ULTRASTRUCTURE OF PRIMARY MESENCHYME CELL INGRESSION IN THE SEA-URCHIN LYTECHINUS-PICTUS
ULTRASTRUCTURE OF PRIMARY MESENCHYME CELL INGRESSION IN THE SEA-URCHIN LYTECHINUS-PICTUS
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DOI：
10.1002/jez.1402130211
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发表时间：
1980-01-01
影响因子：
--
通讯作者：
SOLURSH, M
中科院分区：
文献类型：
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作者：
KATOW, H;SOLURSH, M
本文报道了海胆初生间充质细胞形成过程中的超微结构变化。用透射电镜（TEM）和扫描电镜（SEM）研究了红腹叶蜂的形态结构。在侵入早期，大约有30个假定的初级间充质细胞可以被识别，它们形成一个环，围绕着位于植物极顶端的8个中央细胞。第一步包括植物板区域的基底层的丧失和30个假定的初级间充质细胞的纤毛的丧失。这些细胞然后伸长成瓶状细胞，其具有球根状的、无附属物的基部末端，突出到囊胚腔中，以及形成许多顶端细胞突起的细颈区域。在瓶状细胞的颈部区域的外周细胞质和紧密粘附的相邻非间充质卵裂球的相邻细胞质中观察到纵向取向的微管。在顶端连接消失后，瓶状细胞的颈部区域缩短，导致细胞移位到囊胚腔中，成为圆形的初级间充质。间充质细胞移位导致在囊胚壁中暂时形成窗孔，窗孔由从邻近的卵裂球延伸的顶端细胞突起填充。这些形态学变化与其他从上皮细胞退出的细胞的例子有几个共同的特征，并且与涉及假定的初级间充质细胞的基底细胞质松弛的形态学序列一致，随后是它们的主动伸长和邻近细胞的侧向压缩。
The ultrastructural changes associated with primary mesenchyme cell formation in the sea urchin L. pictus were studied by transmission (TEM) and scanning electron microscopy (SEM). Early during ingression, about 30 presumptive primary mesenchyme cells can be recognized which form a ring around 8 central cells located at the apex of the vegetal pole. The 1st steps involve the loss of the basal lamina in the vegetal plate region and the loss of cilia from the 30 presumptive primary mesenchyme cells. These cells then elongate into bottle-shaped cells which have bulbous, appendage-free basal ends that protrude into the blastocoel, and thin neck regions that form numerous apical cell processes. Longitudinally oriented microtubules are observed in the peripheral cytoplasma in the neck regions of the bottle-shaped cells and in the adjacent cytoplasm of closely adherent neighboring non-mesenchymal blastomeres. After the disappearance of apical junctions, the neck regions of the bottle-shaped cells shorten, resulting in the transposition of the cells into the blastocoel as rounded primary mesenchyme. Mesenchyme cell displacement results in the temporary formation of fenestrae in the blastular wall, which are filled in by apical cell processes that extend from neighboring blastomeres. These morphological changes have several features in common with other examples of cells which exit from epithelia and are consistent with a morphological sequence involving the relaxation of the basal cytoplasm of the presumptive primary mesenchyme cells, followed by their active elongation and lateral compression by adjacent cells.