Fine structures and functional characteristics of the gamete of the Japanese sand lance, Ammodytes personatus.

概要

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The unfertilized egg of <I>Ammodytes personatus</I> was small spherical and has the adhesive membrane developed from the zona radiata externa covering en-tire surface. This membrane is composed of the adhesive projection of cylindrical structures of many filaments and basement layer with regular arrangement of small holes. The adhesive membrane of the fertilized egg showed tongue-like structure transformed from adhesive filament. When attached to substrates, the tips of the adhesive filament are subjected to adhesive types of transformation. The spermato-zoon was about 25μm in total length, which comprised the asymmetrically elon-gated nucleus with the hiatus near the top, a single small mitochondrion and a sin-gle flagellum. The mitochondrion was located at the posterior side of the elongated nucleus, abutting the flagellum. The flagellum showed the typical 9+2 structure and was remarkably swollen. The A-tubules of doublets 1, 2, 5 and 6 contained a dense substance. The sperm showed a progressive speed of 85.5μm/sec. In seawa-ter, the spermatozoa usually maintained a circular motion for 20sec. Morphologi-cal and/or motility characteristics of gametes are discussed in relation to the func-tional aspects which are probably associated with the unique mode of spawning of this species.
日本魚類学会の論文