Ascomycota is the division or phyla of the Kingdom of mushrooms which, together with Basidiomycota, form the Subkingdom of Dikarya. Its members are commonly known as sac fungi or ascomycetes . They are the largest phylum of Fungi, with more than 64,000 species. The distinguishing feature of this group of mushrooms is "ascus" (from Greek: ????? ( askos ), meaning "pouch" or "wine skin"), a microscopic sexual structure in which nonmotil spores, called ascospores, are formed. However, some Ascomycota species are asexual, meaning that they have no sexual cycles and thus do not form ASCI or ascospores. Previously placed in Deuteromycota along with asexual species from other fungal taxa, ascomual (or anamorphic) ascomycetes are now identified and classified based on morphological or physiological similarities to ascus-bearing taxa, and by phylogenetic analysis of DNA sequences.
Ascomycetes are a monophyletic group, which contains all the offspring of one common ancestor. This group has particular relevance to humans as a source of important medical compounds, such as antibiotics and for making bread, alcoholic beverages, and cheese, but also as human and plant pathogens. Examples of familiar mushroom sacs include morels, truffles, brewer's yeast and bread yeast, dead man's fingers, and mushroom cups. Mushroom symbionts in most of the moss (called "ascolichens") such as Ascomycota's Cladonia . There are many plant-pathogenic ascomycetes, including apple scab, rice blast, ergot fungus, black knot, and powdery mildew. Some species of ascomycetes are organisms of biological models in laboratory studies. Most famous, Neurospora crassa , some species of yeast, and Aspergillus species are used in many genetic studies and cell biology. Penicillium species in cheese and those who produce antibiotics to treat bacterial infections are examples of Ascomycota's taxa.
Video Ascomycota
Asexual reproduction in ascomycetes and its characteristics
Ascomycetes:
Ascomycetes is a 'spore shooter'. They are mushrooms that produce microscopic spores in cells or elongated sacs, known as 'asci', which gives the group its name.
Asexual reproduction:
Asexual reproduction is the dominant form of propagation in Ascomycota, and is responsible for rapid dissemination of this fungus to new areas. Ascomual ascomycetes reproduction is very diverse from a structural and functional point of view. The most important and common is the production of conidia, but chlamydospores are also often produced. In addition, Ascomycota also reproduces asexually through buds.
1) Conidia formation:
Asexual reproduction may occur through vegetative reproductive spores, conidia. Asexual, non-motile haploid spores of mushrooms, named after the Greek word for dust; conia and hence also known as conidiospores and mythospores. The conidiospores generally contain one core and are the product of the mitotic cell division and thus sometimes call mythospores , which are genetically identical to the mycelium from which they originate. They are usually formed at the end of a special hypha, konidiophores. Depending on the species they may be dissolved by wind or water, or by animals. Koniophores can easily branch off from the mycelia or they can form in the body of the fruit.
The hyphae that creates the sporing tip (conidiation) can be very similar to the hyphae's normal, or distinguishable tip. The most common differentiation is the formation of a bottle-shaped cell called phialide, from which the spores are produced. Because all these asexual structures are not single hyphae. In some groups, conidiophores (structures that bear conidia) are collected to form thick structures.
For example. In the order of Moniliales, are all single hyphae with the exception of aggregation, referred to as coremia or synnema. This results in a somewhat stoke-like structure of corn, with many conidia being produced in the mass of aggregate conidiophores.
Conidia and diverse conidiofors sometimes develop in asexual sporocarps with different characteristics (eg aecervulus, pycnidium, sporodochium). Some species of Ascomycetes form their structures within plant tissues, either as parasites or saprophytes. These fungi have evolved more complex asexual spore structures, probably influenced by the cultural conditions of plant tissue as substrate. This structure is called sporodochium . These are conidioforal pads that are formed from pseudoparenchymatous stroma in plant tissues. The pycnidium is a round shape for the pumpkin-shaped parenchyma structure, coated on an inner wall with conidiofor. The acervulus is a flat plate-shaped bed of conidiofores produced under the cuticle of the plant, which eventually erupts through the cuticle for dispersal.
2) Budding:
The asexual reproductive process in ascomycetes also involves the shoots we clearly observe in yeast . This is called a "blastic process". This involves blowing out or blebbing off the wall of a tip of hialus. The blastic process can involve all layers of the wall, or there can be a new synthesized cell wall extruded from within the old wall.
Early shoot events can be seen as the development of a chitin ring around the point where the bud will appear. It strengthens and stabilizes the cell wall. Enzymatic activity and turgor pressure act to weaken and extrude cell walls. New cell wall materials are included during this phase. The contents of the cells are forced into the progeny cell, and when the final phase of mitosis ends the cell plate, the point at which the new cell wall will grow into from, the shape.
Ascomycetes Characteristics
- Ascomycota is morphologically diverse. This group includes organisms from unicellular yeast to complex cup cups.
- There are 2000 identified genera and 30,000 species of Ascomycota.
- The unifying characteristic of these diverse groups is the existence of a reproductive structure known as ascus , although in some cases it has a diminished role in the life cycle.
- Many ascomycetes have commercial interests. Some play a useful role, such as yeast used in baking, brewing, and fermenting grapes, plus truffles and morel, which are held as gourmet delicacies.
- Many of them cause tree diseases, such as Dutch elm disease and blight apples.
- Some plant plant ascomycetes are apple scabies, rice explosions, ergot mushrooms, black knots, and powdery mildew.
- Yeast is used to produce alcoholic beverages and bread. Prints Penicillium is used to produce anti-biotic penicillin.
- Almost half of all members of the Ascomycota phyla form symbiotic associations with algae to form moss.
- Others, such as morels, form important botanical relationships with plants, thereby providing increased water and nutrient uptake and, in some cases, protection from insects.
- Most ascomycetes are terrestrial or parasitic. However, some have adapted to marine or freshwater environments.
- The cell wall of hyphae varies consisting of chitin and? -glucans, same as in Basidiomycota. However, these fibers are arranged in a glycoprotein matrix containing galactose and mannose sugars.
- Mycelium ascomycetes usually consists of septate hyphae . However, there is not necessarily a fixed number of cores in each division.
- Septum walls have septal pores that provide cytoplasmic continuity throughout individual hyphae. Under appropriate conditions, the nuclei may also migrate between the septal compartments through the pores of the septum.
- The unique character of Ascomycota (but not present in all ascomycetes) is the existence of the Woronin body on each side of the septa that separates the hyphae segment that controls the pores of the septum. If the adjacent hyphae bursts, Woronin's body blocks the pores to prevent cytoplasmic loss into the broken compartment. Woronin's body is round, hexagonal, or rectangular bonding structure with a crystalline protein matrix.
Maps Ascomycota
Modern classification
There are three subphyla that are described and accepted:
- The Pezizomycotina is the largest subphylum and contains all ascomycetes that produce ascocarps (the fruit body), except for one genus, Neolecta in Taphrinomycotina. This is roughly equivalent to the previous taxon, Euascomycetes . Pezizomycotina includes most macroscopic "ascos" such as truffles, ergot, ascolichens, bowl bowls (discomycetes), pyrenomycetes, lorchels, and caterpillar fungi. It also contains microscopic fungi such as powdery mildew, dermatophyte fungi, and Laboulbeniales.
- The Saccharomycotina consists of mostly "authentic" yeasts, such as yeast bread and Candida , which are single-celled (unicellular) fungi, which reproduce vegetatively with buds. Most of these species were previously classified in taxon called Hemiascomycetes .
- The Taphrinomycotina belongs to a distinct and basal group in Ascomycota that is recognized following molecular analysis (DNA). The taxon was originally called Archiascomycetes (or Archaeascomycetes ). These include the hyphae fungi ( Neolecta , Taphrina , Archaeorhizomyces ), fission yeast ( Schizosaccharomyces ), and lung parasitic mammals, Pneumocystis .
Name of outdated taxon
Some obsolete taxon name - based on morphological features - sometimes still used for Ascomycota species. This includes sexual groups (teleomorfik) below, defined by their sexual fruiting body structure: Discomycetes, which includes all species forming apothecia; Pyrenomycetes, which included all sac fungi that form Perithecia or pseudothecia, or any structure that resembles the structure of this morphology; and Plectomycetes, which includes species that form cleistothecia. Hemiascomycetes including yeast and yeast-like fungus that has now been placed into Saccharomycotina or Taphrinomycotina, while Euascomycetes including remaining species of the Ascomycota, which are now in Pezizomycotina, and Neolecta, in Taphrinomycotina.
Some ascomycetes do not reproduce sexually or are not known to produce ASCI and are therefore anamorphic species. Anamorphs that produce conidia (mythospores) were previously described as Ascomycota mythospores. Some taxonomists place this group into a separate artificial phylum, Deuteromycota (or "Fungi Imperfecti"). Where recent molecular analysis has identified close association with shade taxa, anamorphic species have been grouped into Ascomycota, although no ascus determines. Sexual and asexual isolates of the same species generally carry the names of different binomial species, such as, for example, Aspergillus nidulans and Emericella nidulans, for asexual and sexual isolation, respectively, of the same species.
Deuteromycota species are classified as Coelomycetes if they produce their conidia in plates or plate-shaped conidiomates, known technically as pycnidia and acervuli . Hyphomycetes is a species in which conidiophores ( i.e. , the hypha structure carrying conidia-forming cells at the end) are free or loose. They are mostly isolated but sometimes also appear as parallel parallel cell bundles (described as synnematal ) or as pillow-shaped masses (described as sporodochial ).
Morphology
Most species grow as microscopic structures called hipha or as single cell buds (yeasts). Many hyphae are interconnected to form the thallus usually referred to as the mycelium, which - when seen by the naked eye (macroscopic) - is commonly called a fungus. During sexual reproduction, many Ascomycota usually produce large amounts of ASCI. Ascus is often contained in multicellular fruitful structures, sometimes easily visible, ascocarp (also called ascoma ). Ascocarps come in very large shapes: cup-shaped, club-shaped, like potatoes, like sponges, like seeds, flowing and like acne, like coral, like-nit, golf ball, hollow ball, spherical tennis ball, pillow-shaped, plated and furry in miniature (Laboulbeniales), classical microscopic shield-shaped Greek, lurking or sessile. They can appear solitary or clustered. The texture can also vary greatly, including meat, such as charcoal (carbonated), rough, chewy, gelatin-like, slimy, like flour powder, or like a cob. Ascocarps come in different colors like red, orange, yellow, brown, black, or, less often, green or blue. Some ascomyceous mushrooms, such as Saccharomyces cerevisiae, grow as single cell yeast, which - during sexual reproduction - develops into ascus, and does not form a fruit body.
In lichenized species, the fungal thallus defines the symbiotic colony form. Some dimorphic species, such as Candida albicans, can alternate between growth as a single cell and as a stringy multicellular hyphae. Other species are pleomorphic, showing asexual (anamorphic) as well as a form of sexual growth (teleomorphic).
Except for the moss, the non-reproductive (vegetative) mycelium of most ascomycetes is usually inconspicuous because it is generally grown on a substrate, such as soil, or grows in or inside a living host, and only ascomas can be seen when fruiting. Pigmentation, such as melanin in the hypha wall, along with fertile growth on the surface can produce visible fungal colonies; examples include the Cladosporium species, which make up black spots in caulking showers and other moist areas. Many ascomycetes cause decay of food, and therefore, the pellicle or moldy layer that develops on jam, juice, and other foods is a mycelia of this species or sometimes Mucoromycotina and almost never Basidiomycota. The sooty mushroom that grows on plants, especially in the tropics is thalli of many species.
Large mass of yeast cells, asci or cells such as ascus, or konidia can also form macroscopic structures. As an example. Pneumocystis species can colonize the lung cavity (seen in x-rays), causing the form of pneumonia. Asci from Ascosphaera fills the larvae and the honeybee pupae causes mummification with a chalk-like appearance, hence the name "chalkbrood". Yeast for small colonies in vitro and in vivo, and excessive growth of Candida species in the mouth or vagina causes "canker sores", a form of candidiasis.
Ascomycetes cell wall almost always contains chitin and β-glucans, and divisions in hyphae, called "septa", are the internal boundaries of individual cells (or compartments). Cell and septa walls provide stability and stiffness against hyphae and can prevent cytoplasmic loss if local damage occurs in cell walls and cell membranes. Septa generally has a small hole in the center, which functions as a cytoplasmic connection between adjacent cells, also occasionally allowing the movement of the nucleus cells in a hypha. The vegetative hyphae of most ascomycetes contains only one nucleus per cell ( uninucleate hyphae), but multinucleated cells - especially in the apical regions of the growing hyphae - may also be present.
Metabolism
Similar to other fungal phyla, Ascomycota is a heterotrophic organism that requires organic compounds as a source of energy. This is obtained by feeding on various organic substrates including dead matter, foodstuffs, or as a symbiont in or on other living organisms. To get these nutrients from their environment, ascomycetous fungi secrete strong digestive enzymes that break down organic matter into smaller molecules, which are then taken into cells. Many species live in dead plant material such as leaves, twigs, or logs. Some species colonize plants, animals, or other fungi as parasites or mutualistic symbionts and obtain all of their metabolic energy in the form of nutrients from their host tissues.
Due to their long evolutionary history, Ascomycota has evolved the capacity to break down almost every organic substance. Unlike most organisms, they can use their own enzymes to digest plant biopolymers such as cellulose or lignin. Collagen, an abundant structural protein in animals, and keratin - a protein that forms hair and nails--, can also serve as a food source. Unusual examples include Aureobasidium pullulans, which eat wall paint, and the kerosene fungus Amorphotheca resinae, which feeds airplanes (causing problems occasionally for the aviation industry), and possibly sometimes blocking fuel pipes. Other species can withstand high and growing osmotic stress, for example, in salted fish, and some ascomycetes are aquatic.
Ascomycota is characterized by a high degree of specialization; for example, certain Laboulbeniales species attack only one particular leg of a particular insect species. Many Ascomycota are involved in symbiotic relationships such as lichens - symbiotic associations with green algae or cyanobacteria - in which the mushroom symbionts directly acquire photosynthesis products. As with many basidiomycetes and Glomeromycota, some ascomycetes form symbioses with plants by colonizing the roots to form mycorrhizal associations. Ascomycota also represents several carnivorous fungi, which have developed a hyphae trap to capture small protists such as amoebae, as well as roundworms, rotifers, tardigrades, and small arthropods such as springtail ( Collembola >).
Distribution and environment
Ascomycota is represented in all terrestrial ecosystems around the world, which occur in all continents including Antarctica. Spores and hypha fragments are dispersed in the atmosphere and freshwater environments, as well as coastal and tidal zones. Distribution of species varies; while some are found on all continents, others, such as the white truffle Tuber magnatum , occur only in remote locations in Italy and Eastern Europe. Distribution of plant parasite species is often limited by host distribution; for example, Cyttaria is found only in Nothofagus (Southern Beech) in the Southern Hemisphere.
Reproduction
Asexual Reproduction
Asexual reproduction is the dominant form of propagation in Ascomycota, and is responsible for rapid dissemination of this fungus to new areas. This occurs through vegetatively reproductive spores, conidia. Konidiospores generally contain one nucleus and are the product of the cell division of mitosis and thus are sometimes called mythospores, which are genetically identical to the mycelium from which they originate. They are usually formed at the end of a special hypha, conidiophores . Depending on the species they may be dissolved by wind or water, or by animals.
Asexual spores
Different types of asexual spores can be identified by color, shape, and how they are released as individual spores. This type of spore can be used as a taxonomic character in the classification in Ascomycota. The most common type is a single-celled spore, called amerospores . If the spores are divided into two by cross-wall (septum), it is called didymospore .
When there are two or more cross-wall, the classification depends on the shape of the spores. If septa transversal , like the staircase, it is phragmospore , and if they have a net-like structure it is dictyospore me. In staurospores rays like arms radiate from the central body; on the other ( helicospores ) the entire spore is arranged spiral like a spring. Spores are very long such as worms with a ratio of length to diameter over 15: 1, called scolecospores .
Configuration and Confusion
The important characteristic of anamorphs from Ascomycota is conidiogenesis , which includes the formation of spores and dehiscence (separation from the parent structure). Koniogenesis corresponds to the embryology of animals and plants and can be divided into two basic forms of development: blastic conidiogenesis, in which spores have been proven before separating from conidiogenic hypotheses, and thallic conidiogenesis, at where newly formed cross-cell and cell forms develop into spores. Spores may or may not be generated in large-scale specialized structures that help to spread them.
These two basic types can be further classified as follows:
- blastic-acropetal (repetitive repetition at the end of a conicogenic hyphae, so the spore chains are formed with the youngest spores on the end),
- blastic-synchronous (simultaneous spore formation of central cells, occasionally with secondary acropetal chains formed from early spores),
- blastic-sympodial (repeated spore formation from behind the leading spores, so the oldest spores are on the main edge),
- blastic-annellidic (each spore separates and leaves a ring-shaped scar inside the scar left by the previous spores),
- blastic-phialidic (the spores arise and are removed from the open end of a special koniogenic cell called phialides, which remain constant in length),
- basauxic (where the conidia chain, in its younger developmental stages, is transmitted from the stem cell),
- blastic-retrogresive (spores are separated by cross-leg formation near the end of the conidiogenic hyphae, thus becoming shorter),
- thallic-arthric (the double cell wall divides the conidiogenic hyphae into a cell that develops into a short cylindrical spore called arthroconidia , sometimes every second cell dies leaving the artroconidia free),
- thallic-solitary (a large protruding cell separating itself from a conidiogenic hyphae, forming an internal wall, and developing into phragmospore ).
Sometimes conidia is produced in a structure visible to the naked eye, which helps to distribute spores. This structure is called "konidiomata" (singular: konidioma), and can take the form of pycnidia (which is pumpkin-shaped and embossed in the fungal tissue) or acervuli (which is cushioned and appears in network host).
Dehiscence occurs in two ways. In dehiscence schizolytic , double divider walls with lamella centers (layers) form between cells; the central layer is then damaged so it releases the spores. In dehiscence heterocyanosis and parasexuality
Some species of Ascomycota are not known to have a sexual cycle. Such asexual species may experience genetic recombination between individuals with processes involving heterokaryosis and parasexual.
Parasexuality refers to the process of heterokaryosis, caused by the incorporation of two hyphae belonging to different individuals, by a process called anastomosis , followed by a series of events that produce genetically different cell nuclei in mycelium. The incorporation of nuclei is not followed by meiotic events, such as gamete formation and resulting in an increase in the number of chromosomes per nucleus. Mitotic crossover can allow recombination, ie the exchange of genetic material between homologous chromosomes. The chromosome number can then be returned to its haploid state by nuclear division, with each daughter's nucleus genetically distinct from the original parent nuclei. Alternatively, nuclei may lose several chromosomes, producing aneuploid cells. Candida albicans (Saccharomycetes class) is an example of a fungus that has a parasexual cycle (see Candida albicans and Parasexual cycles).
Sex Sexual reproduction
Sexual reproduction in Ascomycota leads to the formation of ascus , the structure that defines this group of fungi and differentiates it from other fungal phyla. The ascus is a tubular vessel, an meiosporangium , containing the sexual spores produced by meiosis and the so-called ascospores .
Apart from some exceptions, such as Candida albicans , most ascomycetes are haploid, that is, they contain a set of chromosomes per nucleus. During sexual reproduction there is a diploid phase, which is usually very short, and meiosis restores the haploid state. The sexual cycle of a well-studied Ascomycota representative species is described in more detail in Neurospora crassa.
Sexual spore formation
The sexual part of the life cycle begins when the two paired hypha structures. In the case of homothalik species, marriage is activated between the hyphae of the same fungal clone, whereas in the heterothalic species, both hyphae must originate from genetically distinct fungal clones, ie, those who have different types of mating. This type of mating is typical of fungi and is associated roughly with the sexes in plants and animals; However one species may have more than two types of mating, so sometimes complex vegetative incompatibility systems. The adaptive function of the mating type is discussed in Neurospora crassa.
Gametangia is a sexual structure formed from hyphae, and is a generative cell. A very fine hyphae, called trichogyne arises from one gametangium, ascogonium , and merges with gametangium ( antheridium ) from other fungal isolates. The nucleus in the antheridium then migrates to ascogonium, and plasmogamy - cytoplasmic mixing - occurs. Unlike in animals and plants, plasmogamy is not immediately followed by core incorporation (called karyogami ). Conversely, the nuclei of two pairs of hyphae forms, initiates the dikaryophase of the sexual cycle, during which time the nucleus couple simultaneously divides. The combination of a paired core leads to the mixing of genetic material and recombination and is followed by meiosis. A similar sexual cycle is present in blue green algae (Rhodophyta). The wasted hypothesis states that a second cariogamous event occurred in ascogonium before ascogeny, resulting in a tetraploid nucleus divided into four diploid nuclei by meiosis and then into eight haploid nuclei by a process called brachymeiosis, but this hypothesis was not proven in the 1950s.
From the fertilized ascogonium, hyphae dinucleate occurs where each cell contains two nuclei. This hyphae is called ascogenous or fertile hyphae. They are supported by a vegetative mycelium containing a sterile, sterile hyphae (or mono-) nucleus. Mycelium containing sterile and fertile hyphae can grow into a fruit body, ascocarp , which may contain millions of fertile hyphae.
The sexual structure is formed in the fruiting layers of ascocarp, the hymenium. At one end of the askogenous hyphae, a typical U-shaped hook develops, which curves backward in contrast to the direction of hyphae growth. The two nuclei present in the apical part of each hyphae divide in such a way that the threads from their mitotic spiders run parallel, creating two genetically different sets of nuclei. One female nucleus migrates close to the hook, while the other daughter's nucleus puts into the basal part of the hyphae. The formation of two parallel cross walls then divides the hyphae into three parts: one on a hook with one nucleus, one in the original hyphae basal containing one nucleus, and one separating the U-shaped part, which contains two other nuclei.
The incorporation of nuclei (karyogami) occurs in U-shaped cells in the himenium, and results in the formation of a diploid zygote. Zygote grows into ascus, tubular capsule or elongated cylinder. Meiosis then elicits four haploid nuclei, usually followed by a further mitotic division that produces eight nuclei in each ascus. The nucleus along with some of the cytoplasm becomes closed in the membrane and cell wall to produce harmonized ascospores in ascus like peas in pods. (For a general description of meiosis and its adaptability functions see Meiosis and Bernstein and Bernstein).
When opening ascus, ascospores may be dispersed by the wind, while in some cases the spores are forcibly removed to form ascus; Certain species have evolved cannon spores, which can excrete ascospor up to 30 cm. far. When the spores reach the corresponding substrate, they sprout, forming a new hyphae, which restarts the life cycle of the fungus.
The ascus form is important for classification and is divided into four basic types: unitunicate-operculate, unitunicate-inoperculate, bitunicate, or prototunicate. See the article on ASCI for more details.
Ecology
Ascomycota fulfills a central role in most terrestrial-based ecosystems. They are important decomposers, break down organic materials, such as leaves and dead animals, and help detritivores (animals that eat decomposing materials) to get their nutrients. Ascomycetes along with other fungi can break up large molecules such as cellulose or lignin, and thus have an important role in nutrient cycles such as the carbon cycle.
The fruit body of Ascomycota provides food for many animals ranging from insects and snails and slugs ( Gastropoda ) to larger rodents and mammals such as deer and wild boar.
Many ascomycetes also form symbiotic relationships with other organisms, including plants and animals.
Lumut
Perhaps since the beginning of their evolutionary history, Ascomycota has formed symbiotic associations with green algae ( Chlorophyta), and other types of algae and cyanobacteria. This mutualistic association is commonly known as moss, and can grow and survive in terrestrial regions of the earth that are not friendly to other organisms and are characterized by extremes in temperature and humidity, including the Arctic, Antarctica, deserts, and mountain peaks. While the photoautotropic algal counterpart generates metabolic energy through photosynthesis, the fungus offers a stable matrix that supports and protects cells from radiation and dehydration. Approximately 42% of Ascomycota (about 18,000 species) form lichens, and almost all the fungal partners of the moss are derived from Ascomycota. Mycorrhizal Fungus and endophytes
Ascomycota members form two important types of relationships with plants: as mycorrhizal fungi and endophytes. Mycorrhiza is a symbiotic association of fungi with plant root systems, which can be very important for the growth and persistence of plants. The delicate mycelium tissue of the fungus allows an increase in the absorption of mineral salts occurring at low levels in the soil. In return, plants provide mushrooms with metabolic energy in the form of photosynthesis products.
Endophytic fungi live in plants, and those who form mutualistic or commensal associations with their host, do not damage their host. The exact nature of the relationship between endophytic and host fungi depends on the species involved, and in some cases the colonization of plant fungi may provide higher resistance to insects, roundworms (nematodes), and bacteria; in the case of grass endophytes, mushroom symbionts produce toxic alkaloids, which can affect the health of plant-eating mammals (herbivores) and prevent or kill herbivorous insects.
Symbiotic relationship with animals
Some ascomycetes of the genus Xylaria colonize ant ant leaf nests and other ants that grow from the Attini tribe, and the termite fungus garden (Isoptera). Because they do not produce the fruit body until the insects leave the nest, it is suspected that, as confirmed in some cases of Basidiomycota species, they can be cultivated.
Leather beetle (Scolytidae family) is an important symbiotic partner of ascomycetes. The female beetles transport the fungal spores to the new host in a typical tissue on their skin, mycetangia . The beetle tunnel enters the wood and into the big room where they lay their eggs. Spores released from mycetangia germinate into hyphae, which can break wood. The beetle larvae then eat mushroom mycelium, and, on reaching maturity, bring new spores with them to renew the infection cycle. A well-known example of this is the Dutch Elm disease, caused by ulmi ophiostoma , carried by European elm bark beetle, Scolytus multistriatus .
Importance for humans
Ascomycetes makes many contributions to the good of mankind, and also has many adverse effects.
Malicious interactions
One of their most dangerous roles is as an agent of many plant diseases. Example:
- Dutch Elm Disease, caused by closely related species Ophiostoma ulmi and Ophiostoma novo-ulmi , has caused the deaths of many elms in Europe and North America.
- The origin of Asia Cryphonectria parasitica is responsible for attacking Sweet Chestnuts ( Castanea sativa ), and almost eliminates the ever widespread American Chestnut ( Castanea dentata ),
- The maize disease ( Zea mays ), which occurs mainly in North America, is caused by Cochliobolus heterostrophus .
- Tafrina deformans causes the peach leaves of curls.
- Uncinula necator is responsible for the powdery mildew disease, which attacks the grape plant.
- The Moniacia Species causes brown decay like peaches ( Prunus persica ) and sour cherries ( Prunus ceranus ).
- Ascomycota members like Stachybotrys chartarum are responsible for woolen textile waning, which is a common problem especially in the tropics.
- Blue-green, red and brown prints attack and destroy foodstuffs - for example Penicillium italicum decaying oranges.
- Infected cereal Fusarium graminearum contains mycotoxins such as deoxynivalenol (DON), which can cause skin and mucous membrane lesions when pigs eat.
- Ergot ( Claviceps purpurea ) is a direct threat to humans when it attacks wheat or rye and produces highly toxic and carcinogenic alkaloids, causing ergotism if consumed. Symptoms include hallucinations, abdominal cramps, and burning sensations in the limbs ("Fire of Saint Anthony").
- Aspergillus flavus , grown in peanuts and other host, produces aflatoxin, which is liver damaging and highly carcinogenic. Candida albicans, yeast that attacks the mucous membranes, can cause an infection of the mouth or vagina called thrush or candidiasis, and is also blamed for "yeast allergy".
- Fungi such as Epidermophyton cause skin infections but are not very harmful for people with healthy immune systems. However, if the immune system is damaged they can be life-threatening; for example, Pneumocystis jirovecii is responsible for severe lung infections that occur in AIDS patients.
Positive effects
On the other hand, ascus fungus has brought some important benefits to mankind.
- The most famous case is probably the Penicillium chrysogenum fungus (formerly Penicillium notatum ), which, possibly attacking competing bacteria, produces antibiotics that, by pen name isilin, triggered a revolution in the treatment of bacterial infections in the 20th century.
- The importance of Tolypocladium niveum health as immunosuppressant can not be overstated. This secretes Ciclosporin, which, as well as given during organ transplants to prevent rejection, is also prescribed for auto-immune diseases such as multiple sclerosis, although there is some doubt over the long-term side effects of treatment. li>
- Some ascomycete mushrooms can be changed relatively easily through genetic engineering procedures. They can then produce useful proteins such as insulin, human growth hormone, or TPa, which is used to dissolve blood clots.
- Some species are common model organisms in biology, including Saccharomyces cerevisiae , Schizosaccharomyces pombe , and Neurospora crassa . The genomes of a number of ascomycete mushrooms have been completely sequenced.
- Yeast Baker ( Saccharomyces cerevisiae ) is used to make bread, beer and wine, in which processed sugars such as glucose or sucrose are fermented to make ethanol and carbon dioxide. Bakers use yeast to produce carbon dioxide, causing bread to rise, with boiling ethanol during cooking. Most vintners use it for ethanol production, with carbon dioxide released into the atmosphere during fermentation. Brewers and traditional producers of sparkling wine use both, with primary fermentation for alcohol and the second to produce carbon dioxide bubbles that provide beverage with a "shimmering" texture in the case of wine and foam desired in the case of beer.
- The enzyme of Penicillium camemberti plays a role in the making of Camembert and Brie cheese, while those of Penicillium roqueforti do the same for Gorgonzola, Roquefort and Stilton.
- In Asia, Aspergillus oryzae is added to soaked soybeans to make soy sauce, and is used to break down starch in rice and other grains into simple sugars for fermentation to East Asian alcohol drinks such as huangjiu and sake.
- Finally, some Ascomycota members are a selection of edibles; Morchella spp., truffles Tuber spp.), and lobster mushroom (Hypomyces lactifluorum ) are some of the most sought after delicacies of mushrooms.
See also
- List of Ascomycota families incertae sedis
- List of Ascomycota genera incertae sedis
Note
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Source of the article : Wikipedia
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