两种发育型鱼类卵母细胞成熟过程中促精核发育现象的研究
STUDIES ON THE PHENOMENA OF STIMULATING THE DEVELOPMENT OF SPERM NUCLEUS DURING OOCYTE MATURATION IN TWO TYPES OF FISHES
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摘要: 采用实验细胞学技术,比较研究了红鲤精核在雌核发育鱼类(银鲫)和两性融合发育鱼类(红鲤、彩鲫)卵母细胞成熟各阶段中的发育状况,结果表明:在两性融合发育鱼类中,当卵母细胞发育到胚泡破裂期吋,精核开始解凝发育,及至第一次成熟分裂中期后阶段,高度解凝的精核才开始原核化,相应地,在雌核发育银鲫中,精核也只有在与胚泡物质接触后,才能开始解凝,并且在三极纺锤体形成后期初步原核化,但与两性融合发育鱼类相比,精核的原核化程度明显降低。这些实验结果初步揭示,在两性融合和雌核发育鱼类卵中均可产生促精核解凝和原核化的两类因子(SNDFs和SPDFs),其中SNDFs的活性表达起始于卵母细胞胚泡破裂时期,而SPDFs活性则产生于第一次成熟分裂中期后或三极纺锤体形成后阶段,并且两性融合发育鱼类卵中的SPDFs活性远远高于雌核发育鱼类卵母细胞。Abstract: Using the experimental cytological methods, we studied the development of the injected red carp (Cyprinus carpio red variety) sperm nuclei in the oocytes at different stages of maturation in the amphimictic fishes red carp and colored goldfish (Carassius auratus colored variety) and the gynogenetic crucian carp (Carassius auratus gibelio). The results showed that, in the oocytes of amphimictic and gynogeneic fishes, the decondensation of injected sperm nuclei began at the same time (GVBD), but their pronucleation started at the later metaphase of the meiosis I and the later phase of the formation of the tripolar spindle respectively. In oocytes of the gynogenetic crucian carp, the decondensed degree of the sperm nuclei was same as those in the amphimictic fishes, but their pronucleated degree was much lower. Based on those results, we concluded that, during the oocyte maturation in red carp and colored goldfish, two types of factors could be produced successfully. One type controls the decondensation of sperm nucleus (termed sperm nucleus decondensation factors: SNDFs), while the other controls pronucleation (termed sperm pronucleus developmental factors: SPDFs). During the oocyte maturation in the gynogenetic crucian carp, the activities of the SNDFs were the same as those in the amphimictic fishes, but the activities of SPDFs were very low. The expression of the activitis of SNDFs in the ova of both amphimictic and gynogenetic fishes is related to the GV materials, but the expression of the activities of SPDFs is different between two types of fishes. The activities of SPDFs appear to bear an important relationship to the normal completion of meiosis I. The gynogenetic crucian carps, which have the abnormal meiosis I, show reduced activities of SPDFs.