Ultrastructural investigations on spermatogenesis and spermatozoan morphology in the endangered Adriatic sturgeon, Acipenser naccarii (Chondrostei, Acipenseriformes).

摘要: Spermatogenesis was investigated in the Adriatic sturgeon, Acipenser naccarii, by light and electron microscopy. The testis of unrestricted type had a germinal compartment composed lobules containing germ cells Sertoli cells, separated basal lamina from interstitial compartment, which Leydig myoid were detected for first time Acipenseridae. occurred spermatocysts produced when became associated with A spermatogonia subsequent generations, clone synchronized aligned spermatogonia. In primary spermatocytes at zygo-pachytene stage, large spherical nucleus contained synaptonemal complexes. smaller secondary ovoid central round scarce cytoplasm. Spermatids interconnected cytoplasmic bridges until early spermiogenesis. Chromatin initially condensed as long, twisted, nonhomogeneous fibers finally compact structure made thick filaments. Early spermatids showed flagellum, primordia centriole complex "implantation fossa," followed acrosomal vesicle formed Golgi complexes fibrous body to complex. spermatozoan head 10 postero-lateral projections trapezoidal nucleus, cylindrical midpiece six eight mitochondria, complex, "9 + 2" flagellum pair lateral fins. Three helical endonuclear canals crossed acrosome base implantation fossa; their spiralization that chromatin suggest spiral twisting during performed phagocytosis degenerating spermatozoa. Significant interindividual differences most morphological parameters Data on spermatogenesis A. naccarii morphometric measurements mature spermatozoa provide information about reproductive biology species useful not only phylogenetic studies but also evaluation sperm quality artificial reproduction projects restocking this other critically endangered sturgeon species.