ascus

American  

[as-kuhs] / ˈæs kəs /

noun

Mycology.

asci plural

1. the sac in ascomycetes in which the sexual spores are formed.

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ascus British  

/ ˈæskəs /

noun

1. a saclike structure that produces (usually) eight ascospores during sexual reproduction in ascomycetous fungi such as yeasts and mildews

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ascus Scientific  

/ ăs′kəs /

asci plural

1. A membranous, often club-shaped structure inside which ascospores are formed through sexual reproduction in species of the fungi known as ascomycetes. The ascus is unique to ascomycetes and distinguishes them from other kinds of fungi. Asci are formed when two hyphae that are sexually compatible conjugate. Each ascus typically develops eight ascospores. Asci swell at maturity until they burst, shooting the ascospores into the air.

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Other Word Forms

Inflected Forms

noun

• asci
  plural

Etymology

Origin of ascus

1820–30; < New Latin < Greek askós bag, sac

Example Sentences

A dikaryotic ascus that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores.

From Textbooks • Jan. 1, 2015

The zygote undergoes meiosis without cell division, resulting in an ascus with four 1n nuclei arranged in a row.

From Textbooks • Jan. 1, 2015

In each ascus, two or more haploid ascospores fuse their nuclei in karyogamy.

From Textbooks • Jan. 1, 2015

You can count the eight ascospores in this ascus: The tasty, tasty asci of a Morchella sp.

From Scientific American • Sep. 5, 2012

Spores larger, usually 8 in each ascus, Spores hyaline.

From Ohio Biological Survey, Bull. 10, Vol. 11, No. 6 The Ascomycetes of Ohio IV and V by Hilker, Leafy Jane Corrington