A mycotoxin (from the Greek μύκης mykes , "fungus" and τοξικός toxikos , "poisonous") is a toxic secondary metabolite produced by fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' is usually reserved for the toxic chemical products produced by fungi that readily colonize crops.
102-636: Archescytinidae is an extinct family of fungus -feeding thrips belonging to the order Thysanoptera that was first defined by Robert John Tillyard in 1926. They are the oldest known thrips family and they existed between the Asselian epoch of the Early Permian and the Toarcian epoch of the Early Jurassic . Fungus A fungus ( pl. : fungi or funguses ) is any member of
204-477: A gametangium , a specialized cell structure that becomes a fertile gamete -producing cell. The gametangium develops into a zygospore , a thick-walled spore formed by the union of gametes. When the zygospore germinates, it undergoes meiosis , generating new haploid hyphae, which may then form asexual sporangiospores . These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia. The spores of most of
306-421: A monophyletic origin of fungi. The taxonomy of fungi is in a state of constant flux, especially due to research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings . There is no unique generally accepted system at
408-495: A certain water activity requirement. It has become difficult to identify mycotoxin production by indoor molds for many variables, such as (i) they may be masked as derivatives, (ii) they are poorly documented, and (iii) the fact that they are likely to produce different metabolites on building materials. Some of the mycotoxins in the indoor environment are produced by Alternaria , Aspergillus (multiple forms), Penicillium , and Stachybotrys . Stachybotrys chartarum contains
510-735: A cup-shaped fruit body that is often macroscopic and holds the hymenium , a layer of tissue containing the spore-bearing cells. The fruit bodies of the basidiomycetes ( basidiocarps ) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms . The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios . Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues. They can exert large penetrative mechanical forces; for example, many plant pathogens , including Magnaporthe grisea , form
612-615: A few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies . Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g., rice blast disease ) or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little
714-496: A fungal mycelium separates into pieces, and each component grows into a separate mycelium. Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific niche , and allow more rapid dispersal than sexual reproduction. The "Fungi imperfecti" (fungi lacking the perfect or sexual stage) or Deuteromycota comprise all the species that lack an observable sexual cycle. Deuteromycota (alternatively known as Deuteromycetes, conidial fungi, or mitosporic fungi)
816-405: A high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate , ammonia , acetate , or ethanol . In some species the pigment melanin may play a role in extracting energy from ionizing radiation , such as gamma radiation . This form of " radiotrophic " growth has been described for only a few species,
918-444: A higher number of mycotoxins than other molds grown in the indoor environment and has been associated with allergies and respiratory inflammation. The infestation of S. chartarum in buildings containing gypsum board, as well as on ceiling tiles, is very common and has recently become a more recognized problem. When gypsum board has been repeatedly introduced to moisture, S. chartarum grows readily on its cellulose face. This stresses
1020-445: A history of infecting the grain of developing cereals such as wheat and maize . They include a range of mycotoxins, such as: the fumonisins , which affect the nervous systems of horses and may cause cancer in rodents ; the trichothecenes , which are most strongly associated with chronic and fatal toxic effects in animals and humans; and zearalenone , which is not correlated to any fatal toxic effects in animals or humans. Some of
1122-573: A motile zoospore , enabling them to propel themselves through water and enter their amphibian host. Other examples of aquatic fungi include those living in hydrothermal areas of the ocean. As of 2020, around 148,000 species of fungi have been described by taxonomists , but the global biodiversity of the fungus kingdom is not fully understood. A 2017 estimate suggests there may be between 2.2 and 3.8 million species. The number of new fungi species discovered yearly has increased from 1,000 to 1,500 per year about 10 years ago, to about 2,000 with
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#17327728270571224-492: A nephrotoxin, and has been linked to tumors in the human urinary tract, although research in humans is limited by confounding factors . Citrinin is a toxin that was first isolated from Penicillium citrinum , but has been identified in over a dozen species of Penicillium and several species of Aspergillus . Some of these species are used to produce human foodstuffs such as cheese ( Penicillium camemberti ), sake, miso , and soy sauce ( Aspergillus oryzae ). Citrinin
1326-402: A new haploid mycelium. Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a clamp connection , is formed at each hyphal septum. As with
1428-431: A peak of more than 2,500 species in 2016. In the year 2019, 1,882 new species of fungi were described, and it was estimated that more than 90% of fungi remain unknown. The following year, 2,905 new species were described—the highest annual record of new fungus names. In mycology, species have historically been distinguished by a variety of methods and concepts. Classification based on morphological characteristics, such as
1530-516: A process called branching , or occasionally growing hyphal tips fork, giving rise to two parallel-growing hyphae. Hyphae also sometimes fuse when they come into contact, a process called hyphal fusion (or anastomosis ). These growth processes lead to the development of a mycelium , an interconnected network of hyphae. Hyphae can be either septate or coenocytic . Septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to
1632-399: A regulated mycotoxin involves a wide array of in-laboratory testing that includes extracting, clean-up columns, and separation techniques. Most official regulations and control methods are based on high-performance liquid techniques (e.g., HPLC ) through international bodies. It is implied that any regulations regarding these toxins will be in co-ordinance with any other countries with which
1734-455: A single group of related organisms, named the Eumycota ( true fungi or Eumycetes ), that share a common ancestor (i.e. they form a monophyletic group ), an interpretation that is also strongly supported by molecular phylogenetics . This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to
1836-567: A small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g ; the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below. Other fungi, like the puffballs , rely on alternative mechanisms for spore release, such as external mechanical forces. The hydnoid fungi (tooth fungi) produce spores on pendant, tooth-like or spine-like projections. The bird's nest fungi use
1938-581: A structure called an appressorium that evolved to puncture plant tissues. The pressure generated by the appressorium, directed against the plant epidermis , can exceed 8 megapascals (1,200 psi). The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes . The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol . Adaptations such as these are complemented by hydrolytic enzymes secreted into
2040-635: A study by the Center for Disease Control (CDC) in Cleveland, Ohio , reported an association between mycotoxins from Stachybotrys spores and pulmonary hemorrhage in infants. However, in 2000, based on internal and external reviews of their data, the CDC concluded that because of flaws in their methods, the association was not proven. Stachybotrys spores in animal studies have been shown to cause lung hemorrhaging, but only at very high concentrations. One study by
2142-488: A terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism , saprobism , and the development of mutualistic relationships such as mycorrhiza and lichenization. Studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times. In May 2019, scientists reported
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#17327728270572244-668: A third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph (sexual reproduction) and the anamorph (asexual reproduction). Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules . Asexual reproduction occurs via vegetative spores ( conidia ) or through mycelial fragmentation . Mycelial fragmentation occurs when
2346-440: A toxic mixture of alkaloids in the sclerotia of species of Claviceps , which are common pathogens of various grass species. The ingestion of ergot sclerotia from infected cereals, commonly in the form of bread produced from contaminated flour, causes ergotism , the human disease historically known as St. Anthony's Fire . There are two forms of ergotism: gangrenous, affecting blood supply to extremities, and convulsive, affecting
2448-469: A trade agreement exists. Many of the standards for the method performance analysis for mycotoxins is set by the European Committee for Standardization (CEN). However, one must take note that scientific risk assessment is commonly influenced by culture and politics, which, in turn, will affect trade regulations of mycotoxins. Food-based mycotoxins were studied extensively worldwide throughout
2550-479: A type of mycotoxin produced by Aspergillus species of fungi, such as A. flavus and A. parasiticus . The umbrella term aflatoxin refers to four different types of mycotoxins produced, which are B 1 , B 2 , G 1 , and G 2 . Aflatoxin B 1 , the most toxic, is a potent carcinogen and has been directly correlated to adverse health effects, such as liver cancer , in many animal species. Aflatoxins are largely associated with commodities produced in
2652-472: Is chitin in their cell walls . Fungi, like animals, are heterotrophs ; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize . Growth is their means of mobility , except for spores (a few of which are flagellated ), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in
2754-407: Is a nonchlorinated form of Ochratoxin A (OTA) and that Ochratoxin C (OTC) is an ethyl ester form Ochratoxin A. Aspergillus ochraceus is found as a contaminant of a wide range of commodities including beverages such as beer and wine. Aspergillus carbonarius is the main species found on vine fruit, which releases its toxin during the juice making process. OTA has been labeled as a carcinogen and
2856-407: Is about mycotoxins that are found in microfungi other than poisons from mushrooms or macroscopic fungi. Buildings are another source of mycotoxins and people living or working in areas with mold increase their chances of adverse health effects. Molds growing in buildings can be divided into three groups – primary, secondary, and tertiary colonizers. Each group is categorized by the ability to grow at
2958-503: Is associated with yellowed rice disease in Japan and acts as a nephrotoxin in all animal species tested. Although it is associated with many human foods ( wheat , rice , corn , barley , oats , rye , and food colored with Monascus pigment) its full significance for human health is unknown. Citrinin can also act synergistically with Ochratoxin A to depress RNA synthesis in murine kidneys. Ergot alkaloids are compounds produced as
3060-404: Is considered to be the publication of Pier Antonio Micheli 's 1729 work Nova plantarum genera . Micheli not only observed spores but also showed that, under the proper conditions, they could be induced into growing into the same species of fungi from which they originated. Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753),
3162-663: Is destroyed by the fermentation process and so is not found in apple beverages, such as cider . Although patulin has not been shown to be carcinogenic, it has been reported to damage the immune system in animals. In 2004, the European Community set limits to the concentrations of patulin in food products. They currently stand at 50 μg/kg in all fruit juice concentrations, at 25 μg/kg in solid apple products used for direct consumption, and at 10 μg/kg for children's apple products, including apple juice. Fusarium toxins are produced by over 50 species of Fusarium and have
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3264-625: Is known of the true biodiversity of the fungus kingdom, which has been estimated at 2.2 million to 3.8 million species. Of these, only about 148,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus , Christiaan Hendrik Persoon , and Elias Magnus Fries , fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology . Advances in molecular genetics have opened
3366-645: Is not an accepted taxonomic clade and is now taken to mean simply fungi that lack a known sexual stage. Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota (genetic analysis suggests meiosis in Glomeromycota as well). It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Mating experiments between fungal isolates may identify species on
3468-413: Is one example. It has been suggested that mycotoxins in stored animal feed are the cause of rare phenotypical sex changes in hens that causes them to look and act male. Mycotoxins impact on health may be "very hard" and can be categorized in three forms "as mutagenic, carcinogenic , and genotoxic ." Mycotoxicosis is the term used for poisoning associated with exposures to mycotoxins. Mycotoxins have
3570-537: Is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy. It recognizes seven phyla , two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya , the most species rich and familiar group, including all the mushrooms, most food-spoilage molds, most plant pathogenic fungi, and
3672-427: Is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization and is likely required for hybridization between species, which has been associated with major events in fungal evolution. In contrast to plants and animals , the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include
3774-612: The Cambrian (542–488.3 Ma), also long before land plants. Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales , and existed at a time when the land flora likely consisted of only non-vascular bryophyte -like plants. Prototaxites , which was probably a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian . Fungal fossils do not become common and uncontroversial until
3876-698: The Latin fungus (mushroom), used in the writings of Horace and Pliny . This in turn is derived from the Greek word sphongos (σφόγγος 'sponge'), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German Schwamm ('sponge') and Schimmel ('mold'). The word mycology is derived from the Greek mykes (μύκης 'mushroom') and logos (λόγος 'discourse'). It denotes
3978-545: The ascomycete genus Cochliobolus , and the ascomycete Pneumocystis jirovecii . The earliest mode of sexual reproduction among eukaryotes was likely homothallism, that is, self-fertile unisexual reproduction . Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus , may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells. The frequency and relative importance of parasexual events
4080-440: The biopolymer chitin. Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates , such as damp walls and spoiled food, where they are commonly called molds . Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies . These colonies can exhibit growth shapes and colors (due to spores or pigmentation ) that can be used as diagnostic features in
4182-477: The central nervous system . Modern methods of grain cleaning have significantly reduced ergotism as a human disease; however, it is still an important veterinary problem. Ergot alkaloids have been used pharmaceutically. Patulin is a toxin produced by the P. expansum , Aspergillus , Penicillium , and Paecilomyces fungal species. P. expansum is especially associated with a range of moldy fruits and vegetables , in particular rotting apples and figs. It
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4284-455: The roots of plants. As eukaryotes, fungi possess a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks . Plants and some other organisms have an additional terpene biosynthesis pathway in their chloroplasts, a structure that fungi and animals do not have. Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants. Many of
4386-470: The tropics and subtropics , such as cotton , peanuts , spices , pistachios , and maize . According to the USDA, "They are probably the best known and most intensively researched mycotoxins in the world." Ochratoxin is a mycotoxin that comes in three secondary metabolite forms, A, B, and C. All are produced by Penicillium and Aspergillus species. The three forms differ in that Ochratoxin B (OTB)
4488-496: The 20th century. In Europe, statutory levels of a range of mycotoxins permitted in food and animal feed are set by a range of European directives and EC regulations. The U.S. Food and Drug Administration (FDA) has regulated and enforced limits on concentrations of mycotoxins in foods and feed industries since 1985. It is through various compliance programs that the FDA monitors these industries to guarantee that mycotoxins are kept at
4590-676: The Center of Integrative Toxicology at Michigan State University investigated the causes of Damp Building Related Illness (DBRI). They found that Stachybotrys is possibly an important contributing factor to DBRI. So far animal models indicate that airway exposure to S. chartarum can evoke allergic sensitization, inflammation, and cytotoxicity in the upper and lower respiratory tracts. Trichothecene toxicity appears to be an underlying cause of many of these adverse effects. Recent findings indicate that lower doses (studies usually involve high doses) can cause these symptoms. Some toxicologists have used
4692-567: The CoNTC. Mycotoxins can appear in the food chain as a result of fungal infection of crops , either by being eaten directly by humans or by being used as livestock feed. In 2004 in Kenya, 125 people died and nearly 200 others required medical treatment after eating aflatoxin -contaminated maize. The deaths were mainly associated with homegrown maize that had not been treated with fungicides or properly dried before storage. Due to food shortages at
4794-520: The Concentration of No Toxicological Concern (CoNTC) measure to represent the airborne concentration of mycotoxins that are expected to cause no hazard to humans (exposed continuously throughout a 70–yr lifetime). The resulting data of several studies have thus far demonstrated that common exposures to airborne mycotoxins in the built indoor environment are below the CoNTC, however agricultural environments have potential to produce levels greater than
4896-601: The Dutch Christiaan Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill as to be considered a founder of modern mycology. Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and microscopic characteristics, methods still used by taxonomists today. Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley , August Carl Joseph Corda , Anton de Bary ,
4998-718: The Homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the Agaricomycetes ). Two amber -preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius leggetti ) appeared during the late Cretaceous , 90 Ma. Some time after the Permian–Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments ) formed, suggesting that fungi were
5100-546: The Middle East. In a 2015 analysis of plant-based dietary supplements, the highest mycotoxin concentrations were found in milk thistle -based supplements, at up to 37 mg/kg. Some of the health effects found in animals and humans include death, identifiable diseases or health problems, weakened immune systems without specificity to a toxin, and as allergens or irritants. Some mycotoxins are harmful to other micro-organisms such as other fungi or even bacteria; penicillin
5202-487: The air over long distances. Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins ), enable efficient spore ejection. For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air. The forcible discharge of single spores termed ballistospores involves formation of
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#17327728270575304-645: The apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs. Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants —has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication . Fungi are traditionally considered heterotrophs , organisms that rely solely on carbon fixed by other organisms for metabolism . Fungi have evolved
5406-414: The basis of biological species concepts. The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia , can be used in the identification of ascomycetes and basidiomycetes, respectively. Fungi employ two mating systems : heterothallic species allow mating only between individuals of
5508-497: The basis of comparisons of the rate of evolution in closely related groups. The oldest fossilizied mycelium to be identified from its molecular composition is between 715 and 810 million years old. For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant chytrids in having flagellum-bearing spores. The evolutionary adaptation from an aquatic to
5610-877: The beer, wine, and bread yeasts. The accompanying cladogram depicts the major fungal taxa and their relationship to opisthokont and unikont organisms, based on the work of Philippe Silar, "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. 2018. The lengths of the branches are not proportional to evolutionary distances. Rozellomycetes Mitosporidium Paramicrosporidium Nucleophaga Metchnikovellea Mycotoxin Examples of mycotoxins causing human and animal illness include aflatoxin , citrinin , fumonisins , ochratoxin A , patulin , trichothecenes , zearalenone , and ergot alkaloids such as ergotamine . One mold species may produce many different mycotoxins, and several species may produce
5712-692: The brothers Louis René and Charles Tulasne , Arthur H. R. Buller , Curtis G. Lloyd , and Pier Andrea Saccardo . In the 20th and 21st centuries, advances in biochemistry , genetics , molecular biology , biotechnology , DNA sequencing , and phylogenetic analysis have provided new insights into fungal relationships and biodiversity , and have challenged traditional morphology-based groupings in fungal taxonomy . Most fungi grow as hyphae , which are cylindrical, thread-like structures 2–10 μm in diameter and up to several centimeters in length. Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by
5814-621: The cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized. Septa have pores that allow cytoplasm , organelles , and sometimes nuclei to pass through; an example is the dolipore septum in fungi of the phylum Basidiomycota. Coenocytic hyphae are in essence multinucleate supercells. Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into
5916-796: The decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. They have long been used as a direct source of human food , in the form of mushrooms and truffles ; as a leavening agent for bread; and in the fermentation of various food products, such as wine , beer , and soy sauce . Since the 1940s, fungi have been used for the production of antibiotics , and, more recently, various enzymes produced by fungi are used industrially and in detergents . Fungi are also used as biological pesticides to control weeds, plant diseases, and insect pests. Many species produce bioactive compounds called mycotoxins , such as alkaloids and polyketides , that are toxic to animals, including humans. The fruiting structures of
6018-525: The discovery of a fossilized fungus, named Ourasphaira giraldae , in the Canadian Arctic , that may have grown on land a billion years ago, well before plants were living on land. Pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) have been reported in South China. Earlier, it had been presumed that the fungi colonized the land during
6120-602: The dominant life form at this time, representing nearly 100% of the available fossil record for this period. However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. Sixty-five million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there
6222-547: The early Devonian (416–359.2 Ma), when they occur abundantly in the Rhynie chert , mostly as Zygomycota and Chytridiomycota . At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged, and all modern classes of fungi were present by the Late Carboniferous ( Pennsylvanian , 318.1–299 Ma). Lichens formed a component of the early terrestrial ecosystems, and
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#17327728270576324-412: The effects on growth rates are small, and the underlying biophysical and biochemical processes are not well known. This process might bear similarity to CO 2 fixation via visible light , but instead uses ionizing radiation as a source of energy. Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. It is estimated that
6426-427: The environment to digest large organic molecules—such as polysaccharides , proteins , and lipids —into smaller molecules that may then be absorbed as nutrients. The vast majority of filamentous fungi grow in a polar fashion (extending in one direction) by elongation at the tip (apex) of the hypha. Other forms of fungal growth include intercalary extension (longitudinal expansion of hyphal compartments that are below
6528-535: The estimated age of the oldest terrestrial lichen fossil is 415 Ma; this date roughly corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert. The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus , found permineralized with a fern from the Pennsylvanian. Rare in the fossil record are
6630-413: The food chain in meat and dairy products. Even temperature treatments, such as cooking and freezing, do not destroy some mycotoxins. In the feed and food industry, it has become common practice to add mycotoxin binding agents such as montmorillonite or bentonite clay in order to effectively adsorb the mycotoxins. To reverse the adverse effects of mycotoxins, the following criteria are used to evaluate
6732-535: The force of falling water drops to liberate the spores from cup-shaped fruiting bodies. Another strategy is seen in the stinkhorns , a group of fungi with lively colors and putrid odor that attract insects to disperse their spores. In homothallic sexual reproduction , two haploid nuclei derived from the same individual fuse to form a zygote that can then undergo meiosis . Homothallic fungi include species with an Aspergillus -like asexual stage (anamorphs) occurring in numerous different genera, several species of
6834-417: The formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus (plural asci ) is then formed, in which karyogamy (nuclear fusion) occurs. Asci are embedded in an ascocarp , or fruiting body. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores . After dispersal, the ascospores may germinate and form
6936-537: The functionality of any binding additive: Since not all mycotoxins can be bound to such agents, the latest approach to mycotoxin control is mycotoxin deactivation. By means of enzymes ( esterase , de-epoxidase ), yeast ( Trichosporon mycotoxinvorans ), or bacterial strains ( Eubacterium BBSH 797 developed by Biomin ), mycotoxins can be reduced during pre-harvesting contamination. Other removal methods include physical separation, washing, milling, nixtamalization , heat-treatment, radiation, extraction with solvents, and
7038-414: The general public due to their historical classification, as well as several similarities. Like plants, fungi often grow in soil and, in the case of mushrooms , form conspicuous fruit bodies , which sometimes resemble plants such as mosses . The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago (around
7140-411: 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 one of the traditional eukaryotic kingdoms , along with Animalia , Plantae , and either Protista or Protozoa and Chromista . A characteristic that places fungi in a different kingdom from plants , bacteria , and some protists
7242-414: The growth or the development of the fungi. Because mycotoxins weaken the receiving host, they may improve the environment for further fungal proliferation. The production of toxins depends on the surrounding intrinsic and extrinsic environments and these substances vary greatly in their toxicity, depending on the organism infected and its susceptibility, metabolism, and defense mechanisms. Aflatoxins are
7344-777: The higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature . Until relatively recent (2012) changes to the International Code of Nomenclature for algae, fungi and plants , fungal species could also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Web sites such as Index Fungorum and MycoBank are officially recognized nomenclatural repositories and list current names of fungal species (with cross-references to older synonyms ). The 2007 classification of Kingdom Fungi
7446-408: The host cells to consume nutrients. Although fungi are opisthokonts —a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum —all phyla except for the chytrids have lost their posterior flagella. Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan ) and other typical components, also contains
7548-411: The identification of species or groups. Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria solidipes , which extends over an area of more than 900 ha (3.5 square miles), with an estimated age of nearly 9,000 years. The apothecium —a specialized structure important in sexual reproduction in the ascomycetes—is
7650-508: The importance of moisture controls and ventilation within residential homes and other buildings. The negative health effects of mycotoxins are a function of the concentration , the duration of exposure, and the subject's sensitivities. The concentrations experienced in a normal home, office, or school are often too low to trigger a health response in occupants. In the 1990s, public concern over mycotoxins increased following multimillion-dollar toxic mold settlements. The lawsuits took place after
7752-416: The intense UV and cosmic radiation encountered during space travel. Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungi Batrachochytrium dendrobatidis and B. salamandrivorans , parasites that have been responsible for a worldwide decline in amphibian populations. These organisms spend part of their life cycle as
7854-607: The nature of fungal fruiting bodies , which are soft, fleshy, and easily degradable tissues, and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi. Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy . Researchers study compression fossils by dissolving
7956-401: The opposite mating type , whereas homothallic species can mate, and sexually reproduce, with any other individual or itself. Most fungi have both a haploid and a diploid stage in their life cycles. In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis , is required for the initiation of
8058-399: The other major types of Fusarium toxins include: enniatins such as beauvericin ), butenolide , equisetin , and fusarins . Although various wild mushrooms contain an assortment of poisons that are definitely fungal metabolites causing noteworthy health problems for humans, they are rather arbitrarily excluded from discussions of mycotoxicology. In such cases the distinction is based on
8160-460: The performance of farm animals and potentially kill them. Several mycotoxins reduce milk yield when ingested by dairy cattle . Contamination of medicinal plants with mycotoxins can contribute to adverse human health problems and therefore represents a special hazard. Numerous natural occurrences of mycotoxins in medicinal plants and herbal medicines have been reported from various countries including Spain, China, Germany, India, Turkey and from
8262-445: The phrase fauna and flora be replaced by fauna, flora, and funga . Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile , and have similarities in general morphology and growth habitat. Although inaccurate, the common misconception that fungi are plants persists among
8364-468: The plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and convergent evolution of these enzymes in the fungi and plants. Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations or ionizing radiation , as well as in deep sea sediments. Some can survive
8466-418: The potential for both acute and chronic health effects via ingestion, skin contact, inhalation, and entering the blood stream and lymphatic system. They inhibit protein synthesis, damage macrophage systems, inhibit particle clearance of the lung, and increase sensitivity to bacterial endotoxin. Testing for mycotoxicosis can be conducted using immunoaffinity columns. The symptoms of mycotoxicosis depend on
8568-417: The preparation of leavened bread and fermented juices. Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi. Mycology became a systematic science after the development of the microscope in the 17th century. Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology
8670-451: The researched species of fungi are transported by wind. Such species often produce dry or hydrophobic spores that do not absorb water and are readily scattered by raindrops, for example. In other species, both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as traveling through
8772-466: The resolution and added robustness to estimates of genetic diversity within various taxonomic groups. Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. The field of phytopathology ,
8874-439: The same mycotoxin. Most fungi are aerobic (use oxygen) and are found almost everywhere in extremely small quantities due to the diminutive size of their spores . They consume organic matter wherever humidity and temperature are sufficient. Where conditions are right, fungi proliferate into colonies and mycotoxin levels become high. The reason for the production of mycotoxins is not yet known; they are not necessary for
8976-460: The scientific study of fungi. The Latin adjectival form of "mycology" ( mycologicæ ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon . The word appeared in English as early as 1824 in a book by Robert Kaye Greville . In 1836 the English naturalist Miles Joseph Berkeley 's publication The English Flora of Sir James Edward Smith, Vol. 5. also refers to mycology as
9078-420: The sexual cycle. Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis ). In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook (crozier) at the hyphal septum. During cell division ,
9180-508: The size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy. Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests . The biological species concept discriminates species based on their ability to mate . The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced
9282-696: The size of the producing fungus and human intention. Mycotoxin exposure is almost always accidental whereas with mushrooms improper identification and ingestion causing mushroom poisoning is commonly the case. Ingestion of misidentified mushrooms containing mycotoxins may result in hallucinations. The cyclopeptide-producing Amanita phalloides is well known for its toxic potential and is responsible for approximately 90% of all mushroom fatalities. The other primary mycotoxin groups found in mushrooms include: orellanine , monomethylhydrazine , disulfiram-like, hallucinogenic indoles, muscarinic, isoxazole, and gastrointestinal (GI)-specific irritants. The bulk of this article
9384-598: The start of the Neoproterozoic Era). Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms: Shared features: Unique features: Most fungi lack an efficient system for the long-distance transport of water and nutrients, such as the xylem and phloem in many plants. To overcome this limitation, some fungi, such as Armillaria , form rhizomorphs , which resemble and perform functions similar to
9486-609: The structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment. A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis. The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section). In fungi formerly classified as Zygomycota , haploid hyphae of two individuals fuse, forming
9588-604: The study of fungi is known as mycology (from the Greek μύκης mykes , mushroom). In the past, mycology was regarded as a branch of botany , although it is now known that fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites . They may become noticeable when fruiting , either as mushrooms or as molds. Fungi perform an essential role in
9690-594: The study of fungi. A group of all the fungi present in a particular region is known as mycobiota (plural noun, no singular). The term mycota is often used for this purpose, but many authors use it as a synonym of Fungi. The word funga has been proposed as a less ambiguous term morphologically similar to fauna and flora . The Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN) in August 2021 asked that
9792-616: The study of plant diseases, is closely related because many plant pathogens are fungi. The use of fungi by humans dates back to prehistory; Ötzi the Iceman , a well-preserved mummy of a 5,300-year-old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder ( Fomes fomentarius ), or for medicinal purposes ( Piptoporus betulinus ). Ancient peoples have used fungi as food sources—often unknowingly—for millennia, in
9894-511: The surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details. The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some 2,400 million years ago ( Ma ); these multicellular benthic organisms had filamentous structures capable of anastomosis . Other studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on
9996-1114: The time, farmers may have been harvesting maize earlier than normal to prevent thefts from their fields, so that the grain had not fully matured and was more susceptible to infection. Spices are susceptible substrate for growth of mycotoxigenic fungi and mycotoxin production. Red chilli, black pepper, and dry ginger were found to be the most contaminated spices. Physical methods to prevent growth of mycotoxin‐producing fungi or remove toxins from contaminated food include temperature and humidity control, irradiation and photodynamic treatment. Mycotoxins can also be removed chemically and biologically using antifungal/anti‐mycotoxins agents and antifungal plant metabolites . Dimorphic fungi , which include Blastomyces dermatitidis and Paracoccidioides brasiliensis , are known causative agents of endemic systemic mycoses . There were outbreaks of dog food containing aflatoxin in North America in late 2005 and early 2006, and again in late 2011. Mycotoxins in animal fodder, particularly silage , can decrease
10098-541: The type of mycotoxin; the concentration and length of exposure; as well as age, health, and sex of the exposed individual. The synergistic effects associated with several other factors such as genetics, diet, and interactions with other toxins have been poorly studied. Therefore, it is possible that vitamin deficiency, caloric deprivation, excessive alcohol use, and infectious disease status can all have compounded effects with mycotoxins. Mycotoxins greatly resist decomposition or being broken down in digestion, so they remain in
10200-436: The use of chemical or biological agents. Irradiation methods have proven to be effective treatment against mold growth and toxin production. Many international agencies are trying to achieve universal standardization of regulatory limits for mycotoxins. Currently, over 100 countries have regulations regarding mycotoxins in the feed industry, in which 13 mycotoxins or groups of mycotoxins are of concern. The process of assessing
10302-420: The way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the first decade of the 21st century have helped reshape the classification within the fungi kingdom, which is divided into one subkingdom , seven phyla , and ten subphyla . The English word fungus is directly adopted from
10404-410: Was a dramatic increase in evidence of fungi; apparently the death of most plant and animal species led to a huge fungal bloom like "a massive compost heap". Although commonly included in botany curricula and textbooks, fungi are more closely related to animals than to plants and are placed with the animals in the monophyletic group of opisthokonts . Analyses using molecular phylogenetics support
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