| Revision as of 20:11, 14 March 2007 editMartinBot (talk | contribs)190,136 editsm BOT - rv 68.162.220.195 (talk) to last version by Optichan← Previous edit | Revision as of 21:37, 14 March 2007 edit undo68.228.133.127 (talk) →BiologyNext edit → | ||
| Line 15: | Line 15: | ||
| ] | ] | ||
| There are thousands of known species of molds, which include ]s, exclusive ]s, aquatic species and ]s.<ref name=Sherris>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | pages= pp. 633–8 | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | id = ISBN 0838585299 }}</ref> Like all fungi, molds derive energy not through ] but from the ] matter on which they live. Typically, molds secrete hydrolytic ] from predominantly the hyphal tips. These enzymes degrade complex ] such as ], ] and ] into simpler substances which can enter the hyphae. In this way, molds play a major role in causing ] of organic material, enabling the recycling of nutrients throughout ]s. Many molds also secrete ]s which, together with hydrolytic enzymes, inhibit the growth of competing ]s. | There are thousands of known species of molds, which include ]s, exclusive ]s, aquatic species and ]s.<ref name=Sherris>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | pages= pp. 633–8 | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | id = ISBN 0838585299 }}</ref> Like all fungi, molds derive energy not through ] but from the ] matter on which they live. Typically, molds secrete hydrolytic ] from predominantly the hyphal tips. These enzymes degrade complex ] such as ], ] and ] into simpler substances which can enter the hyphae. In this way, molds play a major role in causing ] of organic material, enabling the recycling of nutrients throughout ]s. Many molds also secrete ]s which, together with hydrolytic enzymes, inhibit the growth of competing ]s. | ||
| Molds reproduce through small ].<ref name=Sherris /> Mold spores can be asexual (the products of ]) or sexual (the products of ]), and many species can produce both types. They may contain a single ] or many. Some can remain airborne indefinitely, and many are able to survive extremes of temperature and pressure. | Molds reproduce through small ].<ref name=Sherris /> Mold spores can be asexual (the products of ]) or sexual (the products of ]), and many species can produce both types. They may contain a single ] or many. Some can remain airborne indefinitely, and many are able to survive extremes of temperature and pressure. | ||
| Line 23: | Line 23: | ||
| Some molds can begin growing at temperatures as low as 2°C. When conditions do not enable growth, molds can remain alive in a dormant state, within a large range of temperatures before they die. This explains how molds can survive harsh conditions such as containers in refrigerators or inside building structure cavities. | Some molds can begin growing at temperatures as low as 2°C. When conditions do not enable growth, molds can remain alive in a dormant state, within a large range of temperatures before they die. This explains how molds can survive harsh conditions such as containers in refrigerators or inside building structure cavities. | ||
| ] molds use the humidity in the air as their only water source; other molds need more moisture. | ] molds use the humidity in the air as their only water source; other molds need more moisture.fuck you all | ||
| == Uses == | == Uses == | ||
Revision as of 21:37, 14 March 2007
 | It has been suggested that Toxic mold be merged into this article. (Discuss) Proposed since January 2007. |
Molds (or moulds, see spelling differences) include all species of microscopic fungi that grow in the form of multicellular filaments, called hyphae. In contrast, microscopic fungi that grow as single cells are called yeasts. 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.
Biology
There are thousands of known species of molds, which include opportunistic pathomgens, exclusive saprotrophs, aquatic species and thermophiles. Like all fungi, molds derive energy not through photosynthesis but from the organic matter on which they live. Typically, molds secrete hydrolytic enzymes from predominantly the hyphal tips. These enzymes degrade complex biopolymers such as starch, cefuck you llulose and lignin into simpler substances which can enter 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. Mold spores can be asexual (the products of mitosis) or sexual (the products of meiosis), and many species can produce both types. They may contain a single nucleus or many. 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, 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 surfaces. Thus buildings, being stable environments, enable mold proliferation.
Some molds can begin growing at temperatures as low as 2°C. When conditions do not enable growth, molds can remain alive in a dormant state, within a large range of temperatures before they die. This explains how molds can survive harsh conditions such as containers in refrigerators or inside building structure cavities.
Xerophilic molds use the humidity in the air as their only water source; other molds need more moisture.fuck you all
Uses
Cultured molds are used in the production of foods including cheese (Penicillium spp), tempeh (Rhizopus oligosporus), quorn (Fusarium venenatum), the black tea pu-erh and some sausages.
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.
Other molds are cultivated for their ability to produce useful substances. Aspergillus niger is used in the production of citric acid, gluconic acid and many other compounds and enzymes. Alexander Fleming's famous discovery of the antibiotic penicillin involved the mold Penicillium notatum.
The molds Neurospora crassa and Aspergillus nidulans are commonly used model organisms.
Health effects
Some mycotoxins produced by molds are harmful to all people. Other mycotoxins cause immune system responses that vary considerably, depending on the individual. The duration of exposure is a key factor in triggering immune system response. Farm animals often die or suffer from mycotoxin poisoning. Mycotoxins resist decomposition from cooking, and remain in the food chain.
Mold spores can be allergenic. When inhaled, mold spores may germinate, attaching to cells along the respiratory tract and causing further problems in those with weak immune systems. One example is Stachybotrys chartarum which has been associated with sick building syndrome.
Infection by opportunistic pathogen molds such as Penicillium marneffei and Aspergillus fumigatus is a common cause of death among immunocompromised people, including AIDS patients.
Growth in buildings
 | This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Mold" – news · newspapers · books · scholar · JSTOR (January 2007) (Learn how and when to remove this message) |
Mold colonies are commonly seen in damp areas such as basements and bathrooms, and can also grow inside building structures. Growth is fostered by moisture, especially following floods and water leaks. Mold may produce an identifiable smell. However, the main problem with the presence of mold in buildings is the inhalation of mycotoxins. After a flood or major leak, mycotoxin levels are higher in the building even after it has dried out (source: CMHC).
Food sources for molds in buildings include cellulose-based materials, such as wood, cardboard, and the paper facing on both sides of drywall, and all other kinds of organic matter, such as soap and dust. Carpet contains dust and other organic matter.
If a house has excessive mold, there is usually too much moisture in the house, possibly from the basement, a leaking roof, or leaks from plumbing pipes behind the walls. Insufficient ventilation can also enable moisture build-up. The more people in a space, the more humidity builds up. This is from normal breathing and perspiring. Mold colonies often form where ventilation is poorest, and on perimeter walls, because they are coolest, thus closest to the dew point. If there are mold problems in a house only during certain times of the year, then it is probably either too air-tight, or too drafty. Mold problems occur in airtight homes more frequently in the warmer months (when humidity reaches high levels inside the house, and moisture is trapped), and occur in drafty homes more frequently in the colder months (when warm air escapes from the living area into unconditioned space, and condenses). If a house is humidified artificially during the winter, this can create conditions favorable to mold. Moving air may prevent mold from growing since it has the same desiccating effect as lowering humidity.
There are many ways to prevent mold growth; see ventilation issues in houses.
In extreme cases of mold growth in buildings, it may be easier to condemn the building rather than clean the mold to safe levels; see Deutsche Bank Building.
See also
References
- Madigan M; Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed. ed.). Prentice Hall. ISBN 0131443291.
{{cite book}}:|author=has generic name (help);|edition=has extra text (help)CS1 maint: multiple names: authors list (link) - ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. pp. pp. 633–8. ISBN 0838585299.
{{cite book}}:|author=has generic name (help);|edition=has extra text (help);|pages=has extra text (help)CS1 maint: multiple names: authors list (link)