Biological Institute, Faculty of Education, Biological Institute, Yamaguchi University, Yamaguchi, Japan.
Department of Biology, Faculty of Science, Yamaguchi University, Yamaguchi, Japan.
J Exp Zool B Mol Dev Evol. 2019 Nov;332(7):245-257. doi: 10.1002/jez.b.22899. Epub 2019 Sep 18.
Mechanisms of cell mass (CM) formation were analyzed by microsurgery in two temnopleurid sea urchins, Mespilia globulus and Temnopleurus toreumaticus. The CM in temnopleurids is formed at the early larval stage from the left ectodermal invagination, and with the hydrocoel derived from the mesoderm, forms an adult rudiment. After serial removal of the CM, it was strongly regenerated until its attachment to the hydrocoel, with the same timing as in control larvae. Embryos that had the tip of the archenteron or the coelomic pouches removed formed a CM in the normal manner. Removal of the CM plus the left somatocoel or the hydrocoel allowed CM regeneration with and without adult rudiment formation. A transplanted CM enlarged autonomously but did not contribute to adult rudiment formation, and larvae formed a new CM. Our observations suggest that the hydrocoel recognizes its distance from the CM to induce the growth of the CM and controls the normal timing of adult rudiment formation.
通过对两种海参纲海胆，即 globulus 和 toreumaticus 的显微手术分析，研究了细胞团 (CM) 的形成机制。在 temnopleurids 中，CM 是在早期幼虫阶段由左侧外胚层内陷形成的，与来自中胚层的 hydrocoel 一起形成成体原基。在连续去除 CM 后，它强烈再生，直到与 hydrocoel 附着，与对照幼虫的时间相同。去除原肠胚的尖端或体腔囊的胚胎以正常方式形成 CM。去除 CM 加左侧 somatocoel 或 hydrocoel 允许 CM 再生，有或没有成体原基形成。移植的 CM 自主增大，但不参与成体原基形成，并且幼虫形成新的 CM。我们的观察表明，hydrocoel 识别其与 CM 的距离以诱导 CM 的生长，并控制成体原基形成的正常时间。
