雌核发育和两性融合发育鱼卵调控精核受精发育的生化特性研究

BIOCHEMICAL CHARACTERISTICS OF GYNOGENETIC AND BISEXUAL REPRODUCTIVE FISH EGGS REGULATING THE DEVELOPMENT OF SPERM NUCLEI DURING EARLY FERTILIZATION

两性融合生殖的鱼卵受精后，精核能疏松、解凝，形成雄性原核：雌核发育银鲫卵子受精后，精核发育受到抑制，无法形成原核。采用显微注射去膜精核以及细胞学和电镜观察的方法，本文对两类鱼卵受精后精核早期发育的生化性质进行了初步探讨，并着重研究了雌核发育银鲫卵子控制精核发育的生化特征。实验结果显示，两性融合生殖鱼类卵质中，一定量的Ｃａ２＋的存在，二硫键的还原作用对于精核的发育显然是必要的；而在雌核发育银鲫卵中，Ｃａ２＋的功能和二硫键的还原作用与精核发育受到抑制之间并无直接联系。银鲫卵质中似乎显示出异常的磷酸酶脂解活性，导致磷酸化过程无法进行，使精核解凝受到阻碍。另外，两性融合生殖的鱼卵重质层中具有大量诱导精核原核化的有关因子，而银鲫卵质中则缺少该因子（或活性极低）。银鲫卵质中还可能缺乏某些与雄性原核的核膜重组装有关的大分子物质。

Sperm nuclei have the ability of swelling and forming male pronuclei immediately after fertilization in eggs of bisexual reproductive fish. By contrast, the fertilized eggs of gynogenetic crucian carp (Carassius auratus gibelio) suppressed the appearance of male pronuclei. Using the method of demenbraned sperm injection together with cytological and ultrastructural observation, we made a preliminary examination on the biochemical charateristics in sperm nucleus development at early fertilization of two kinds of fish eggs, and focused mainly on the egg of gynogenetic crucian carp which regulated the unique reproduction via fertilization. The result that in cytoplasm of bisexual eggs the presence of certain concentration of Ca2+and the reduction of disulfide bond is of necessity at the development of sperm nucleus. But in ooplasm of gynogenetic crucian carp the Ca2+and disulfide bond reduction was not directly related to the inhibition of sperm nuclear development. On the other hand, the cytoplasm in gynogenetic eggs abnormaly high activity of phosphatase. Further research showed that there are plenty of relative factors which induce the forming of pronuclei from sperm nuclei in heavy ooplasmic fraction of bisexual eggs but none or less in gynogenetic eggs. The ooplasm of gynogenetic crucian carp may also lack some high molecules responsible for membrane assembly of male pronucleus.