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Fundamental mechanisms of viviparity in some teleost fishes

一些硬骨鱼胎生的基本机制

基本信息

批准号：
63560177
负责人：
TAKANO Kazunori
金额：
$ 1.47万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

The present research was planned to elucidate physiological mechanisms supporting phenomena of viviparity in some rockfish species of the genera Sebastes and Sebastiscus.Seasonal reproductive cycles were examined histologically in male and female Sebastes taczanowskii. On the basis of a comparison of reproductive cycles among four Sebastes species, it was suggested that the northern species tended to prolong gametogenesis in both sexes, and that sperm storage in the ovary also tended to be longer in the northern than in the southern species. In vitro incubation experiments revealed that 17alpha, 20beta- dihydroxy-4-pregnen-3-one (17alpha,20beta-DP) had the most significant effect in inducing oocyte maturation. Furthermore, changes in serum steroid hormone levels were studied during the reproductive cycles. It was suggested that estradiol-17beta was the most important steroid involved in vitellogenesis and 17alpha,20beta-DP possibly played an important role in gestation in S.taczanowski … More i and Sebastiscus marmoratus. In two oviparous teleosts, Oryzias latipes and Gasterosteus aculeatus, on the other hand, fertilization and early embryonic development could be experimentally induced in their ovaries after artificial insemination. These results indicate that physiological innovation on the maternal side, which is concerned with the maintenance of embryonic development during late pregnancy and the induction of parturition, may be essential for successful attainment of viviparity.Female-specific serum proteins (FSSPs) in S. faczanowskii were identified and partially characterized by immunochemical procedures. It was suggested that, among multiple FSSPs, vitellogenin was used only for yolk formation in ovarian oocytes and was not a direct nutritional source for developing embryos during gestation.In S. taczanowskii and S. schlegeli, it was confirmed morphologically and histochemically that developing embryos ingested yolk-like materials through their hindgut during late pregnancy. An increase in levels of Na,K-ATPase activity during the same period was observed in embryos of these two species. Furthermore, some ultrastructural features observed in ovarian tissues suggested possible underlying physiological mechanisms correlated with the maintenance of pregnancy in Sebastes. Less

本研究计划阐明支持 Sebastes 和 Sebastiscus 属的一些岩鱼物种胎生现象的生理机制。对雄性和雌性 Sebastes taczanowskii 的季节性繁殖周期进行了组织学检查。根据对四种塞巴斯特物种生殖周期的比较，有人认为北方物种往往会延长两性的配子发生，而且北方物种在卵巢中的精子储存时间也往往比南方物种更长。体外孵化实验表明，17α，20β-二羟基-4-pregnen-3-one（17α，20β-DP）在诱导卵母细胞成熟方面具有最显着的作用。此外，还研究了生殖周期期间血清类固醇激素水平的变化。有人认为雌二醇-17β是参与卵黄发生的最重要的类固醇，17α，20β-DP可能在S.taczanowski和Sebastiscus marmoratus的妊娠中发挥重要作用。另一方面，在两种卵生硬骨鱼（Oryzias latipes 和 Gasterosteus aculeatus）中，人工授精后可以在其卵巢中通过实验诱导受精和早期胚胎发育。这些结果表明，母体方面的生理创新（涉及妊娠晚期胚胎发育的维持和诱导分娩）可能对于成功获得胎生至关重要。通过免疫化学程序鉴定并部分表征了 S. faczanowskii 中的雌性特异性血清蛋白（FSSP）。研究表明，在多种FSSP中，卵黄原蛋白仅用于卵巢卵母细胞中卵黄的形成，并不是妊娠期间发育胚胎的直接营养来源。在S. taczanowskii和S. schlegeli中，形态学和组织化学证实发育中胚胎在妊娠后期通过后肠摄入卵黄样物质。在同一时期，这两个物种的胚胎中 Na,K-ATP 酶活性水平有所增加。此外，在卵巢组织中观察到的一些超微结构特征表明，Sebastes 可能存在与维持妊娠相关的潜在生理机制。较少的