ANALYSIS OF THE ORGANIZER CENTER IN THE EARLY CHICK EMBRYO .1. LOCALIZATION OF PROSPECTIVE NOTOCHORD AND SOMITE CELLS
ANALYSIS OF THE ORGANIZER CENTER IN THE EARLY CHICK EMBRYO .1. LOCALIZATION OF PROSPECTIVE NOTOCHORD AND SOMITE CELLS
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DOI：
10.1002/jez.1401280106
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发表时间：
1955-01-01
影响因子：
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通讯作者：
SPRATT, NT
中科院分区：
文献类型：
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作者：
SPRATT, NT
最后的条纹、头突和早期体节胚层的节区内和周围的预期脊索、体节和侧板细胞的定位，用碳素、胭脂红和活性染料标记；移植胚层的横向和斜行切片；节区小细胞群的切除；分离的结节区域的外植；用新四氮唑盐进行还原酶活性的定位等。结果似乎表明，定位于结节内的一组相对较小的脊索中心(组织者)细胞和位于结节后外侧的两组体节中心细胞与较大的节索和位于结节后的体节细胞群不同。外延切片中脊索和体节的持续形成取决于中心的存在以及相应的预期细胞。完全切除中枢会导致脊索和体节的形成停止，但在这些阶段和早期阶段不完全去除之后，可能会完全调节和不间断的轴向器官发育。在退化过程中，结节的上胚层部分与后神经板的一部分一起，相对于腹侧和中胚层中更多的后索和体节形成细胞向后移动。一些(大多数？)脊索和体节的中央细胞与结节上胚层一起退化，留下分化的脊索和体节。
Localization of prospective notochord, somite and lateral plate cells in and around the node area of definitive streak, head-process and early somite blastoderms has been revealed by carbon, carmine and vital dye marking; transverse and diagonal transec-tions of explanted blastoderms; excision of small cell groups in the node area; explantation of the isolated node area; localization of reducing enzyme activities with neotetrazolium chloride; etc. Results seem to demonstrate the existence of a relatively small group of chorda center (organizer) cells localized within the node and two groups of somite center cells just postero-lateral to the node as distinct from larger groups of prospective notochord and somite cells posterior to the node. Continued formation of notochord and somites in explanted pieces depends upon the presence of the centers as well as upon the corresponding prospective cells. Complete excision of the centers results in cessation of chorda and somite formation, but incomplete removal at these and earlier stages may be followed by complete regulation and uninterrupted axial organ development. During regression, the epiblastic portion of the node, along with part of the posterior neural plate, moves posteriorly relative to the ventral and originally more posterior chorda and somite forming cells in the mesoblast. Some (most?) of the chorda and somite center cells regress along with the node epiblast leaving behind the differentiated notochord and somites.