[Mechanisms of competency of early embryonic tissues].

The results of the author's studies of cell competence at the early embryonic stages, are summarized. The experiments with the isolation of four animal blastomeres of the newt at the eight-cell stage of development have shown that the presumptive ectoderm is determined to the development into epidermis already at this very early stage. The electron microscopi study of epidermis developing from the explanted ectoderm has shown that by its ultrastructure it does not differ from the normal larval epidermis. The loss by the ectoderm of the competence to the development under the effect of various morphogenetic factors appears to be related to the synthesis of a protein inhibitor during gastrulation. The data on the role of cell surface, adhesion and cell affinity in the early development are considered. Differences in the structure of surface between the cells experienced and not experienced the inductive influence were revealed with the help of electron microscope. The results of studying the mechanism of reaggregation of the embryonic cells using concanavalin A are also provided.