Structural organization of the toe pads in the amphibian Philautus annandalii (Boulenger, 1906)
Structural organization of the toe pads in the amphibian Philautus annandalii (Boulenger, 1906)
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DOI：
10.1111/azo.12008
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发表时间：
2014-01-01
期刊：
影响因子：
1.2
通讯作者：
Nag, Tapas C.
中科院分区：
文献类型：
--
作者：
Chakraborti, Saurabh;Das, Debasish;Nag, Tapas C.
我们描述了喜马拉雅树蛙 Philautus annandalii 趾垫的形态。这些是扩大的手指尖端，并显示出其腹侧表皮的粘附变化。趾垫表皮 (TPE) 的外细胞具有角化的表面微结构 (0.7x0.2m)。它们的细胞质不含细胞器，但含有多形性细胞核和粘合角蛋白丝的粘液颗粒（0.4-0.5m）。在 TPE 的中间细胞层中，存在与外层细胞类似的角化微结构，因此当外层脱落时，它就具备了粘附功能。这些细胞比外部细胞含有更多的角蛋白。基底细胞层含有薄角蛋白束和常见的细胞器。真皮含有粘液分泌腺，其导管在外表皮细胞层中开口。背侧表皮细胞缺乏表面微结构和角蛋白束。超微结构特征表明，趾垫利用表面微结构在粘液的辅助下进行粘附，其中中间细胞层似乎承受运动过程中产生的剪切应力。此外，TPE 可以膨胀并适应基材增加的接触面积。长的表面微观结构也可能有助于与植物粗糙表面的机械互锁。
We describe the morphology of toe pads in the Himalayan tree frog Philautus annandalii. These are expanded tips of digits and show modifications of their ventral epidermis for adhesion. The outer cells of toe pad epidermis (TPE) bear surface microstructures (0.7x0.2m), which are keratinized. Their cytoplasm contains no organelles, but pleomorphic nuclei and mucous granules (0.4-0.5m) that glue the keratin filaments. In the intermediate cell layer of TPE, similar keratinized microstructures as in the outer cells are present, so that when the outer layer is shed, it is ready with features for adhesion. These cells contain more keratin than the outer cells. The basal cell layer contains thin keratin bundles and usual cell organelles. The dermis contains mucous-secreting glands, whose ducts open in the outer epidermal cell layer in channels. The dorsal epidermal cells lack surface microstructures and keratin bundles. Ultrastructural features suggest that toe pads utilize the surface microstructures for adhesion aided by mucus, in which the intermediate cell layer seems to bear the shear stress generated during locomotion. Further, TPE can expand and fit into an increased contact area of the substrate. The long, surface microstructures may also help in mechanical interlocking with rough surfaces on plants.