Mold
Overview
Molds are fungi that grow in the form of multicellular
Multicellular organism
Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. Most life that can be seen with the the naked eye is multicellular, as are all animals and land plants.-Evolutionary history:Multicellularity has evolved independently dozens of times...

 filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

s. A connected network of these tubular branching hyphae has multiple, genetically identical nuclei
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 and is considered a single organism, referred to as a colony
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...

.

Molds do not form a specific taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 or phylogenetic grouping, but can be found in the divisions Zygomycota
Zygomycota
Zygomycota, or zygote fungi, is a phylum of fungi. The name comes from zygosporangia, where resistant spherical spores are formed during sexual reproduction. Approximately 1060 species are known. They are mostly terrestrial in habitat, living in soil or on decaying plant or animal material...

, Deuteromycota and Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...

.
Encyclopedia
Molds are fungi that grow in the form of multicellular
Multicellular organism
Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. Most life that can be seen with the the naked eye is multicellular, as are all animals and land plants.-Evolutionary history:Multicellularity has evolved independently dozens of times...

 filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

s. A connected network of these tubular branching hyphae has multiple, genetically identical nuclei
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 and is considered a single organism, referred to as a colony
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...

.

Molds do not form a specific taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 or phylogenetic grouping, but can be found in the divisions Zygomycota
Zygomycota
Zygomycota, or zygote fungi, is a phylum of fungi. The name comes from zygosporangia, where resistant spherical spores are formed during sexual reproduction. Approximately 1060 species are known. They are mostly terrestrial in habitat, living in soil or on decaying plant or animal material...

, Deuteromycota and Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...

. Some molds cause disease or food spoilage
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

, others play an important role in biodegradation
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...

 or in the production of various foods, beverages, antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

s and enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s.

Biology

There are thousands of known species of molds which include opportunistic pathogens, saprotrophs, aquatic species, and thermophile
Thermophile
A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122  °C . Many thermophiles are archaea...

s. Like all fungi, molds derive energy not through photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

 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
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

, cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 and lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...

 into simpler substances which can be absorbed by the hyphae. In this way, molds play a major role in causing decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

 of organic material, enabling the recycling of nutrients throughout ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s. Many molds also secrete mycotoxin
Mycotoxin
A mycotoxin is a toxic secondary metabolite produced by organisms of the fungus kingdom, commonly known as molds. The term ‘mycotoxin’ is usually reserved for the toxic chemical products produced by fungi that readily colonize crops...

s which, together with hydrolytic enzymes, inhibit the growth of competing microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...

s.

Molds reproduce through small spores, which may contain a single nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 or be multinucleate. Mold spores can be asexual (the products of mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...

) or sexual (the products of meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

); many species can produce both types. Mold spores may remain airborne indefinitely, may cling to clothing or fur, or may be 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
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...

 grow. A mold colony does not comprise discrete organisms, but an interconnected network of hyphae called a mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...

. 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.

Few molds can begin growing at 4 °C (39.2 °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, anti-bacterial soap and even petroleum products such as jet fuel.

Xerophilic
Xerophile
Xerophiles are extremophilic organisms that can grow and reproduce in conditions with a low availability of water, also known as water activity. Water activity is a measure of the amount of water within a substrate that an organism can use to support sexual growth. Xerophiles are often said to...

 molds use the humidity in the air as their only water source; other molds need more moisture.

Common molds

  • Acremonium
    Acremonium
    Acremonium is a genus of Fungi in the Hypocreaceae family; it was previously known as "Cephalosporium".-Description:Acremonium species are usually slow growing and are initially compact and moist. Acremonium hyphae are fine and hyaline and produce mostly simple phialides. Their conidia are usually...

  • Aspergillus
    Aspergillus
    Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli...

  • Cladosporium
    Cladosporium
    Cladosporium is a genus of fungi including some of the most common indoor and outdoor molds. Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains....

  • Fusarium
    Fusarium
    Fusarium is a large genus of filamentous fungi widely distributed in soil and in association with plants. Most species are harmless saprobes, and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health...

  • Mucor
    Mucor
    Mucor is a microbial genus of about 3000 species of moulds commonly found in soil, digestive systems, plant surfaces, and rotten vegetable matter.-Description:...

  • Penicillium
    Penicillium
    Penicillium is a genus of ascomycetous fungi of major importance in the natural environment as well as food and drug production. Members of the genus produce penicillin, a molecule that is used as an antibiotic, which kills or stops the growth of certain kinds of bacteria inside the body...

  • Rhizopus
    Rhizopus
    Rhizopus is a genus of common saprobic fungi on plants and specialized parasites on animals. They are found on a wide variety of organic substrates, including "mature fruits and vegetables", faeces, jellies, syrups, leather, bread, peanuts and tobacco. Some Rhizopus species are opportunistic agents...

  • Stachybotrys
    Stachybotrys
    Stachybotrys is a genus of molds, or asexually-reproducing, filamentous fungi. Closely related to the genus Memnoniella, most Stachybotrys species inhabit materials rich in cellulose. The genus has a widespread distribution, and contains about 50 species.The most infamous species, S. chartarum and S...

  • Trichoderma
    Trichoderma
    Trichoderma is a genus of fungi that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts.-Species:...

  • Alternaria
    Alternaria
    Alternaria is a genus of ascomycete fungi. Alternaria species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma...



Food production

The molds are a group of Aspergillus
Aspergillus
Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli...

species, notably Aspergillus oryzae
Aspergillus oryzae
Aspergillus oryzae is a filamentous fungus . It is used in Chinese and Japanese cuisine to ferment soybeans. It is also used to saccharify rice, other grains, and potatoes in the making of alcoholic beverages such as huangjiu, sake, and shōchū...

, and secondarily A. sojae
Aspergillus sojae
Aspergillus sojae is a mold species in the genus Aspergillus.In Japan it is used to make the ferment of soy sauce, the mirin and other lacto-fermented condiments like tsukemono...

, that have been cultured in eastern Asia for many centuries. They are used to ferment a soybean and wheat mixture to make soybean paste
Miso
is a traditional Japanese seasoning produced by fermenting rice, barley and/or soybeans, with salt and the fungus , the most typical miso being made with soy. The result is a thick paste used for sauces and spreads, pickling vegetables or meats, and mixing with dashi soup stock to serve as miso...

 and soy sauce. Koji molds break down the starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

 in rice, barley, sweet potatoes, etc, a process called saccharification, in the production of sake, shōchū
Shochu
is a Japanese distilled beverage. It is typically distilled from barley, sweet potatoes, or rice, though it is sometimes produced from other ingredients such as brown sugar, buckwheat or chestnut. Typically shōchū contains 25% alcohol by volume...

and other distilled spirits. Koji molds are also used in the preparation of Katsuobushi
Katsuobushi
is the Japanese name for dried, fermented, and smoked skipjack tuna .Shaved Katsuobushi and dried kelp - kombu - are the main ingredients of dashi, a broth that forms the basis of many soups and sauces in Japanese cuisine.Katsuobushi's distinct umami flavor comes from its high...

.

Red rice yeast is a product of the mold Monascus purpureus
Monascus purpureus
Monascus purpureus is a species of mold that is purplish-red in color...

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. 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
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 as effectively as certain commercial statin
Statin
Statins are a class of drugs used to lower cholesterol levels by inhibiting the enzyme HMG-CoA reductase, which plays a central role in the production of cholesterol in the liver. Increased cholesterol levels have been associated with cardiovascular diseases, and statins are therefore used in the...

 drugs.

Some sausage
Sausage
A sausage is a food usually made from ground meat , mixed with salt, herbs, and other spices, although vegetarian sausages are available. The word sausage is derived from Old French saussiche, from the Latin word salsus, meaning salted.Typically, a sausage is formed in a casing traditionally made...

s, such as salami
Salami
Salami is cured sausage, fermented and air-dried meat, originating from one of a variety of animals. Historically, salami has been popular among Southern European peasants because it can be stored at room temperature for periods of up to 10 years, supplementing a possibly meager or inconsistent...

, use starter cultures in their production, to improve flavour and reduce spoilage during curing.

Other molds that have been used in food production include:
  • Fusarium venenatum
    Fusarium venenatum
    Fusarium venenatum is a microfungus of the genus Fusarium that has a high protein content. One of its strains is used commercially for the production of the single cell protein mycoprotein....

    quorn
    Quorn
    Quorn is the leading brand of mycoprotein food product in the UK and Ireland. The mycoprotein used to produce Quorn is extracted from a fungus, Fusarium venenatum, which is grown in large vats....

  • Geotrichum candidum
    Geotrichum candidum
    Geotrichum candidum is a Fungi or mold that can act as a plant pathogen causing sour rot on peach, nectarine, tomato and carrot. It is also widely used in the production of many dairy products including many natural rind cheeses such as Camembert and other bloomy rind cheese, Saint-Nectaire, Tomme...

    cheese
    Cheese
    Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....

  • Neurospora sitophilaoncom
    Oncom
    Oncom is one of the traditional staple foods of West Javan cuisine. There are two kinds of oncom: red oncom and black oncom...

  • Penicillium
    Penicillium
    Penicillium is a genus of ascomycetous fungi of major importance in the natural environment as well as food and drug production. Members of the genus produce penicillin, a molecule that is used as an antibiotic, which kills or stops the growth of certain kinds of bacteria inside the body...

    spp. – cheese
  • Rhizomucor miehei
    Rhizomucor miehei
    Rhizomucor miehei is a species of fungus. It is commercially used to produce enzymes which can be used to produce a microbial rennet to curd milk and produce cheese.-External links:* listing...

    rennet
    Rennet
    Rennet is a complex of enzymes produced in any mammalian stomach to digest the mother's milk, and is often used in the production of cheese. Rennet contains many enzymes, including a proteolytic enzyme that coagulates the milk, causing it to separate into solids and liquid...

     for making vegetarian and other cheese
  • Rhizopus oligosporus
    Rhizopus oligosporus
    Rhizopus oligosporus is a fungus of the family Mucoraceae that is a widely used starter culture for the home production of tempeh. The spores produce fluffy, white mycelia, binding the beans together to create an edible “cake” of partly fermented soybeans.Rhizopus oligosporus produces an...

    tempeh
    Tempeh
    Tempeh , or tempe , is a traditional soy product originally from Indonesia. It is made by a natural culturing and controlled fermentation process that binds soybeans into a cake form, similar to a very firm vegetarian burger patty...

  • Ustilago maydis – filling in tortilla
    Tortilla
    In Mexico and Central America, a tortilla is a type of thin, unleavened flat bread, made from finely ground maize...

    -based foods

Drug creation

Alexander Fleming
Alexander Fleming
Sir Alexander Fleming was a Scottish biologist and pharmacologist. He wrote many articles on bacteriology, immunology, and chemotherapy...

's famous discovery of the antibiotic penicillin
Penicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....

 involved the mold Penicillium chrysogenum
Penicillium chrysogenum
Penicillium chrysogenum is common in temperate and subtropical regions and can be found on salted food products, but it is mostly found in indoor environments, especially in damp or waterdamaged buildings. It was previously known as Penicillium notatum. It has rarely been reported as a cause of...

.

Several cholesterol-lowering drugs (such as Lovastatin
Lovastatin
Lovastatin is a member of the drug class of statins, used for lowering cholesterol in those with hypercholesterolemia and so preventing cardiovascular disease...

, from Aspergillus terreus) are derived from molds.

Howard Florey made Penicillin into a miracle drug and save over 6 million lives.

The immunosuppressant drug cyclosporine, used to suppress the rejection of transplanted organs, is derived from the mold Tolypocladium inflatum
Tolypocladium inflatum
Tolypocladium inflatum is an asexual ascomycete fungus originally isolated from a Norwegian soil sample that, in certain conditions, produces ciclosporin....

.

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
Stachybotrys chartarum
Stachybotrys chartarum, also called Stachybotrys atra, Stachybotrys alternans or Stilbospora chartarum, is a black mold that produces its conidia in slime heads. It is sometimes found in soil and grain, but mostly isolated from cellulose-rich building materials in damp or water-damaged buildings. S...

, and not to all molds in general.

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.

Growth in buildings and homes

Mold growth in buildings can lead to a variety of health problems. 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. Removal of affected materials after the source of moisture has been reduced and/or eliminated may be necessary for remediation.

See also

  • Bioaerosol
    Bioaerosol
    A bioaerosol is a suspension of airborne particles that contain living organisms or were released from living organisms. These particles are very small and range in size from less than one micrometer to one hundred micrometers . Bioaerosols react to air currents and move quickly or slowly...

  • Decay
    Decomposition
    Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

  • Medicinal mushrooms
    Medicinal mushrooms
    Medicinal mushrooms are mushrooms, or mushroom extracts, that are used or studied as possible treatments for diseases. Lentinula edodes , Grifola frondosa , Ganoderma lucidum , and Cordyceps, have a history of medicinal use spanning millennia in parts of Asia...

  • Mildew
    Mildew
    Mildew refers to certain kinds of molds or fungi.In Old English, it meant honeydew , and later came to mean mildew in the modern sense of mold or fungus....

  • Mold mite
  • Mycorrhiza
    Mycorrhiza
    A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

  • Oomycete


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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