Light microscopic and ultrastructural study of the development of the saccus vasculosus in the rainbow trout, Oncorhynchus mykiss
Light microscopic and ultrastructural study of the development of the saccus vasculosus in the rainbow trout, Oncorhynchus mykiss
复制标题
虹鳟鱼血管囊发育的光学显微镜和超微结构研究
作者：
A. Corujo;I. Rodríguez;R. Anadón
这项使用光学和电子显微镜的研究表明，血管囊在 9 毫米胚胎中是可区分的，并且在整个胚胎发育到成年阶段持续生长。在血管囊中，在所研究的所有阶段都观察到上皮有丝分裂。冠状细胞发育中的中心粒发生、纤毛发生和小球形成的阶段已被表征。在中心体发生阶段，新的中心粒与先前存在的中心粒相关，而不是在后体上出现。纤毛发生后，每个纤毛几乎与冠状细胞的其他纤毛同时分化成小球。小球的内膜系统似乎源自纤毛质膜。该膜系统在发育过程中经常产生膜螺纹。在同一个体和除 9 毫米胚胎之外的所有研究阶段中都发现了冠状细胞发育的不同阶段。从 12 毫米胚胎开始，在囊上皮中就观察到了脑脊液接触神经元，并且与早期形成阶段的冠状细胞有区别。血管囊的三种细胞类型在发育过程中数量不断增加。神经突起存在于胚胎的血管囊中，而分化的突触则稍后出现在鱼苗中。讨论了与成人中假定的冠细胞和/或小球更新周期相关的持续冠细胞形成的重要性。
This study using light and electron microscopy indicates that the saccus vasculosus is distinguishable in 9‐mm embryos and grows continuously throughout embryonic development to the adult stage. In the saccus vasculosus, epithelial mitoses are observed in all stages studied. Phases of centriologenesis, ciliogenesis, and globule formation have been characterized in developing coronet cells. During the phase of centriologenesis, new centrioles appear in association with pre‐existing centrioles and not on deuterosomes. After ciliogenesis, each cilium differentiates to a globule almost at the same time as the other cilia of the coronet cell. The inner membrane system of the globules seems to derive from the ciliary plasma membrane. This membrane system often produces membrane whorls during the development. The different phases of coronet cell development have been found in the same individual and in all the stages studied except the 9‐mm embryo. Cerebrospinal fluid‐contacting neurons are observed in the saccus epithelium from the 12‐mm embryos on and are distinguishable from coronet cells in their early formative stages. The three cell types of the saccus vasculosus increase continuously in number during development. Nerve processes are found in the saccus vasculosus of embryos, whereas differentiated synapses appear later in the fry. The significance of continued coronet cell formation is discussed in relation to a putative coronet cell and/or a globule renewal cycle in the adult.