CHANGES ASSOCIATED WITH THE BASAL LAMINA DURING METAMORPHOSIS OF XENOPUS-LAEVIS

We examined the changes in the morphology of the basal lamina of the c olon, abdominal wall and tail muscles of tadpoles during metamorphosis and compared our results to those previously obtained for the small i ntestine. At the early stage of metamorphic climax (stages 60-62), we observed a curving of the basal lamina along the processes of the epit helial cells. At a later stage of metamorphic climax (stages 63-66), m ore extensive curving and folding of the basal lamina were observed. T he basal lamina of the mesothelial cells in the abdominal wall did not change extensively as compared to the colon. Folded basal lamina was observed among degenerated muscle cells. Our results suggest that the folding of the basal lamina depends on the degree of deformation of th e particular organ, which occurs mainly by physical factors such as th e shortening or shrinking of the organ due to cellular degeneration. C ells that are newly differentiated produce an additional basal lamina, which results in transient doubling or layering. The combination of p hysical factors and cell differentiation results in a basal lamina tha t is more complex and contains folds and layers.