[Modality and structure of Japanese eel (Anguilla japonica) during spermiogenesis].

Abstract

The special process and special structure which bring organelle during the spermiogenesis of Japanese eel, Anguilla japonica were observed by scanning electron microscope and transmission electron microscope. The process which spermatoblast became sperm including four special stages, the early stage, the middle stage, the later stage and the spermic stage, then came into being a normal mature sperm. In the early stage, cell nucleus became long form gradually by the oval form. In one side of the cell nucleus, there was a big and special globoid structure dyeing lower, account for 1/3 of cell nucleus cubage. It contains a little of deep dyeing grain form and the lines form material, the outside is wrapped by plasmalemma separated with the cell nucleus, the outside of that structure and cell nucleus still lay a plasmalemma. The spermiogenesis of early stage did not form independent centriolar complex and mitochondria. In the middle stage, the cell nucleus presented a long form with the globoid structure on the top of the nucleus, and the down side had no globoid structure where the flagellum primordium appears. The globoid structure changed with the spermiogenesis. The inner part of the globoid differentiated a centriolar complex and mitochondria step by step. The lysosomes distributed in the medium segment of the cell nucleus obviously. In the late stage, the cell nucleus was similar with the shape of eyebrow or crescent. The centriolar complex released from the globoid structure, then became an independent structure. There were mitochondria which had not become the independent structure still in the globoid structure. Under the karyon, there was flagellum primordium where sent a rather long flagellum. The flagellum formed a typical "9+0" microtubular structure at that time. The spermatozoa in this phase has movable ability. In the spermic stage, the cell nucleus was round in shape. The centriolar complex was inside implantation fossa. Mitochondria were under karyon. And under the mitochondria was the central space of the sleeve. The flagellum formed a typical "9+2" microtubular structure at that time. The spermatozoa of Japanese eel, A. japonica became complete mature spermatozoa must pass through four phases for abnormality.