True enamel covering in teeth of the Australian lungfish Neoceratodus forsteri.
True enamel covering in teeth of the Australian lungfish Neoceratodus forsteri.
复制标题
澳大利亚肺鱼 Neoceratodus forsteri 牙齿上覆盖着真正的牙釉质。
DOI：
10.1007/s004419900132
复制
发表时间：
2000
影响因子：
3.6
通讯作者：
Diekwisch,TG
中科院分区：
文献类型：
--
作者：
Satchell,PG;Shuler,CF;Diekwisch,TG
肺鱼是一个独特的顺序sarcopterygian鱼类cleidographically之间的四足动物和鱼类定位。一个不间断的4亿年前的化石记录证明了肺鱼的骨骼元素自泥盆纪早期以来几乎保持不变。在目前的研究中，我们调查了肺鱼牙齿的釉质层，以确定是否有证据表明，在澳大利亚肺鱼的高等脊椎动物“真正的”釉质。幼年肺鱼从布里斯班河进行处理的光镜和电子显微镜和分析参数指示真正的釉质形成。利用抗釉原蛋白一抗进行免疫检测和蛋白质印迹分析，对肺鱼牙齿发育过程中的釉蛋白表位进行了检测。利用透射电子显微镜和电子衍射分析，长和平行取向的羟基磷灰石晶体观察肺鱼外牙覆盖物。我们的研究结果表明，澳大利亚肺鱼的牙齿被一层真正的釉质覆盖。根据肺鱼化石记录，我们得出结论，真正的釉质形成的特点可能是4亿年前。根据分类学的分类，我们证实，真正的搪瓷不仅发现在四足动物，而且在sarcopterygian分支的theNathostomata。
Lungfish are a unique order of sarcopterygian fish cleidographically positioned between tetrapods and fish. An uninterrupted 400-million-year-old fossil record has documented lungfish skeletal elements to remain virtually unchanged since the Early Devonian. In the current study we investigated the enamel layer of lungfish teeth in order to determine whether there was evidence for higher vertebrate "true" enamel in the Australian lungfish. Juvenile lungfish from the Brisbane River were processed for light and electron microscopy and analyzed for parameters indicative of true enamel formation. Using anti-amelogenin primary antibodies for immunodetection and Western blots, enamel protein epitopes were detected in developing lungfish teeth. Using transmission electron microscopy and electron diffraction analysis, long and parallel-oriented hydroxyapatite crystals were observed in lungfish outer tooth coverings. Our findings indicate that Australian lungfish teeth are covered by a layer of true enamel. Based on the lungfish fossil record we conclude that features of true enamel formation may be as old as 400 million years. Based on taxonomic classification we confirm that true enamel is found not only in tetrapods but also in the sarcopterygian clade of theGnathostomata.