Observation on the basal lamina of duodenal mesothelial cells during metamorphosis of Xenopus laevis.
Morphologic changes in the basal lamina of duodenal mesothelial cells during metamorphosis of Xenopus laevis were observed. In the prometamorphosis stage (Stage 56-59), the basal lamina was almost completely flat; the lamina densa of the basal lamina was a 50 nm layer of high electron density. In the early stages of metamorphic climax (Stage 60-62), the basal lamina showed occasional slight folding (stage 60), with the lapse of time, the folding became continuous and deeper. The development of an additional thin basal lamina was observed in areas where the folded basal lamina was separated from mesothelial cells, viz. on the side adjacent to the mesothelium. The lamina densa in this stage was approximately twice the thickness of the prometamorphosis stage and exhibited high electron density. In the later stages of metamorphic climax (stage 63-66), the basal lamina just under mesothelium became more apparent. The folded basal lamina shifted from the mesothelium into the subserosa and gradually disappeared, and the basal lamina became a single layer. The thickness of the lamina densa was almost the same as in the prometamorphosis stage. Since the timing of the folding of the basal lamina coincides with the shortening of the digestive tract and the marked narrowing of the lumen, we suggest that physical changes in the digestive tract during metamorphosis may play an important role in these morphologic changes of the basal lamina.
Murata
E
E
Fujita
K
K
Akita
M
M
Kaneko
K
K
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D004386:Duodenum / Q000166:cytology*; D007814:Larva / Q000033:anatomy & histology; D008675:Metamorphosis, Biological; D008854:Microscopy, Electron; D014982:Xenopus laevis / Q000033:anatomy & histology*