Ascomycetes:
Ascomycota is a division or phylum of the kingdom Fungi that, together with the Basidiomycota, form the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. They are the largest phylum of Fungi, with over 64,000 species.[2] The defining feature of this fungal group is the "ascus" (from Greek: ?s??? (askos), meaning "sac" or "wineskin"), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Previously placed in the Deuteromycota along with asexual species from other fungal taxa, asexual (or anamorphic) ascomycetes are now identified and classified based on morphological orphysiological similarities to ascus-bearing taxa, and by phylogenetic analyses of DNA sequences.[3][4]
The ascomycetes are a monophyletic group, i.e. it contains all descendants of one common ancestor. This group is of particular relevance to humans as sources for medicinally important compounds, such as antibiotics and for making bread, alcoholic beverages, and cheese, but also as pathogens of humans and plants. Familiar examples of sac fungi include morels, truffles, brewer's yeast and baker's yeast,dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as Cladonia belong to the Ascomycota. There are many plant-pathogenic ascomycetes, including apple scab, rice blast, the ergot fungi, black knot, and thepowdery mildews. Several species of ascomycetes are biological model organisms in laboratory research. Most famously, Neurospora crassa, several species of yeasts, and Aspergillus species are used in many genetics and cell biology studies. Penicillium species on cheeses and those producing antibiotics for treating bacterial infectious diseases are examples of taxa that belong to the Ascomycota.(Wikipedia 2016)
Most species grow as filamentous, microscopic structures called hyphae. Many interconnected hyphae form a mycelium, which—when visible to the naked eye (macroscopic)—is commonly called mold (or, in botanical terminology, thallus). During sexual reproduction, many Ascomycota typically produce large numbers of asci. The asci is often contained in a multicellular, occasionally readily visible fruiting structure, the ascocarp (also called an ascoma). Ascocarps come in a very large variety of shapes: cup-shaped, club-shaped, potato-like, spongy, seed-like, oozing and pimple-like, coral-like, nit-like, golf-ball-shaped, perforated tennis ball-like, cushion-shaped, plated and feathered in miniature (Laboulbeniales), microscopic classic Greek shield-shaped, stalked or sessile. They can appear solitary or clustered. Their texture can likewise be very variable, including fleshy, like charcoal (carbonaceous), leathery, rubbery, gelatinous, slimy, powdery, or cob-web-like. Ascocarps come in multiple colors such as red, orange, yellow, brown, black, or, more rarely, green or blue. Some ascomyceous fungi, such as Saccharomyces cerevisiae, grow as single-celled yeasts, which—during sexual reproduction—develop into an ascus, and do not form fruiting bodies.
In lichenized species, the thallus of the fungus defines the shape of the symbiotic colony. Somedimorphic species, such as Candida albicans, can switch between growth as single cells and as filamentous, multicellular hyphae. Other species are pleomorphic, exhibiting asexual (anamorphic) as well as a sexual (teleomorphic) growth forms.
Except for lichens, the non-reproductive (vegetative) mycelium of most ascomycetes is usually inconspicuous because it is commonly embedded in the substrate, such as soil, or grows on or inside a living host, and only the ascoma may be seen when fruiting.Pigmentation, such as melanin in hyphal walls, along with prolific growth on surfaces can result in visible mold colonies; examples includeCladosporium species, which form black spots on bathroom caulking and other moist areas. Many ascomycetes cause food spoilage, and, therefore, the pellicles or moldy layers that develop on jams, juices, and other foods are the mycelia of these species or occasionallyMucoromycotina and almost never Basidiomycota. Sooty molds that develop on plants, especially in the tropics are the thalli of many species.[clarification needed]
Large masses of yeast cells, asci or ascus-like cells, or conidia can also form macroscopic structures. For example. Pneumocystis species can colonize lung cavities (visible in x-rays), causing a form of pneumonia.[7] Asci of Ascosphaera fill honey bee larvae and pupae causing mummification with a chalk-like appearance, hence the name "chalkbrood".[8] Yeasts for small colonies in vitro and in vivo, and excessive growth of Candida species in the mouth or vagina causes "thrush", a form of candidiasis.
The cell walls of the ascomycetes almost always contain chitin and ß-glucans, and divisions within the hyphae, called "septa", are the internal boundaries of individual cells (or compartments). The cell wall and septa give stability and rigidity to the hyphae and may prevent loss ofcytoplasm in case of local damage to cell wall and cell membrane. The septa commonly have a small opening in the center, which functions as acytoplasmic connection between adjacent cells, also sometimes allowing cell-to-cell movement of nuclei within a hypha. Vegetative hyphae of most ascomycetes contain only one nucleus per cell (uninucleate hyphae), but multinucleate cells—especially in the apical regions of growing hyphae—can also be present.
Dedicated to:
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| Dr. Alka Pande |
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About Database
The Indian Rust Fungal Database (IRFD) is a simple reference database.
Beinig a database of references, the structure of this relational database is very simple and easy to use.
Each record in the database has a unique identification number. For example, 'UID123' stands for 'Unique Identification number 123'. In addition to this identification number there is another identification number which uniquely identifies individual species. This number is called 'IMD' number. This number is useful since there can be more than one references to a single individual species. For example, there are two records for Abortiporus biennis. Thus this record has two UIDs, viz. UID99 and UID729. But the species has single unique IMD number IMD.
1. Search : Users can build simple as well as complex queries. The search results are alphabettically arranged according to generic and specific names. The IMD numbers are also given in the search results.
2. Browse : Database can be browsed by three hierarchical catagories viz. Family, Genus and Species. In addition to this, all records can also be browsed at a time. The number of sub entries are shown at each level of browsing.
Above two options allow the users to query the database in varied ways.
All information of a particular record can be viewed in a card viewer which opens in the same page by clicking on a name in the search/browse result.
The Indian Myxomycetous Database (IMD) has been linked to MycoBank.
Database Management System : MySQL 5.0
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Myxomycetous Photogallery
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Education
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DIV 4
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| Introduction |
| About Database |
| Photogallery |
| Education |
Database statistics
| Number of Families | : | 128 | | Number of Genus | : | 460 | | Total number of Species | : | 1160 | | Total number of records | : | 1604 |
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