Alibardi L
Dipartimento di Biologia Evoluzionistica e Sperimentale, University of Bologna, Italy.
J Anat. 1998 Feb;192 ( Pt 2)(Pt 2):173-86. doi: 10.1046/j.1469-7580.1998.19220173.x.
The formation of the first epidermal generations and in particular of the shedding complex in the developing scales of the lizards Anolis lineatopus and Podarcis muralis was studied by electron microscopy. The initially linear and bilayered epidermis turned into symmetric papillae, which became asymmetric scales. The outer periderm was more electrondense than the following layer, provisionally named 'inner periderm' but probably derived from the basal layer. Coarse thick filaments progressively filled the cytoplasm of the inner periderm or formed reticulate bodies resembling avian peridermal granules. Peridermal cells cornified slightly and could be shed in ovo. From the basal layer various suprabasal epithelial layers were produced. The first layer contained keratohyalin-like granules and was identified as a clear layer. Beneath it a spinulated (Anolis) or serrated (Podarcis) oberhäutchen differentiated. The clear and 'oberhäutchen' layers constitute the first shedding complex. The first epidermal layers that were shed consisted of flaking periderm or periderm together with the clear layer. The differentiation of a mesos layer was under way before hatching, when the epidermal morphology resembled a stage 4-5 of the adult shedding cycle. Fibroblasts under the inner side of the scale made few contacts with the basement membrane and their cytoplasmic elongations were mostly oriented parallel to the dense lamina. Instead, fibroblasts under the basal layer of the outer scale surface (BLOS) made numerous contacts with the basement membrane, suggesting that more dermal-epidermal interactions take place on this side of the scale.
通过电子显微镜研究了绿安乐蜥(Anolis lineatopus)和意大利壁蜥(Podarcis muralis)发育鳞片中第一代表皮尤其是蜕皮复合体的形成。最初呈线性的双层表皮转变为对称的乳头,进而成为不对称的鳞片。外层的周皮比其下一层电子密度更高,下一层暂称为“内周皮”,但可能源自基底层。粗大的粗丝逐渐充满内周皮的细胞质,或形成类似鸟类周皮颗粒的网状体。周皮细胞略有角质化,可在卵内脱落。从基底层产生了各种基底层以上的上皮层。第一层含有透明角质颗粒样颗粒,被鉴定为透明层。在其下方,分化出有小刺(安乐蜥)或锯齿状(意大利壁蜥)的表层。透明层和“表层”构成了第一个蜕皮复合体。最初脱落的表皮层由片状周皮或周皮与透明层组成。在孵化前中皮层的分化就已开始,此时表皮形态类似于成年蜕皮周期的4-5阶段。鳞片内侧下方的成纤维细胞与基底膜接触较少且其细胞质延伸大多与致密板平行。相反,外层鳞片表面基底层(BLOS)下方的成纤维细胞与基底膜有大量接触,这表明在鳞片的这一侧发生了更多的真皮-表皮相互作用。