Definitions for ascusˈæs kəs; ˈæs aɪ, -kaɪ, -ki
This page provides all possible meanings and translations of the word ascus
Random House Webster's College Dictionary
as•cusˈæs kəs; ˈæs aɪ, -kaɪ, -ki(n.)(pl.)as•ci
the sac in ascomycetes in which the spores are formed.
Origin of ascus:
1820–30; < NL < Gk askós bag, sac
saclike structure in which ascospores are formed through sexual reproduction of ascomycetes
A sac-shaped cell present in ascomycete fungi; it is a reproductive cell in which meiosis and an additional cell division produce eight spores.
Origin: From ἀσκός.
a small membranous bladder or tube in which are inclosed the seedlike reproductive particles or sporules of lichens and certain fungi
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can occur in numbers of one, two, four, or multiples of four. In a few cases, the ascospores can bud off conidia that may fill the asci with hundreds of conidia, or the ascospores may fragment, e.g. some Cordyceps, also filling the asci with smaller cells. Ascospores are nonmotile, usually single celled, but not infrequently may be coenocytic, and in some cases coenocytic in multiple planes. Mitotic divisions within the developing spores populate each resulting cell in septate ascospores with nuclei. In many cases the asci are formed in a regular layer, the hymenium, in a fruiting body which is visible to the naked eye, here called an ascocarp or ascoma. In other cases, such as single-celled yeasts, no such structures are found. In rare cases asci of some genera can regularly develop inside older discharged asci one after another, e.g. Dipodascus.
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