Frankenberg S, Newell G, Selwood L
School of Zoology, La Trobe University, Bundoora, Vic, Australia.
Reprod Fertil Dev. 1996;8(4):541-6. doi: 10.1071/rd9960541.
Ovaries from young of the brushtail possum, Trichosurus vulpecula, were examined histologically and histochemically to determine stages of oogenesis. Groups of dividing oogonia were first present in a 13-day-old pouch young, with extensive oogonial proliferation after about 23 days of age. Meiosis was initiated in some oogonia by 48 days of age, and by 88 days numerous early primordial follicles were present. The first primary follicles had formed by 103 days of age. In oocytes of quiescent primordial follicles, dark granular material, which stained positively for protein, mainly occupied the perinuclear cytoplasm. Associated with the transition to primary follicles and continuing throughout oocyte growth was the production within the central cytoplasm of large clear vesicles and, to a lesser extent, lipid-like yolk bodies. The former were analogous to similar vesicles found in other species of marsupial, and have a putative role in development of the blastocyst. By contrast, yolk-like bodies are not found in all marsupial oocytes and their importance in development is unknown.
对帚尾袋貂（Trichosurus vulpecula）幼崽的卵巢进行了组织学和组织化学检查，以确定卵子发生的阶段。在13日龄的育儿袋幼崽中首次出现成群分裂的卵原细胞，约23日龄后卵原细胞大量增殖。48日龄时，一些卵原细胞开始减数分裂，到88日龄时出现大量早期原始卵泡。到103日龄时形成了第一批初级卵泡。在静止原始卵泡的卵母细胞中，主要占据核周细胞质的深色颗粒物质对蛋白质呈阳性染色。与向初级卵泡的转变相关并在整个卵母细胞生长过程中持续存在的是中央细胞质内产生的大的透明囊泡，以及程度较轻的类脂卵黄小体。前者类似于在其他有袋动物物种中发现的类似囊泡，并且在囊胚发育中具有假定作用。相比之下，并非所有有袋动物的卵母细胞中都有类卵黄小体，其在发育中的重要性尚不清楚。
