Alibardi Lorenzo, Bonfitto Antonio
Comparative Histolab Padova, Italy.
Department of Biological, Geological and Environmental Sciences (BiGeA), Bologna, Italy.
Zoology (Jena). 2019 Apr;133:1-9. doi: 10.1016/j.zool.2019.01.003. Epub 2019 Feb 1.
After tail loss in the African gecko Lygodactylus capensis (Smith, 1949) a new tail is regenerated, including caudal adhesive pads. The axial skeleton of the regenerating tail consists in an elastic cartilaginous tube replacing the original vertebrae that allows interacting with the substrate like in the original tail. The formation of adhesive setae has been analyzed using transmission and scanning electron microscopy coupled to immunolabeling for Corneous Beta Proteins. During progressive stages of epidermal differentiation new setae are developed at stage 4 of the shedding cycle and contain Corneous Beta Proteins. These structural proteins are faintly localized in the Oberhäutchen but are abundant in the beta-layer, indicating that the two epidermal layers have a different protein composition. The setae originate from the growth of Oberhäutchen spinulae into the cytoplasm of clear cells and the latter produce a thick fibrous meshwork of keratin and other unknown proteins localized around the growing setae. This cytoskeleton likely allows molding tail setae like for digital setae. A graded development of setae is observed from the base to the tip of regenerated pads and from the periphery to more central areas. The terminal end of the setae is subdivided into numerous filamentous spatulae that increase the adhesion contact. Sensory boutons are frequently detected at the margin of tail scales and adhesive pads, likely improving compliance with the substrate. The present study indicates that tail regeneration is a convenient experimental model to analyze adhesive setae formation, microstructures that allow to these lizards climbing vertical and arboreal substrates.
在非洲壁虎海角睑虎（Lygodactylus capensis，史密斯，1949年）尾部丢失后，会再生出一条新尾巴，包括尾部的黏附垫。再生尾巴的轴向骨骼由一个弹性软骨管组成，取代了原来的椎骨，使其能够像原来的尾巴一样与底物相互作用。利用透射电子显微镜和扫描电子显微镜结合角质β蛋白免疫标记技术，对黏附刚毛的形成进行了分析。在表皮分化的渐进阶段，新的刚毛在蜕皮周期的第4阶段发育形成，并含有角质β蛋白。这些结构蛋白在表层（Oberhäutchen）中定位较浅，但在β层中含量丰富，这表明两个表皮层具有不同的蛋白质组成。刚毛起源于表层小刺（Oberhäutchen spinulae）向透明细胞细胞质中的生长，透明细胞产生围绕生长中的刚毛定位的角蛋白和其他未知蛋白质的厚纤维网络。这种细胞骨架可能像塑造指部刚毛一样塑造尾部刚毛。在再生垫的基部到尖端以及从周边到更中心的区域观察到刚毛的分级发育。刚毛的末端细分为许多丝状匙形结构，增加了黏附接触面积。在尾鳞和黏附垫的边缘经常检测到感觉小体，这可能有助于更好地贴合底物。本研究表明，尾巴再生是分析黏附刚毛形成的一个便捷实验模型，这些微观结构使这些蜥蜴能够攀爬垂直和树栖底物。
