and a "greasy" non-polar part that will not dissolve in water (the lipid tail).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In water, phospholipids cluster together, with the polar phosphate heads facing the water and the non-polar lipid tails facing away from the water.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Thirdly, the lipid tails of the phospholipids of archaea are chemically different from those in other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .This causes them to assemble into layers.^ This causes them to assemble into layers.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer.^ The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Some bacteria that colonize mucosal surfaces, such as Neisseria , express a truncated and nonrepeating O-antigen glycan ; in these cells, the lipid-A-based structure is called lipooligosaccharide ( LOS ) instead of LPS .
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 ^ In many archaeas, the membrane is a mixture of these, making the membrane a mixed mono- and bi-layer...and very heat resistant.
  • Kingdom Archaea 11 September 2009 0:47 UTC plantphys.info [Source type: FILTERED WITH BAYES]
.The phospholipids in the membranes of archaea are unusual in four ways.^ The phospholipids in the membranes of archaea are unusual in four ways.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ And in some ways, Archaea are different that either Bacteria or Eukarya, the most obvious being membrane lipids.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .Firstly, bacteria and eukaryotes have membranes composed mainly of glycerol-ester lipids, whereas archaea have membranes composed of glycerol-ether lipids.^ Bacteria and eukaryotes do contain some ether lipids, but in contrast to archaea these lipids are not a major part of their membranes.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Firstly, bacteria and eukaryotes have membranes composed mainly of glycerol-ester lipids , whereas archaea have membranes composed of glycerol-ether lipids .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The Archaea, or Archaebacteria have cell membrane of prenyl ether lipids.
  • Palaeos Bacteria: Bacteria 19 January 2010 9:52 UTC www.palaeos.com [Source type: FILTERED WITH BAYES]

 [54] .The difference between these two types of phospholipid is the type of bond that joins the lipids to the glycerol group; these two types of bonds (ester and ether) are shown in yellow in the Figure at the right.^ The difference between these two types of phospholipid is the type of bond that joins the lipids to the glycerol group; these two types of bonds are shown in yellow in the Figure at the right.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These shaps are shown in Figures 7 and 8.

 ^ In ester lipids this is an ester bond , whereas in ether lipids this is an ether bond .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Ether bonds are chemically more resistant, which might contribute to the ability of some archaea to survive at extremes of temperature and in very acidic or alkaline environments.^ Other archaea exist in very acidic or alkaline conditions.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Ether bonds are chemically more resistant then ester bonds, which might contribute to the ability of some archaea to survive at extremes of temperature and in very acidic or alkaline environments.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Other archaea do not live in extreme environments.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [55] .Bacteria and eukaryotes do contain some ether lipids, but these are not a major part of their membranes.^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Endotoxins are lipopolysaccharide components of the outer membrane of some gram-negative bacteria.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Some bacteria that colonize mucosal surfaces, such as Neisseria , express a truncated and nonrepeating O-antigen glycan ; in these cells, the lipid-A-based structure is called lipooligosaccharide ( LOS ) instead of LPS .
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]
.Secondly, archaeal lipids are unique because the stereochemistry of the glycerol group is the reverse of that in other organisms.^ Secondly, archaeal lipids are unique because the stereochemistry of the glycerol group is the reverse of that found in other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The existence of archaeal transcription factors that have no homologs in the other two domains, such as GvpE ( 61 ), points to the fact that archaeal transcription may contain elements that are unique.
  • Transcription in Archaea — PNAS 19 January 2010 9:52 UTC www.pnas.org [Source type: Academic]

 ^ Archaeal chaperonin subunits in a given organism tend to be more similar to each other than to their homologs from other archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 .The two forms of the glycerol group are enantiomers: molecules which are mirror images of one another.^ The glycerol group can occur in two forms that are mirror images of one another, which may be called the right-handed and left-handed forms; in chemical terms these forms are called enantiomers .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Additionally, Archaeal RNA polymerases sequences are more similar to eukaryotic RNA polymerases II and III sequences than the two are to one another (Woese 1993).
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ Two pathogens of humans are found among the spiral forms in the Epsilon group of Proteobacteria.

 .Just as a right hand does not fit easily into a left-handed glove, a right-handed glycerol molecule generally cannot be used or made by enzymes adapted for the left-handed form.^ Just as a right hand does not fit easily into a left-handed glove, a right-handed glycerol molecule generally cannot be used or made by enzymes adapted for the left-handed form.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Using the homology data, it was therefore predicted that an intervening sequence existed in the T. litoralis DNA separating the left and right halves of the DNA polymerase homology region III. .
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 .This suggests that archaea use entirely different enzymes for synthesizing their phospholipids than do bacteria and eukaryotes; since such enzymes developed very early in life's history, this in turn suggests that the archaea split off very early from the other two domains.^ This suggests that archaea use entirely different enzymes for synthesizing their phospholipids than do bacteria and eukaryotes; since such enzymes developed very early in life's history, this in turn suggests that the archaea split off very early from the other two domains.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The two prokaryotic domains are Eubacteria (bacteria) and Archaea .

 ^ The Tree shows the procaryotes in two Domains, Archaea and Bacteria.

 [53]
.Thirdly, the lipid tails of the phospholipids of archaea are chemically different from those in other organisms.^ Thirdly, the lipid tails of the phospholipids of archaea are chemically different from those in other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ This suggests that archaea use entirely different enzymes for synthesizing their phospholipids than do bacteria and eukaryotes; since such enzymes developed very early in life's history, this in turn suggests that the archaea split off very early from the other two domains.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ And in some ways, Archaea are different that either Bacteria or Eukarya, the most obvious being membrane lipids.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings.^ Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ This is in contrast to the fatty acids found in other organisms' membranes, which have straight chains with no branches or rings.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The archaeal species branch distinctly from all other organisms in phylogenetic trees based on 16S rRNA and many other gene/protein sequences [ 2 , 7 , 23 - 25 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [56] .This is in contrast to the fatty acids found in other organisms' membranes, which have straight chains with no branches or rings.^ This is in contrast to the fatty acids found in other organisms' membranes, which have straight chains with no branches or rings.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ By comparing predicted amino acid sequences with those of known proteins, they found a surprising abundance of signaling proteins thought to be used only by multicellular organisms.

 ^ Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Although isoprenoids play an important role in the biochemistry of many organisms, only the archaea use them to make phospholipids.^ Prokaryotes play an important role in this process.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Bacteria play important ecological roles as decomposers, as well as important elements of phytoplantonic organisms at the base of many food chains.

 ^ By comparing predicted amino acid sequences with those of known proteins, they found a surprising abundance of signaling proteins thought to be used only by multicellular organisms.

 .These branched chains may help prevent archaean membranes from leaking at high temperatures.^ These findings support recent reports that Crenarchaeota are not restricted to high-temperature environments.
  • Communities of Archaea and Bacteria in a Subsurface Radioactive Thermal Spring in the Austrian Central Alps, and Evidence of Ammonia-Oxidizing Crenarchaeota -- Weidler et al. 73 (1): 259 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 ^ These organisms require a very high temperature (80 degrees to 105 degrees) for growth.

 ^ Several modified sugar-degrading pathways that are operational at extremely high temperatures have been identified in some of these hyperthermophiles (reviewed in [ 10–14 ]).
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 [57]
.Finally, in some archaea the phospholipid bilayer is replaced by a single monolayer.^ Finally, some archaea are fundamental components of the biogeochemical cycles on earth or dominate special ecosystems that are of great interest.
  • What Archaea Have to Tell Biologists -- Whitman et al. 152 (4): 1245 -- Genetics 19 January 2010 9:52 UTC www.genetics.org [Source type: Academic]

 ^ Many are bacteria or similar single-celled organisms called Archaea, but some lichens called cryptoendoliths go to extremes by colonising pores in Antarctic rock.
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 ^ Some archaea have only a single protein or glycoprotein S-layer as their cell wall (e.g.

 .In effect, the archaea have fused the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments.^ What makes the cell more resistant to stressors?
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ In effect, the archaea have fused the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Still, it is clear that very early in the history of life on Earth, prokaryotes diverged into two main lineages: bacteria and archaea.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [58] .For example, all the lipids in Ferroplasma are of this type, which is thought to aid this organism's survival in the extraordinarily acidic environments in which it thrives.^ For example, all the lipids in Ferroplasma are of this type, which is thought to aid this organism's survival in the extraordinarily acidic environments in which it thrives.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ The first prokaryotes to be classified in domain Archaea are species that can live in environments so extreme that few other organisms can survive there.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [59]

Cell wall and flagella

Further information: Cell wall
.Most archaea possess a cell wall—the exceptions being Thermoplasma and Ferroplasma.^ Further information: Cell wall Most archaea possess a cell wallthe exceptions being Thermoplasma and Ferroplasma .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Cell wall polymers in Archaea (Archaebacteria).
  • Archaea & Eubacteria 19 January 2010 9:52 UTC euarch.blogspot.com [Source type: Academic]
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Cell wall polymers in Archaea (Archaebacteria) .

 [45] .In most archaea the wall is assembled from surface-layer proteins, which form an S-layer.^ In most archaea the wall is assembled from surface-layer proteins, which form an S-layer .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In Archaea, the cell wall has a surface layer ( S layer ), which is composed of glycoproteins and pseudomurein.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 ^ Further information: Cell wall Most archaea possess a cell wallthe exceptions being Thermoplasma and Ferroplasma .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [60] .An S-layer is made of a rigid array of protein molecules that cover the outside of the cell like chain mail.^ Their cell walls are made up of an extracellular protein S-layer.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ An S-layer is made of a rigid array of protein molecules that cover the outside of the cell like chain mail.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Bacterial communication, toxin production tied to intriguing cell protein , and: "Polyphosphate is a long, chain-like molecule found in every living cell.

 [61] .This layer provides both chemical and physical protection, and can act as a barrier preventing macromolecules from coming into contact with the cell membrane.^ This layer provides both chemical and physical protection, and can act as a barrier preventing macromolecules from coming into contact with the cell membrane.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The O-antigen apparently provides a hydrophilic barrier that protects against hydrophobic antibiotics (natural fungal and bacterial metabolites), bile acids (in enterobacteria), and complement.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 ^ Plasmids may be transferred between cells by physical contact, in a process that may be similar to bacterial conjugation .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [62] .In contrast to bacteria, most archaea lack peptidoglycan in their cell walls.^ As true Bacteria, cyanobacteria contain peptidoglycan or murein in their cell walls.

 ^ Cell wall polymers in Archaea (Archaebacteria).

 ^ The cell walls of archaea contain polysaccharides and proteins, but lack peptidoglycan.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [63] .The exception is pseudopeptidoglycan, which is found in Methanobacteriales, but this polymer is different from the peptidoglycan of bacteria since it lacks D-amino acids and N-acetylmuramic acid.^ The exception is pseudopeptidoglycan , which is found in Methanobacteriales , but this polymer is different from the peptidoglycan of bacteria since it lacks D-amino acids and N-acetylmuramic acid .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, the ratio of Bacteria to Archaea they found for three different hot springs (80, 75 and 1, respectively) are comparable to ours and also suggest that the dominance of Archaea in high-temperature environments is the exception rather than the rule.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ They lack the peptidoglycan found in almost all bacteria and instead contain a pseudomurein layer, which is similar to the peptidoglycan structure.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 [62]
.Archaea also have flagella, and these operate in a similar way to bacterial flagella—they are long stalks that are driven by rotatory motors at the base of the flagella.^ Archaea also have flagella , and these operate in a similar way to bacterial flagellathey are long stalks that are driven by rotatory motors at the base of the flagella.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Another group of microbes, the archaea, meet these criteria but are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life.
  • Bacteria 11 September 2009 0:44 UTC users.rcn.com [Source type: FILTERED WITH BAYES]

 .These motors are powered by the proton gradient across the membrane.^ These motors are powered by the proton gradient across the membrane.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The archaeal flagellar motor is driven directly by ATP hydrolysis rather than the flow of protons across the cell membrane - it is a chemical motor rather than an electric motor.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Like most acidophiles, they are sensitive to fatty acid toxicity; fatty acids are protonated and so uncharged at these environmental pH’s, diffuse readily through the cytoplasmic membrane, then ionize at the more moderate cytoplasmic pH. This results in an uncoupling of the proton gradient and acidification of the cytoplasm.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .However, archaeal flagella are notably different in their composition and development.^ However, archaeal flagella are notably different in their composition and development.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ At present, however, little information is available on the identity of the archaeal enzymes or on the actual composition of the pathway(s) involved.
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 ^ However, there are differences between the three archaeal loci.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [51] .The two types of flagella evolved from different ancestors, the bacterial flagellum shares a common ancestor with the type III secretion system,[64][65] while archaeal flagella appear to have evolved from the bacterial type IV pili.^ The two types of flagella evolved from different ancestors, the bacterial flagellum shares a common ancestor with the type III secretion system , [64 ] [65 ] while archaeal flagella appear to have evolved from the bacterial type IV pili .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ "Phylogenetic analyses of the constituents of Type III protein secretion systems".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The two archaeal Hsp70 proteins in this group appeared to have an ancestor in common with T. maritima .
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [66] .In contrast to the bacterial flagellum, which is a hollow stalk and is assembled by subunits moving up the central pore and then adding onto the tip of the flagella, archaeal flagella are synthesized by adding subunits onto their base.^ In contrast to the bacterial flagellum, which is a hollow stalk and is assembled by subunits moving up the central pore and then adding onto the tip of the flagella, archaeal flagella are synthesized by adding subunits onto their base.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In contrast, gene expression and transcription initiation signals and factors are of the eucaryal type, which suggests a hybrid archaeal-bacterial complexion for the Hsp70 system.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ The two types of flagella evolved from different ancestors, the bacterial flagellum shares a common ancestor with the type III secretion system , [64 ] [65 ] while archaeal flagella appear to have evolved from the bacterial type IV pili .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [67]

Metabolism

Further information: Microbial metabolism
.Archaea exhibit a great variety of chemical reactions in their metabolism and use many different sources of energy.^ Back to top ] Further information: Microbial metabolism Archaea exhibit a great variety of chemical reactions in their metabolism and use many different sources of energy.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Many of its constituents are derived from the Earth by way of chemical and biochemical reactions.

 ^ Although isoprenoids play an important role in the biochemistry of many organisms, only the archaea use them to make phospholipids.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .These forms of metabolism are classified into nutritional groups, depending on the source of energy and the source of carbon.^ These forms of metabolism are classified into nutritional groups , depending on the source of energy and the source of carbon.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In these organisms, carbon-fixation is powered by inorganic sources of energy, rather than by capturing sunlight as in plants and cyanobacteria .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The species from both these groups, particularly Euryarchaeota, are highly diverse in terms of their metabolism and physiology.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .Some archaea obtain their energy from inorganic compounds such as sulfur or ammonia (they are lithotrophs).^ Some archaea obtain their energy from inorganic compounds such as sulfur or ammonia (they are lithotrophs ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Chemosynthetic bacteria are autotrophic , and obtain energy from the oxidation of inorganic compounds such as ammonia, nitrite (to nitrate), or sulfur (to sulfate).

 ^ Some are lithotrophs that oxidize sulfur as an energy source.

 .These archaea include nitrifiers, methanogens and anaerobic methane oxidisers.^ These archaea include nitrifiers , methanogens and anaerobic methane oxidisers .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Studies of some endosymbiotic methanogens in arthropods and ruminants based on transmission electron microscopy reveal these archaea inside membrane-bound vacuoles ( 15 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [68] .In these reactions one compound passes electrons to another (in a redox reaction), releasing energy that is then used to fuel the cell's activities.^ In these reactions one compound passes electrons to another (in a redox reaction), releasing energy that is then used to fuel the cell's activities.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ A common feature of all these reactions is that the energy released is used to generate adenosine triphosphate (ATP) through chemiosmosis , which is the same basic process that happens in the mitochondrion of animal cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Methanogens obtain energy by the reduction of one- or two-carbon compounds to methane.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .One compound acts as an electron donor and one as an electron acceptor.^ Organics are the electron donor for electron transport and sulfur (or sulfur compounds) is the terminal electron acceptor.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ One compound acts as an electron donor and one as an electron acceptor .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Bacterial photosynthesis utilizes a type of chlorophyll other than chlorophyll a, and only one photosystem, photosystem I. The electron donor for bacterial photosynthesis is never H 2 O but may be H 2 , H 2 S or S o , or certain organic compounds.

 .A common feature of all these reactions is that the energy released is used to generate adenosine triphosphate (ATP) through chemiosmosis, which is the same basic process that happens in the mitochondrion of animal cells.^ A common feature of all these reactions is that the energy released is used to generate adenosine triphosphate (ATP) through chemiosmosis , which is the same basic process that happens in the mitochondrion of animal cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ What features are common to all cellular life?
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 ^ The suggestion has been made that the common ancestor of all three domains was not yet a properly developed, integrated cell, but a ‘progenote.’ Woese (2002) .
  • Palaeos Bacteria: Bacteria 19 January 2010 9:52 UTC www.palaeos.com [Source type: FILTERED WITH BAYES]

 [69]
.Other groups of archaea use sunlight as a source of energy (they are phototrophs).^ Other groups of archaea use sunlight as a source of energy (they are phototrophs ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Another group of microbes, the archaea, meet these criteria but are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life.
  • Bacteria 11 September 2009 0:44 UTC users.rcn.com [Source type: FILTERED WITH BAYES]

 ^ They are distinguished from all other prokaryotes by their ability to obtain all or most of their energy via the reduction of CO 2 to methane or by the process of methanogenesis.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .However, oxygen-generating photosynthesis does not occur in any of these organisms.^ However, oxygen-generating photosynthesis does not occur in any of these organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ General characteristics of these organisms include: eukaryotic cell type, mitochondria , and a complex nervous system.

 ^ The process of nitrogen fixation, specifically the enzyme nitrogenase, only functions in anaerobic conditions so the organism must maintain these oxygen-free compartments in order for N2 fixation to occur.

 [69] .Many basic metabolic pathways are shared between all forms of life; for example, archaea use a modified form of glycolysis (the Entner–Doudoroff pathway) and either a complete or partial citric acid cycle.^ Many basic metabolic pathways are shared between all forms of life; for example, archaea use a modified form of glycolysis (the EntnerDoudoroff pathway ) and either a complete or partial citric acid cycle .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In the archaea, this process involves either a highly modified form of the Calvin cycle , [76 ] or a recently discovered metabolic pathway called the 3-hydroxypropionate/4-hydroxybutyrate cycle.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are now recognized as a major part of life on Earth and may play an important role in both the carbon cycle and nitrogen cycle .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [70] .These similarities with other organisms probably reflect both the early evolution of these parts of metabolism in the history of life and their high level of efficiency.^ These similarities with other organisms probably reflect both the early evolution of these parts of metabolism in the history of life and their high level of efficiency.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Another group of microbes, the archaea, meet these criteria but are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life.
  • Bacteria 11 September 2009 0:44 UTC users.rcn.com [Source type: FILTERED WITH BAYES]

 ^ Still, it is clear that very early in the history of life on Earth, prokaryotes diverged into two main lineages: bacteria and archaea.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [71]
Nutritional types in archaeal metabolism
Nutritional type Source of energy Source of carbon Examples
 Phototrophs   Sunlight   Organic compounds   Halobacteria 
 Lithotrophs  Inorganic compounds  Organic compounds or carbon fixation  Ferroglobus, Methanobacteria or Pyrolobus 
 Organotrophs  Organic compounds   Organic compounds or carbon fixation   Pyrococcus, Sulfolobus or Methanosarcinales 
.Some Euryarchaeota are methanogens and produce methane gas in anaerobic environments such as swamps.^ The methanogens live under anaerobic environments (e.g., marshes) where they produce methane.

 ^ Some Euryarchaeota are methanogens and produce methane gas in anaerobic environments such as swamps.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .This form of metabolism evolved early, and it is even possible that the first free-living organism was a methanogen.^ This form of metabolism evolved early, and it is even possible that the first free-living organism was a methanogen.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Prokaryotes were the first organisms to live on Earth.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ The first prokaryotes to be classified in domain Archaea are species that can live in environments so extreme that few other organisms can survive there.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [72] .A common reaction in these organisms involves the use of carbon dioxide as an electron acceptor to oxidize hydrogen.^ A common reaction in these organisms involves the use of carbon dioxide as an electron acceptor to oxidize hydrogen .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ A common feature of all these reactions is that the energy released is used to generate adenosine triphosphate (ATP) through chemiosmosis , which is the same basic process that happens in the mitochondrion of animal cells.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Other organic compounds such as alcohols , acetic acid or formic acid are used as alternative electron acceptors by methanogens.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .Methanogenesis involves a range of coenzymes that are unique to these archaea, such as coenzyme M and methanofuran.^ Methanogenesis involves a range of coenzymes that are unique to these archaea, such as coenzyme M and methanofuran .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Among the genes that are uniquely shared by various methanogenic archaea (or these archaea plus A. fulgidus ), two large gene clusters responsible for methanogenesis are found.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ It is concluded that regulation of the glycolytic flux in archaea, such as Pyrococcus furiosus , involves modulation of gene expression, rather than allosteric regulation of enzyme activities.
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 [73] .Other organic compounds such as alcohols, acetic acid or formic acid are used as alternative electron acceptors by methanogens.^ Other organic compounds such as alcohols , acetic acid or formic acid are used as alternative electron acceptors by methanogens.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Organics are the electron donor for electron transport and sulfur (or sulfur compounds) is the terminal electron acceptor.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Bacterial photosynthesis utilizes a type of chlorophyll other than chlorophyll a, and only one photosystem, photosystem I. The electron donor for bacterial photosynthesis is never H 2 O but may be H 2 , H 2 S or S o , or certain organic compounds.

 .These reactions are common in gut-dwelling archaea.^ These reactions are common in gut -dwelling archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The involvement of archaea in ammonia oxidation reactions was recently discovered; these being particularly important in the oceans.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The genes for these proteins likely evolved in a common ancestor of the Archaea and were then vertically acquired by other archaeal species.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .Acetic acid is also broken down into methane and carbon dioxide directly, by acetotrophic archaea.^ Acetic acid is also broken down into methane and carbon dioxide directly, by acetotrophic archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In the carbon cycle , methanogen archaea are significant as methane producers.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ There are no known archaea that carry out photosynthesis , which is when light is used by photoautotrophs as a source of energy as well as driving the fixation of carbon dioxide.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .These acetotrophs are archaea in the order Methanosarcinales, and are a major part of the communities of microorganisms that produce biogas.^ These acetotrophs are archaea in the order Methanosarcinales , and are a major part of the communities of microorganisms that produce biogas .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, methanogenic archaea are a vital part of sewage treatment , since they are part of the community of microorganisms that carry out anaerobic digestion and produce biogas .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaea are now recognized as a major part of life on Earth and may play an important role in both the carbon cycle and nitrogen cycle .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [74]
.
Bacteriorhodopsin from Halobacterium salinarum.^ Bacteriorhodopsin from Halobacterium salinarum .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .The retinol cofactor and residues involved in proton transfer are shown as ball-and-stick models.^ The retinol cofactor and residues involved in proton transfer are shown as ball-and-stick models .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These systems utilize a common mechanism involving transfer of a high-energy phosphoryl group from a histidine protein kinase to an aspartate residue of a response regulator protein.

 ^ Several nif genes are also involved in cofactor biosynthesis, electron transfer and regulation.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [75]
.Other archaea use CO2 in the atmosphere as a source of carbon, in a process called carbon fixation (they are autotrophs).^ Other archaea use CO 2 in the atmosphere as a source of carbon, in a process called carbon fixation (they are autotrophs ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Other groups of archaea use sunlight as a source of energy (they are phototrophs ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ They are distinguished from all other prokaryotes by their ability to obtain all or most of their energy via the reduction of CO 2 to methane or by the process of methanogenesis.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .In the archaea, this process involves either a highly modified form of the Calvin cycle,[76] or a recently discovered metabolic pathway called the 3-hydroxypropionate/4-hydroxybutyrate cycle.^ In the archaea, this process involves either a highly modified form of the Calvin cycle , [76 ] or a recently discovered metabolic pathway called the 3-hydroxypropionate/4-hydroxybutyrate cycle.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ "A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ It is crushingly hot and acidic at the surface but the clouds are much milder, and have oxidised and reduced sulfur side by side (highly indicative of a metabolic process going on).
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 [77] .The Crenarchaeota also use the reverse Krebs cycle and the Euryarchaeota also use the reductive acetyl-CoA pathway.^ The Crenarchaeota also use the reverse Krebs cycle and the Euryarchaeota also use the reductive acetyl-CoA pathway .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Here, comparative genomics is used to visualize the mosaic of conserved CoA biosynthetic genes and to reconstitute the so far unexplored CoA biosynthetic pathway in archaea.
  • Coenzyme A Biosynthesis: Reconstruction of the Pathway in Archaea and an Evolutionary Scenario Based on Comparative Genomics -- Genschel 21 (7): 1242 -- Molecular Biology and Evolution 19 January 2010 9:52 UTC mbe.oxfordjournals.org [Source type: Academic]

 ^ This review covers the current knowledge on the nitrate reduction processes and other pathways of the N-cycle in archaea.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [78] .In these organisms, carbon-fixation is powered by inorganic sources of energy, rather than by capturing sunlight as in plants and cyanobacteria.^ In these organisms, carbon-fixation is powered by inorganic sources of energy, rather than by capturing sunlight as in plants and cyanobacteria .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Salt-tolerant archaea (the Halobacteria ) use sunlight as a source of energy, and other species of archaea fix carbon ; however, unlike plants and cyanobacteria , no species of archaea is known to do both.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Clearly these structures are analogous rather than homologous; they evolved from independent origins, and are a classic example of evolutionary convergence.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .There are no known archaea that carry out photosynthesis, which is when light is used by photoautotrophs as a source of energy as well as driving the fixation of carbon dioxide.^ How can bacteria carry out photosynthesis?

 ^ Most methanogens are autotrophs, and use the methanogenic pathway for carbon fixation as well as energy production.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ There are no known archaea that carry out photosynthesis , which is when light is used by photoautotrophs as a source of energy as well as driving the fixation of carbon dioxide.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [79] .The energy sources used by archaea to fix carbon are extremely diverse, and range from the oxidation of ammonia by the Nitrosopumilales[80][81] to the oxidation of hydrogen sulfide or elemental sulfur by species of Sulfolobus, using either oxygen or metal ions as electron acceptors.^ Some are anaerobes that use sulfur as an electron acceptor for respiration in place of oxygen.

 ^ Most hyperthermophilic archaea are heterotrophs that use polypeptides as carbon and energy sources.
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 ^ The energy sources used by archaea to fix carbon are extremely diverse, and range from the oxidation of ammonia by the Nitrosopumilales [80 ] [81 ] to the oxidation of hydrogen sulfide or elemental sulfur by species of Sulfolobus , using either oxygen or metal ions as electron acceptors.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [69]
.Phototrophic archaea use light to produce chemical energy in the form of ATP. In the Halobacteria, light-activated ion pumps like bacteriorhodopsin and halorhodopsin generate ion gradients by pumping the ions out of the cell across the plasma membrane.^ Under anoxic conditions it can use light-driven ion pumping by bacteriorhodopsin (bR) as means for producing ATP phototrophically [12] , [13] , [14] .
  • PLoS ONE: Diurnally Entrained Anticipatory Behavior in Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 ^ Phototrophic archaea use light to produce chemical energy in the form of ATP. In the Halobacteria , light-activated ion pumps like bacteriorhodopsin and halorhodopsin generate ion gradients by pumping the ions out of the cell across the plasma membrane .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The plasma membrane of Archaea also contains sulfolipids .

 .The energy stored in these electrochemical gradients is then converted into ATP by ATP synthase.^ The energy stored in these electrochemical gradients is then converted into ATP by ATP synthase .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These translocated, energy-coupling ion pumps result in an electrochemical gradient that catalyzes energy transduction.
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ These forms of metabolism are classified into nutritional groups , depending on the source of energy and the source of carbon.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [39] .This process is a form of photophosphorylation.^ This process is a form of photophosphorylation .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .The structure and function of these light-driven pumps has been studied in great detail, which has revealed that their ability to move ions across membranes depends on light-driven changes in the structure of a retinol cofactor buried in the center of the protein.^ The structure and function of these light-driven pumps has been studied in great detail, which has revealed that their ability to move ions across membranes depends on light-driven changes in the structure of a retinol cofactor buried in the center of the protein.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Phototrophy is driven by a single protein, bacteriorhodopsin, that is a light-driven proton pump.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Most of these proteins are of unknown function.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [82]

Genetics

Further information: Plasmid, Genome
.Archaea usually have a single circular chromosome,[83] the size of which may be as great as 5,751,492 base pairs in Methanosarcina acetivorans,[84] the largest archaean genome sequenced to date.^ Back to top ] Further information: Plasmid , Genome Archaea usually have a single circular chromosome , [83 ] the size of which may be as great as 5,751,492 base pairs in Methanosarcina acetivorans , [84 ] the largest archaean genome sequenced to date.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The genome sequence of its single 1.59Mbp circular chromosome has been determined from cells physically isolated from this culture on the basis of their unusually high resistance to the detergent SDS; this resistance is presumably due to its very dense and orderly S-layer.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ At one-tenth of this size is the tiny 490,885 base-pair genome of Nanoarchaeum equitans , which is the smallest archaeal genome known; it is estimated to contain only 537 protein-encoding genes.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .At one-tenth of this size is the tiny 490,885 base-pair genome of Nanoarchaeum equitans, which is the smallest archaeal genome known; it is estimated to contain only 537 protein-encoding genes.^ The genome of this tiny archaean is one of the smallest known of any organisms, containing only 500,000 base pairs.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Nanoarchaeum equitans Kin4-M has 536 genes.
  • MYcroarray - Catalog Archaea Oligonucleotide Microarrays 19 January 2010 9:52 UTC www.mycroarray.com [Source type: Academic]

 ^ N. equitans is the only hyperthermophilic symbiont known, and the only archaeal parasite or pathogen.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [85] .Smaller independent pieces of DNA, called plasmids, are also found in archaea.^ Smaller independent pieces of DNA, called plasmids , are also found in archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Prokaryotes may also have smaller rings of DNA called plasmids, which consist of only a few genes.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 .Plasmids may be transferred between cells by physical contact, in a process that may be similar to bacterial conjugation.^ Plasmids may be transferred between cells by physical contact, in a process that may be similar to bacterial conjugation .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Transfer of the F + plasmid converts an F - cell to an F + cell.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Because R plasmids also have genes that encode for sex pili, they can be transferred from one cell to another by conjugation.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [86][87]
Sulfolobus infected with the DNA virus STSV1.[88] Bar is 1 micrometer.
.Archaea can be infected by double-stranded DNA viruses that are unrelated to any other form of virus and have a variety of unusual shapes, with some resembling bottles, hooked rods, or teardrops.^ Sulfolobus infected with the DNA virus STSV1.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In some respects, Archaea do resemble Bacteria.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Archaea can be infected by double-stranded DNA viruses that are unrelated to any other form of virus and have a variety of unusual shapes, with some resembling bottles, hooked rods, or teardrops.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [89] .These viruses have been studied in most detail in the thermophilic archaea, particularly the orders Sulfolobales and Thermoproteales.^ Advances in the study of viruses from thermophilic Archaea: Gordon conference on Archaea.
  • Dr. Kenneth Stedman - Publications 19 January 2010 9:52 UTC web.pdx.edu [Source type: Academic]

 ^ Cultivated crenarchaea are all thermophilic, and most are extremely thermophilic, with optimal growth temperatures above 80°C. As a group, these are the most thermophilic organisms known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ The cellular functions of most of these proteins are not known and further studies in this regard should prove very helpful in the discovery of novel biochemical and physiological characteristics that are unique to either all or different groups of archaea [ 38 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [90] .However, one example of a single-stranded DNA virus that infects halophilic archaea was identified in 2009.[91] Defenses against these viruses may involve RNA interference from repetitive DNA sequences within archaean genomes that are related to the genes of the viruses.^ These developments, which are attributable to rapid advances in molecular sequencing of highly conserved regions of the procaryotic genome, most notably genes coding for the RNA of the small ribosomal subunit, have lead to a natural classification that reflects the evolutionary history of Bacteria and Archaea, and to the development of new, universally applicable methods of identifying these organisms.

 ^ However, no homologues of any bacterial genes involved in flagella structure have yet been identified in any archaeon, including those archaea in which the complete genome sequence has been published.

 ^ The genome of this tiny archaean is one of the smallest known of any organisms, containing only 500,000 base pairs.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [92][93]
.Archaea are genetically distinct from bacteria and eukaryotes, with up to 15% of the proteins encoded by any one archaeal genome being unique to the Archaea, although most of these unique genes have no known function.^ Over half of archaeal genes encode unique proteins with unknown functions ( 18 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ These proteins are encoded by dozens of genes, including the genes for biofilm production.

 ^ Genetics of Methanococcus : possibilities for functional genomics in Archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [94] .Of the remainder of the proteins unique to archaea that have an identified function, most are involved in methanogenesis.^ Of the remainder of the genes unique to archaea that have an identified function, most are involved in methanogenesis.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Most of these proteins are of unknown function.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ It is likely that these proteins are involved in some aspects of methanogenesis or other unknown pathways unique to methanogenic archaea.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .The proteins that are shared between archaea, bacteria and eukaryotes form a common core of cell function, relating mostly to transcription, translation, and nucleotide metabolism.^ Archaea share certain traits with bacteria and other traits with eukaryotes.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Spores are made by both bacteria and eukaryotes, but are not formed in any of the known archaea.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The genes that are shared between archaea, bacteria and eukaryotes form a common core of cell function, relating mostly to transcription , translation , and nucleotide metabolism .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [95] .Other characteristic features of archaean genomes are the organization of genes of related function—such as enzymes catalysing steps in the same metabolic pathway—into novel operons, and large differences in tRNA genes and their aminoacyl tRNA synthetases.^ Other characteristic features of archaean genomes are the organization of genes of related functionsuch as enzymes catalysing steps in the same metabolic pathway into novel operons , and large differences in tRNA genes and their aminoacyl tRNA synthetases .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Based on their metabolic and physiological characteristics and other unique features, five functionally distinct groups within Euryarchaeota are currently recognized: methanogens, sulfate reducers, extreme halophiles, cell wall-less archaea, and extremely thermophilic sulfur metabolizing archaea [ 2 , 13 , 32 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ This suggests that archaea use entirely different enzymes for synthesizing their phospholipids than do bacteria and eukaryotes; since such enzymes developed very early in life's history, this in turn suggests that the archaea split off very early from the other two domains.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [95]
.Transcription and translation in archaea are more similar to these processes in eukaryotes than in bacteria, with the archaean RNA polymerase and ribosomes being very close to their equivalents in eukaryotes.^ What it very tentatively implies is that archaea and eukaryotes may have shared a more recent ancestor than either shares with bacteria, as is often shown in textbooks, but this too is not certain, since the relationships between these three groups is also a point of controversy [see Forterre & Philippe 1999; Pennisi 1999]!
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 ^ Transcription in archaea resembles the eukaryotic process more than the bacterial, and could be considered as a simplified version of the eukaryotic transcription complex (Bell & Jackson, 2001 ).
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ In general, archaeal replication, transcription and translation are more related to eukaryal than to bacterial processes (Bell & Jackson, 2001 ; Kelman & Kelman, 2003 ; Reeve, 2003 ), but archaeal central metabolism components are more closely related to bacterial proteins.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [83] .Although archaea only have one type of RNA polymerase, its structure and function in transcription seems to be close to that of the eukaryotic RNA polymerase II, with similar assemblies of proteins (the general transcription factors) directing the binding of the RNA polymerase to a gene's promoter.^ The regulator gene codes for a repressor protein that binds to the operator, obstructing the promoter (thus, transcription) of the structural genes.

 ^ Ribosomes have RNA in their structure that is essential for function.

 ^ Eukaryotic transcription factors.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [96] .However, other archaean transcription factors are closer to those found in bacteria.^ It is not known to what extent the archaeal proteins resemble those from the other two domains in their interaction with each other and with substrates, nucleotides, ions, cochaperones, auxiliary factors, and regulatory molecules.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Most metabolic proteins are similar to those of Bacteria, as are gene and chromosome structure, the processes of replication, transcription, and translation, and the cytoskeleton.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ However, considering the range of known pathogens within the domains Bacteria and Eukarya , the complete absence of recognized pathogens within Archaea , whose ubiquity and phylogenetic diversity are comparable to those of the other two domains, is striking.
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 [97] .Post-transcriptional modification is simpler than in eukaryotes, since most archaean genes lack introns, although there are many introns in their transfer RNA and ribosomal RNA genes,[98] and introns may occur in a few of their protein-encoding genes.^ If the repressor protein is removed, transcription may occur.

 ^ "Introns in protein-coding genes in Archaea".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Post-transcriptional modification is simpler than in eukaryotes, since most archaean genes lack introns , although there are many introns in their transfer RNA and ribosomal RNA genes, [98 ] and introns may occur in a few of their protein-encoding genes.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [99][100]

Reproduction

Further information: Asexual reproduction
.Archaea reproduce asexually by binary or multiple fission, fragmentation, or budding; meiosis does not occur, so if a species of archaea exists in more than one form, these will all have the same genetic material.^ They form complexes with the same general design in all species.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Archaea reproduce asexually and divide by binary fission , fragmentation, or budding; in contrast to bacteria and eukaryotes, no species of archaea are known that form spores .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Therefore, it does not matter at what level phosphorylation occurs in these archaea.
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 [39] .Cell division is controlled in the archaea in a cell cycle; after the cell's chromosome is replicated and the two daughter chromosomes are separated, the cell divides.^ The cells become merodiploid or merooligoploid for the origin-proximal genes [4] , and if replication reinitiation is prevented with rifampicin, end up with 2, 4 or 8 chromosomes [5] .
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 ^ Use of time-lapse microscopy to visualize rapid movement of the replication origin region of the chromosome during the cell cycle in Bacillus subtilis .
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 ^ A cell replicates its chromosome and surrounds one chromosome with a durable wall to form the endospore.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 [101] .The details of the archaeal cell cycle have only been investigated in the genus Sulfolobus, but here it has characters that are similar to both bacterial and eukaryotic systems.^ The origin of the eukaryotic cell: a genomic investigation.
  • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

 ^ Archaea and Bacteria are similar in that they are both single-celled prokaryotic microorganisms with cell walls and circular DNA. However, archaeal cell walls lack peptidoglycan universal to all bacterial cell walls and instead contain pseudomurein (or pseudopeptidoglycan), polysaccharide, or protein (White, 2000).
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ Figs 2 and 3 schematize the different organization of the bacterial and archaeal respiratory nitrate-reducing systems, and the other enzymes involved in the whole denitrification pathway (see below).
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 .In this archaean, the chromosomes are replicated from multiple starting-points (origins of replication) using DNA polymerases that resemble the equivalent eukaryotic enzymes.^ DNA polymerases are a family of enzymes involved in DNA repair and replication.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ NEB#720 yielded 1700 units of DNA polymerase activity per gram of cells and was used for the large scale preparation of this enzyme.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ As a result, Taq DNA polymerase is prone to base incorporation errors, making its use in certain applications undesirable.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 [102] .However, the proteins that direct cell division, such as the protein FtsZ, which forms a contracting ring around the cell, and the components of the septum that is constructed across the center of the cell, are similar to their bacterial equivalents.^ The two proteins form homoheptameric rings.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Archaea and Bacteria are similar in that they are both single-celled prokaryotic microorganisms with cell walls and circular DNA. However, archaeal cell walls lack peptidoglycan universal to all bacterial cell walls and instead contain pseudomurein (or pseudopeptidoglycan), polysaccharide, or protein (White, 2000).
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ These solutes balance osmotic pressure and allow the cell to function using normal enzymes and proteins that would otherwise be dysfunctional at such a high salinity.
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 [101]
.Spores are made by both bacteria and eukaryotes, but are not formed in any of the known archaea.^ This enzyme is PP i -dependent and is also found among some bacteria and eukaryotes, and is distantly related to ATP-PFK [ 61 ] (both belonging to COG 0205) ( Table 2 ).
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 ^ Members of the domain Archaea , one of the three domains of life, are a highly diverse group of prokaryotes, distinct from bacteria and eukaryotes.
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 ^ A notable genotypic adaptation observed in both Archaea and Bacteria is the proportion of unsaturated fatty acid in the organisms of varying temperature ranges.
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 [103] .Some species of Haloarchaea undergo phenotypic switching and grow as several different types of cell, including thick-walled structures that are resistant to osmotic shock and allow the archaea to survive in water at low concentrations of salt, but these are not reproductive structures and may instead help them disperse to new habitats.^ Cell wall polymers in Archaea (Archaebacteria).
  • Archaea & Eubacteria 19 January 2010 9:52 UTC euarch.blogspot.com [Source type: Academic]
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ In some cases, different species of prokaryotes may cooperate.
  • Chapter 27 - Bacteria and Archaea 19 January 2010 9:52 UTC web.me.com [Source type: Academic]

 ^ Cell wall polymers in Archaea (Archaebacteria) .

 [104]

Ecology

Habitats

.Archaea exist in a broad range of habitats, and are a major part of global ecosystems,[7] and may contribute up to 20% of the total biomass on Earth.^ The relative contribution of square archaea to the total community of prokaryotes was assessed in the phase contrast microscope under a 100× objective.
  • Saline Systems | Full text | Buoyancy studies in natural communities of square gas-vacuolate archaea in saltern crystallizer ponds 19 January 2010 9:52 UTC www.salinesystems.org [Source type: Academic]

 ^ The total load of methanogenic archaea ranged from 3.3 x 10 4 to 2.8 x 10 5 mcrA gene target molecules (Fig.
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 ^ Thus, the data presented here are likely to be conservative with respect to the contribution of bacterial rRNA, and the actual contribution of Archaea may be even lower.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [105] Multiple archaeans are extremophiles, and historically this was seen as their ecological niche.[68] .Indeed, some archaea survive high temperatures, often above 100 °C, as found in geysers, black smokers, and oil wells.^ However, the ratio of Bacteria to Archaea they found for three different hot springs (80, 75 and 1, respectively) are comparable to ours and also suggest that the dominance of Archaea in high-temperature environments is the exception rather than the rule.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Tardigrades (water bears) can survive temperatures, pressures and radiation levels found in space...
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 ^ The temperature, right here on Earth, goes well below 0°C. Once you get down so far, the pressure is too high for the water to freeze.
  • The most extreme life-forms in the universe - space - 26 June 2008 - New Scientist 19 January 2010 9:52 UTC www.newscientist.com [Source type: News]

 .Others are found in very cold habitats and others in highly saline, acidic, or alkaline water.^ Other archaea exist in very acidic or alkaline conditions.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Others are found in very cold habitats and others in highly saline , acidic , or alkaline water.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaeal species were earlier believed to inhabit only extreme environments such as extremely hot, or hot and acidic, extremely saline, or very acidic or alkaline conditions [ 15 - 19 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 .However, other archaea are mesophiles that grow in much milder conditions, in marshland, sewage, the oceans, and soils.^ However, other archaea are mesophiles that grow in much milder conditions, in marshland , sewage , the oceans , and soils .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, nitrogen metabolism is much less known in archaea than in bacteria.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ None of the other Archaea are pathogens either, but considering the conditions under which most of them grow, this is perhaps not surprizing.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [7]
Image of plankton (light green) in the oceans; archaea form a major part of oceanic life.
.Extremophile archaea are members of four main physiological groups.^ Extremophile archaea are members of four main physiological groups.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Many groups consist of members that are phenotypically and physiologically unrelated.

 ^ Most of the culturable and well-investigated species of archaea are members of two main phyla , the Euryarchaeota and Crenarchaeota .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .These are the halophiles, thermophiles, alkaliphiles, and acidophiles.^ These are the halophiles , thermophiles , alkaliphiles , and acidophiles .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [106] .These groups are not comprehensive or related to which phylum the organisms belong to, nor are they mutually exclusive, since some archaea belong to several of these groups.^ Cultivated crenarchaea are all thermophilic, and most are extremely thermophilic, with optimal growth temperatures above 80°C. As a group, these are the most thermophilic organisms known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Some of these groups, such as methanogens, are polyphyletic in different phylogenetic trees [ 13 , 33 , 34 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ It is likely that these proteins are involved in some aspects of methanogenesis or other unknown pathways unique to methanogenic archaea.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 Nonetheless, they are a useful starting point for classification.
.Halophiles, including the genus Halobacterium, live in extremely saline environments such as salt lakes and start outnumbering their bacterial counterparts at salinities greater than 20–25%.^ Archaea , one of the three domains of life, is a highly diverse and abundant group of prokaryotes, and includes a number of "extremophiles" that thrive in such environments as hot springs, salt lakes, and submarine volcanic habitats ( 33 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 ^ They can inhabit extreme environments, typically characterized by high temperature or pressure (e.g., deep sea thermal vents) or extreme salinity, alkalinity, or acidity.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 [68] .Thermophiles grow best at temperatures above 45 °C, in places such as hot springs; hyperthermophilic archaea are defined as those that grow optimally at temperatures greater than 80 °C.[107] The archaeal Methanopyrus kandleri Strain 116 grows at 122 °C, which is the highest recorded temperature at which any organism will grow.^ The most progress has been made with hyperthermophilic archaea that grow optimally above 80 °C on a variety of sugars.
  • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

 ^ Archaea , one of the three domains of life, is a highly diverse and abundant group of prokaryotes, and includes a number of "extremophiles" that thrive in such environments as hot springs, salt lakes, and submarine volcanic habitats ( 33 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Archaea are represented by a relatively small group of single-celled organisms that mostly live in extremely hot, salty, or acidic anaerobic environments.
  • 101 Taxonomy - www.101science.com 11 September 2009 0:44 UTC www.101science.com [Source type: FILTERED WITH BAYES]

 [108] .Other archaea exist in very acidic or alkaline conditions.^ Other archaea exist in very acidic or alkaline conditions.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The origin of Archaea appears very old indeed and the archaeal lineage may be the most ancient that exists on earth.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaeal species were earlier believed to inhabit only extreme environments such as extremely hot, or hot and acidic, extremely saline, or very acidic or alkaline conditions [ 15 - 19 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [106] .For example, one of the most extreme archaean acidophiles is Picrophilus torridus, which grows at pH 0, which is equivalent to thriving in 1.2 Molar sulfuric acid.^ They are also one the most primitive organisms known; this is a general rule, that thermophiles, and especially extreme thermophiles, are primitive, at least in terms of their ssu-rRNA sequences.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ One archaean has a type of peptidoglycan called pseudomurein (because it lacks N-acetylmuramic acid).

 ^ Genome sequence of Picrophilus torridus and its implications for life around pH 0.
  • Protein thermostability in Archaea and Eubacteria 19 January 2010 9:52 UTC www.funpecrp.com.br [Source type: Academic]

 [109]
.This resistance to extreme environments has made archaea the focus of speculation about the possible properties of extraterrestrial life.^ This resistance to extreme environments has made archaea the focus of speculation about the possible properties of extraterrestrial life .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Life in extreme environments.
  • Chapter 6 Notes: Diversification of Bacteria and Archaea. I: Phylogeny and Biology 19 January 2010 9:52 UTC evolution-textbook.org [Source type: Academic]

 ^ Over the past 50 years, the search for microorganisms in seemingly uninhabitable environments, such as at the extremes of pH, temperature, nutrient concentration, and pressure, has yielded a great deal of information about the diversity and origins of microbial life.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [110] .This has focused on the possibility that microbial life may exist on Mars,[111] and has even led to the suggestion that viable microbes could be transferred between planets in meteorites.^ "The transfer of viable microorganisms between planets".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ This has focused on the possibility that microbial life may exist on Mars , [111 ] and has even led to the suggestion that viable microbes could be transferred between planets in meteorites .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ It is possible such structures may be involved in host-microbe adherence or microbe-microbe interactions within a potential host.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [112]
.Recently, several studies have shown that archaea exist not only in mesophilic and thermophilic environments but are also present, sometimes in high numbers, at low temperatures as well.^ Recently, several studies have shown that archaea exist not only in mesophilic and thermophilic environments but are also present, sometimes in high numbers, at low temperatures as well.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ They can inhabit extreme environments, typically characterized by high temperature or pressure (e.g., deep sea thermal vents) or extreme salinity, alkalinity, or acidity.
  • Eubacteria and Archaea -- Essentials of Glycobiology -- NCBI Bookshelf 19 January 2010 9:52 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

 ^ However, the ratio of Bacteria to Archaea they found for three different hot springs (80, 75 and 1, respectively) are comparable to ours and also suggest that the dominance of Archaea in high-temperature environments is the exception rather than the rule.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 .For example, archaea are common in cold oceanic environments such as polar seas.^ Habitat Extremely halophilic Archaea are common in hypersaline seas and lakes, salt evaporation pools, salted meats, salt marshes, and subterranean salt deposit.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Genetic diversity of archaea in deep-sea hydrothermal vent environments.
  • Distribution of Archaea in a Black Smoker Chimney Structure -- Takai et al. 67 (8): 3618 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 ^ However, they are common organisms, found in all types of anaerobic environments, and are certainly the most prevalent cultivable Archaea in the “moderate” world.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [113] .Even more significant are the large numbers of archaea found throughout the world's oceans in the plankton community (as part of the picoplankton).^ Among the genes that are uniquely shared by various methanogenic archaea (or these archaea plus A. fulgidus ), two large gene clusters responsible for methanogenesis are found.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ Figure 4 presents this point more clearly; the number of TF families levels off with large numbers of TFs.
  • Genome-Wide Survey of Transcription Factors in Prokaryotes Reveals Many Bacteria-Specific Families Not Found in Archaea -- Minezaki et al. 12 (5): 269 -- DNA Research 19 January 2010 9:52 UTC dnaresearch.oxfordjournals.org [Source type: Academic]

 ^ Both major phyla are also home to a large number of ssu-rRNA sequences apparently from planktonic marine species; the phenotypes of these organisms are not known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [114] .Although these archaea can be present in extremely high numbers (up to 40% of the microbial biomass), almost none of these species have been isolated and studied in pure culture.^ In the present study we have studied the relative abundance of two domains of life, Archaea and Bacteria (Woese et al.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Because of the frequent isolation of Archaea from these habitats it was assumed that Archaea dominate these communities (Stetter et al.
  • Relative abundance of Archaea and Bacteria along a thermal gradient of a shallow-water hydrothermal vent quantified by rRNA slot-blot hybridization -- Sievert et al. 146 (6): 1287 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Surprisingly, these proteins are present in different combinations of halobacterial species.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 [115] .Consequently, our understanding of the role of archaea in the ecology of the oceans is rudimentary, so their full influence on global biogeochemical cycles remains largely unexplored.^ Such experiments may eventually lead to a full understanding of the ecological role of the gas vesicles in halophilic archaea.
  • Saline Systems | Full text | Buoyancy studies in natural communities of square gas-vacuolate archaea in saltern crystallizer ponds 19 January 2010 9:52 UTC www.salinesystems.org [Source type: Academic]

 ^ It remains to be investigated whether AT repeats play similar roles in Archaea.
  • Comparison of simple sequence repeats in 19 Archaea 19 January 2010 9:52 UTC www.funpecrp.com.br [Source type: Academic]

 ^ There are several aspects that are unique to the archaea and whose elucidation will enhance our understanding of protein biogenesis and molecular chaperoning in general.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [116] .Some marine Crenarchaeota are capable of nitrification, suggesting these organisms may be important in the oceanic nitrogen cycle,[117] although these oceanic Crenarchaeota may also use other sources of energy.^ Some marine Crenarchaeota are capable of nitrification , suggesting these organisms may be important in the oceanic nitrogen cycle , [117 ] although these oceanic Crenarchaeota may also use other sources of energy.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, their influence on community structure and ecology is still elusive, partly because none of these organisms, with the exception of one marine Crenarchaeon ( 26 ), could be cultured until now, but recent reports show the possible importance of these organisms in the nitrogen cycle of the world ( 16 , 41 , 48 ).
  • Communities of Archaea and Bacteria in a Subsurface Radioactive Thermal Spring in the Austrian Central Alps, and Evidence of Ammonia-Oxidizing Crenarchaeota -- Weidler et al. 73 (1): 259 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 ^ These forms of metabolism are classified into nutritional groups , depending on the source of energy and the source of carbon.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [118] .Vast numbers of archaea are also found in the sediments that cover the sea floor, with these organisms making up the majority of living cells at depths over 1 meter into this sediment.^ A diverse array of living organisms (life forms) can be found in the biosphere on Earth, and properties common to these organisms—plants, animals, fungi, protists, archaea, and bacteria — are a carbon- and water-based cellular form with complex organization and heritable genetic information.
  • I can't tell the difference (subjectively) between life and death - Philosophy, Sociology & Psychology - Shroomery Message Board 19 January 2010 9:52 UTC www.shroomery.org [Source type: FILTERED WITH BAYES]

 ^ Differences in composition and properties of major components such as cytoplasmic membranes, enzymes, and proteins of these extreme Archaea were found to play major roles in maintaining archaeal stability in seemingly inhospitable environments.
  • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

 ^ However, both species were found to be highly polyploid and to downregulate the number of genome copies as cells enter stationary phase.
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 [119][120]

Role in chemical cycling

Further information: Biogeochemical cycle
.Archaea are part of the systems on Earth that recycle elements such as carbon, nitrogen and sulfur through the various habitats in ecosystems.^ Of the proteins that are commonly shared by A. fulgidus and various methanogenic archaea, MMP0607 is reported to be a novel repressor of nif and glnA genes, which are involved in nitrogen assimilation [ 79 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ They can fix their own carbon from CO2, synthesize all their vitamins, fix their own nitrogen from N2, fix sulfur from H2S, &c.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ In addition to symbiotic nitrogen-fixing bacteria, there are various free-living nitrogen-fixing procaryotes in both soil and aquatic habitats.

 .Although these activities are vital for the normal function of ecosystems, archaea can also contribute to the changes that humans have made in the environment, and even cause pollution.^ For exonuclease functions of polymerases sensitive to the rate of polymerization, changes in exonuclease activity are parallel with increases in deoxynucleotide concentrations.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ Although the Archaea are often inhabitants of extreme environments, there may be corresponding species of Bacteria, and even eucaryotes, in these habitats as well.

 ^ Although tetra- and pentanucleotide repeat densities are more abundant in non-coding regions compared to coding regions, in some Archaea these repeats are absent in non-coding sequences.
  • Comparison of simple sequence repeats in 19 Archaea 19 January 2010 9:52 UTC www.funpecrp.com.br [Source type: Academic]
.Archaea carry out many steps in the nitrogen cycle, this includes both dissimilatory reactions that remove nitrogen from ecosystems, such as nitrate-based respiration and denitrification: as well as assimilatory processes that introduce nitrogen, such as nitrate assimilation and nitrogen fixation.^ In addition to ammonium assimilation, members of archaea can drive all the reductive pathways of the N-cycle, either dissimilatory reactions, such as nitrate respiration and denitrification, or assimilatory pathways like N 2 fixation and nitrate assimilation.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Some hyperthermophilic archaea are also able to respire nitrate.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Archaea are able to perform different reductive pathways of the N-cycle, including both assimilatory processes, such as nitrate assimilation and N 2 fixation, and dissimilatory reactions, such as nitrate respiration and denitrification.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [121][122] .The involvement of archaea in ammonia oxidation reactions was recently discovered; these being particularly important in the oceans.^ Interestingly, certain archaea ( Archaeoglobus spp., Pyrococcus , and Methanococcus jannaschii ) have recently been discovered to contain efflux pumps of the resistance nodulation division superfamily ( 56 ).
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ The species distributions of these proteins provide novel insights into the evolutionary relationships among different groups within Archaea, particularly regarding the origin of methanogenesis.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ Ubiquity and diversity of ammonia-oxidizing archaea in water columns and sediments of the ocean.
  • Communities of Archaea and Bacteria in a Subsurface Radioactive Thermal Spring in the Austrian Central Alps, and Evidence of Ammonia-Oxidizing Crenarchaeota -- Weidler et al. 73 (1): 259 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 [123][124] .The archaea also appear to be crucial for ammonia oxidation in soils, this produces nitrite, which is then oxidized to nitrate by other microbes, and then taken up by plants and other organisms.^ "Archaea predominate among ammonia-oxidizing prokaryotes in soils".
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The archaea also appear to be crucial for ammonia oxidation in soils, this produces nitrite , which is then oxidized to nitrate by other microbes, and then taken up by plants and other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The well-characterized interactions between archaea and other organisms are either mutualism or commensal .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [125]
.In the sulfur cycle, archaea that grow by oxidizing sulfur compounds are important as they release this element from rocks, making it available to other organisms.^ In the sulfur cycle , archaea that grow by oxidizing sulfur compounds are important as they release this element from rocks, making it available to other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Bacteria play important ecological roles as decomposers, as well as important elements of phytoplantonic organisms at the base of many food chains.

 ^ Archaea are now recognized as a major part of life on Earth and may play an important role in both the carbon cycle and nitrogen cycle .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .However, the archaea that do this, such as Sulfolobus, can cause environmental damage since they produce sulfuric acid as a waste product, and the growth of these organisms in abandoned mines can contribute to acid mine drainage.^ Most of these Archaea require elemental sulfur for growth.

 ^ Thus, these organisms are called “extremophiles” and, unlike Eubacteria and Eukarya, they depend for survival on environmental conditions such as high salinity, extremes of temperature, unusual chemical substrates, or high pressure.

 ^ Cultivated crenarchaea are all thermophilic, and most are extremely thermophilic, with optimal growth temperatures above 80°C. As a group, these are the most thermophilic organisms known.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 [126]
.In the carbon cycle, methanogen archaea are significant as methane producers.^ Methanogens obtain energy by the reduction of one- or two-carbon compounds to methane.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ Measurement of breath methane excretion is a method that has been used to determine gut methane production ( 5 ) and may be an indirect means of determining the contribution of active methanogenic archaea to disease.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Methanogens make methane and fixed carbon from H2 and CO2, whereas Archaeoglobus makes CO2 and H2 from organic carbon.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .The ability of these archaea to remove hydrogen is important in the degradation of organic matter by the populations of microorganisms that act as decomposers in anaerobic ecosystems, such as sediments, marshes and sewage treatment works.^ Because archaea are the predominant microbial populations in extreme environments, such as highly saline water and hot springs, they sustain the N-cycle in these special and severe ecosystems.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ The methanogenic archaea in these trees are interspersed by other groups of non-methanogenic archaea such as Halobacteriales, Archaeoglobus, Thermoplasmatales and Thermococcales (see Fig.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ The detection of anaerobic archaea in the human colonic ( 36 ), vaginal ( 2 ), and oral microbial flora ( 1 ) demonstrates their ability to colonize the human host.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 [127] .However, methane is one of the most abundant greenhouse gases in Earth's atmosphere, constituting 18% of the global total.^ However, methane is one of the most abundant greenhouse gases in Earth's atmosphere, constituting 18% of the global total.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ N 2 is the most abundant gas in Earth's atmosphere, but it is highly stable and unreactive and is only used as nitrogen source by some prokaryotic organisms.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ However, even that skeptical article notes another one that got the methane story right...
  • Martian methane - sci.astro.amateur | Google Groups 19 January 2010 9:52 UTC groups.google.com.au [Source type: FILTERED WITH BAYES]

 [128] .It is 25 times more potent as a greenhouse gas than carbon dioxide.^ It is 25 times more potent as a greenhouse gas than carbon dioxide.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Methane has a higher molecular weight than carbon dioxide.
  • Martian methane - sci.astro.amateur | Google Groups 19 January 2010 9:52 UTC groups.google.com.au [Source type: FILTERED WITH BAYES]

 ^ Normally bacteria have short generation times, mutations are generated and distributed throughout bacterial populations more quickly than in eukaryotes.

 [129] .Methanogens are the primary source of atmospheric methane, and are responsible for most of the world's yearly methane emissions.^ N 2 is the most abundant gas in Earth's atmosphere, but it is highly stable and unreactive and is only used as nitrogen source by some prokaryotic organisms.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Methanogen metabolism created most the natural gas (fossil fuel) reserves that are tapped as energy sources for domestic or industrial use.

 ^ Most methanogens, including members of the genus Methanobrevibacter , metabolize molecular hydrogen (H 2 ) and carbon dioxide (CO 2 ) with methane as the resultant product.
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 [130] As a consequence, these archaea contribute to global greenhouse gas emissions and global warming.

Interactions with other organisms

Further information: Biological interaction
Methanogenic archaea form a symbiosis with termites.
.The well-characterized interactions between archaea and other organisms are either mutualism or commensal.^ Archaeal chaperonin subunits in a given organism tend to be more similar to each other than to their homologs from other archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Pentanucleotide repeats in Archaea show characteristic distributions as diverse as in other organisms (Toth et al., 2000; Gur-Arie et al., 2000; Lim et al., 2004).
  • Comparison of simple sequence repeats in 19 Archaea 19 January 2010 9:52 UTC www.funpecrp.com.br [Source type: Academic]

 ^ Because the last common ancestor is apparently on the branch between the Bacteria and Archaea/Eukarya, any trait common to Bacteria and either Archaea or Eukarya probably existed in the last common ancestor.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 .As of 2007, no clear examples of archaeal pathogens or parasites are known.^ N. equitans is the only hyperthermophilic symbiont known, and the only archaeal parasite or pathogen.
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ As of 2007, no clear examples of archaeal pathogens or parasites are known.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ No clear examples of archaeal pathogens or parasites are known, but they are often mutualists or commensals .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [131][132] .However, a relationship has been proposed between the presence of some species of methanogens and infections in the mouth,[133][134] and Nanoarchaeum equitans may be a parasite of another species of archaea, since it only survives and reproduces within the cells of the Crenarchaeon Ignicoccus hospitalis,[135] and appears to offer no benefit to its host.^ However, a relationship has been proposed between the presence of some species of methanogens and infections in the mouth , [133 ] [134 ] and Nanoarchaeum equitans may be a parasite of another species of archaea, since it only survives and reproduces within the cells of the Crenarchaeon Ignicoccus hospitalis , [135 ] and appears to offer no benefit to its host .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ N. equitans is an obligate parasite of the crenarchaeote Ignicoccus .
  • MB 451 Microbial Diversity 19 January 2010 9:52 UTC www.mbio.ncsu.edu [Source type: FILTERED WITH BAYES]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [136]
.One well-understood example of mutualism is the interaction between protozoa and methanogenic archaea in the digestive tracts of animals that digest cellulose, such as ruminants and termites.^ Our results also suggest a closer relationship of the Thermococcales to the Archaeoglobus and methanogenic archaea, although this relationship is not as strongly supported as between Archaeoglobus and Methanogens.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ The operon numbers of 16S rRNA genes have been reported to range from one to four copies in archaea ( 1 ), while methanogens harbor one to two copies of the mcrA gene ( 25 ).
  • Identification and Quantification of Archaea Involved in Primary Endodontic Infections -- Vianna et al. 44 (4): 1274 -- Journal of Clinical Microbiology 19 January 2010 9:52 UTC jcm.asm.org [Source type: Academic]

 ^ One recent example is the demonstration that while some archaea have the hsp70 gene, others do not, and those that have it probably received it via lateral transfer ( 99 , 164 ).
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [137] .In these anaerobic environments, protozoa break down cellulose from plant material to obtain energy.^ However, they are usually unable to degrade biopolymers in their environment, such as cellulose and lignin, and their role in anaerobic decomposition is minimal.

 .This process releases hydrogen as a waste product, but high levels of hydrogen will reduce the energy released by this reaction.^ Proteins are gene products, and at the level of genes, duplication, recombination, fusion and fission are the processes that produce new genes.

 ^ Nitrogenase extracts N 2 from the atmosphere and reduces it to NH 3 in a reaction that requires substantial reducing power (electrons) and energy (ATP).

 .When methanogens convert the hydrogen to methane, the protozoa benefit as they will gain more energy from breaking down cellulose.^ They are distinguished from all other prokaryotes by their ability to obtain all or most of their energy via the reduction of CO 2 to methane or by the process of methanogenesis.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ This complex catalyzes the final reaction of the energy conserving pathway in which methylcoenzyme M and coenzyme B are converted to methane and the heterodisulfide CoM-S-S-CoB [ 87 , 88 ].
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ The methanogens live under anaerobic environments (e.g., marshes) where they produce methane.

 [138]
.These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes.^ Colonies can also be produced by an association between different species.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These archaea include nitrifiers , methanogens and anaerobic methane oxidisers .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [139][140] .Similar associations with larger organisms are now being found, with the discovery that the marine archaean Cenarchaeum symbiosum lives within (it is an endosymbiont of) the sponge Axinella mexicana.^ A psychrophilic crenarchaeon inhabits a marine spong e: Cenarchaeum symbiosum gen.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Similar associations with larger organisms are now being found, with the discovery that the marine archaean Cenarchaeum symbiosum lives within (it is an endosymbiont of) the sponge Axinella mexicana .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Vast numbers of archaea are also found in the sediments that cover the sea floor , with these organisms making up the majority of living cells at depths over 1 meter into this sediment.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [141]
.Archaea can also be commensals, benefiting from an association without helping or harming the other organism.^ Archaea can also be commensals, benefiting from an association without helping or harming the other organism.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The well-characterized interactions between archaea and other organisms are either mutualism or commensal .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ In the sulfur cycle , archaea that grow by oxidizing sulfur compounds are important as they release this element from rocks, making it available to other organisms.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 .For example, the methanogen Methanobrevibacter smithii is by far the most common archaean in the human flora, with this species making up about one in ten of all the prokaryotes in the human gut.^ Isolation of Methanobrevibacter smithii from human feces.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Most, but not all, of the Gram negative bacteria that are important pathogens of humans are found scattered throughout the Proteobacteria.

 ^ Polyploidy is common in higher eukaryotes, especially in plants, but it is generally assumed that most prokaryotes contain a single copy of a circular chromosome and are therefore monoploid.
  • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

 [142] .As in termites, these methanogens may in fact be mutualists in humans, interacting with other microbes in the gut to aid the digestion of food.^ As in termites, these methanogens may in fact be mutualists in humans, interacting with other microbes in the gut to aid the digestion of food.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ The whole eha operon is composed of 20 ORFs in the genome of M. thermoautotrophicus and of these only these 12 proteins are restricted to these methanogens while the other subunits have counterparts in bacteria.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ Methanosarcinas and other methanogens are found in these granular consortia.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [143] .Communities of archaea are also associated with a range of other organisms, such as on the surface of corals,[144] and in the region of soil that surrounds plant roots (the rhizosphere).^ Communities of archaea are also associated with a range of other organisms, such as on the surface of corals , [144 ] and in the region of soil that surrounds plant roots (the rhizosphere ).
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ Archaeal chaperonin subunits in a given organism tend to be more similar to each other than to their homologs from other archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Archaea can also be commensals, benefiting from an association without helping or harming the other organism.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [145][146]

Significance in technology and industry

Further information: Biotechnology
.Extremophile archaea, particularly those resistant either to heat or to extremes of acidity and alkalinity, are a source of enzymes that function under these harsh conditions.^ Structure, function and stability of enzymes from the archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ Thus, these organisms are called “extremophiles” and, unlike Eubacteria and Eukarya, they depend for survival on environmental conditions such as high salinity, extremes of temperature, unusual chemical substrates, or high pressure.

 ^ The question remains open whether these seemingly unique features of the molecule from the extreme halophile reflect an adaptation to life under high-salinity conditions and/or to cope with salinity changes.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 [147][148] .These enzymes have a wide range of uses.^ The first of these mechanisms may be the most primitive and highly conserved across a wide range of known microbial virulence scenarios.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ The key enzymes involved in these pathways are not conserved in archaea, which may, therefore, synthesize ß-alanine using an unrelated enzyme or by yet another route.
  • Coenzyme A Biosynthesis: Reconstruction of the Pathway in Archaea and an Evolutionary Scenario Based on Comparative Genomics -- Genschel 21 (7): 1242 -- Molecular Biology and Evolution 19 January 2010 9:52 UTC mbe.oxfordjournals.org [Source type: Academic]

 ^ These enzymes have a variety of uses in recombinant DNA technology including, for example, labelling of DNA by nick translation, second-strand cDNA synthesis in cDNA cloning, and DNA sequencing.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 .For example, thermostable DNA polymerases, such as the Pfu DNA polymerase from Pyrococcus furiosus, have revolutionized molecular biology by allowing the polymerase chain reaction to be used as a simple and rapid technique for cloning DNA. In industry, amylases, galactosidases and pullulanases in other species of Pyrococcus that function at over 100 °C allow food processing at high temperatures, such as the production of low lactose milk and whey.^ For example, thermostable DNA polymerases , such as the Pfu DNA polymerase from Pyrococcus furiosus , have revolutionized molecular biology by allowing the polymerase chain reaction to be used as a simple and rapid technique for cloning DNA. In industry, amylases , galactosidases and pullulanases in other species of Pyrococcus that function at over 100 C allow food processing at high temperatures, such as the production of low lactose milk and whey.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ DNA fragment which codes for the thermostable DNA polymerase.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ In accordance with the present invention, cross hybridization of a target Archaebacterium genomic DNA library using an DNA probe prepared from the DNA polymerase gone of T. litoralis and/or cross-reactivity with mouse anti-T. litoralis antiserum allows for the identification and isolation of the DNA polymerase genes from other archaebacterium, such as Methanococcus, Methanobacter, Methanomicrobium, Halobacter, Thermoplasma, Thermococcus, Pyrococcus, and the like (see, e.g.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 [149] .Enzymes from these thermophilic archaea also tend to be very stable in organic solvents, allowing their use in environmentally friendly processes in green chemistry that synthesize organic compounds.^ Structure, function and stability of enzymes from the archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ If some archaea behave as pathogens they probably follow this basic scheme, but they may use fundamentally different mechanisms at some or all of these steps.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ On the other hand, autotrophic species in Gammaproteobacteria, Bacillales and other phyla tend to have many kinds of TFs to control cellular processes in response to environmental changes.
  • Genome-Wide Survey of Transcription Factors in Prokaryotes Reveals Many Bacteria-Specific Families Not Found in Archaea -- Minezaki et al. 12 (5): 269 -- DNA Research 19 January 2010 9:52 UTC dnaresearch.oxfordjournals.org [Source type: Academic]

 [148] .The stability of thermophilic enzymes also makes them easier to use in structural biology, consequently the counterparts of bacterial or eukaryotic enzymes from extremophile archaea are often used in structural studies.^ Structure, function and stability of enzymes from the archaea.
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ The stability of thermophilic enzymes also makes them easier to use in structural biology , consequently the counterparts of bacterial or eukaryotic enzymes from extremophile archaea are often used in structural studies.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ This suggests that archaea use entirely different enzymes for synthesizing their phospholipids than do bacteria and eukaryotes; since such enzymes developed very early in life's history, this in turn suggests that the archaea split off very early from the other two domains.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [150]
.In contrast to the range of applications of archaean enzymes, the use of the organisms themselves in biotechnology is more restricted.^ As with T. litoralis The archaebacterium DNA once isolated can be used to construct genomic libraries as either random fragments or restriction enzyme fragments.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ Other restriction enzymes such as BamHI, NruI and XbaI can also be used.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 ^ In addition, European Patent Application 0258017 discloses Taq polymerase as the preferred enzyme for use in the PCR process discussed above.
  • Recombinant thermostable DNA polymerase from archaebacteria - Patent 5352778 11 September 2009 0:44 UTC www.freepatentsonline.com [Source type: Academic]

 .However, methanogenic archaea are a vital part of sewage treatment, since they are part of the community of microorganisms that carry out anaerobic digestion and produce biogas.^ These acetotrophs are archaea in the order Methanosarcinales , and are a major part of the communities of microorganisms that produce biogas .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ However, methanogenic archaea are a vital part of sewage treatment , since they are part of the community of microorganisms that carry out anaerobic digestion and produce biogas .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These associations between methanogens and protozoa are taken a step further in several species of anaerobic protozoa, such as Plagiopyla frontata ; here the archaea actually reside inside the protozoa and consume the hydrogen produced in their hydrogenosomes .
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 [151] .In mineral processing, Acidophilic archaea display promise for the extraction of metals from ores, including gold, cobalt and copper.^ Archaea are able to perform different reductive pathways of the N-cycle, including both assimilatory processes, such as nitrate assimilation and N 2 fixation, and dissimilatory reactions, such as nitrate respiration and denitrification.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 [152]
.A new class of potentially useful antibiotics has been discovered in archaea.^ First, the use of antibiotics may inhibit the growth of some archaea.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 .A few of these archaeocins have been characterized, but hundreds more are believed to exist, especially within Haloarchaea and Sulfolobus.^ Note that pathogens exist within the Fusobacteria, Acanthamoebidae, Stramenophiles, and Mesomycetozoa; however, these divisions are not pictured.
  • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

 ^ Because two or more phosphorylation events ( figure showing phosphorelay system) occur, it is believed that these systems can integrate more signals into the signaling cascade and are more fine tuned.

 [153] .These compounds are important since they are different in structure to bacterial antibiotics, so they may have novel modes of action.^ Differences by comparison with the bacterial machine will probably be found, since differences in binding properties between the cytosolic and mitochondrial Hsp70 molecules, for example, have been demonstrated ( 7 ).
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ However, biochemical and functional studies are necessary to confirm the assimilatory nature of these putative nitrate and nitrite reductases and to establish if these archaeal enzymes are structurally different from the bacterial assimilatory enzymes.
  • Nitrate reduction and the nitrogen cycle in archaea -- Cabello et al. 150 (11): 3527 -- Microbiology 19 January 2010 9:52 UTC mic.sgmjournals.org [Source type: Academic]

 ^ Intracellular signaling not only brings bacteria together in biofilms, it also regulates the coordinated delivery of high doses of these antibiotics from the denser bacterial population.

 .In addition, they may allow the creation of new selectable markers for use in archaeal molecular biology.^ In addition, they may allow the creation of new selectable markers for use in archaeal molecular biology.
  • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

 ^ These proteins provide molecular markers for methanogens, which can be used for identification of new archaeal species capable of methane production.
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ They may be a nuisance if they bloom in large numbers and then die and decay in bodies of fresh water that are used for drinking or recreational purposes.

 .The discovery of new archaeocins depends on successful recovery and cultivation of new species of archaea from the environment.^ The discovery of extremely halophilic archaeal rDNA and successful cultivation of halophilic microorganisms were achieved specifically from the inside structures of the chimney.
  • Distribution of Archaea in a Black Smoker Chimney Structure -- Takai et al. 67 (8): 3618 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 ^ However, the discovery of extremely halophilic archaeal rDNA and the successful cultivation of halophilic bacteria suggest that partially hypersaline microhabitats allowing the survival or growth of halophilic archaea and bacteria occur in the chimney structure.
  • Distribution of Archaea in a Black Smoker Chimney Structure -- Takai et al. 67 (8): 3618 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

 ^ Although the Archaea are often inhabitants of extreme environments, there may be corresponding species of Bacteria, and even eucaryotes, in these habitats as well.

 [154]

See also

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  122. ^ Mehta MP, Baross JA (December 2006). "Nitrogen fixation at 92 degrees C by a hydrothermal vent archaeon". Science (journal) 314 (5806): 1783–6. doi:10.1126/science.1134772. PMID 17170307.  
  123. ^ Francis CA, Beman JM, Kuypers MM (May 2007). "New processes and players in the nitrogen cycle: the microbial ecology of anaerobic and archaeal ammonia oxidation". ISME J 1 (1): 19–27. doi:10.1038/ismej.2007.8. PMID 18043610.  
  124. ^ Coolen MJ, Abbas B, van Bleijswijk J, et al. (April 2007). "Putative ammonia-oxidizing Crenarchaeota in suboxic waters of the Black Sea: a basin-wide ecological study using 16S ribosomal and functional genes and membrane lipids". Environ. Microbiol. 9 (4): 1001–16. doi:10.1111/j.1462-2920.2006.01227.x. PMID 17359272.  
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  132. ^ Cavicchioli R, Curmi P, Saunders N, Thomas T (2003). "Pathogenic archaea: do they exist?". Bioessays 25 (11): 1119–28. doi:10.1002/bies.10354. PMID 14579252.  
  133. ^ Lepp P, Brinig M, Ouverney C, Palm K, Armitage G, Relman D (2004). "Methanogenic Archaea and human periodontal disease". Proc Natl Acad Sci USA 101 (16): 6176–81. doi:10.1073/pnas.0308766101. PMID 15067114.  
  134. ^ Vianna ME, Conrads G, Gomes BP, Horz HP (April 2006). "Identification and quantification of archaea involved in primary endodontic infections". J. Clin. Microbiol. 44 (4): 1274–82. doi:10.1128/JCM.44.4.1274-1282.2006. PMID 16597851. PMC 1448633. http://jcm.asm.org/cgi/pmidlookup?view=long&pmid=16597851.  
  135. ^ Waters E, Hohn MJ, Ahel I, et al. (October 2003). "The genome of Nanoarchaeum equitans: insights into early archaeal evolution and derived parasitism". Proc. Natl. Acad. Sci. U.S.A. 100 (22): 12984–8. doi:10.1073/pnas.1735403100. PMID 14566062. PMC 240731. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=14566062.  
  136. ^ Jahn U, Gallenberger M, Paper W, et al. (March 2008). "Nanoarchaeum equitans and Ignicoccus hospitalis: new insights into a unique, intimate association of two archaea". J. Bacteriol. 190 (5): 1743–50. doi:10.1128/JB.01731-07. PMID 18165302. PMC 2258681. http://jb.asm.org/cgi/pmidlookup?view=long&pmid=18165302.  
  137. ^ Chaban B, Ng SY, Jarrell KF (February 2006). "Archaeal habitats—from the extreme to the ordinary". Can. J. Microbiol. 52 (2): 73–116. doi:10.1139/w05-147. PMID 16541146.  
  138. ^ Schink B (June 1997). "Energetics of syntrophic cooperation in methanogenic degradation". Microbiol. Mol. Biol. Rev. 61 (2): 262–80. PMID 9184013.  
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  141. ^ Preston, C.M; Wu, K.Y; Molinski, T.F; Delong, E.F (1996). "A psychrophilic crenarchaeon inhabits a marine sponge: Cenarchaeum symbiosum gen. nov., sp. nov". Proc Natl Acad Sci USA 93 (13): 6241–6. doi:10.1073/pnas.93.13.6241. PMID 8692799.  
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  144. ^ Wegley, L; Yu; Breitbart; Casas; Kline; Rohwer (2004). "Coral-associated Archaea" (PDF). Marine Ecology Progress Series 273: 89–96. doi:10.3354/meps273089. http://www.marine.usf.edu/genomics/PDFs%20of%20papers/wegleyetal2004.pdf.  
  145. ^ Chelius MK, Triplett EW (April 2001). "The Diversity of Archaea and Bacteria in Association with the Roots of Zea mays L". Microb. Ecol. 41 (3): 252–63. doi:10.1007/s002480000087. PMID 11391463.  
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  148. ^ a b Egorova K, Antranikian G (2005). "Industrial relevance of thermophilic Archaea". Curr. Opin. Microbiol. 8 (6): 649–55. doi:10.1016/j.mib.2005.10.015. PMID 16257257.  
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  152. ^ Norris PR, Burton NP, Foulis NA (2000). "Acidophiles in bioreactor mineral processing". Extremophiles 4 (2): 71–6. doi:10.1007/s007920050139. PMID 10805560.  
  153. ^ O'Connor EM, Shand RF (January 2002). "Halocins and sulfolobicins: the emerging story of archaeal protein and peptide antibiotics". J. Ind. Microbiol. Biotechnol. 28 (1): 23–31. doi:10.1038/sj/jim/7000190. PMID 11938468.  
  154. ^ Shand RF; Leyva KJ (2008). "Archaeal Antimicrobials: An Undiscovered Country". in Blum P (ed.). .Archaea: New Models for Prokaryotic Biology.^ Archaea: New Models for Prokaryotic Biology .
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     ^ Plasmids and Cloning vectors for Thermophilic Archaea, In: Prokaryotes from Geothermal Environments: Biology and Technology (F. Robb, A. Driessen, G. Antranikian, D. Grogan Eds).
    • Dr. Kenneth Stedman - Publications 19 January 2010 9:52 UTC web.pdx.edu [Source type: Academic]

     ^ This new appreciation of the importance and ubiquity of archaea came from using the polymerase chain reaction to detect prokaryotes in samples of water or soil from their nucleic acids alone.
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     .Caister Academic Press.^ Caister Academic Press.
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     ISBN 978-1-904455-27-1.      

Further reading

  • Howland, John L. (2000). .The Surprising Archaea: Discovering Another Domain of Life.^ PMID: 8885405 Life's third domain (Archaea): an established fact or an endangered paradigm?

     ^ Such an approach generates the Phylogenetic Tree of Life (below) that lands the procaryotes in two Domains, Archaea and Bacteria.

     ^ Genome copiy numbers were also determined for several species from the third domain of life, the archaea.
    • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

     .Oxford: Oxford University Press.^ Edited by: Sapp J. New York, Oxford University Press; 2005:160-183.
    • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

     ^ Oxford: Oxford University Press.
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     ISBN 0-19-511183-4.      
  • Martinko JM, Madigan MT (2005). .Brock Biology of Microorganisms (11th ed.^ Brock biology of microorganisms.
    • Archaea and Their Potential Role in Human Disease -- Eckburg et al. 71 (2): 591 -- Infection and Immunity 19 January 2010 9:52 UTC iai.asm.org [Source type: Academic]

     ^ Brock biology of microorganisms, 8th ed.
    • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

     ). Englewood Cliffs, N.J: Prentice Hall. ISBN 0-13-144329-1.      
  • Garrett RA, Klenk H (2005). .Archaea: Evolution, Physiology and Molecular Biology.^ The evolution of Hsp70(DnaK) in archaea is puzzling, as discussed elsewhere in this review, and challenges the imagination of evolutionary and molecular biologists and taxonomists.
    • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

     ^ Lange M, Ahring BK: A comprehensive study into the molecular methodology and molecular biology of methanogenic Archaea.
    • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

     ^ Gordon Conference on Archaea: Ecology, Metabolism and Molecular Biology .
    • Dr. Kenneth Stedman - Publications 19 January 2010 9:52 UTC web.pdx.edu [Source type: Academic]

     WileyBlackwell. ISBN 1-40-514404-1.      
  • Cavicchioli R (2007). .Archaea: Molecular and Cellular Biology.^ Escherichia coli and Salmonella typhimurium : cellular and molecular biology.
    • Coenzyme A Biosynthesis: Reconstruction of the Pathway in Archaea and an Evolutionary Scenario Based on Comparative Genomics -- Genschel 21 (7): 1242 -- Molecular Biology and Evolution 19 January 2010 9:52 UTC mbe.oxfordjournals.org [Source type: Academic]

     ^ Cellular and Molecular Biology .
    • Prediction of transcription regulatory sites in Archaea by a comparative genomic approach -- Gelfand et al. 28 (3): 695 -- Nucleic Acids Research 19 January 2010 9:52 UTC nar.oxfordjournals.org [Source type: Academic]

     ^ Bachmann BJ (1996) Derivations and genotypes of some mutant derivatives of Escherichia coli K-12, in Escherichia coli and Salmonella Cellular and Molecular Biology,.
    • PLoS ONE: Regulated Polyploidy in Halophilic Archaea 19 January 2010 9:52 UTC www.plosone.org [Source type: Academic]

     .American Society for Microbiology.^ American Society for Microbiology 99th General Meeting, May 30-June 3, 1999, Chicago, U.S.A. .
    • Dr. Kenneth Stedman - Publications 19 January 2010 9:52 UTC web.pdx.edu [Source type: Academic]

     ^ Reprinted from reference 44 with permission of the American Society for Microbiology.
    • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

     ^ AEM.01570-06 Copyright © 2007 , American Society for Microbiology .
    • Communities of Archaea and Bacteria in a Subsurface Radioactive Thermal Spring in the Austrian Central Alps, and Evidence of Ammonia-Oxidizing Crenarchaeota -- Weidler et al. 73 (1): 259 -- Applied and Environmental Microbiology 19 January 2010 9:52 UTC aem.asm.org [Source type: Academic]

     ISBN 1-55-581391-7.      
  • Blum P (editor) (2008). .Archaea: New Models for Prokaryotic Biology.^ Archaea: New Models for Prokaryotic Biology .
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     ^ Plasmids and Cloning vectors for Thermophilic Archaea, In: Prokaryotes from Geothermal Environments: Biology and Technology (F. Robb, A. Driessen, G. Antranikian, D. Grogan Eds).
    • Dr. Kenneth Stedman - Publications 19 January 2010 9:52 UTC web.pdx.edu [Source type: Academic]

     ^ This new appreciation of the importance and ubiquity of archaea came from using the polymerase chain reaction to detect prokaryotes in samples of water or soil from their nucleic acids alone.
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     .Caister Academic Press.^ Caister Academic Press.
    • Archaea (Kingdom) 19 January 2010 9:52 UTC zipcodezoo.com [Source type: Academic]

     ISBN 978-1-904455-27-1.      
  • Lipps G (2008). ."Archaeal Plasmids". Plasmids: Current Research and Future Trends.^ As pointed out above, it has been suggested that the archaeal non-phosphorylating ED pathway may be reversible [ 1 ]; future research should reveal whether alternative pathways for gluconeogenesis exist.
    • Biochem. J. (2003) 375, 231-246 - C.H. Verhees and others - Glycolysis in Archaea 19 January 2010 9:52 UTC www.biochemj.org [Source type: Academic]

     Caister Academic Press. ISBN 978-1-904455-35-6.      

External links

General
Classification
Genomics
Archaea classification
Domain : Archaea - Bacteria - Eukaryota
Crenarchaeota
Euryarchaeota
Thaumarchaeota
Other
Extremophiles
Types Deinococcus radiodurans
Notable
extremophiles
Archaea
Related articles

Wiktionary

Up to date as of January 14, 2010

Definition from Wiktionary, a free dictionary

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Wikipedia has an article on:

Contents

Translingual

Alternative forms

Etymology

.From Ancient Greek ἀρχαῖα (arkhaia), “‘ancient’”), neuter plural of ἀρχαῖος (arkhaios), “‘ancient’”).^ Word origin: New Latin, from Greek arkhaion , neuter singular of arkhaios , ancient.
  • Archaea - definition from Biology-Online.org 19 January 2010 9:52 UTC www.biology-online.org [Source type: FILTERED WITH BAYES]

 ^ Archaea - definition from Biology-Online.org Word origin: New Latin, from Greek arkhaion, neuter singular of arkhaios, ancient.
  • archae- - Search Results - MSN Encarta 24 September 2009 17:12 UTC encarta.msn.com [Source type: General]
Wikispecies-logo.svg
Wikispecies has information on:

Proper noun

Archaea
  1. A taxonomic domain of single-celled organisms lacking nuclei, formerly called archaebacteria but now known to differ fundamentally from bacteria.

Usage notes

.Whereas in the three-domain system the Archaea comprise a domain, in the short-lived two-empire system they were a kingdom in the domain (or "empire") Prokaryota.^ Mayr E: Two empires or three?
  • BioMed Central | Full text | Phylogenomic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis 19 January 2010 9:52 UTC www.biomedcentral.com [Source type: Academic]

 ^ Two empires or three?
  • Bacterial/ Prokaryotic Phylogeny 19 January 2010 9:52 UTC www.bacterialphylogeny.info [Source type: Academic]
  • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]

 ^ The three domains are bacteria, archaea and eukarya.
  • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

Synonyms

Hyponyms

Derived terms

External links


Wikispecies

Up to date as of January 23, 2010

From Wikispecies

Taxonavigation

.Main Page
Superregnum: Archaea
Phyla: Crenarchaeota - Euryarchaeota - ?^ Phylogenetic analysis of both clone libraries revealed the presence of two major lineages, belonging to the Euryarchaeota and Crenarchaeota phyla.
  • Archaea in the Earth System I Posters - Biogeosciences [B] 19 January 2010 9:52 UTC www.agu.org [Source type: Academic]

 ^ Within the archaea, there are two main divisions called crenarchaeota (4 complete genomes) and euryarchaeota (12 complete genomes).
  • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

 ^ Main page Bioremediation Ethiopian Rhizobia Rhizobial diversity Co-evolution "Petri" Guests projects Archaea   .
  • University of Helsinki - Plant-Microbe Interaction and Microbial Biodiversity - K. Lindström 19 January 2010 9:52 UTC www.biocenter.helsinki.fi [Source type: Academic]

 Korarchaeota - ?Nanoarchaeota - Thaumarchaeota

Name

Archaea

References

.
  • Becerra, A.; Delaye, L.; Islas, S.; Lazcano, A. 2007: The very early stages of biological evolution and the nature of the last common ancestor of the three major cell domains.^ The nature of the last universal common ancestor.
    • My Name is LUCA—The Last Universal Common Ancestor (ActionBioscience) 19 January 2010 9:52 UTC www.actionbioscience.org [Source type: Academic]

     ^ Features that are present in all three domains were probably present in the common ancestor.
    • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
    • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

     ^ What are the three common shapes for eubacteria cells?

     .Annual review of ecology, evolution, and systematics, 38: 361-379.
  • Brochier-Armanet, C.; Boussau, B.; Gribaldo, S.; Forterre, P. 2008: Mesophilic Crenarchaeota: proposal for a third archaeal phylum, the Thaumarchaeota.^ MOLECULAR MECHANISM OF PHOTOSIGNALING BY ARCHAEAL SENSORY RHODOPSINS Wouter D. Hoff, Kwang-Hwan Jung, and , John L. Spudich Annual Review of Biophysics and Biomolecular Structure .
    • RETINYLIDENE PROTEINS: Structures and Functions from Archaea to Humans - Annual Review of Cell and Developmental Biology, 16(1):365 - Abstract 19 January 2010 9:52 UTC arjournals.annualreviews.org [Source type: Academic]

     ^ Brochier C, Forterre P , Gribaldo S. (2005) An emerging phylogenetic core of Archaea: phylogenies of transcription and translation machineries converge following addition of new genome sequences.
    • Publications du BMGE 19 January 2010 9:52 UTC archaea.u-psud.fr [Source type: Academic]

     ^ Gribaldo, Simonetta and Brochier-Armanet, Celine.
    • Evolution of Thermophilic Archaea - MicrobeWiki 19 January 2010 9:52 UTC microbewiki.kenyon.edu [Source type: FILTERED WITH BAYES]

     .Nature reviews microbiology, 6: 245-252.
  • Brochier, C.; Gribaldo, S.; Zivanovic, Y.; Confalonieri, F.; Forterre, P. 2005: Nanoarchaea: representatives of a novel archaeal phylum or a fast-evolving euryarchaeal lineage related to Thermococcales?^ The Korarchaeota represent what could be one of the least evolved lineages of modern life that has been detected in nature so far.

     ^ Brochier C, Forterre P , Gribaldo S. (2005) An emerging phylogenetic core of Archaea: phylogenies of transcription and translation machineries converge following addition of new genome sequences.
    • Publications du BMGE 19 January 2010 9:52 UTC archaea.u-psud.fr [Source type: Academic]

     ^ Brochier C, Gribaldo S, Zivanovic Y, Confalonieri F, Forterre P (2005) Nanoarchaea: representatives of a novel archaeal phylum or a fast-evolving euryarchaeal lineage related to Thermococcales?
    • Publications du BMGE 19 January 2010 9:52 UTC archaea.u-psud.fr [Source type: Academic]

     Genome biology, 6: R42. [1]

links

.
  • Tree of Life Web Project.^ Version 01 January 1997 (temporary) in The Tree of Life Web Project Vernacular names .

     ^ If you are interested in bacterial phylogeny, or taxonomy, have a look at a magnificant web site: the Tree of Life.

     ^ According to the Tree of Life Web Project, two alternative views on the relationship of the major lineages (omitting viruses) are currently regarded as viable (right - click to enlarge image).

     1997. Archaea. Version 01 January 1997 (temporary) in The Tree of Life Web Project

Vernacular names

Alemannisch: Archaebakterie
العربية: عتائق
Asturianu: Archaea
Azərbaycan: Arxeya
Bahasa Indonesia: Archaea
Bahasa Melayu: Arkea
বাংলা: আর্কিয়া
Bân-lâm-gú: Kó͘-seng-khún
Български: Археа
Català: Arqueobacteri
Česky: Archea
Cymraeg: Archaea
Dansk: Archaea
Deutsch: Archaeen
Eesti: Arhed
English: Archaea
Español: Archaea
Esperanto: Arkioj
Euskara: Arkeobakterio
فارسی: باستانیان
Français: Archaea
Gaeilge: Aircéach
한국어: 고세균
Հայերեն: Նախակենդանիներ
हिन्दी: आर्किया
Hrvatski: Archaea
Íslenska: Forngerlar
Italiano: Archaea
עברית: חיידקים קדומים
Kapampangan: Archaea
Kiswahili: Archaea
Latina: Archaea
Lëtzebuergesch: Archaeën
Lietuvių: Archėja
Magyar: Archeák
Македонски: Археи
Nederlands: Archaea
नेपाल भाषा: आर्केया
日本語: 古細菌
‪Norsk (bokmål)‬: Arkebakterier
‪Norsk (nynorsk)‬: Arkar
Occitan: Archaea
Plattdüütsch: Archaeen
Polski: Archeowce
Português: Archaea
Runa Simi: Ñawpa añaki
Русский: Археи
Саха тыла: Архей
Simple English: Archaea
Slovenčina: Archaea
Slovenščina: Arheje
Srpskohrvatski / Српскохрватски: Arheja
Suomi: Arkkieliöt
Svenska: Arkéer
Tagalog: Archaea
தமிழ்: ஆர்க்கீயா
ไทย: อาร์เคีย
Tiếng Việt: Vi khuẩn cổ
Türkçe: Arkea
Українська: Археї
Winaray: Archaea
中文: 古菌

References

.
  • C. Woese, O. Kandler, M. Wheelis: Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.^ The three domains are bacteria, archaea and eukarya.
    • Bioc 811 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]
    • http://drnelson.utmem.edu/evolution.html 19 January 2010 9:52 UTC drnelson.utmem.edu [Source type: FILTERED WITH BAYES]

     ^ Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.
    • Bacterial/ Prokaryotic Phylogeny 19 January 2010 9:52 UTC www.bacterialphylogeny.info [Source type: Academic]
    • Stress Genes and Proteins in the Archaea -- Macario et al. 63 (4): 923 -- Microbiology and Molecular Biology Reviews 19 January 2010 9:52 UTC mmbr.asm.org [Source type: Academic]
    • Protein thermostability in Archaea and Eubacteria 19 January 2010 9:52 UTC www.funpecrp.com.br [Source type: Academic]
    • JYI.org :: Halophilic, Thermophilic, and Psychrophilic Archaea: Cellular and Molecular Adaptations and Potential Applications 19 January 2010 9:52 UTC www.jyi.org [Source type: Academic]

     ^ Compare and contrast the bacteria and archaea domains?
    • WikiAnswers - Compare archaea and eubacteria 19 January 2010 9:52 UTC wiki.answers.com [Source type: General]

     Proc. Natl. Acad. Sci. .U.S.A. 87(12): 4576-9 (1990).^ Proc Natl Acad Sci U S A. 1990 Jun; 87 (12):4576–4579.
    • Transcription in archaea: similarity to that in eucarya. 19 January 2010 9:52 UTC ukpmc.ac.uk [Source type: Academic]

     ^ Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya , Proceedings of the National Academy of Sciences USA , 87 :4576–4579, 1990.
    • Round and round we go—proposed evolutionary relationships among archaea, eubacteria, and eukarya 19 January 2010 9:52 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

     ^ Proceedings of the National Academy of Sciences 87 (12): 4576–4579.

     PMID 2112744
Wikimedia Commons For more multimedia, look at .Archaea on Wikimedia Commons.^ Archaea on Wikimedia Commons .

 ^ Category:Archaea - Wikimedia Commons .
  • Category:Archaea - Wikimedia Commons 19 January 2010 9:52 UTC commons.wikimedia.org [Source type: Reference]

 ^ Retrieved from " http://commons.wikimedia.org/wiki/Category:Archaea " Categories : Procaryota .
  • Category:Archaea - Wikimedia Commons 19 January 2010 9:52 UTC commons.wikimedia.org [Source type: Reference]

Simple English

Archaea
Fossil range: Archaean — Recent
Scientific classification
Domain: Archaea
Woese, Kandler & Wheelis, 1990
Kingdoms and phyla

Crenarchaeota
Euryarchaeota
Korarchaeota
Nanoarchaeota
Thaumarchaeota

File:Colourful Thermophilic Archaebacteria Stain in Midway Geyser
Colourful archaea at Midway Geyser.

The Archaea (or Archea) are a group of single-celled organisms. The name comes from Greek αρχαία, "old ones". Another name for them is Archaebacteria. They are a major division of living organisms.

Archaea are tiny, simple organisms. They were originally discovered in extreme environments (extremophiles), but are now thought to be common to more average conditions. Many can survive at very high (over 80 °C) or very low temperatures, or highly salty, acidic or alkaline water. Some have been found in geysers, black smokers, oil wells, and hot vents in the deep ocean. Recent research has found ammonia-eating archaea in soil and seawater. This may indicate a more important role of archaea than previously thought.

Archaea, Bacteria and Eukaryotes are the domains in the three-domain system. Archaea are, like bacteria, single-celled organisms lacking nuclei and are therefore classified as prokaryotes — known as Monera in the five-kingdom taxonomy.

Retrieved from "http://yak.rapint.com/wiki/Archaea"

Citable sentences

Up to date as of December 18, 2010

Here are sentences from other pages on Archaea, which are similar to those in the above article.








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