ELECTRON-MICROSCOPIC STUDY OF THE DEVELOPMENT OF AMPHIOXUS, BRANCHIOSTOMA-BELCHERI-TSINGTAUENSE - THE GASTRULA
ELECTRON-MICROSCOPIC STUDY OF THE DEVELOPMENT OF AMPHIOXUS, BRANCHIOSTOMA-BELCHERI-TSINGTAUENSE - THE GASTRULA
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DOI：
10.1002/jmor.1052070106
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发表时间：
1991-01-01
影响因子：
1.5
通讯作者：
KAJITA, N
中科院分区：
文献类型：
--
作者：
HIRAKOW, R;KAJITA, N
本文用扫描电镜和透射电镜对文昌鱼受精后4 ~ 10小时的7个时期的原肠胚进行了观察。 在整个原肠胚形成过程中，扫描电镜显示囊胚口唇细胞的细微差异。 在早期和中期的骨折标本中，发现了两个形状、大小和组成细胞连接不同的相对区：一个是由柱状的小细胞紧密接触组成的动物区，另一个是由圆形或多边形的大细胞松散连接组成的植物区。 在约25%的病例中，在早期原肠胚的凹面植物表面意外地发现极体。 这可能是极体迁移的结果。 在原肠胚中期，每个细胞上都有一条短纤毛，后来又伸长。 最后阶段原肠胚背表面（神经外胚层）的纤毛比表皮外胚层的纤毛短。 透射电镜观察表明，原肠胚细胞的细胞质成分与卵裂细胞的细胞质成分基本相同。 但是，在卵裂过程中看到的同质核变成了一个异质结构，其中可以看到核仁和致密颗粒。 直到晚期，区域特征的原肠胚明确表示前-后和背-腹极性没有检测到在本扫描电镜和透射电镜研究。
The gastrulae of amphioxus were investigated by means of scanning and transmission electron microscopy (SEM and TEM) during 7 arbitrary stages that were seen about 4 to 10 hr after fertilization. Throughout gastrulation, SEM revealed subtle differences in cells of the blastoporal lip. In fractured specimens at early and middle stages, two opposing zones different in shape, size, and connection of the component cells were found: one which consists of columnar smaller cells in close contact in animal region and the other which is composed of round or polygonal larger cells in looser association in vegetal region. The polar body was found unexpectedly on the concave vegetal surface of the early gastrula in about 25% of cases. This might be the result of migration of the polar body. A short cilium that later elongated was recognized on each cell at mid-gastrula stage. The cilia on the dorsal surface (the neural ectoderm) of the final-stage gastrula became shorter than those on the epidermal ectoderm. TEM of thin sections demonstrated that the cytoplasmic components of gastrula cells are essentially the same as those of cleavage cells. But, the homogeneous nucleus seen during cleavage changed into a heterogeneous structure in which a nucleolus and dense particles were seen. Until the late stage, regional characteristics of the gastrulae indicating definitively the anterior-posterior and dorso-ventral polarity were not detected in the present SEM and TEM study.