Effect of concanavalin A and vegetalizing factor on the outer and inner ectoderm layers of early gastrulae of Xenopus laevis after treatment with cytochalasin B.
Neural (archencephalic) structures have been evoked in the competent ectoderm (consisting of both ectodermal layers) of Xenopus laevis by treatment with Concanavalin A (Con A), which probably acts on the plasma membrane. The size of the neural structures is increased when the ectoderm is incubated in Cytochalasin B prior to the Con A treatment. The results indicate that Cytochalasin B could have an influence on the binding of Con A to receptors on the plasma membrane. On the other hand, Cytochalasin B seems to have an inhibitory effect on the action of the vegetalizing factor, which could be correlated with the decline of endocytotic processes and internalization. In further series, it could be shown that the isolated superficial ectoderm, in contrast to the inner ectoderm layer, does not react to Con A treatment with the differentiation of neural structures. Studies with FITC-Con A indicate that the marker binds less to the outer ectoderm than to the inner ectoderm layer. However, by xenoplastic combinations of the outer ectoderm layer of X. laevis as reacting tissue and chordamesoderm of Triturus vulgaris as inducer, it could be demonstrated that the superficial layer, which is normogenesis does not come into contact with the inducing chordamesoderm but forms the ependymal part of the brain only, is also able to form archencephalic brain structures under in vitro conditions.
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology*; D003571:Cytochalasin B / Q000494:pharmacology*; D004475:Ectoderm / Q000187:drug effects; D005775:Gastrula / Q000166:cytology / Q000187:drug effects*; D014020:Tissue Extracts / Q000494:pharmacology; D014319:Triturus / Q000196:embryology; D014982:Xenopus laevis / Q000196:embryology*
D014020:Tissue Extracts; D003208:Concanavalin A; D003571:Cytochalasin B