"(Ascomycota) Caloscypha fulgens (3)" by tgoralsky1 is licensed under CC BY 2.0
Definition of Ascomycota
Ascomycota are also known as the sac fungi . A fungi or fungal sexual reproduction by making ascospores in the ascus ( ascus = sac or bag / purse). Ascus is a kind of sporangium that produces ascospores.
Several asci usually cluster and gather to form a fruiting body called ascorcarp or ascoma (if many are called askomata). Askomata can be in the form of a bowl, a bottle, or like a balloon). Hyphae of Ascomycotina are generally monokaryotic (uninucleate or have a single nucleus) and the cells are separated by simple septa.
So, the ascus is a common structure that is owned by members of the Ascomycota Division. Some of their bodies are unicellular and some are multicellular. Live as saprophytes and parasites. Some types of them can also be in symbiosis with living creatures blue-green algae and green algae that form one-celled lichens.
Ascomycota Characteristics
In general, the characteristics or characteristics of fungi that are included in the Ascomycota division are as follows.
■ It is true fungi (Eumycota) along with Basidiomycota and Deuteromycota.
■ Single-celled (unicellular) or multicellular (multicellular).
■ Ascomycota multicellular have insulated hyphae
■ The cell walls made of chitin.
■ Characteristically well as saprophyte heterotrophic well as parasites and there are symbiotic with another organism.
The hyphae are insulated and each cell usually has one nucleus (haploid).
■ Some types of Ascomycota can be symbiotic with green algae and blue algae to form lichens.
■ Having a tool called the ascus spore, which is a cell in the form of a bubble or tube where the formation of ascospores. Ascospores are the result of sexual reproduction.
The ascus has a sac-like structure.
■ Form askokarp diverse or varied, shaped like bottles, bowls and balls.
■ Reproductive do both sexually and asexually.
Ascomycota Body Structure
Ascomycota fungi have a thallus consisting of a septate mycelium. Sexual reproduction by forming ascospores in the ascus, while asexually by forming single conidia or chains at the ends of special hyphae called conidiophores. This collection of ascus will form ascocarp which have various shapes and most of them are cup-shaped.
There are Ascomycota fungi that live as saprophytes that destroy organic remains, some are parasites that can cause disease. Examples of fungi that include Ascomycotina are as follows.
■ yeast ( Saccharomyces )
This group does not form ascocarp, no clear hyphae are seen like other fungi. The body consists of round oval cells and can sprout / form a bud to form a chain of cells or pseudo hyphae. Yeast can ferment a variety of organic materials, one of the most common is fermentation in the formation of alcohol. According to the chemical reaction as follows.
C 6 H 12 O 6 → 2C 2 H 5 OH + 2CO 2 + Energy
■ Penicillium
This type of fungus likes habitats that contain sugar, such as bread or ripe fruit. These mushrooms appear green or bluish in color. Asexual reproduction by formation of conidia in chains on erect conidiophores.
Types of species are Penicillium notatum , Penicillium chryzogenum , producing antibiotics. Penicillium camemberti and Penicillium requoforti for quality improvement in cheese making, Penicillium italicum , Penicillium digitatum citrus fruit spoiler
Aspergillus fumigatus causes aspergillosis (a dangerous disease in domestic and wild birds that attacks the respiratory tract). This fungus grows on feces. Aspergillus flavus produces aflatoxins, which are thought to cause liver cancer. This type grows on peanuts that are not fresh or foods made from peanuts.
The Ascomycota Way of Life
Ascomycota live as decomposers of organic matter, especially from plants or the remains of organisms in the soil and also in the sea. Single-celled ascomycota or yeast live in materials containing sugar or carbohydrates, such as cassava which produces tapai or grape juice used to make red wine ( wine ). Some species exist that live as parasites in other organisms.
The morel fungus or Morchella esculenta lives in a mutualistic symbiosis with plants by forming mycorrhizae. Ascomycota can protect plants from insect pests by releasing toxins for Ascomycota that live on the surface of leaf mesophyll cells. There are about 30,000 species or half of the existing Ascomycota species found living in symbiosis with algae to form lichens (lichens).
Ascomycota Reproduction Method
As previously explained, Ascomycota are unicellular and multicellular and reproduce in two ways, namely asexually (vegetatively) and sexually (generatively). Thus there are 4 types of reproduction in Ascomycota, namely as follows.
1. Unicellular Ascomycota Asexual Reproduction
For unicellular cell type Ascomycota, asexual reproduction is carried out by cell division or budding from the parent cell. The bud that is released will become a new fungal cell. However, if they are not released, the stem cells will form a chain of pseudohyphae (pseudo hyphae).
2. Unicellular Ascomycota Sexual Reproduction
In unicellular Ascomycota, sexual reproduction begins with conjugation or the union of two haploid (n) cells of different types. The result of the union of the two cells will produce a zygote with a diploid (2n) chromosome. The zygote grows into a diploid ascus. The diploid nucleus (nucleus) in the ascus divides by meiosis to produce 4 nuclei with haploid (n) chromosomes.
Around the four nuclei, a cell wall with 4 ascospores is formed in the ascus with haploid (n) chromosomes. If the ascus is ripe, then the ascus will rupture by releasing ascospores. Ascospores will grow into new fungal cells that are haploid (n).
3. Multicellular Ascomycota Asexual Reproduction
For multicellular cell type Ascomycota, asexual reproduction is carried out in two ways, namely hyphae fragmentation and conidiospore asexual spore formation. The severed adult hyphae will grow into a new fungal hyphae. The mature haploid (n) hyphae will produce conidiophores (conidia stalks).
Conidia have a haploid number of chromosomes (n). Conidia in Ascomycota mushrooms are colorful, including orange, black, blue or brown. If the environmental conditions are favorable, the conidia will germinate into haploid hyphae. Hyphae will branch to form mycelium with haploid (n) chromosomes.
4. Multicellular Ascomycota Sexual Reproduction
The sexual reproduction in multicellular Ascomycota has several stages, namely as follows.
● hyphae (+) and hyphae (-), each of which has a haploid chromosome adjacent. Hyphae (+) form ascogonium (female reproductive organs), while hyphae (-) form antheridia (male reproductive organs).
● Askogonium will form a channel leading trikogen Antheridium called. Through the tricogen, the process of plasmogamy (cytoplasmic fusion) occurs. The ascogonium will receive a nucleus with haploid chromosomes from the antheridium so that the ascogonium has many nuclei from both (dikaryotic).
● Askogonium will grow into a dikaryotic hyphae branching and incorporated in askokarp (fruiting bodies).
● The ends of hyphae on askokarp will form the ascus dikaryotic.
● In the case aksus kariogami (core fusion) that will form the core of chromosome diploid (2n).
● Core diploid contained in the ascus will divide meiosis to produce four haploid nucleus (n).
● Each of the haploid nuclei will divide by mitosis so that in the ascus there are 8 nucleus. Furthermore, around the nucleus will form a cell wall and form ascospores with haploid (n) chromosomes.
● If the ascus has been cooked, then ascospores will grow simultaneously. This happens because if one ascus ruptures, it will result in the rupture of another ascus.
● ascospores fall in place matches will germinate into new haploid hyphae (n). Haploid hyphae will grow branches to form haploid mycelium (n).
Ascomycota Life Cycle
The cycle or life cycle of Ascomycota starts from ascospores which grow into branching threads (hyphae). Then, one of the several cells at the tip of the hyphae differentiates into an ascogonium, which is wider than a regular hyphae. The other end of the hyphae forms an antheridium. The antheridium and ascogonium are located close together and have a number of haploid nuclei.
The ascogonium grows tricogonium which connects the ascogonium with antheredium. Through this tricogonium the nucleus of the antheredium moves to the ascogonium and then pairs with the nucleus of the ascogonium. Furthermore, the ascogonium grows a number of hyphae called ascogonium hyphae. The nuclei divide by mitosis and remain in pairs.
Ascogonium hyphae grow to form branching septa. The ascogonium has many nuclei, while at the ends it has 2 nuclei. These ascogonial hyphae then develop with the growth of a compact vegetative mycelium, forming a fruiting body.
Two nuclei on the ascus will form a diploid nucleus which then divides by meiosis to produce 8 ascus spores (ascospores). If the ascospores fall in a suitable environment, they will grow to form new hyphae or mycelium.
Examples and Roles of Ascomycota
The Ascomycota division consists of many colorful fungi that grow on food, destroying fruit, field crops, and other plants. Some Ascomycota secrete cellulase and protease enzymes that can damage cotton and wool fabrics, especially in warm and humid places.
These environmental conditions can make mushrooms grow well. However, Ascomycota also bring benefits to plants through mutualistic relationships with plant roots. The following are some examples of fungi belonging to the Ascomycota Division and their role in life.
■ Morchella esculenta is a fungus that has a body with juicy fruit. Morchella esculenta mushrooms are very delicious to eat which can be found under fruit trees.
■ Saccharomyces cerevisiae is a single-celled fungus and have ascus walls are thin and are also known as yeast. The benefits or uses of Saccharomyces cerevisiae are used in the manufacture of alcoholic beverages, tapai, and as a bread dough developer. This fungus can convert sugar into alcohol and carbon dioxide (CO 2 ) by going through a fermentation process (anaerobic respiration). Gas CO 2 formed will make the bread rise.
■ Trichophyton mentagrophytes is a type of fungus that causes ringworm skin disease on the body and scalp.
■ Neurospora crassa and Neurospora sitophila is mushroom pie which has spores with orange. Neurospora crassa is also used for genetic research, because its sexual life cycle is short.
■ Candida albicans is a parasitic life in epithelial tissues moist, such as respiratory tract, gastrointestinal tract, and female genital or cause of vaginal discharge.
■ Penicillum notatum and Penicillium chrysogenum is the fungus that is used as the manufacture of penicillin that is done by extracting the liquid culture. Penicillin is used to kill bacteria, such as Neisseria meningitidis , Streptococcus pneumoniae and Staphylococcus sp .
■ Claviceps purpurea is Ascomycota fungus that has a purple color called ergot , parasitic on rye (rye). If this fungus is also ground with wheat and mixed in flour, and until it is consumed by humans, then what happens will cause gangrene . The symptoms experienced are such as nerve spasms, burning sensation, temporary insanity (temporary), and hallucinations.
■ Tuber Melanosporum ( truffle ) is a fungus that lives in symbiosis with plant roots to form mikorhiza. Truffles are very popular with food tasters because of their delicious taste. Truffle seekers usually use the help of dogs who have a keen sense of smell to find them.
■ Blue mold or blue mold is a fungus that grows on citrus fruits. Blue mold is a penicillum fungus whose life is saproba.
■ Aspergillus flavus is a fungus which generally live saproba on food and grains. Colonies of Aspergillus flavus produce spores that have a greenish brown or black color and secrete aflatoxin compounds that are toxic to humans.
■ Aspergillus oryzae used to mengempukkan bread dough, and the fungus can produce a protease enzyme.
■ Aspergillus wentii role in the manufacture of sake, soy sauce, tauco, citric acid, oxalic acid and formic acid, as well as producing the protease enzyme.
■ Aspegillus niger used to degas O 2 from the juice, and can clear it. The fungus can also produce the enzymes glucose oxidase and pectinase.
■ Aspergillus fumigatus is a fungus that can cause cancer of the lungs of a bird.
■ Apergillus nidulans live as parasites in the ear, causing automikosis.
■ Piedraia hortai cause infection in human hair.
