Summary
The fission yeast, Schizosaccharomyces pombe, a homothallic haploid strain NCYC 132, was induced to flocculate and conjugate to facilitate the study of the ascosporogenesis. It is found that two nuclei are formed during meiosis I and these nuclei divide again during meiosis II. The forespore membrane emerges at the beginning of meiosis II, elongates without fragmentation to enclose the nucleus and other cytoplasmic organelles, including mitochondria and ER. Meiosis occurs without fragmentation of the nuclear membrane. Immediately after the enclosure of the nucleus, the forespore membrane is resolved into two separate membranes. The inner one appears to become the spore plasmalemma and the outer one, if it persists, becomes a limiting membrane of the spore wall. In some cases, the outer membrane is seen to be ruptured. Spore wall materials deposite in the space between the inner and outer membranes.
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This investigation was supported by a research grant to B. Y. Yoo from the National Research Council of Canada (A-3651).
Postdoctoral fellow of the National Research Council of Canada (1969–1971).
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Yoo, B.Y., Calleja, G.B. & Johnson, B.F. Ultrastructural changes of the fission yeast (Schizosaccharomyces pombe) during ascospore formation. Archiv. Mikrobiol. 91, 1–10 (1973). https://doi.org/10.1007/BF00409533
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DOI: https://doi.org/10.1007/BF00409533