泥螺卵黄发生过程中线粒体的变化

Mitochondrial Changes During Vitellogenesis in Oocytes of Bullacta exarata

利用透射电镜 (TEM)技术研究了泥螺卵黄发生过程中线粒体的形态结构的变化特点。结果表明 ,从卵黄发生早期到晚期 ,卵母细胞内线粒体经历了从外部形态到内部结构的一系列变化。卵黄合成初期的卵母细胞内 ,线粒体多 ,结构典型 ,仅部分线粒体外膜破裂 ,嵴和内膜逐渐消失。卵黄发生中期 ,线粒体基质空泡化 ,嵴和内膜消失 ,腔内充满颗粒状物质 ,最后演变成卵黄颗粒。随着卵母细胞的发育 ,卵黄颗粒的数量和直径逐渐增加 ;卵黄发生后期 ,卵质中胞器不发达 ,细胞质中充满卵黄颗粒 ,在卵黄颗粒之间仅有少量线粒体存在 ,提供细胞代谢所需的能量。此外 ,对线粒体在卵黄形成中的功能。

The changes of mitochondrial ultrastructure during vitellogenesis in oocytes of Bullacta exarata were investigated by transmission electron microscope method. The results show that mitochondria are the organelles that first involved in the information of yolk granules,their outer and inner morphology differ in different oocyte stages,and the numbers of typical ones decrease during the process of vitellogenesis. At the early stage of vitellogenesis,there are many mitochondria in ooplasm of the oocytes. These are rounded with numerous cristae and electron dense matrix. Then some mitochondrial cristae and inner membrane begin to degenerate. At the mid stage,the cristae and inner membrane disappear,there are a great number of small dense masses in the mitochondrial lumen,these masses grow in size and develop into mature yolk granules,many of these granules resemble mitochondria,and a number of transitional stages share both mitochondria and yolk body features. At the end stage of vitellogenesis,there are lots of yolk bodies increasing in the number and diameter,and there are some mitochondria among yolk bodies that supply energy to cell metabolism. Finally,the changes and functions of the mitochondria in vitellogenesis are discussed.