ISSN:
1040-452X
Schlagwort(e):
Chromatin
;
Acrosome
;
Spermiogenesis
;
Ensis ensis
;
Mollusca
;
Bivalvia
;
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Biologie
Notizen:
We describe chromatin condensation and acrosome development during spermiogenesis of Ensis ensis. The overall shape of the mature spermatozoon corresponds to the primitive type. The nucleus is oval and on its superior pole there is an elongated acrosome; the middle piece contains four mitochondria around the centriolar complex. The condensation of the nuclei seems to occur in three steps: first the diameter of chromatin fibers increases slightly from 17 to 20 nm; second, in midspermatids fiber pairs coalesce; and third, the coalescence continues by addition of other fibers until the nuclei become highly compacted. Chromatin changes are related with nuclear protein composition. Small proacrosomal vesicles show two regions of different electron density. At a later stage they fuse to give a single, spherical vesicle in round spermatids, which migrates to the upper pole and transforms into a tapered acrosome (18 μm long) with a central channel filled with finely fibrous material. © 1994 Wiley-Liss, Inc.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrd.1080370214
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