Comparative analysis of amphibian somite morphogenesis: cell rearrangement patterns during rosette formation and myoblast fusion.
Comparative analysis of amphibian somite morphogenesis: cell rearrangement patterns during rosette formation and myoblast fusion.
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两栖动物体节形态发生的比较分析：莲座形成和成肌细胞融合过程中的细胞重排模式。
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
Malacinski Gm
中科院分区：
文献类型：
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作者：
Youn Bw;Malacinski Gm
对两种有尾两栖动物Ambystoma mexicanum和Pleurodeles waltlii以及一种无尾两栖动物蛙蛙（Rana sphenocephala）体节形成过程中细胞形态、排列和接触的变化进行了详细的扫描电镜观察。固定后，将胚胎横向、水平和近尖部断裂，并用扫描电镜检查体内细胞排列模式。结果表明，钝口鱼和鲽目胚胎在花结形成和成肌细胞融合方面遵循完全相同的发育顺序。然而，蛙体节似乎并不形成节。这些肌瘤细胞在发生几次分割后立即发生融合。细胞重排的模式也被描述在有尾目动物玫瑰花结形成的时候，体节分割和成肌细胞融合。在这些过程中，细胞的形状和方向发生了广泛的变化。当细胞改变方向时，它们通常呈现三角形构型。这些三角形的细胞在玫瑰花结形成和成肌细胞融合的可能作用进行了讨论。在成肌细胞或肌瘤细胞融合的初始阶段，细胞首先发出特化的细胞突起，然后建立它们的细胞-细胞接触。这种接触的建立最终导致紧密的膜并置和融合。由于成肌细胞融合似乎发生在两个串联排列成玫瑰花结的细胞之间，因此对融合细胞中多核性的起源进行了讨论。最后，对不同种类两栖动物体节的形成和肌肉的发育模式进行了比较分析。的可能性进行了讨论，体节发生的模式可能提供有用的指标，以确定如何不同的家庭的两栖动物进化。
Detailed SEM observations of the changes in cellular morphology, arrangements, and contacts that occur during the process of somite formation were made in two species of urodele amphibians, Ambystoma mexicanum and Pleurodeles waltlii, and one species of anuran amphibian, Rana sphenocephala. After fixation, embryos were fractured transversely, horizontally, and parasagittally, and the intrasomitic cellular arrangement pattern was examined with the SEM. It was found that Ambystoma and Pleurodeles embryos followed exactly the same development sequence in rosette formation and myoblast fusion. Rana somites did not, however, appear to form rosettes. Those myotomal cells underwent fusion immediately after a few segmentations occurred. Patterns of cellular rearrangement were also described during urodele rosette formation at the time of somite segmentation and during myoblast fusion. Extensive changes in cell shape and orientation appeared to occur during those processes. When cells changed their orientation, they often exhibited a triangular configuration. Probable roles of these triangular-shaped cells in rosette formation and myoblast fusion are discussed. During the initial period of myoblast or myotomal cell fusion, cells first send out specialized cell processes and then establish their cell-cell contacts. The establishment of such contacts eventually leads to tight membrane appositions and fusion. Since myoblast fusion appeared to occur between two cells which were tandemly arranged in a rosette, the origin of multi-nuclearity in the fused cells is discussed. Finally, comparative analyses of the pattern of somite formation and subsequent muscle development were made between different species of amphibians. The possibility is discussed that patterns of somitogenesis may provide useful indicators for determining how different families of amphibians evolved.