Oogenesis in Xenopus laevis (Daudin). V. Relationships between developing oocytes and their investing follicular tissues
Oogenesis in Xenopus laevis (Daudin). V. Relationships between developing oocytes and their investing follicular tissues
复制标题
非洲爪蟾 (Daudin) 的卵子发生。
作者：
J. Dumont;A. R. Brummett
用扫描电镜和透射电镜研究了非洲爪蟾卵泡发育过程中细胞和组织的相互关系。囊状卵巢的体腔侧被鳞状上皮覆盖。上皮细胞广泛交错，每一个都有一个短的，位于中央的纤毛。卵巢的内腔表面覆盖着一层无纤毛的鳞状细胞。细胞-细胞接触区域的特征在于两种上皮细胞中的桥粒，并且上皮细胞之间存在结缔组织层-膜-其含有胶原纤维、血管、神经、平滑肌细胞和卵原细胞。在每个卵泡的卵泡膜下面是单层扁平的星状卵泡细胞。相邻毛囊细胞之间的联合是间歇性的，留下宽的空间或通道。相邻毛囊细胞之间的连接以桥粒为特征。从每个卵泡细胞的基底表面延伸出长而宽的大绒毛，这些大绒毛穿透下面的无细胞卵黄被膜并接触卵母细胞的表面。有证据表明，卵泡细胞可能产生和释放参与卵黄包膜形成的成分，卵黄包膜由绳状纤维的三维网格组成。通过卵黄膜的通道允许维持卵母细胞和卵泡细胞之间的接触，并且还允许物质容易地渗透到卵母细胞（例如，卵黄蛋白原）并从中（例如，皮质颗粒物质）在其发育的不同阶段。
The relationship of the cells and tissues which comprise the developing ovarian follicle in Xenopus laevis has been studied with scanning and transmission electron microscopy. The saclike ovary is covered on its coelomic side by a squamous epithelium. The cells of this epithelium are extensively interdigitated, and each bears a short, centrally positioned cilium. The lumenal surface of the ovary is covered with a layer of nonciliated squamous cells. The areas of cell‐cell contact are characterized by desmosomes in both epithelia, and between the epithelia lies a connective tissue layer‐the theca‐which contains collagen fibers, blood vessels, nerves, smooth muscle cells and oogonia. Beneath the theca in each follicle lies a single layer of flat stellate follicle cells. Associations between adjacent follicle cells are intermittent, leaving wide spaces or channels. Junctional contacts between neighboring follicle cells are characterized by desmosomes. From the basal surface of each follicle cell extend long, broad macrovilli which penetrate the underlying acellular vitelline envelope and contact the surface of the oocyte. Evidence is presented which suggests that follicle cells may produce and release components which participate in the formation of the vitelline envelope which consists of a 3‐dimensional lattice of ropey fibers. Passageways through the vitelline envelope allow the maintenance of contact between oocyte and follicle cells and also allow ready penetration of materials both to the oocyte (e.g., vitellogenin) and from it (e.g., cortical granule material) at different stages of its development.