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首页> 外文期刊>Protoplasma: An International Journal of Cell Biology >An ultrastructural study of the ovary cord organization and oogenesis in the amphibian leechBatracobdella algira(Annelida, Clitellata, Hirudinida)
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An ultrastructural study of the ovary cord organization and oogenesis in the amphibian leechBatracobdella algira(Annelida, Clitellata, Hirudinida)

机译：两栖利用卵巢组织和卵泡菌的超微结构研究（Amphibian Leechbatrobdella Algira（Annelida，Clitellata，Hirudinida）

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摘要

This study reveals the ovary micromorphology and the course of oogenesis in the leechBatracobdella algira(Glossiphoniidae). Using light, fluorescence, and electron microscopies, the paired ovaries were analyzed. At the beginning of the breeding season, the ovaries were small, but as oogenesis progressed, they increased in size significantly, broadened, and elongated. A single convoluted ovary cord was located inside each ovary. The ovary cord was composed of numerous germ cells gathered into syncytial groups, which are called germ-line cysts. During oogenesis, the clustering germ cells differentiated into two functional categories, i.e., nurse cells and oocytes, and therefore, this oogenesis was recognized as being meroistic. As a rule, each clustering germ cell had one connection in the form of a broad cytoplasmic channel (intercellular bridge) that connected it to the cytophore. There was a synchrony in the development of the clustering germ cells in the whole ovary cord. In the immature leeches, the ovary cords contained undifferentiated germ cells exclusively, from which, previtellogenic oocytes and nurse cells differentiated as the breeding season progressed. Only the oocytes grew considerably, gathered nutritive material, and protruded at the ovary cord surface. The vitellogenic oocytes subsequently detached from the cord and filled tightly the ovary sac, while the nurse cells and the cytophore degenerated. Ripe eggs were finally deposited into the cocoons. A comparison of the ovary structure and oogenesis revealed that almost all of the features that are described in the studied species were similar to those that are known from other representatives of Glossiphoniidae, which indicates their evolutionary conservatism within this family.
机译：本研究揭示了舌鳎科（leechBatracobdella algira）卵巢的微形态和卵子发生过程。利用光镜、荧光镜和电子显微镜对配对卵巢进行分析。在繁殖季节开始时，卵巢很小，但随着卵子发生的进展，卵巢显著增大、变宽和拉长。每个卵巢内都有一条卷曲的卵巢索。卵巢索由许多生殖细胞组成，聚集成合胞体群，称为生殖系囊肿。在卵子发生过程中，聚集的生殖细胞分化为两个功能类别，即哺乳细胞和卵母细胞，因此，这种卵子发生被认为是半着丝粒的。通常，每一个聚集的生殖细胞都有一个连接，以一个广泛的细胞质通道（细胞间桥）的形式连接到细胞质。整个卵巢索中聚集的生殖细胞的发育是同步的。在未成熟水蛭中，卵巢索中只含有未分化的生殖细胞，随着繁殖季节的进展，这些生殖细胞分化出前卵母细胞和哺乳细胞。只有卵母细胞大量生长，聚集营养物质，并在卵巢索表面突出。卵黄原性卵母细胞随后从脐带中分离并紧紧填充卵巢囊，而滋养细胞和细胞质退化。成熟的卵最终被放入茧中。卵巢结构和卵子发生的比较显示，研究物种中描述的几乎所有特征都与舌蝇科其他代表已知的特征相似，这表明它们在该科中的进化保守。

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