文昌鱼受精机理研究——受精卵的超显微结构

MECHANISM OF FERTILIZATION OF AMPHIOXUS (BRANCHIOSTOMA BELCHERI TSINGTAOENSIS)—THE ULTRASTRUCTURE OF FERTILIZED EGGS

青岛文昌鱼受精后受精膜即刻明显举起,皮层颗粒以完整形式胞吐到卵周腔中,分散后大部分皮层颗粒物质与卵黄膜结合一起组成三层结构的受精膜,随着受精膜的举起,它由厚变薄。雄性原核以核膜破裂,染色质去浓缩,扩大重建原核膜形成雄性原核,雌性原核形成是由分离的具有双层膜的染色体联合,膨大而成,雄性原核形成早于雌性原核。雄性原核的迁移受微丝控制。文昌鱼卵黄颗粒中存在线行和环形结构,这种亚显微结构电子密度很高,经实验证明,它既不是微管又不是微丝。

The fertilization membrane of the amphioxus (Branchiostoma belcheri tsingtaoensis Tchang et Koo) apparently extrusion soon after fertilization. The contents of the cortical granule which secret into the perivitelline space by complete exocytosis, associate with the vitelline membrane to form the tri-layer fertilization membrane. Following the extrusion of the fertilization membrane, the layer of cortical granules becames thinner. The male pronucleus was transformed from both the decondensed chromation and the reformed pronuclear envelope; while the female pronucleus was developed from the isolated chromosomes with bi-layer membrane which had gathered and swollen, furthermore, the male pronucleus was formed earlier than the female pronucleus, and the movement of the former was controlled by microfilaments. In addition, a special structure was observed in the yolk granules of the amphioxus eggs. This structure, Which was linear or circular, showed deep high eletron-density at the ultrastructural level. Our evidences demonstrate that it is neither microtubule nor microfilament.