FINE STRUCTURE OF FERTILIZATION AND CYTOPLASMIC COMPONENTS OF THE PRONUCLEAR EMBRYOS IN THE GOAT / 解剖学报

Light and electron microscopic observations revealed that most of the embryos collected 15-16 hours after fertilization were at the pronuclear stage. Many supernumerary spermatozoa were found on the surface and in the outer zone of the zona pellucida, but none of them got into the inner zone of the zona or the perivitelline space. Some spermatozoa on the zona surface were observed in acrosome reaction stage, and those penetrated into the zona always left some acrosome reaction vesicles behind on the surface of the zona. The fertilized ovum eliminated almost all of its cortical granules and where there were some granules left, in the area that the plasma membrane had fewer microvilli. The cortical cytoplasm of the pronuclear zygote was populated with clustered hooded mitochondria, SER vesicles, yolk vacuoles and lipid droplets. Directly surrounding the pronucleus were a variety of organelles including welldeveloped Golgi complex, SER, mitochondria and annulate lamellae. The significance of these morphological changes of the fertilized ovum was discussed.

ULTRASTRUCTURAL STUDIES ON THE GOAT OOGENESIS / 解剖学报

The cytoplasmic and nuclear changes during the development of goat oocytes were studied with light and electron microscopy. The oocyte development may be divided into 8 stages in accordance with the number and distribution of follicle cells and the size of the follicle. The results indicated that the Golgi complex, mitochondria, smooth endoplasmic reticulum and cortical granules became well developed and they moved into the cortical region as the oocyte development proceeded. In the oocytes in the follicle of 1.5-3mm in diameter, all the mitochondria became hooded and the number and size of fibrillar centers in the nucleolus reached maximum, but the nucleolar compaction still not occured at this stage. By the time when the follicle reached 3.5-5mm in diameter, the follicular cell processes began to degenerate, the microvilli of the oocyte withdrew from the zona pellueida and the oocytes might be cultured to mature in vitro. In the mature oocytes, Golgi complex and rough endoplasmic reticulum disappeared, the cortical granules arranged themselves in one layer beneath the oolemma, the mitochondria dispersed in the central region of cytoplasm and the eggs were ready for fertilization.