Frolich L M, Schmid T M
Department of Organismal Biology and Anatomy, University of Chicago, Illinois 60637.
J Morphol. 1991 Apr;208(1):99-107. doi: 10.1002/jmor.1052080105.
The orientation of the fibers in the dermis of the tiger salamander, Ambystoma tigrinum, undergoes a dramatic repatterning at metamorphosis. The pre-metamorphic, larval dermis is a tight layer composed of crossed fibers that wind helically around the trunk. This condition is retained by neotenic adults which do not undergo metamorphosis. In contrast, the neotenic adults which do not undergo metamorphosis. In contrast, the metamorphosed adult dermis consists of a superficial, loose network of fibers invested with large multicellular glands--the stratum spongiosum--and a deeper tight layer of fibers--the stratum densum. However, unlike the crossed fibers of the pre-metamorphic dermis, there is no preferred orientation to the fibers in either layer of the post-metamorphic dermis. In order to evaluate whether these two distinctly different fiber patterns are constructed from biochemically similar fibers, the collagen types present in the pre- and post-metamorphic dermis were determined using SDS-polyacrylamide gel electrophoresis. Type I collagen is the predominant collagen of the dermis and the same major collagen types are present for all individuals, whether pre- or post-metamorphic. Thus, the major types of collagen that compose the dermal fibers do not change during metamorphic repatterning of the dermis.
虎螈（钝口螈属虎螈）真皮层中纤维的排列方向在变态过程中会经历显著的重新排列。变态前的幼体真皮层是一层紧密的组织，由交叉的纤维组成，这些纤维呈螺旋状缠绕在躯干周围。未经历变态的幼态成熟成体保留了这种状态。相比之下，经历变态的成体真皮层由一个浅层的、松散的纤维网络组成，其中分布着大型多细胞腺体——海绵层，以及一个更深层的紧密纤维层——致密层。然而，与变态前真皮层的交叉纤维不同，变态后真皮层的两层纤维都没有特定的排列方向。为了评估这两种截然不同的纤维模式是否由生物化学性质相似的纤维构成，研究人员使用SDS-聚丙烯酰胺凝胶电泳法测定了变态前和变态后真皮层中存在的胶原类型。I型胶原是真皮层的主要胶原，所有个体，无论变态前还是变态后，主要的胶原类型都是相同的。因此，在真皮层变态重新排列过程中，构成真皮纤维的主要胶原类型不会发生变化。
