Fine structure of the spermatozoa of Crassostrea gigas (Mollusca, Bivalvia).
We describe sperm ultrastructure and acrosome differentiation during spermiogenesis in Crassostrea gigas (Mollusca Bivalvia). The sperm cell is a uniflagellated cell of the primitive type. The head region contains a rounded or conical nucleus surmounted by small acrosome. This organelle consists of a membrane-bound acrosomal granule, the contents of which have a homogeneous density, except in the anterior region, which is positive for PTA. The acrosome also surrounds the perforatorium, which includes oriented fibrillar elements: this is the axial body. The middle piece contains four mitochondria encircling two perpendicular centrioles. The distal centriole is provided with a system of mechanical fixation to the plasma membrane, consisting of nine fibers in radial arrangement. The tail flagellum, about 50 microns long, contains the usual microtubular axoneme.
Gràcia Bozzo
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Department of Biochemistry and Physiology, Faculty of Biology, University of Barcelona, Spain.
Ribes
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E
Sagrista
E
E
Poquet
M
M
Durfort
M
M
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D008297:Male; D010125:Ostreidae / Q000166:cytology*; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*