Ultrastructural and cytochemical studies on the matrix vesicle calcification in the teeth of the killifish, Oryzias latipes.
Ultrastructural and cytochemical studies on the matrix vesicle calcification in the teeth of the killifish, Oryzias latipes.
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鳉鱼牙齿基质囊泡钙化的超微结构和细胞化学研究。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
H. Ozawa
中科院分区：
文献类型：
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作者：
Marie Yamada;Marie Yamada;H. Ozawa
通过超微结构和细胞化学方法检查了鳉鱼的牙胚。牙本质在其发育早期钙化阶段的超微结构与哺乳动物的超微结构相似。在牙本质前间隙中可以看到许多细胞外膜边界的囊泡，基质囊泡，特别是在牙胚的基底部分中大量存在。与其他高等脊椎动物相比，它们的数量更多，外观也更均匀。在即将开始钙化的地方，在囊状结构中发现了一些可辨认的针状磷灰石晶体。晶体数量增多，充满囊泡，进而充满周围，最终形成许多钙化小球。在钙化更广泛的地方，基质囊泡已被钙化埋藏在小球之间，不再可见。与普遍的看法相反，胶原纤维和矿物质的初始沉积之间没有发现任何关系，也就是说，胶原纤维似乎不能作为钙化的初始部位。相反，成牙本质细胞的基质囊泡和质膜可能参与钙化，因为它们都表现出碱性磷酸酶活性。因此，这项研究的超微结构和细胞化学结果表明，鳉鱼牙胚的钙化不是在牙釉质中开始的，而是在牙本质中通过基质囊泡开始的，基质囊泡主要通过细胞过程的破碎从成牙本质细胞释放到牙本质基质中。
Tooth germs of killifish were examined by both ultrastructural and cytochemical methods. The ultrastructure of the dentin in the early calcification stage of its development resembled that of mammals. Numerous extracellular membrane-bounded vesicles, matrix vesicles, were seen in the predentinal space, especially abundantly in the basal portion of the tooth germ. They were more numerous and more uniform in appearance than in any other higher vertebrates. Where calcification was going to start, slightly identifiable needles of apatite crystals were found in the vesicular structures. Crystals increase in number filling up the vesicles and then ther surroundings, finally to form many calcified spherules. Where calcification was more extensive, the matrix vesicles were no longer visible having been buried calcified among spherules. Contrary, to popular belief, there was no relationship seen between collagen fibrils and the initial deposits of minerals, that is, collagen fibrils did not seem to work as the initial site of calcification. Instead, matrix vesicles and plasma membranes of odontoblasts likely were involved in calcification as they both showed alkaline phosphatase activity. The ultrastructural and cytochemical findings from this study thus indicated that calcification of the killifish tooth germs was initiated not in the enamel, but in their dentin by the matrix vesicles which were liberated into the dentin matrix from odontoblasts mainly by way of fragmentation of cell processes.