Takaya Hirosi, Kayahara Tetsuro
Department of Biology, Faculty of Science, Konan University, Okamoto, Kobe 658, Japan.
Dev Growth Differ. 1978;20(2):143-150. doi: 10.1111/j.1440-169X.1978.00143.x.
Processes of vacuolation were investigated with the explanted and implanted rudiments of amphibian notochord. Explanted notochords generally underwent vacuolation when they were surrounded by other differentiating tissues. In the absence of these tissues, they were not only unable to vacuolate but also unable to survive. When the notochords were implanted into the ventral mass of yolk granules of neurula, they showed no vacuolation and died within a few days if they were alone and not surrounded by other differentiating tissues. These facts suggest that the presence of other differentiating tissues surrounding the notochord is a requisite for the notochord to vacuolate. Further, the fact that in explanted notochords, vacuolation was frequently interrupted and was left unfinished when the surrounding tissues were scarce, suggests that the quantity of the surrounding tissues is important in promoting vacuolation. Interruption of the vacuolation occurs in the explanted notochord at any stage from the beginning to the end of the process. Therefore, almost all the stages of vacuolation were observed in these notochords. Very frequently, different parts of a single notochord presented different stages of vacuolation. All these stages were essentially the same as those found in the normal notochord. From these results, it emerges that although vacuolation of the explanted and implanted notochords is carried out with the same process as in the normal intact one, it is accomplished only when they are surrounded by a sufficient quantity of other differentiating tissues.
利用两栖类动物脊索的外植体和植入物对空泡化过程进行了研究。当外植的脊索被其他正在分化的组织包围时，通常会发生空泡化。如果没有这些组织，它们不仅无法空泡化，而且无法存活。当脊索被植入神经胚的卵黄颗粒腹块中时，如果它们单独存在且没有被其他正在分化的组织包围，它们不会出现空泡化，并会在几天内死亡。这些事实表明，脊索周围存在其他正在分化的组织是脊索空泡化的必要条件。此外，在外植的脊索中，当周围组织稀少时空泡化经常被中断且未完成，这一事实表明周围组织的数量对促进空泡化很重要。空泡化的中断在从开始到过程结束的任何阶段在外植的脊索中都会发生。因此，在这些脊索中观察到了空泡化的几乎所有阶段。非常常见的是，单个脊索的不同部分呈现出不同的空泡化阶段。所有这些阶段与正常脊索中的阶段基本相同。从这些结果可以看出，尽管外植和植入的脊索的空泡化过程与正常完整脊索相同，但只有当它们被足够数量的其他正在分化的组织包围时才能完成。
