Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland.
Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
J Morphol. 2022 May;283(5):605-617. doi: 10.1002/jmor.21461. Epub 2022 Feb 21.
The main goal of the article is to describe the ovary organization and oogenesis in Peristodrilus montanus, an aquatic oligochaete of the subfamily Rhyacodrilinae. The presented analysis will not only enrich the knowledge about how eggs are formed but, because of the suggested conservatism of ovary organization in clitellate annelids, can contribute to disentangling the complex phylogenetic relationships of the rhyacodrilines within Naididae. The paired, conically shaped ovaries are located in segment XI. They are composed of a dozen or so syncytial germ-line cysts, which are associated with somatic cells. Each germ cell in a cyst has one intercellular bridge that joins it to a central and anuclear cytoplasmic mass, the cytophore. This pattern of cyst organization is typical for all clitellates that have been studied to date. Initially, the germ cells in a cyst undergo a synchronous development, however, there is no synchrony between cysts, and therefore there is a developmental gradient (oogonia, pre-diplotene germ cells, germ cells in diplotene) of oogenesis along the long ovary axis. The cysts are composed of a maximum of 32 cells. Cysts with cells in diplotene detach from the ovaries and the extraovarian phase of oogenesis begins. The developmental synchrony is lost, one cell (an oocyte) per cyst starts to gather cell components and yolk and grows considerably. The remaining cells grow to some extent and function as nurse cells. Like in other microdriles, P. montanus oocytes are rich in yolk; other features of oogenesis are also similar to those that are known from other microdrile taxa. The system of ovary organization found in the studied species is broadly similar to the corresponding features known from Naidinae and Phreodrilidae and, to some extent, in Enchytraeidae. However, this system is different from the one that is known in Tubificinae, Limnodriloidinae and Branchiurinae.
本文的主要目的是描述水生寡毛类环节动物 Rhyacodrilinae 亚科 Peristodrilus montanus 的卵巢组织和卵子发生。所提出的分析不仅将丰富有关卵子形成的知识，而且由于卵巢组织在环节动物中具有保守性，因此可以有助于阐明 Naididae 中 rhyacodrilines 的复杂系统发育关系。成对的圆锥形卵巢位于第 XI 节。它们由十几个合胞生殖系胞组成，这些胞与体细胞相关联。在一个胞中的每个生殖细胞都有一个细胞间桥，将其与中央和无核细胞质体，即细胞质核相连。这种胞组织的模式是迄今为止所有已研究的环节动物的典型特征。最初，一个胞中的生殖细胞经历同步发育，但是，胞之间没有同步性，因此沿长卵巢轴存在卵子发生的发育梯度（卵原细胞、预减数分裂生殖细胞、减数分裂生殖细胞）。胞由最多 32 个细胞组成。具有减数分裂生殖细胞的胞从卵巢上脱落，卵子发生的卵巢外阶段开始。发育同步性丧失，每个胞中只有一个细胞（卵母细胞）开始聚集细胞成分和卵黄并显著生长。其余细胞在一定程度上生长并起滋养细胞的作用。与其他微丝蚓一样，P. montanus 的卵母细胞富含卵黄；卵子发生的其他特征也与其他微丝蚓类群已知的特征相似。在所研究的物种中发现的卵巢组织系统与从 Naidinae 和 Phreodrilidae 中已知的相应特征广泛相似，在某种程度上也与 Enchytraeidae 相似。然而，该系统与在 Tubificinae、Limnodriloidinae 和 Branchiurinae 中已知的系统不同。
