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A mold () or mould () is one of the structures certain
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
can form. The dust-like, colored appearance of molds is due to the formation of
spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...
containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form
mushrooms A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...
; others grow as single cells and are called microfungi (for example
yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...
s). A large and
taxonomically In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given ...
diverse number of fungal species form molds. The growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a
mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...
, is considered a single
organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
. The hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls (septa) may delimit connected compartments along the hyphae, each containing one or multiple, genetically identical nuclei. The dusty texture of many molds is caused by profuse production of asexual spores ( conidia) formed by differentiation at the ends of hyphae. The mode of formation and shape of these spores is traditionally used to classify molds. Many of these spores are colored, making the fungus much more obvious to the human eye at this stage in its life-cycle. Molds are considered to be
microbes A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
and do not form a specific taxonomic or
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
grouping, but can be found in the divisions
Zygomycota Zygomycota, or zygote fungi, is a former division or phylum of the kingdom Fungi. The members are now part of two phyla: the Mucoromycota and Zoopagomycota. Approximately 1060 species are known. They are mostly terrestrial in habitat, living ...
and Ascomycota. In the past, most molds were classified within the Deuteromycota. Mold had been used as a common name for now non-fungal groups such as water molds or
slime molds Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic mu ...
that were once considered fungi. Molds cause
biodegradation Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegrada ...
of natural materials, which can be unwanted when it becomes
food spoilage Food spoilage is the process where a food product becomes unsuitable to ingest by the consumer. The cause of such a process is due to many outside factors as a side-effect of the type of product it is, as well as how the product is packaged and s ...
or damage to property. They also play important roles in biotechnology and food science in the production of various pigments, foods, beverages, antibiotics, pharmaceuticals and
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s. Some diseases of animals and humans can be caused by certain molds: disease may result from allergic sensitivity to mold spores, from growth of
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
ic molds within the body, or from the effects of ingested or inhaled toxic compounds (
mycotoxin A mycotoxin (from the Greek μύκης , "fungus" and τοξίνη , "toxin") is a toxic secondary metabolite produced by organisms of kingdom Fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' ...
s) produced by molds.


Biology

There are thousands of known species of mold fungi with diverse life-styles including
saprotroph Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...
s, mesophiles,
psychrophile Psychrophiles or cryophiles (adj. ''psychrophilic'' or ''cryophilic'') are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from to . They have an optimal growth temperature at . They are found in ...
s and
thermophile A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...
s, and a very few
opportunistic pathogen An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...
s of humans. They all require moisture for growth and some live in aquatic environments. Like all fungi, molds derive energy not through
photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
but from the organic matter on which they live, utilizing
heterotroph A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...
y. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips. These enzymes degrade complex
biopolymers Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, c ...
such as starch,
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
and lignin into simpler substances which can be absorbed by the hyphae. In this way, molds play a major role in causing
decomposition Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is e ...
of organic material, enabling the recycling of nutrients throughout
ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
s. Many molds also synthesize
mycotoxin A mycotoxin (from the Greek μύκης , "fungus" and τοξίνη , "toxin") is a toxic secondary metabolite produced by organisms of kingdom Fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' ...
s and
siderophore Siderophores (Greek: "iron carrier") are small, high-affinity iron- chelating compounds that are secreted by microorganisms such as bacteria and fungi. They help the organism accumulate iron. Although a widening range of siderophore functions is n ...
s which, together with
lytic The lytic cycle ( ) is one of the two cycles of viral reproduction (referring to bacterial viruses or bacteriophages), the other being the lysogenic cycle. The lytic cycle results in the destruction of the infected cell and its membrane. Bacter ...
enzymes, inhibit the growth of competing
microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s. Molds can also grow on stored food for animals and humans, making the food unpalatable or toxic and are thus a major source of food losses and illness. Many strategies for food preservation (salting, pickling, jams, bottling, freezing, drying) are to prevent or slow mold growth as well as the growth of other microbes. Molds reproduce by producing large numbers of small
spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...
, which may contain a single
nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...
or be
multinucleate Multinucleate cells (also known as multinucleated or polynuclear cells) are eukaryotic cells that have more than one nucleus per cell, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordina ...
. Mold spores can be asexual (the products of mitosis) or sexual (the products of
meiosis Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately r ...
); many species can produce both types. Some molds produce small,
hydrophobic In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, t ...
spores that are adapted for wind dispersal and may remain airborne for long periods; in some the cell walls are darkly pigmented, providing resistance to damage by
ultraviolet radiation Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
. Other mold spores have slimy sheaths and are more suited to water dispersal. Mold spores are often spherical or ovoid single cells, but can be multicellular and variously shaped. Spores may cling to clothing or fur; some are able to survive extremes of temperature and pressure. Although molds can grow on dead organic matter everywhere in nature, their presence is visible to the unaided eye only when they form large
colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...
. A mold colony does not consist of discrete organisms but is an interconnected network of hyphae called a
mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...
. All growth occurs at hyphal tips, with
cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...
and organelles flowing forwards as the hyphae advance over or through new food sources. Nutrients are absorbed at the hyphal tip. In artificial environments such as 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 temperatures of or below, so food is typically
refrigerated The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...
at this temperature. When conditions do not enable growth to take place, molds may remain alive in a dormant state depending on the species, within a large range of temperatures. 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 molds are able to grow in relatively dry, salty, or sugary environments, where
water activity Water activity (''aw'') is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same tempe ...
(aw) is less than 0.85; other molds need more moisture.


Common molds

Common genera of molds include: * ''
Acremonium ''Acremonium'' is a genus of fungi in the family Hypocreaceae. It used to be known as ''Cephalosporium''. Description ''Acremonium'' species are usually slow-growing and are initially compact and moist. Their hyphae are fine and hyaline, and pro ...
'' * ''
Alternaria ''Alternaria'' is a genus of Deuteromycetes fungi. All 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. They ...
'' * ''
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. Viewing the fungi under a microscope, Mic ...
'' * ''
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. Many species ...
'' * ''
Fusarium ''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...
'' * ''
Mucor ''Mucor'' is a microbial genus of approximately 40 species of molds in the family Mucoraceae. Species are commonly found in soil, digestive systems, plant surfaces, some cheeses like Tomme de Savoie, rotten vegetable matter and iron oxide re ...
'' * ''
Penicillium ''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production. Some members of the genus produce pe ...
'' * ''
Rhizopus ''Rhizopus'' is a genus of common saprophytic fungi on plants and specialized parasites on animals. They are found in a wide variety of organic substances, including "mature fruits and vegetables", jellies, syrups, leather, bread, peanuts, and ...
'' * '' Stachybotrys'' * ''
Trichoderma ''Trichoderma'' is a genus of fungi in the family Hypocreaceae 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. This ref ...
'' * ''
Trichophyton ''Trichophyton'' is a genus of fungi, which includes the parasitic varieties that cause tinea, including athlete's foot, ringworm, jock itch, and similar infections of the nail, beard, skin and scalp. Trichophyton fungi are molds characterize ...
''


Food production

The molds are a group of ''
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. Viewing the fungi under a microscope, Mic ...
'' species, notably '' Aspergillus oryzae'', and secondarily '' A. sojae'', 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. ''Koji'' molds break down the starch in rice, barley, sweet potatoes, etc., a process called
saccharification In chemistry, saccharification is a term for denoting any chemical change wherein a monosaccharide molecule remains intact after becoming unbound from another saccharide. For example, when a carbohydrate is broken into its component sugar molecul ...
, in the production of ''
sake Sake, also spelled saké ( ; also referred to as Japanese rice wine), is an alcoholic beverage of Japanese origin made by fermenting rice that has been polished to remove the bran. Despite the name ''Japanese rice wine'', sake, and indee ...
'', '' shōchū'' and other distilled spirits. ''Koji'' molds are also used in the preparation of Katsuobushi.
Red rice yeast Red yeast rice (), red rice ''koji'' (べにこうじ, lit. 'red ''koji), red fermented rice, red kojic rice, red ''koji'' rice, ''anka'', or ''angkak'', is a bright reddish purple fermented rice, which acquires its color from being cultivate ...
is a product of the mold ''
Monascus purpureus ''Monascus purpureus'' (syn. ''M. albidus'', ''M. anka'', ''M. araneosus'', ''M. major'', ''M. rubiginosus'', and ''M. vini''; , lit. "red yeast") is a species of mold that is purplish-red in color. It is also known by the names ang-khak rice mo ...
'' grown on rice, and is common in Asian diets. The yeast contains several compounds collectively known as
monacolin Monacolins are a group of compounds found in yeast species: * Monacolin J * Monacolin K or lovastatin Lovastatin, sold under the brand name Mevacor among others, is a statin medication, to treat high blood cholesterol and reduce the risk of c ...
s, which are known to inhibit cholesterol synthesis. A study has shown that red rice yeast used as a dietary supplement, combined with fish oil and healthy lifestyle changes, may help reduce "bad"
cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
as effectively as certain commercial
statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...
drugs. Nonetheless, other work has shown it may not be reliable (perhaps due to non-standardization) and even toxic to liver and kidneys. Some
sausage A sausage is a type of meat product usually made from ground meat—often pork, beef, or poultry—along with salt, spices and other flavourings. Other ingredients, such as grains or breadcrumbs may be included as fillers or extenders. ...
s, such as
salami Salami ( ) is a cured sausage consisting of fermented and air-dried meat, typically pork. Historically, salami was popular among Southern, Eastern, and Central European peasants because it can be stored at room temperature for up to 45 days ...
, incorporate starter cultures of molds to improve flavor and reduce bacterial spoilage during curing. '' Penicillium nalgiovense'', for example, may appear as a powdery white coating on some varieties of dry-cured sausage. Other molds that have been used in food production include: * ''
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. ''Fusarium venenatum'' was discover ...
'' –
quorn Quorn is a brand of meat substitute products, or the company that makes them. Quorn originated in the UK and is sold primarily in Europe, but is available in 14 countries. The brand is owned by parent company Monde Nissin. Quorn is sold as b ...
* ''
Geotrichum candidum ''Geotrichum candidum'' is a fungus which is a member of the human microbiome, notably associated with skin, sputum, and faeces where it occurs in 25–30% of specimens. It is common in soil and has been isolated from soil collected around the w ...
'' – cheese * ''
Neurospora sitophila ''Neurospora sitophila'' is a species of fungus also known as red bread fungus or orange bread fungus. It is a mold that spoils various foods and is responsible for occupational asthma in the wood and cork industry. Classification ''Chrysoni ...
'' –
oncom Oncom ( Aksara Sunda: ; IPA: ) is one of the traditional staple foods of West Java ( Sundanese) cuisine of Indonesia. There are two kinds of oncom: red oncom and black oncom. Oncom is closely related to tempeh; both are foods fermented using mold. ...
* ''
Penicillium ''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production. Some members of the genus produce pe ...
'' spp. – various cheeses including
Brie Brie (; ) is a soft cow's-milk cheese named after Brie, the French region from which it originated (roughly corresponding to the modern ''département'' of Seine-et-Marne). It is pale in color with a slight grayish tinge under a rind of white mo ...
and Blue cheese * ''
Rhizomucor miehei ''Rhizomucor miehei'' (also: ''Mucor miehei'' ) is a species of fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar ...
'' – microbial rennet for making vegetarian and other cheeses * ''
Rhizopus oligosporus ''Rhizopus oligosporus'' is a fungus of the family Mucoraceae and is a widely used starter culture for the production of tempeh at home and industrially. As the mold grows it produces fluffy, white mycelia, binding the beans together to create ...
'' –
tempeh Tempeh or tempe (; jv, ꦠꦺꦩ꧀ꦥꦺ, témpé, ) is a traditional Indonesian food made from fermented soybeans. It is made by a natural culturing and controlled fermentation process that binds soybeans into a cake form. A fungus, '' Rhiz ...
* ''
Rhizopus oryzae ''Rhizopus oryzae'' is a filamentous heterothallic microfungus that occurs as a saprotroph in soil, dung, and rotting vegetation. This species is very similar to ''Rhizopus stolonifer'', but it can be distinguished by its smaller sporangia and a ...
'' – tempeh, jiuqu for
jiuniang ''Jiuniang'' ( zh, s=酒酿, t=酒釀, also called ''láozāo'' (), ''jiāngmǐjiǔ'' (), or ''tiánbáijiǔ'' () in Yunnan) is a sweet, soup- or pudding-like dish in Chinese cuisine. It is also known as sweet wine or sweet rice wine. It consis ...
or precursor for making Chinese rice wine


Pharmaceuticals from molds

Alexander Fleming's accidental discovery of the antibiotic penicillin involved a ''
Penicillium ''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production. Some members of the genus produce pe ...
'' mold called ''Penicillium rubrum'' (although the species was later established to be ''
Penicillium rubens ''Penicillium rubens'' is a species of fungus in the genus ''Penicillium'' and was the first species known to produce the antibiotic penicillin. It was first described by Philibert Melchior Joseph Ehi Biourge in 1923. For the discovery of penici ...
''). Fleming continued to investigate Penicillin, showing that it could inhibit various types of bacteria found in infections and other ailments, but he was unable to produce the compound in large enough amounts necessary for production of a medicine. His work was expanded by a team at Oxford University; Clutterbuck, Lovell, and Raistrick, who began to work on the problem in 1931. This team was also unable to produce the pure compound in any large amount, and found that the purification process diminished its effectiveness and negated the anti-bacterial properties it had. Howard Florey, Ernst Chain,
Norman Heatley Norman George Heatley OBE (10 January 1911 – 5 January 2004) was an English biologist and biochemist. He was a member of the team of Oxford University scientists who developed penicillin. Norman Heatley developed the back-extraction technique ...
,
Edward Abraham Sir Edward Penley Abraham, (10 June 1913 – 8 May 1999) was an English biochemist instrumental in the development of the first antibiotics penicillin and cephalosporin. Early life and education Abraham was born on 10 June 1913 at 47 Sout ...
, also all at Oxford, continued the work. They enhanced and developed the concentration technique by using organic solutions rather than water, and created the "Oxford Unit" to measure penicillin concentration within a solution. They managed to purify the solution, increasing its concentration by 45–50 times, but found that a higher concentration was possible. Experiments were conducted and the results published in 1941, though the quantities of Penicillin produced were not always high enough for the treatments required. As this was during the Second World War, Florey sought USA Government involvement. With research teams in the UK and some in the US, industrial-scale production of crystallized penicillin was developed during 1941–1944 by the
USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...
and by Pfizer. Several
statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...
cholesterol-lowering drugs (such as
lovastatin Lovastatin, sold under the brand name Mevacor among others, is a statin medication, to treat high blood cholesterol and reduce the risk of cardiovascular disease. Its use is recommended together with lifestyle changes. It is taken by mouth. ...
, from ''Aspergillus terreus'') are derived from molds. The immunosuppressant drug
cyclosporine Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease ...
, used to suppress the rejection of transplanted organs, is derived from the mold ''
Tolypocladium inflatum ''Tolypocladium inflatum'' is an ascomycete fungus originally isolated from a Norwegian soil sample that, under certain conditions, produces the immunosuppressant drug ciclosporin. In its sexual stage ( teleomorph) it is a parasite on scarab b ...
''.


Health effects

Molds are
ubiquitous Omnipresence or ubiquity is the property of being present anywhere and everywhere. The term omnipresence is most often used in a religious context as an attribute of a deity or supreme being, while the term ubiquity is generally used to describ ...
, 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 home exposure, may be particularly harmful. Research on the health impacts 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.Indoor Environmental Quality: Dampness and Mold in Buildings
. National Institute for Occupational Safety and Health. August 1, 2008.
Mold in the home can usually be found in damp, dark or steamy areas, e.g. bathrooms, kitchens, 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. Molds can also pose a hazard to human and animal health when they are consumed following the growth of certain mold species in stored food. Some species produce toxic secondary metabolites, collectively termed
mycotoxin A mycotoxin (from the Greek μύκης , "fungus" and τοξίνη , "toxin") is a toxic secondary metabolite produced by organisms of kingdom Fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' ...
s, including
aflatoxin Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly ''Aspergillus'' species. The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, sweetcorn ...
s,
ochratoxin Ochratoxins are a group of mycotoxins produced by some ''Aspergillus'' species (mainly ''A. ochraceus'' and A. ''carbonarius'', but also by 33% of ''A. niger'' industrial strains) and some ''Penicillium'' species, especially ''P. verrucosum''. ...
s,
fumonisin The fumonisins are a group of mycotoxins derived from ''Fusarium'' and their Liseola section. They have strong structural similarity to sphinganine, the backbone precursor of sphingolipids. More specifically, it can refer to: * Fumonisin B1 * Fum ...
s,
trichothecene The trichothecenes are a large family of chemically related mycotoxins. They are produced by various species of ''Fusarium'', ''Myrothecium'', ''Trichoderma''/''Podostroma'', '' Trichothecium'', ''Cephalosporium'', '' Verticimonosporium'', and ''S ...
s, citrinin, and
patulin Patulin is an organic compound classified as a polyketide. It is a white powder soluble in acidic water and in organic solvents. It is a lactone that is heat-stable, so it is not destroyed by pasteurization or thermal denaturation.http://www.s ...
. These toxic properties may be used for the benefit of humans when the toxicity is directed against other organisms; for example, penicillin adversely affects the growth of Gram-positive bacteria (e.g. Clostridium species), certain
spirochetes A spirochaete () or spirochete is a member of the phylum Spirochaetota (), (synonym Spirochaetes) which contains distinctive diderm (double-membrane) gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or ...
and certain
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
.


Growth in buildings and homes

Mold growth in buildings generally occurs as fungi colonize porous building materials, such as wood. Many building products commonly incorporate paper, wood products, or solid wood members, such as paper-covered drywall, wood cabinets, and insulation. Interior mold colonization can lead to a variety of health problems as microscopic airborne reproductive spores, analogous to tree pollen, are inhaled by building occupants. High quantities of indoor airborne spores as compared to exterior conditions are strongly suggestive of indoor mold growth. Determination of airborne spore counts is accomplished by way of an air sample, in which a specialized pump with a known flow rate is operated for a known period of time. To account for background levels, air samples should be drawn from the affected area, a control area, and the exterior. The air sampler pump draws in air and deposits microscopic airborne particles on a culture medium. The medium is cultured in a laboratory and the fungal genus and species are determined by visual microscopic observation. Laboratory results also quantify fungal growth by way of a spore count for comparison among samples. The pump operation time is recorded and when multiplied by pump flow rate results in a specific volume of air obtained. Although a small volume of air is actually analyzed, common laboratory reports extrapolate the spore count data to estimate spores that would be present in a cubic meter of air. Mold spores are drawn to specific environments, making it easier for them to grow. These spores will usually only turn into a full-blown outbreak if certain conditions are met. 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. Air filtration reduces the number of spores available for germination, especially when a High Efficiency Particulate Air (HEPA) filter is used. A properly functioning AC unit also reduces the relative humidity in rooms. The United States Environmental Protection Agency (EPA) currently recommends that relative humidity be maintained below 60%, ideally between 30% to 50%, to inhibit mold growth. Eliminating the moisture source is the first step at fungal remediation. Removal of affected materials may also be necessary for remediation, if materials are easily replaceable and not part of the load-bearing structure. Professional drying of concealed wall cavities and enclosed spaces such as cabinet toekick spaces may be required. Post-remediation verification of moisture content and fungal growth is required for successful remediation. Many contractors perform post-remediation verification themselves, but property owners may benefit from independent verification.


Use in art

Various artists have used mold in various artistic fashions. Daniele Del Nero, for example, constructs scale models of houses and office buildings and then induces mold to grow on them, giving them an unsettling, reclaimed-by-nature look. Stacy Levy sandblasts enlarged images of mold onto glass, then allows mold to grow in the crevasses she has made, creating a macro-micro portrait.
Sam Taylor-Johnson Samantha Louise Taylor-Johnson OBE (née Taylor-Wood; 4 March 1967) is a British filmmaker and photographer. Her directorial feature film debut was 2009's ''Nowhere Boy'', a film based on the childhood experiences of The Beatles songwriter an ...
, director of ''Nowhere Boy'' and ''Fifty Shades of Grey'' (among others), has made a number of time-lapse films capturing the gradual decay of classically arranged still lifes.


See also

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Slime mold Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic mul ...
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Water mold Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result ...


References


External links


The EPA's guide to mold
{{Authority control Fungus common names Articles containing video clips