Map of the Anlage fields in the avian unincubated blastoderm
Map of the Anlage fields in the avian unincubated blastoderm
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DOI：
10.1076/ejom.34.5.347.13056
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发表时间：
1996-12-01
期刊：
影响因子：
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通讯作者：
vanNassauw, L
中科院分区：
文献类型：
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作者：
Callebaut, M;vanNueten, E;vanNassauw, L
通过在不同位点切除未孵育的鸡胚盘的矩形片段，并用未孵育的鹌鹑胚盘的同位素片段替换，我们可以在新鲜产下的禽类胚盘中绘制出第一张完整的Anlage区域地图。所有的原基区（图11）都位于中央区尾侧的上层（UL）（以劳-科二氏镰为界）。在UL的边缘区，外围劳伯-科勒镰刀，既没有原肠胚也没有神经胚形成现象可以观察到。类似的异位替代实验表明，在孵育前，中央区UL的不同部分仍然是未定型或可逆定型的。在未孵育的鸟类胚盘中，成索细胞和定形内胚层（肠内胚层）的原基域似乎位于中央区尾侧的尾侧。据我们所知，我们是第一个证明定形肠内胚层的Anlage场（来自上层：Hunt，1937; Vakaet，1962 b）位于中央区的最尾部上层部分，正好位于Rauber-Koller镰刀的中心。神经板的原基场位于更颅端的内生叶上方的上层。大脑的原基是盾形的，而其他原基场是镰刀形的，与劳伯-科勒镰刀平行。它们一般的半圆形配置和形式似乎仍然反映了（与劳伯-科勒镰刀一样）原始的卵质径向对称性（Callebaut，1972）和深层成分的偏心率，这是在早期蛋黄重力定向对称化过程中观察到的（Callebaut，1993 a，B）。Rauber-Koller镰刀可能与Nieuwkoop（1973）在两栖类囊胚中的植物背侧细胞或中心同源。
By excision at different sites of rectangular fragments from unincubated chicken blastoderms and replacement by isotopic fragments from unincubated quail blastoderms, we could make the first complete map of the Anlage fields in the freshly laid avian blastoderm. All the Anlage fields (Fig. 11) are found in the upper layer (UL) of the caudal half of the area centralis (bordered by the Rauber-Koller's sickle). In the UL of the area marginalis, peripheral to Rauber-Koller's sickle, neither gastrulation nor neurulation phenomena could be observed. Similar heterotopic replacement experiments indicate that before incubation, the different parts of the UL of the area centralis are still uncommitted or reversibly committed. The Anlage fields of chordamesoblast and definitive endoderm (gut endoderm) in unincubated avian blastoderms appeared to be disposed caudally in the caudal half of the area centralis. As far as we know we are the first to demonstrate that the Anlage field of the definitive gut endoderm (which is derived from the upper layer: Hunt, 1937; Vakaet, 1962b) is localized in the most caudal upper layer part of the area centralis just centrally to the Rauber-Koller's sickle. The Anlage field of the neural plate is localized in the upper layer over the more cranial endophyll. The Anlage of the brain is shield-shaped, whilst the other Anlage fields are sickle-shaped, parallel with the Rauber-Koller's sickle. Their general hemicircular disposition and form still seem to reflect (together with the Rauber-Koller's sickle) the original ooplasmic radial symmetry (Callebaut, 1972) combined with the eccentricity of the deep layer components, which was observed during early symmetrization by gravitational orientation of the egg yolk (Callebaut, 1993a,b). The Rauber-Koller's sickle might be homologous with the vegetal dorsalizing cells or centre of Nieuwkoop (1973) in amphibian blastulas.