Studies On Testicular Histology, Spermatogenesis And Amplification Of Sox Gene Of Pelteobagrus Fulvidraco (Richardson)

Gonad was substructure that fishes carries out breeding activity. To completely master the breeding regularity of fishes, we should carry out penetrating investigation on mechanism of sex determination, mechanism of gonadal differentiation, histochemistry and histology of gonad and so on. Only we had understood the mechanism of gonadal differentiation and development and known the breeding habit of fishes, so we would have controlled the breeding activity of fishes and applied to production of fish farming. As testicular structure is relatively complexity and originality, and there is conspicuous difference with outer morphous and interior structure for different fishes, so it has been focused by at home and abroad scholars. Pelteobagrus fulvidraco (Richardson) belongs to the Order of Siluriformes (catfish) .family of Bagridae (Bagrid catfishes). It is now becoming an important economical fish for aquaculture in China. As female and male individuality of Pelteobagrus fulvidraco ( Richardson ) had a conspicuous difference on growth after sex determination, but the report about molecular control mechanism of this specificity didn't appear at present. So this investigation analysised structure of histology and uitrastructure of testis in depth, in order to understand the content of reproductive biology about structure of testis and spermatogenesis. Simultaneously, this investigation approached about Sox gene, in order to understand mechanism of sex determination and characteristic of gonadal development. To know the propagating regularity of the fish could greatly benefit the cultivation in pond.This investigation used sexually matured Pelteobagrus fulvidraco (Richardson) to make materials of experiment. The histology, uitrastructure of testis and sox gene were investigated by light microscope, transmission electron microscope and gene clone technology of molecule biology.1. In the histology research, the result indicated that the testis was lobular type, which was typical of most teleosts. But the structures of seminiferous lobule and seminal vesicle were relatively complexity.2. The spermatogonium consisted of A type and B type, and the spermatogonium of A type had two different type, namely A l type and A2 type, which the A1 type did not have chromatoid body. There was no formation of sleeves or few sleeves occurring in the mitochondria of Al type.3. Each germ cell had chromatoid body except for the spermatogonium of Al type, and the chromatoid body became small and dispersed with the cell developing constantly, disappearing completely in the sperm.4. The prophase of primary spermatocyte would appear synaptonemal complex, which should been the symbol that the homologous chromosome carried through the change of homologous gene.5. The formation of spermatozoa included three periods: prophase. metaphase and anaphase.6. According to the observation in the scan electron microscope, the head of sperm was ellipse, the long diameter being 1.70 μm and the short diameter being 1.50 urn: the length of flagellum of tail was about 25~30μm, the diameter being 0.18μm.7. In addition, the templates from DNA of Pelteobagrus fulvidraco( Richardson) were PCR amplified with the four primer. The results indicated that the 220 bp, 400 bp, 450 bp,750 bp and 900 bp bands were appeared, which showed that there were no sexual difference. Then the 200 bp bands were sequenced, the result proved that the length of the segment was 221 bp, and there was only a different basic group between male and female, which was homologous gene. The identity of the sequence with SRY gene of human was 41.67%. As the homology to the SRY gene was lower, whether this gene was concerned with sexual differentiation was uncertain.