The ultrastructure of odontogenesis in larval and adult urodeles; differentiation of the dental epithelial cells
The ultrastructure of odontogenesis in larval and adult urodeles; differentiation of the dental epithelial cells
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幼虫和成虫牙发育的超微结构；
DOI：
10.1007/bf00560155
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
A. E. W. Miles
中科院分区：
文献类型：
--
作者：
Moya Meredith Smith;A. E. W. Miles
对 Ambystoma 和 Triturus 的未脱矿质牙胚切片进行了检查。早期细菌（幼虫和成虫）以及牙本质发生的超微结构与哺乳动物相似。在成年二尖牙中，一旦牙尖的牙本质被矿化，与早期哺乳动物牙釉质晶体大小相似的矿物晶体就会出现在牙本质和内牙上皮（即内牙上皮）之间。与此同时，i.d.e 显示出哺乳动物分泌成釉细胞的特征。这个新层被认为是真正的牙釉质，缺乏胶原蛋白，具有有序排列的晶体，最大厚度达到 6 μm。 在幼虫单尖牙中，一旦牙本质矿化到达牙尖尖端的内牙质膜，内牙就会形成褶皱边界。在此阶段，尖端的牙本质被视为釉质，非常坚硬且难以切片。褶边边缘是其他运输物质的细胞的特征，被认为表明 i.d.e 正在从釉质体中去除有机物。幼虫和成虫牙齿发育的差异支持这样的概念，即在从幼虫到成虫的变态过程中，i.e.e的细胞活性发生了变化。
Sections of undemineralized tooth germs ofAmbystomaandTrituruswere examined. The ultrastructure of early germs, both larval and adult, and of dentinogenesis, resembled that of mammals. In adult bicuspid teeth, once the dentine of the cusps was mineralized, mineral crystals of a similar size to early mammalian enamel crystals, appeared between the dentine and the inner dental epithelium (i.d.e). Concomitantly, the i.d.e showed features of mammalian secreting ameloblasts. This new layer, regarded as true enamel, lacked collagen, possessed an ordered arrangement of crystals and reached a maximum thickness of 6 μm.In larval monocuspid teeth, once dentine mineralization had reached the plasma membranes of the i.d.e at the tip of the cusp, the i.d.e developed a ruffled border. At this stage the dentine of the tip, regarded as enameloid, was very hard and difficult to section. The ruffled border, characteristic of other cells which transport materials, was regarded as indicating that the i.d.e was removing organic matter from the enameloid. The differences in development between larval and adult teeth support the concept that there is a change in cellular activity of the i.d.e which occurs during metamorphosis from the larval to the adult urodele.