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Moldy peach

Molds (or moulds; see spelling differences) include all species of microscopic fungi that grow in the form of multicellular filaments, called hyphae.[1] In contrast, microscopic fungi that grow as single cells are called yeasts. A connected network of these tubular branching hyphae has multiple, genetically identical nuclei and is considered a single organism, referred to as a colony or in more technical terms a mycelium.

Molds do not form a specific taxonomic or phylogenetic grouping, but can be found in the divisions Zygomycota, Deuteromycota and Ascomycota. Although some molds cause disease or food spoilage, others are useful for their role in biodegradation or in the production of various foods, beverages, antibiotics and enzymes.

Contents

Biology

There are thousands of known species of molds, which include opportunistic pathogens, saprotrophs, aquatic species, and thermophiles.[2] Like all fungi, molds derive energy not through photosynthesis but from the organic matter in which they live. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips. These enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way, molds play a major role in causing decomposition of organic material, enabling the recycling of nutrients throughout ecosystems. Many molds also secrete mycotoxins which, together with hydrolytic enzymes, inhibit the growth of competing microorganisms.

Molds reproduce through small spores,[2] which may contain a single nucleus or be multinucleate. Mold spores can be asexual (the products of mitosis) or sexual (the products of meiosis); many species can produce both types. Some can remain airborne indefinitely, and many are able to survive extremes of temperature and pressure.

Although molds grow on dead organic matter everywhere in nature, their presence is only visible to the unaided eye when mold colonies grow. A mold colony does not comprise discrete organisms, but an interconnected network of hyphae called a mycelium. Nutrients and in some cases organelles may be transported throughout the mycelium. In artificial environments like buildings, humidity and temperature are often stable enough to foster the growth of mold colonies, commonly seen as a downy or furry coating growing on food or other surfaces.

Many molds can begin growing at 4 °C (39 °F), the temperature within a typical refrigerator, or less. When conditions do not enable growth, molds may remain alive in a dormant state depending on the species, within a large range of temperatures before they die. The many different mold species vary enormously in their tolerance to temperature and humidity extremes. Certain molds can survive harsh conditions such as the snow-covered soils of Antarctica, refrigeration, highly acidic solvents, and even petroleum products such as jet fuel.

Xerophilic molds use the humidity in the air as their only water source; other molds need more moisture. Mold has a musty odor.

Common molds

Uses

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Food production

Cultured molds are used in the production of foods, including:

The koji molds are a group of Aspergillus species, notably Aspergillus oryzae, that have been cultured in eastern Asia for many centuries. They are used to ferment a soybean and wheat mixture to make soybean paste and soy sauce. They are also used to break down the starch in rice (saccharification) in the production of sake and other distilled spirits.

Red rice yeast is a product of the mold Monascus purpureus grown on rice, and is common in Asian diets. The yeast contains several compounds collectively known as monacolins, which are known to inhibit cholesterol synthesis.[4] According to a study published in the journal Mayo Clinic Proceedings by Dr. David Becker, red rice yeast used as a dietary supplement, combined with fish oil and healthy lifestyle changes, may help reduce "bad" cholesterol as effectively as certain commercial statin drugs.[5]

Drug creation

Alexander Fleming's famous discovery of the antibiotic penicillin involved the mold Penicillium chrysogenum.

Several cholesterol-lowering drugs (such as Lovastatin, from Aspergillus terreus) are derived from molds.

The immunosuppressant drug cyclosporine, used to suppress the rejection of transplanted organs, is derived from the mold Tolypocladium inflatum.

Health effects

Molds are ubiquitous in nature, and mold spores are a common component of household and workplace dust. However, when mold spores are present in large quantities, they can present a health hazard to humans, potentially causing allergic reactions and respiratory problems.

Some molds also produce mycotoxins that can pose serious health risks to humans and animals. Some studies claim that exposure to high levels of mycotoxins can lead to neurological problems and in some cases death. Prolonged exposure, e.g. daily workplace exposure, may be particularly harmful. Research on the health effects of mold has not been conclusive. The term "toxic mold" refers to molds that produce mycotoxins, such as Stachybotrys chartarum, and not to all molds in general.[6]

Mold in the home can usually be found in damp, dark or steam filled areas e.g. bathroom or kitchen, cluttered storage areas, recently flooded areas, basement areas, plumbing spaces, areas with poor ventilation and outdoors in humid environments. Symptoms caused by mold allergy are watery, itchy eyes, a chronic cough, headaches or migraines, difficulty breathing, rashes, tiredness, sinus problems, nasal blockage and frequent sneezing. In extremely rare cases, over-exposure to mold may result in bucal mold growth leading to death by asphyxiation.

Growth in buildings and homes

Mold growth in buildings can lead to a variety of health issues. Various practices can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels that can facilitate mold growth.[6] Removal of affected materials after the source of moisture has been reduced and/or eliminated may be necessary for remediation.

Gallery

See also

References

  1. ^ Madigan M; Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0131443291. OCLC 57001814. 
  2. ^ a b Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 633–8. ISBN 0838585299. 
  3. ^ L. H. Stahnke, L. O. Sunesen (2003-11). "Mould starter cultures for dry sausages—selection, application and effects". Meat Science 65 (3): 935–948. doi:10.1016/S0309-1740(02)00281-4. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T9G-48V817P-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=d49cf5f0622cb4266ceba3c7f36fa924. Retrieved 2008-06-06. 
  4. ^ "Red yeast rice (Monascus purpureus)". Mayo Clinic. 2009-09-01. http://www.mayoclinic.com/health/red-yeast-rice/NS_patient-redyeast. Retrieved 2010-02-01. 
  5. ^ "Study: Red Rice Yeast Helps Cut Bad Cholesterol". National Public Radio. 2008-07-01. http://www.npr.org/templates/story/story.php?storyId=92103272. Retrieved 2010-02-01. 
  6. ^ a b Indoor Environmental Quality: Dampness and Mold in Buildings. National Institute for Occupational Safety and Health. August 1, 2008.

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

MOLD (formerly Mould, Welsh Y Wyddgrug, a conspicuous barrow, Lat. Mons altus, the translation of the Welsh name), a market town, contributory parliamentary borough of Flintshire, N. Wales; on the London & North-Western railway (Chester and Denbigh branch), 182 m. from London and i i m. from Chester. Pop. of urban district (1901), 4263. The locality is populous owing to the collieries and lead-smelting works in the vicinity. At the north end of the town there is a height, Bailey Hill (perhaps from ballia, the architectural term applied to fortified castle courts). This hill, partly natural and partly artificial, was once the site of a Roman fortification, and in old records is known as Moaldes, Monhault, or Monthault (de monte alto). Mold Castle was probably built by Robert Monthault (temp. William Rufus), was taken and destroyed by Owen Gwynedd in 1144-1145, its site lost to the English and retaken by Llewelyn ap Iowerth in 1201, and by Gruffydd Llwyd in 1322. On this site, too, where there are now no remains of any fortress, were found, in 1849, some 15 skeletons, supposed to be of the 13th or 14th centuries. Maes Garmon (the battlefield of Germanus) is about a mile west of Mold. Here, as is supposed, the "Alleluia Victory" was gained over the Picts and Scots by Lupus and Germanus, bishop of Auxerre, according to some about A.D. 430, but others give A.D. 448, the date of the saint's death. A commemorative obelisk was erected on the Maes by N. Griffith of Rhual (1736). Over a mile south of Mold, on the right of the road to Nerquis, is the "Tower" (15th century, but perhaps restored in the 18th), where, in 1465 or 1 475, the royal chieftain, Rheinallt ab Gruffyd ad Bleddyn, hanged Robert Byrne, mayor of Chester, and subsequently burned alive some 200 Chester folk who tried to 'arrest him. Many tumuli are visible round Mold.


Mold county gaol, bought in 1880 by Jesuits expelled from France, was by them named St Germanus's House. St Mary's church, a Gothic building, is mentioned as early as the time of Henry VII. Its important collieries and lead mines; fire-brick, tile, earthenware, mineral oil, tinplate and nail manufactures, tanneries, breweries and malt-houses, have made Mold the business centre of the county. About 4 m. distant is Cilcain village, of which the church has a carved oak roof, stolen from Basingwerk Abbey at the dissolution of the monasteries. Among the neighbouring Clwyd hills Moel Fammau and Moel Arthur are specially noticeable. On the summit of the former is George III.'s jubilee pyramid. The Ordovices and the Romans fortified Moel Arthur. The sites of seven posts established against Rome may be traced along the hills bounding Flintshire and Denbighshire.


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