Semakova K N, Kiseleva E V
Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk.
Tsitologiia. 2003;45(8):746-57.
A comparative study of amphibian oocyte ultrastructural organization has shown a significant accumulation of elements of the smooth endoplasmic reticulum in the oocyte cytoplasm at the third stage of development. The analysis of oocytes of two frog species, Xenopus laevis and Rana temporaria, at the first and second stages of their development enabled us to recognize in the cytoplasm of the oocyte some myelin-like structures (MLs) made of 30-40 densely packaged membranous layers and shaped as dense bodies. MLs are also present in the adjacent follicular cells and in the intercellular space. In the oocyte cytoplasm these structures are located near the nuclear envelope and other intracellular organelles. At the third stage of oogenesis, which is characterized by a high functional activity of the cells, MLs are seen to unwrap sequentially into double-layer membranes similar to the smooth endoplasmic reticulum cisternae. Intermediate steps of this process being also observed. It is supposed that MLs may play the role of membrane stocks to be used eventually for the formation of nascent endoplasmic membranes in the amphibian oocytes.
一项对两栖动物卵母细胞超微结构组织的比较研究表明，在发育的第三阶段，卵母细胞细胞质中滑面内质网成分有显著积累。对非洲爪蟾和欧洲林蛙这两种蛙类卵母细胞发育第一和第二阶段的分析使我们能够在卵母细胞的细胞质中识别出一些髓磷脂样结构（MLs），这些结构由30 - 40个紧密包裹的膜层组成，呈致密小体状。MLs也存在于相邻的滤泡细胞和细胞间隙中。在卵母细胞细胞质中，这些结构位于核膜和其他细胞内细胞器附近。在以细胞高功能活性为特征的卵子发生第三阶段，可以看到MLs依次展开形成类似于滑面内质网池的双层膜。这一过程的中间步骤也能被观察到。据推测，MLs可能起到膜储备的作用，最终用于两栖动物卵母细胞中新生内质膜的形成。
