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.
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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.
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]
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.
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.
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.
 Bread mold is one of the most common types of mold, and can cover a loaf of bread in less than three days. |
 Mold covering a decaying peach over a period of six days. The frames were taken approximately 12 hours apart. There are 12 frames of changes. |
 Moldy nectarines that were in a refrigerator. The nectarine with black mold is also affecting the nectarine underneath. |
 A bowl of moldy strawberries after being left in a room for several days. |
 Mold cultured from dust shaken from an automotive cabin air filter. 10× objective, 15× eyepiece; each numbered tick is 122 µM. |
 Mold grown from a nasal mucus sample. 10× objective, 15× eyepiece; each numbered tick is 122 µM. |
 Mildew growing on a plastic shower curtain. 10× objective, 15× eyepiece; each numbered tick is 122 µM. |
 Stilton cheese contains edible mold. |
 A moldy tomato |
 Moldy bread |
 Detailed picture of mold on tomato |
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MOULD. (I) (0. Eng. molde, from a Teutonic root meaning to grind, reduce to powder, cf. "meal"), loose fine earth, rich in organic matter, on the surface of cultivated ground, especially the made garden soil suitable for the growth of plants. In the sense of a furry growth, consisting of minute fungi found on animal or vegetable substances exposed to damp, the word may be either an extension of "mould," earth, or an adaptation of an early "moul," with an additional d due to "mould." "Moul" is a Scandinavian word, cf. Swed. mogla, to grow musty, and the Eng. colloquial "muggy." (2) A form or pattern, particularly one by means of which plastic materials may be made into shapes, whence "moulding," the form which the material so shaped takes. The word comes through the 0. Fr. modle, molle, from Lat. modulus, a measure, or standard. The English "model" is another derivative of the same word.
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Categories: MOS-MUL | Fungi and non-flowering plants
[[File:|thumb|right|200px|Mould on the ceiling of a home]]
Mold or mould has two main meanings.
Mold or mould refers to a container used to make the shape of the required parts or products. It works either by pouring molten plastic or metal into the container, or by pressure onto a flat piece of metal.
Mould or mold is a type of tiny fungus. There are thousands of different kinds. They are often seen in wet places. Molds include all species of microscopic fungi. In contrast, microscopic fungi that grow as single cells are called yeasts.
Some molds cause disease or food spoilage. Sometimes people use them to make some kinds of cheese and antibiotics. One special kind of mold can be used to make penicillin, a common antibiotic.
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