Difference between revisions of "Fungus" - New World Encyclopedia

Latest revision as of 08:09, 4 December 2023

Fungi

Orange saprotrophic fungus.

Scientific classification

Domain:	Eukaryota
Kingdom:	Fungi L., 1753

Divisions

Chytridiomycota
Zygomycota
Glomeromycota
Ascomycota
Basidiomycota
Deuteromycota

Fungus growing on a tree in Borneo

Fungi (singular fungus) make up one of the kingdoms into which living things are divided by biologists. A fungus is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells.

Fungi differ from bacteria in having a cell nucleus; from plants in not making their own food through photosynthesis; and from animals in not being mobile and in absorbing nutrition externally rather than internally. Fungi include mushrooms, yeasts, molds, mildews, and others.

Although often unnoticed or misunderstood by humans, fungi play a vital role in the earth's ecosystems and are used extensively by humans. Fungi are the primary decomposers of dead plant and animal matter in many ecosystems, and are commonly seen on old bread as mold. Yeasts are responsible for fermentation of beer and bread, and mushroom farming is a large industry in many countries.

Fungi's mutualistic symbiotic relationship with other organisms and most land plants is reflective of an underlying harmony in biological interactions and the universal principle of bi-level functionality.

Structure

Fungi may be single-celled or multicellular.

Multicellular fungi are composed of networks of long hollow tubes called hyphae. The hyphae often aggregate in a dense network known as mycelium. The mycelium grows through the medium on which the fungus feeds. Because fungi are embedded in the medium in which they grow, most often soil, they are often not visible.

Although fungi lack true organs, the mycelia may become organized into more complex reproductive structures called fruiting bodies, or sporocarps, when conditions are right. "Mushroom" is the common name given to the above-ground fruiting bodies of many fungal species. Although these above-ground structures are the most conspicuous to humans, they make up only a small portion of the entire fungal body.

Some fungi form rhizoids, which are underground, root-like structures that provide support and transport nutrients from the soil to the rest of the mycelium.

The largest organism in the world is said to be a single Armillaria ostoyae individual growing in a forest in eastern Oregon. The underground mycelial network may cover as much as 2,200 acres.

Hyphae as seen under a log

Types of fungi

The major divisions (phyla) of fungi are mainly classified based on their sexual reproductive structures. Currently, five main divisions are recognized:

The Chytridiomycota are commonly known as chytrids. These fungi produce zoospores that are capable of moving on their own by simple flagella.
The Zygomycota are known as zygomycetes and reproduce sexually. Black bread mold (Rhizopus stolonifer) is a common species that belongs to this group. Another is Pilobolus, which shoots specialized structures through the air for several meters.
Members of the Glomeromycota are also known as the arbuscular mycorrhizal fungi. Only one species has been observed forming zygospores; all other species only reproduce asexually.
The Ascomycota, commonly known as sac fungi or ascomycetes, form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This division includes morels, some mushrooms and truffles, as well as single-celled yeasts and many species that have only been observed undergoing asexual reproduction.
Members of the Basidiomycota, commonly known as the club fungi or basidiomycetes, produce meiospores called basidiospores on club-like stalks called basidia. Most common mushrooms belong to this group, as well as rust and smut fungi, which are major pathogens of grains.

The Deuteromycota is a sort of miscellaneous junk category for forms of fungi of uncertain affinity, and include those fungi in which sexual reproduction is unknown. They are also referred to in informal Latin as the Fungi imperfecti, and more recently as mitosporic fungi, and the "imperfect fungi." This division is not treated formally in more recent systems, although it is still used widely by plant pathologists for the purposes of quick diagnosis and when the teleomorph stage of the particular organism is unknown. Because sexual reproduction is the basis for classification of fungi, it is often difficult to place these fungi in their appropriate group (because they lack sexual reproduction).

Although the water molds and slime molds have traditionally been placed in the fungi kingdom and are still studied by mycologists, they are not true fungi. Unlike true fungi, the water molds and slime molds do not have cell walls made of chitin. In the five-kingdom system, they are currently placed in kingdom Protista.

Reproduction

Fungus growing on fallen tree trunks in Belize.

Fungi may reproduce sexually or asexually. In asexual reproduction, the offspring are genetically identical to the “parent” organism (they are clones). During sexual reproduction, a mixing of genetic material occurs so that the offspring exhibit traits of both parents. Many species can use both strategies at different times, while others are apparently strictly sexual or strictly asexual. Sexual reproduction has not been observed in some fungi of the Glomeromycota and Ascomycota. These are commonly referred to as Fungi imperfecti or Deuteromycota.

Yeasts and other unicellular fungi can reproduce simply by budding, or “pinching off” a new cell. Many multicellular species produce a variety of different asexual spores that are easily dispersed and resistant to harsh environmental conditions. When the conditions are right, these spores will germinate and colonize new habitats.

Role in Nature

Most fungi live by decomposing the remains of dead plants and animals. This releases carbon and other materials back to the environment where they can be reused by plants. Some fungi are predators of nematodes, which they capture using an array of devices such as constricting rings or adhesive nets. Other fungi form symbiotic relationships with other plants and animals, whether this close association is beneficial or harmful to the other organisms. In some cases, the fungi are parasites, living in or on the bodies of plants and animals and sometimes causing diseases.

Other fungi may live in mutually beneficial symbiotic relationships (mutualism) with other organisms. Lichens are a combination of an algae, which provides food through photosynthesis, and a fungus, which provides protection to the algae. Leaf-cutter ants and some species of termites live in a symbiotic relationship with fungi in which the insects protect the fungi and provide them with plant material to decompose, while the fungi provide food for the insects.

The most important symbiotic relationship in which fungi take part was unknown until the last part of the twentieth century. That is mycorrhizas, the relationship between fungi and plants. Specialized fungi live on the roots of most land plants (perhaps 95 percent). The hyphae of the fungi extend out into the soil and form a network of fibers that in effect extend the root system of the plant enabling it to more effectively absorb water and minerals. The plant provides the fungi with nutrients produced by its photosynthesis. Most plants could not thrive without a partnership with these fungi.

Fungi and humans

Besides their tremendous indirect importance to humans as a result of their role in the life cycles of plants, fungi also affect people directly in many ways.

Mushrooms

Destroying angel.

Mushrooms are the above ground fruiting bodies of various species of fungus that mostly live on decaying plant material in soil. From prehistoric times, people have consumed them. They are flavorful and provide B vitamins and such minerals as potassium, phosphorus, and iron; but not many calories. Many species of mushrooms contain toxins that can cause sickness or even death. Among the most deadly are the destroying angel and the deathcap, members of the genus Amanita, which have killed many mushroom hunters.

Truffles

White truffle cut in slices

Truffles are the underground fruiting bodies of several species of fungi that live in a mycorrhizal relationship with the roots of oak trees. They are highly prized for their strong flavor. Traditionally, they have been dug up in the woods by using pigs or dogs that find them by their scent. In the nineteenth century in France, it was discovered that by planting the acorns from an affected tree, new "truffle fields" could be created. France is still the main truffle producing nation, but there is a great potential for truffle cultivation's worldwide expansion.

Yeast

Yeasts are single-cell fungi. They break down the carbohydrates in grain and fruit, producing alcohol and carbon dioxide through the process of fermentation. Beginning about 10,000 years ago, they have been used to produce beer, wine, and other alcoholic beverages and also to leaven bread. In recent times, yeast has gained popularity as a nutritional supplement. It has a nutty, cheesy flavor and is sometimes used as a substitute for cheese on pasta and popcorn.

Penicillin

Penicillin was discovered in 1928 by Alexander Fleming when he found a blue-green mold growing in a bacteria culture plate. The mold was releasing a substance that was inhibiting the growth of the bacteria. This was penicillin, part of the mold's natural defense against bacteria. It is estimated that penicillin has saved at least 200 million lives since its first use as a medicine in 1942.

Fungal Diseases

Some diseases are caused by parasitic fungi. Athlete's foot and other skin diseases are the most common. Most fungal diseases are not too serious, but some—such as fungal pneumonia—can be deadly.

Many fungal diseases of humans also occur in animals, particularly mammals. Ringworm is the most common fungal disease that affects animals, and humans can contract ringworm from animals; cats and dogs are often carriers. Contrary to its name, ringworm is not caused by a worm, but by a fungus, and it is quite common, especially among children. Ringworm may be spread by skin-to-skin contact, as well as via contact with contaminated items such as hairbrushes.

Fungi also cause diseases in plants, including smuts, rusts, and mildews. These plant diseases are serious problems in agriculture. Dutch elm disease, caused by fungus species of the genus ‘‘Ophiostomi’’, which are native to Asia (not Holland), has killed almost all of the native elm trees of Northern Europe and North America since it was introduced accidentally in the twentieth century.

Molds

Moldy Bread

Molds are various types of fungi that decompose dead plant and animal material. They are a big cause of the spoilage of foods, and can often be seen growing on food left too long in a refrigerator. They also can damage clothing and wood and other building materials. Molds, like all fungi, need moisture to grow, so the best way to prevent damage from them is too avoid dampness.

Future Developments

Much research is going on worldwide into fungi and their possible benefits to humankind. Some species have been used as biological controls for pests, taking advantage of the fungi's own natural defenses against bacteria, insects, worms, and other fungi. There is even an attempt to use yeast in fuel cells to produce electricity.

References
ISBN links support NWE through referral fees

Kendrick, B. 2000. The Fifth Kingdom : A New Look at Mycology. Mycologue Publications. ISBN 1585100226
Watling, R. 2003. Fungi. Natural World (Smithsonian). ISBN 1588340821

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+{{Copyedited}}{{Paid}}{{Approved}}{{Images OK}}{{Submitted}}
+[[Category:Public]]
 {{Taxobox_begin | color = lightblue | name = Fungi}}
 {{Taxobox_image | image = [[Image:Fungus on log.jpg|200px|Orange saprotrophic fungus]]| caption = ''Orange saprotrophic fungus''.}}
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 {{Taxobox_end_placement}}
 {{Taxobox_section_subdivision | color = lightblue | plural_taxon = Divisions}}
-[[Chytridiomycota]]<br/>
+Chytridiomycota<br/>
-[[Deuteromycota]]<br/>
+Zygomycota<br/>
-[[Zygomycota]]<br/>
+Glomeromycota<br>
-[[Glomeromycota]]<br>
+Ascomycota<br/>
-[[Ascomycota]]<br/>
+Basidiomycota<br/>
-[[Basidiomycota]]
+Deuteromycota
 {{Taxobox_end}}
-[[Image:fungi in Borneo.jpg|right|thumb|Fungus growing on a tree in [[Borneo]]]]
+[[Image:fungi in Borneo.jpg|right|thumb|Fungus growing on a tree in Borneo]]
-A '''fungus''' (plural '''fungi''') is a [[Eukaryote|eukaryotic]] [[organism]] that digests its [[food]] externally and absorbs the [[nutrient]] [[molecule]]s into its [[cell (biology)|cell]]s. Fungi are used extensively by humans: [[yeast]]s are responsible for [[fermentation]] of [[beer]] and [[bread]], and [[mushroom]] farming is a large industry in many countries. Fungi are the primary [[decomposer]]s of dead plant and animal matter in many [[ecosystem]]s, and are commonly seen on old bread as [[mold]]. However, the complex [[biology]] of fungi extends beyond this common knowledge and experience of them.
+'''Fungi''' (singular '''fungus''') make up one of the kingdoms into which living things are divided by [[biology|biologists]]. A fungus is a [[Eukaryote|eukaryotic]] organism that digests its food externally and absorbs the nutrient molecules into its [[cell (biology)|cell]]s.
-==Phylogeny of fungi==
+Fungi differ from [[bacteria]] in having a cell nucleus; from [[plant]]s in not making their own food through [[photosynthesis]]; and from [[animal]]s in not being mobile and in absorbing nutrition externally rather than internally. Fungi include [[mushroom]]s, [[yeast]]s, [[mold]]s, [[mildew]]s, and others.
-Originally classified as [[plant]]s, fungi are not at all plants, because they are [[heterotroph]]s (they do not fix their own carbon through [[photosynthesis]] but use the carbon fixed by other organisms). Indeed, fungi are now thought to be more closely related to [[animal]]s than to plants, and are placed together with animals in the [[monophyletic]] group of [[opisthokont]]s.  However, unlike animals, fungi absorb their food rather than [[Ingestion|ingest]] it, and their cells have [[cell wall]]s surrounding them. For these reasons, these organisms are placed in their own [[kingdom (biology)|kingdom]], '''Fungi'''.
-The Fungi are a [[monophyletic]] group, meaning all varieties of fungi come from a common ancestor. [[Mycologist]]s (scientists who study fungi) believe they are monophyletic because they have [[chitin]] in their cell walls and are absorbtive heterotrophs, along with other shared characteristics.
+Although often unnoticed or misunderstood by humans, fungi play a vital role in the earth's [[ecosystem]]s and are used extensively by humans. Fungi are the primary decomposers of dead plant and animal matter in many [[ecosystem]]s, and are commonly seen on old bread as [[mold]]. [[Yeast]]s are responsible for fermentation of [[beer]] and [[bread]], and mushroom farming is a large industry in many countries.
-==Overview==
+Fungi's mutualistic [[symbiosis|symbiotic]] relationship with other organisms and most land plants is reflective of an underlying harmony in biological interactions and the universal principle of [[Biology#Interactions: Harmony and bi-level functionality|bi-level functionality]].
-Although often inconspicuous, fungi occur in every environment on [[earth]] and play very important roles in most [[ecosystems]]. Many fungi are major [[decomposer]]s of dead plant and animal matter in [[forest]]s and many other environments. Some fungi are [[predators]] of [[nematodes]], which they capture using an array of devices such as constricting rings or adhesive nets ([http://www.uoguelph.ca/~gbarron/MISC2003/illustra.htm see illustrations]). Other types are [[parasite]]s on plants and animals, including [[human]]s. They are responsible for numerous [[disease]]s, such as [[athlete’s foot]] and [[ringworm]] in humans and [[Dutch elm disease]] in plants. Other fungi are partners in [[symbiosis|symbiotic]] relationships with other organisms. For example, [[lichen]]s are formed by a symbiotic relationship between [[algae]] or [[cyanobacteria]] and fungi. Most [[vascular plant]]s benefit from a symbiosis between their [[root]]s and fungi.
-Fungi have a long history of use by humans. Many types of [[mushroom]]s and other fungi are eaten, including [[button mushroom]]s, [[shiitake mushroom]]s, and [[oyster mushroom]]s. Of course, many [[species]] of mushrooms are [[poison]]ous and are responsible for numerous cases of [[sickness]] and [[death]] every year. A type of fungus called [[yeast]] is used in baking [[bread]] and [[ferment]]ing [[alcoholic beverage]]s. Fungi are also used to produce industrial chemicals like [[lactic acid]], and even to make stonewashed [[jeans]]. Some types of fungi are ingested for their [[psychedelic drug|psychedelic]] properties, both [[recreational drug|recreationally]] and religiously (as [[entheogen]]s) (see main article, ''[[Psychedelic mushroom]]'').
+==Structure==
-===Types of fungi===
+Fungi may be single-celled or multicellular.
-The major divisions ([[phyla]]) of fungi are mainly classified based on their sexual [[reproduction|reproductive]] structures. Currently, five divisions are recognized:
-[[Image:K_1033CR08-9_Yellow_fungus_on_stalk.jpg|right|thumb|200px|Yellow fungus]]
+Multicellular fungi are composed of networks of long hollow tubes called hyphae. The hyphae often aggregate in a dense network known as mycelium. The mycelium grows through the medium on which the fungus feeds. Because fungi are embedded in the medium in which they grow, most often [[soil]], they are often not visible.
-* The [[Chytridiomycota]] are commonly known as chytrids. These fungi produce zoospores that are capable of moving on their own through liquid menstrua by simple [[flagellum|flagella]].
+Although fungi lack true organs, the mycelia may become organized into more complex reproductive structures called fruiting bodies, or sporocarps, when conditions are right. "Mushroom" is the common name given to the above-ground fruiting bodies of many fungal species. Although these above-ground structures are the most conspicuous to [[human]]s, they make up only a small portion of the entire fungal body.
-* The [[Zygomycota]] are known as zygomycetes and reproduce sexually with meiospores called zygospores. [[Black bread mold]] (''Rhizopus stolonifer'') is a common species that belongs to this group, another is ''[[Pilobolus]]'', which shoots specialized structures through the air for several meters and was the source of the name for the modern dance troupe.
-* Members of the [[Glomeromycota]] are also known as the arbuscular mycorrhizal fungi. Only one species has been observed forming zygospores; all other species only reproduce asexually. This is an ancient association, with evidence dating to 350 mybp.
-* The [[Ascomycota]], commonly known as sac fungi or ascomycetes, form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This division includes [[morel]]s, some [[mushroom]]s and [[truffle]]s, as well as single-celled [[yeast]]s and many species that have only been observed undergoing asexual reproduction. Because the products of meiosis are retained within the sac-like ascus, several ascomyctes have been used for elucidating principles of genetics and heredity (e.g. ''[[Neurospora crassa]]'').
-* Members of the [[Basidiomycota]], commonly known as the club fungi or basidiomycetes, produce meiospores called [[basidiospore]]s on club-like stalks called [[basidium|basidia]]. Most common [[mushroom]]s belong to this group, as well as [[rust (fungus)]] and [[smut (fungus)|smut fungi]], which are major pathogens of grains.
-Although the [[water mold]]s and [[slime mold]]s have traditionally been placed in kingdom Fungi and are still studied by mycologists, they are not true fungi. Unlike true fungi, the water molds and slime molds do not have cell walls made of [[chitin]]. In the [[kingdom (biology)|5-kingdom system]], they are currently placed in kingdom [[Protist]]a.
+Some fungi form rhizoids, which are underground, root-like structures that provide support and transport nutrients from the soil to the rest of the mycelium.
+The largest organism in the world is said to be a single ''Armillaria ostoyae'' individual growing in a [[forest]] in eastern [[Oregon]]. The underground mycelial network may cover as much as 2,200 acres.
-===Structure===
 [[Image:Hyphae.JPG|thumb|left|Hyphae as seen under a log]]
-Fungi may be single-celled or multicellular. Multicellular fungi are composed of networks of long hollow tubes called [[hyphae]]. The hyphae often aggregate in a dense network known as [[mycelium]]. The mycelium grows through the medium on which the fungus feeds. Because fungi are embedded in the medium in which they grow, they are often not visible to the naked eye.
-Although fungi lack true organs, the mycelia of ascomycetes and basidiomycetes may become organized into more complex reproductive structures called [[fruiting body|fruiting bodies]], or sporocarps, when conditions are right. "Mushroom" is the common name given to the above-ground fruiting bodies of many fungal species. Although these above-ground structures are the most conspicuous to humans, they make up only a small portion of the entire fungal body. Some fungi form [[rhizoid]]s, which are underground root-like structures that provide support and transport nutrients from the soil to the rest of the mycelium.
+==Types of fungi==
+The major divisions (phyla) of fungi are mainly classified based on their [[sexual reproduction|sexual reproductive]] structures. Currently, five main divisions are recognized:
+* The Chytridiomycota are commonly known as chytrids. These fungi produce zoospores that are capable of moving on their own by simple flagella.
+* The Zygomycota are known as zygomycetes and reproduce sexually. Black bread mold (''Rhizopus stolonifer'') is a common [[species]] that belongs to this group. Another is ''Pilobolus'', which shoots specialized structures through the air for several meters.
+* Members of the Glomeromycota are also known as the arbuscular mycorrhizal fungi. Only one species has been observed forming zygospores; all other species only reproduce asexually.
+* The Ascomycota, commonly known as sac fungi or ascomycetes, form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This division includes morels, some mushrooms and truffles, as well as single-celled yeasts and many species that have only been observed undergoing asexual reproduction.
+* Members of the Basidiomycota, commonly known as the club fungi or basidiomycetes, produce meiospores called basidiospores on club-like stalks called basidia. Most common mushrooms belong to this group, as well as rust and smut fungi, which are major pathogens of grains.
-The largest organism in the world is purported to be a single ''[[Armillaria ostoyae]]'' individual growing in a forest in eastern [[Oregon]], [[United States|U.S.]]. The underground mycelial network may cover as much as 890 [[hectare|ha]] (2200 [[acre]]s).
+The ''Deuteromycota'' is a sort of miscellaneous junk category for forms of fungi of uncertain affinity, and include those fungi in which sexual reproduction is unknown. They are also referred to in informal Latin as the ''Fungi imperfecti'', and more recently as ''mitosporic fungi'', and the "imperfect fungi." This division is not treated formally in more recent systems, although it is still used widely by plant pathologists for the purposes of quick diagnosis and when the teleomorph stage of the particular organism is unknown. Because sexual reproduction is the basis for classification of fungi, it is often difficult to place these fungi in their appropriate group (because they lack sexual reproduction).
+Although the water molds and slime molds have traditionally been placed in the fungi kingdom and are still studied by mycologists, they are not true fungi. Unlike true fungi, the water molds and slime molds do not have cell walls made of [[chitin]]. In the five-kingdom system, they are currently placed in kingdom [[Protista]].
+==Reproduction==
 [[Image:Fungi Belize.jpg|right|thumb|200px|Fungus growing on fallen tree trunks in [[Belize]].]]
-===Reproduction===
+Fungi may reproduce sexually or asexually. In asexual reproduction, the offspring are genetically identical to the “parent” organism (they are [[cloning|clones]]). During sexual reproduction, a mixing of genetic material occurs so that the offspring exhibit traits of both parents. Many species can use both strategies at different times, while others are apparently strictly sexual or strictly asexual. Sexual reproduction has not been observed in some fungi of the Glomeromycota and Ascomycota. These are commonly referred to as Fungi imperfecti or Deuteromycota.
-Fungi may reproduce sexually or asexually. In [[asexual reproduction]], the [[offspring]] are genetically identical to the “parent” organism (they are [[Cloning|clones]]). During [[sexual reproduction]], a mixing of [[gene|genetic material]] occurs so that the offspring exhibit traits of both parents. Many species can use both strategies at different times, while others are apparently strictly sexual or strictly asexual. Sexual reproduction has not been observed in some fungi of the [[Glomeromycota]] and [[Ascomycota]]. These are commonly referred to as Fungi imperfecti or [[Deuteromycota]].
+Yeasts and other unicellular fungi can reproduce simply by budding, or “pinching off” a new cell. Many multicellular species produce a variety of different asexual spores that are easily dispersed and resistant to harsh environmental conditions. When the conditions are right, these spores will germinate and colonize new habitats.
+==Role in Nature==
+Most fungi live by decomposing the remains of dead [[plant]]s and [[animal]]s. This releases [[carbon]] and other materials back to the environment where they can be reused by plants. Some fungi are predators of nematodes, which they capture using an array of devices such as constricting rings or adhesive nets. Other fungi form [[symbiosis|symbiotic]] relationships with other plants and animals, whether this close association is beneficial or harmful to the other organisms. In some cases, the fungi are [[parasite]]s, living in or on the bodies of plants and animals and sometimes causing diseases.
+Other fungi may live in mutually beneficial [[symbiosis|symbiotic]] relationships (mutualism) with other organisms. [[Lichen]]s are a combination of an [[algae]], which provides food through photosynthesis, and a fungus, which provides protection to the algae. Leaf-cutter [[ant]]s and some species of [[termite]]s live in a symbiotic relationship with fungi in which the insects protect the fungi and provide them with plant material to decompose, while the fungi provide food for the [[insect]]s.
+The most important symbiotic relationship in which fungi take part was unknown until the last part of the twentieth century. That is mycorrhizas, the relationship between fungi and plants. Specialized fungi live on the roots of most land plants (perhaps 95 percent). The hyphae of the fungi extend out into the [[soil]] and form a network of fibers that in effect extend the root system of the plant enabling it to more effectively absorb water and minerals. The plant provides the fungi with nutrients produced by its photosynthesis. Most plants could not thrive without a partnership with these fungi.
+==Fungi and humans==
+Besides their tremendous indirect importance to [[human]]s as a result of their role in the life cycles of [[plant]]s, fungi also affect people directly in many ways.
+===Mushrooms===
+[[Image:Avirosa L.jpg|right|thumb|200px|Destroying angel.]]
+Mushrooms are the above ground fruiting bodies of various species of fungus that mostly live on decaying plant material in soil. From prehistoric times, people have consumed them. They are flavorful and provide B [[vitamin]]s and such minerals as [[potassium]], [[phosphorus]], and [[iron]]; but not many calories. Many species of mushrooms contain toxins that can cause sickness or even death. Among the most deadly are the destroying angel and the deathcap, members of the genus ''Amanita'', which have killed many mushroom hunters.
+===Truffles===
+[[Image:truffle cutted.jpg|thumb|250px|left|White truffle cut in slices]]
+[[Truffle]]s are the underground fruiting bodies of several species of fungi that live in a mycorrhizal relationship with the roots of [[oak]] trees. They are highly prized for their strong flavor. Traditionally, they have been dug up in the woods by using [[pig]]s or [[dog]]s that find them by their scent. In the nineteenth century in [[France]], it was discovered that by planting the acorns from an affected tree, new "truffle fields" could be created. France is still the main truffle producing nation, but there is a great potential for truffle cultivation's worldwide expansion.
-Yeasts and other unicellular fungi can reproduce simply by [[budding]], or “pinching off” a new cell. Many multicellular species produce a variety of different asexual spores that are easily dispersed and resistant to harsh environmental conditions. When the conditions are right, these spores will [[germination|germinate]] and colonize new [[Habitat (ecology)|habitat]]s.
+===Yeast===
-Sexual reproduction in fungi is somewhat different from that of animals or plants, and each fungal division reproduces using different strategies. Fungi that are known to reproduce sexually all have a [[haploid]] stage and a [[diploid]] stage in their life cycles. Ascomycetes and basidiomycetes also go through a [[dikaryotic]] stage, in which the [[cell nucleus|nuclei]] inherited by the two parents do not fuse right away, but remain separate in the hyphal cells (see [[heterokaryosis]]).
+[[Yeast]]s are single-cell fungi. They break down the [[carbohydrate]]s in grain and fruit, producing [[alcohol]] and [[carbon dioxide]] through the process of [[fermentation]]. Beginning about 10,000 years ago, they have been used to produce beer, wine, and other alcoholic beverages and also to leaven bread. In recent times, yeast has gained popularity as a nutritional supplement. It has a nutty, [[cheese|cheesy]] flavor and is sometimes used as a substitute for cheese on pasta and popcorn.
-In zygomycetes, the haploid hyphae of two compatible individuals fuse, forming a [[zygote]], which becomes a resistant [[zygospore]]. When this zygospore germinates, it quickly undergoes [[meiosis]], generating new haploid hyphae and asexual [[sporangiospore]]s. These sporangiospores may then be distributed and germinate into new genetically-identical individuals, each producing their own haploid hyphae. When the hyphae of two compatible individuals come into contact with one another, they will fuse and generate new zygospores, thus completing the cycle.
+===Penicillin===
+[[Penicillin]] was discovered in 1928 by [[Alexander Fleming]] when he found a blue-green mold growing in a bacteria culture plate. The mold was releasing a substance that was inhibiting the growth of the [[bacteria]]. This was penicillin, part of the mold's natural defense against bacteria. It is estimated that penicillin has saved at least 200 million lives since its first use as a medicine in 1942.
-In ascomycetes, when compatible haploid hyphae fuse with one another, their nuclei do not immediately fuse. The dikaryotic hyphae form structures called [[ascus|asci]] (''sing.'' ascus), in which [[karyogamy]] (nuclear fusion) occurs. These asci are embedded in an [[ascocarp]], or fruiting body, of the fungus. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores. The ascospores are disseminated and germinate to form new haploid mycelium. Asexual [[Conidium|conidia]] may be produced by the haploid mycelium. Many ascomycetes appear to have lost the ability to reproduce sexually and reproduce only via conidia.
+===Fungal Diseases===
-Sexual reproduction in basidiomycetes is similar to that of ascomycetes. Sexually compatible haploid hyphae fuse to produce a dikaryotic mycelium. This leads to the production of a [[basidiocarp]]. The most commonly-known basidiocarps are mushrooms, but they may also take many other forms. Club-like structures known as [[basidia]] generate haploid [[basidiospores]] following karyogamy and meiosis. These basidiospores then germinate to produce new haploid myceliumata.
+Some diseases are caused by parasitic fungi. Athlete's foot and other skin diseases are the most common. Most fungal diseases are not too serious, but some&mdash;such as fungal pneumonia&mdash;can be deadly.
-==Edible and poisonous fungi==
+Many fungal diseases of humans also occur in [[animal]]s, particularly [[mammal]]s. Ringworm is the most common fungal disease that affects animals, and humans can contract ringworm from animals; cats and dogs are often carriers. Contrary to its name, ringworm is not caused by a worm, but by a fungus, and it is quite common, especially among children. Ringworm may be spread by skin-to-skin contact, as well as via contact with contaminated items such as hairbrushes.
-Some of the most well-known types of fungi are the [[Edible mushroom|edible]] and [[Mushroom poisoning|poisonous mushrooms]]. Many species are commercially raised, but others must be harvested from the wild. Button mushrooms (''Agaricus bisporus'') are the most commonly eaten species, used in salads, soups, and many other dishes. [[Button mushroom|Portobello mushrooms]] are also members of this species, but grow to a much larger size. Other commercially-grown mushrooms that have gained in popularity in the West and are often available fresh in grocery stores include oyster mushrooms, shiitakes, and [[enoki]] mushrooms.
-There are many more mushroom species that are [[Mushroom hunting|harvested from the wild]] for personal consumption or commercial sale. [[Morel|Morels]], [[chanterelle]]s, [[truffles]], [[Craterellus|black trumpets]], and [[porcini]] mushrooms (also known as king boletes) all command a high price on the market. They are often used in gourmet dishes.
+Fungi also cause diseases in plants, including smuts, rusts, and mildews. These plant diseases are serious problems in agriculture. Dutch elm disease, caused by fungus species of the genus ‘‘Ophiostomi’’, which are native to Asia (not Holland), has killed almost all of the native elm trees of Northern Europe and North America since it was introduced accidentally in the twentieth century.
-It is also a common practice to permit the growth of specific species of [[mold]] in certain types of cheeses that give them their unique flavor. This mold is non-toxic and is safe for human consumption. Examples of this are Blue Cheese and [[Stilton_cheese|Stilton Cheese]].
+===Molds===
-Hundreds of mushroom species are toxic to humans, causing anything from upset stomachs to [[hallucination]]s to death. Some of the most deadly belong to the genus ''[[Amanita]]'', including ''[[Amanita virosa|A. virosa]]'' (the "Destroying Angel") and ''[[Amanita phalloides|A. phalloides]]'' (the "Death Cap"). Stomach cramps, vomiting, and diarrhea usually occur within 6-24 hours after ingestion of these mushrooms, followed by a brief period of remission (usually 1-2 days). Patients often fail to present themselves for treatment at this time, assuming that they have recovered. However, within 2-4 weeks [[liver]] and [[kidney]] failure leads to death if untreated. There is no antidote for the toxins in these mushrooms, but [[kidney dialysis]] and administration of [[corticosteroids]] may help. In severe cases, a liver transplant may be necessary (Kaminstein 2002). It is difficult to identify a "safe" mushroom without proper training and knowledge, thus it is often advised to assume that a mushroom in the wild is poisonous and leave it alone.
+[[Image:Mouldy_bread.jpg|200px|thumb|right|Moldy Bread]]
+Molds are various types of fungi that decompose dead plant and animal material. They are a big cause of the spoilage of foods, and can often be seen growing on food left too long in a refrigerator. They also can damage clothing and wood and other building materials. Molds, like all fungi, need moisture to grow, so the best way to prevent damage from them is too avoid dampness.
-[[Amanita muscaria|Fly agaric]] mushrooms (''A. muscaria'') are also responsible for a large number of poisonings, but these cases rarely result in death. The most common symptoms are nausea and vomiting, drowsiness, and hallucinations. In fact, this species is used ritually and recreationally for its hallucinogenic properties. However, if it is taken in over a long period of time (regularly over more than six months), this species might cause a temporary loss of sight, which can last from several minutes to an hour.
+===Future Developments===
-==Fungi in the biological control of pests==
+Much research is going on worldwide into fungi and their possible benefits to humankind. Some species have been used as biological controls for pests, taking advantage of the fungi's own natural defenses against [[bacteria]], [[insect]]s, worms, and other fungi. There is even an attempt to use yeast in fuel cells to produce electricity.
-Many fungi compete with other organisms, or directly infect them. Some of these fungi are considered beneficial because they can restrict, and sometimes eliminate, the populations of noxious organisms like pest insects, [[mites]], [[weed]]s, [[nematodes]] and other fungi, such as those that kill plants. There is much interest on the manipulation of these beneficial fungi for the [[biological control]] of pests. Some of these fungi can be used as [[biopesticides]], like the ones that kill insects ([[entomopathogenic fungi]]). Specific examples of fungi that have been developed as [[bioinsecticide]]s are ''[[Beauveria bassiana]]'', ''[[Metarhizium anisopliae]]'', [[Hirsutella]], ''[[Paecilomyces fumosoroseus]]'', and ''[[Verticillium lecanii]]'' (=''[[Lecanicillium lecanii]]'' ).
 ==References==
-* {{cite web
+* Kendrick, B. 2000. ''The Fifth Kingdom : A New Look at Mycology''. Mycologue Publications. ISBN 1585100226
- | url = http://www.healthatoz.com/healthatoz/Atoz/ency/mushroom_poisoning.jsp
+* Watling, R. 2003. ''Fungi''. Natural World (Smithsonian). ISBN 1588340821
- | author = Kaminstein, D.
- | year = 2002
- | title = Mushroom poisoning
- | accessdate = 2006-01-05
- }}
-==External links==
+[[Category:Life sciences]][[Category:Fungi]]
-*[http://www.biocrawler.com/Pictures/?d=Botany/Fungi Fungi pictures on Biocrawler.com]
-*[http://www.cirrusimage.com/fungi-sulphur-shelf.htm Sulphur Shelf Fungus ''Laetiporous sulphureous'' photos and information]
-*[http://www.cirrusimage.com/fungi_giant_puffball.htm Giant Puffball Fungus ''Calvatia gigantea'' photos and information]
-* [http://www.britmycolsoc.org.uk/ British Mycological Society]
-* [http://www.mycolog.com/fifthtoc.html ''The Fifth Kingdom'']
-* [http://www.msafungi.org/ Mycological Society of America]
-* [http://www.mykoweb.com/ MykoWeb]
-* [http://www.fungi.com Fungi Perfecti, Gourmet and medicinal fungi]
-* [http://www.namyco.org/ North American Mycological Society]
-* [http://sydneyfungalstudies.org.au/Intro.html/ Sydney Fungal Studies Group]
-* [http://www.rbg.vic.gov.au/fungimap_/welcome/ Australian FungiMap Project]
-* [http://www.pnwfungi.org/Pacific Northwest Fungi, Online Journal]
-* [http://www.pnwfungi.wsu.edu/programs/aboutDatabase.asp/ Pacific Northwest Fungi Database]
-{{credit|55901665}}
+{{credit3|Fungus|55901665|Deuteromycota|53593605|Ringworm|55570291}}
-[[Category:Life sciences]]