ISSN : 1225-3480
암컷 떡조개, Phacosoma japonicus의 난모세포 발달과 보조세포들과 관련된 난황형성과정의 미세구조적 연구를 위해 전자현미경적 관찰에 의해서 조사를 하였다. 난모세포들 내에서의 난황형성과정은 내인성 자율합성과정과 외인성 타가합성에 의해 일어나고 있다. 내인성 자율합성과정을 통해 일어나는 난황형성은 난모세포질 내의 골지복합체, 조면소포체 그리고 미토콘드리아가 결합된 작용에 의해서 일어난다. 그러나 외인성 타가합성과정은 초기난황형성난모세포들의 기저부로 들어오는 난소외부의 난황전구체물질들의 내포작용 (endocytosis)의 결합이 관여하고 있다. 본 연구에서 전난황형성난모세포들과 난황형성난모세포들에 부착된 보조세포들이 용이하게 관찰되었다. 특히, 보조세포들은 영양공급에 의해 전난황형성 난모세포들의 발달에 관여하며, 난황전구체의 엔도시토시스에 의해 초기 및 후기 난황형성 난모세포들 내에서 난황형성에 관여한다. 성숙난모세포에 부착된 보조세포들의 기능은 보조세포들의 세포질 내에서 난황형성을 위해 지질과립들과 글리코겐입자들을 축적한다.
Ultrastructural studies of oocyte development and vitellogenesis associated with the follicle cells in female Phacosoma japonicus were investigated by electron microscope observations. Vitelloogenesis in the oocytes occured by way of endogenous autosynthesis and exogenous heterosynthesis: vitellogenesis occurred through a process of endogenous autosynthesis, which involves a combined activity of the Golgi complex, rough endoplasmic reticulum, and mitochondria. However, the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors into the basal region of the early vitellogenic oocytes. In this study, follicle cells, which attached to the previtellogenic and vitellogenic oocytes, were easily found. In particular, the follicle cells were involved in the development of previtellogenic oocytes by the supply of nutrients, and vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors. The functions of follicle cells, which attached to mature oocytes, accumulate reserves of lipid granules and glycogen particles for vitellogesis in the cytoplasm of the follicle cells.
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