The Pluripotency of the Pharyngeal Primordium in Urodelan Neurulæ
The Pluripotency of the Pharyngeal Primordium in Urodelan Neurulæ
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Urodelan Neurulæ 咽原基的多能性
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发表时间：
1957
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通讯作者：
T. Okada
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作者：
T. Okada
长期以来，人们想当然地认为两栖动物内胚层器官的原基是在原肠形成之前确定的（参见Holtfreter， 1938 a, b; Stableford, 1948）。然而，有一些数据似乎与这一说法相矛盾。例如，从尾尾动物的神经或更高级的胚胎中切除一些内胚层原基或原基后，剩余的内胚层显示出调节发育成几乎完整的消化道，没有任何内胚层器官的缺陷（Balinsky, 1948; Okada, 1953; Mikami & Murakawa, 1954）。此外，当原肠胚或神经胚的小内胚层片段移植到另一个胚胎的异位部位时，其分化结果在许多情况下不是bedeutungsgemass，而是ortsgemass （Balinsky, 1938, 1948）。根据这些发现，我们不得不得出结论，即使在原肠形成后，每个内胚层原基也不是处于最终决定状态，当然，不稳定决定可能在更早的阶段就已经开始了。
It was for a long time taken for granted that determination of the primordia of the endodermal organs of Amphibia occurs prior to gastrulation (cf. Holtfreter, 1938 a , b ; Stableford, 1948). There have been, however, some data which seem to conflict with this statement. For instance, after the extirpation of some endodermal primordium or primordia from neurulae or more advanced embryos of urodeles, the remaining endoderm shows regulative development into an almost complete digestive tract, no deficiency of any endodermal organs being encountered (Balinsky, 1948; Okada, 1953; Mikami & Murakawa, 1954). Moreover, when a small endodermal fragment from a gastrula or neurula is transplanted into a heterotopic site of another embryo, its resulting differentiation is not bedeutungsgemass , but ortsgemass in many cases (Balinsky, 1938, 1948). Judging from these findings, we cannot help concluding that each endodermal primordium is not in a state of final determination even after gastrulation, although, of course, it may be possible that labile determination has already begun at a much earlier stage.