title: Epithelial locomotion and differentiation in frog skin cultures.
abstract: Small explants from the medioventral skin of the green frog were maintained in culture for 5 days. During the first hours, a rapid outgrowth of the stratum germinativum was observed at the periphery of the fragment (2 X 3 X 0.75 mm). The Malpighian cells stretched and emitted long lamellipodia following the cut edges of the dermis. These cells acquired a fibroblastic shape and were covered by other flattened cells from the stratum spinosum and even from the stratum granulosum. This progression of cells simulated an epiboly; cell divisions occurred and were revealed by autoradiography. The underlying dermis could be totally covered after 3 days. An increase in the number of cellular layers was observed. The migrating cells redifferentiated, in particular at the lower side of the dermis, which provided a suitable substratum for the newly formed epidermis. A new basal lamina was formed. Some exfoliations of keratinized layers were seen. After 5 or 6 days of culture, epiboly was complete, the epithelium formed a closed system, and degenerative processes occurred, probably by non-penetration of the nutritive medium into the deeper regions of the explant.
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D002454:Cell Differentiation; D002465:Cell Movement; D046508:Culture Techniques; D003896:Desmosomes / Q000648:ultrastructure; D004847:Epithelial Cells; D007365:Intercellular Junctions / Q000648:ultrastructure; D007633:Keratins / Q000378:metabolism; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011893:Rana esculenta; D012867:Skin / Q000166:cytology*; D014945:Wound Healing
chemical_list: D007633:Keratins