Nieuwkoop P D
Hubrecht Laboratory, Utrecht, Holland.
Wilhelm Roux Arch Entwickl Mech Org. 1969 Dec;163(4):298-315. doi: 10.1007/BF00577017.
Experiments are described in which in early to late blastulae ofAmbystoma mexicanum (stages 7-8/9 Harrison) the animal, ectodermal "half" (zones I.II) was combined with the vegetative, endodermal yolk mass (zone IV) in various orientations, viz. in random orientation or with the dorso-ventral axes of the two components in identical, opposite or perpendicular orientation (0°, 180°, or 90° translocation respectively). The results demonstrate unequivocally that the dorso-ventral polarity of the induced mesoderm, and thus of the embryo, depends exclusively upon the inherent dorso-ventral polarity of the endoderm, whereas the grey crescent, a considerable part of which is located in the animal, ectodermal "half', plays no causal role whatsoever.The results also show that the dorso-ventral polarity is inherent in the entire endodermal mass, but that the subsequent regional differentiation of the endoderm depends upon stimulating influences emanating from the surrounding mesoderm, the later nutritive yolk representing that part of the endoderm which normally does not come under the influence of the mesoderm, and therefore fails to receive the necessary stimulus for further differentiation.On the basis of these findings "Schultze's Umkehrexperiment" as studied byPENNERS andSCHLEIP, PENNERS, andPASTEELS are reinterpreted, whileDALCQ andPASTEELS' general developmental theory as well asCURTIS' cortical grafting experiments are critically discussed.
本文描述了一系列实验，在这些实验中，将墨西哥钝口螈早期至晚期囊胚（哈里森分期7 - 8/9期）的动物极外胚层“半区”（I、II区）与植物极内胚层卵黄块（IV区）以不同方向组合，即随机方向，或使两个组分的背腹轴呈相同、相反或垂直方向（分别为0°、180°或90°易位）。结果明确表明，诱导中胚层以及胚胎的背腹极性完全取决于内胚层固有的背腹极性，而灰色新月区（其相当一部分位于动物极外胚层“半区”）则毫无因果作用。结果还表明，背腹极性存在于整个内胚层团块中，但内胚层随后的区域分化取决于周围中胚层发出的刺激影响，后来的营养卵黄代表内胚层中通常不受中胚层影响的部分，因此未获得进一步分化所需的刺激。基于这些发现，对彭纳斯、施莱普、彭纳斯以及帕斯特尔斯所研究的“舒尔茨反转实验”进行了重新解释，同时对达尔克和帕斯特尔斯的一般发育理论以及柯蒂斯的皮质移植实验进行了批判性讨论。
