Morphological and Cellular Aspects of Tail and Limb Regenerat... by Lorenzo Alibardi

The detailed ultrastructural immunogold study of the human epidermis reveals a diffuse and uneven labelling in the paler component of the composite keratohyalin granules or among keratin filaments of the transitional layer while the labelling disappears in the corneous layer. The immunofluorescent study on the epidermis of the platypus (monotreme), red kangaroo (marsupials), hamster and human (placentals) reveals a prevalent labelling in the granular, transitional and lowermost part of the stratum corneous layer. A database search indicates that the enzyme shares common sequences in numerous mammalian species so that an antibody against the human sulfhydryl oxidase 2 has been utilized on other species. more The epidermis of representative mammalian species including humans has been examined for the presence of sulfhydryl oxidase, an enzyme likely involved in the oxidation of corneous proteins containing sulfhydryl groups in the epidermis. The epidermis of representative mammalian species including humans has been examined for the pres. This study confirms that, like during regeneration in fishes and amphibians, also the blastema of lizards utilizes common signalling pathways for maintaining regeneration. The lack of activation and production of Msx1-2 protein in the limb are likely due to the intense inflammatory reaction following amputation. The AEP and the ependyma are believed to induce and maintain tail regeneration, and this study suggests that Msx1-2 proteins are components of the signalling system that maintains active growth of the tail blastema. The presence of a proximal–distal gradient of Msx1-2 protein, generated from the apical ependyma, is suggested by the intensity of immunolabelling. No immunolabelling is present in the wound epidermis and scarring blastema of the limb at 18–21 days of regeneration, except for sparse repairing muscles. The AEP is a micro-region of the regenerating epidermis located at the tail tip of the blastema, likely corresponding to the AEC of the amphibian blastema. more The immunolocalization of the muscle segmental homoeobox protein Msx1-2 of 27–34 kDa in the regenerating tail blastema of a lizard shows prevalent localization in the apical ependyma of the regenerating spinal cord and less intense labelling in the wound epidermis, in the apical epidermal peg (AEP), and in the regenerating segmental muscles. The immunolocalization of the muscle segmental homoeobox protein Msx1-2 of 27–34 kDa in the regen.

Morphological and Cellular Aspects of Tail and Limb Regenerat... by Lorenzo Alibardi