Katchburian E, Antoniazzi M M, Jared C, Faria F P, Souza Santos H, Freymüller E
Department of Morphology and Electron Microscopy Center, Federal University of São Paulo, São Paulo, Brazil.
J Morphol. 2001 Apr;248(1):56-63. doi: 10.1002/jmor.1020.
Some species of anuran amphibians possess a calcified dermal layer (the Eberth-Kastschenko layer) located between the "stratum spongiosum" and the "stratum compactum." This layer consists of calcium phosphate deposits, proteoglycans, and glycosaminoglycans. Although regarded as a protective layer against desiccation, a calcium reservoir, or possibly a remnant of a dermal skeleton present in anuran ancestors, very little is known about its origin, structure, and function. Thus, we studied the structure and composition of the mineralized dermal layer of Corythomantis greeningi, a peculiar hylid from the Brazilian semiarid region (caatinga), using conventional and cryosubstitution methods combined with transmission, scanning, and analytical electron microscopy. Results show that the dermal layer consists of dense, closely juxtaposed, globular structures. Although the electron opacity of the globules was variable, depending on the type of preparation, crystal-like inclusions were present in all of them, as confirmed by dark field microscopy. Electron probe X-ray microanalysis showed calcium, phosphorus, and oxygen, and electron diffraction revealed a crystalline structure comparable to that of a hydroxyapatite.
一些无尾两栖动物物种拥有一层钙化的真皮层（埃伯斯-卡斯琴科层），位于“海绵层”和“致密层”之间。这一层由磷酸钙沉积物、蛋白聚糖和糖胺聚糖组成。尽管它被认为是一层防止干燥的保护层、一个钙库，或者可能是无尾目祖先存在的真皮骨骼的残余物，但人们对其起源、结构和功能知之甚少。因此，我们使用传统方法和冷冻置换方法，结合透射电子显微镜、扫描电子显微镜和分析电子显微镜，研究了来自巴西半干旱地区（卡廷加）的一种特殊雨蛙科动物——科里托曼蒂斯·格林吉矿化真皮层的结构和组成。结果表明，真皮层由密集、紧密并列的球状结构组成。尽管小球的电子不透明度因制备类型而异，但暗场显微镜证实，所有小球中都存在类晶体包裹体。电子探针X射线微分析显示含有钙、磷和氧，电子衍射揭示了一种与羟基磷灰石相当的晶体结构。
