[Intercellular relay interactions in explants of amphibian embryonic tissues. I. Intercellular relay interactions in normal explant morphogenesis].

In the explants of lateral mesoderm, together or without the overlaying ectoderm, taken from the neurula-early tail bud of amphibian embryos (Xenopus laevis, Rana temporaria) within 5-30 min, several types of cytological transformations have been observed, some of these being: formation of a microfilamentous layer under the naked explant surface, morphological polarization, and unilateral spreading of cells. These processes are described at the light and electron microscopy levels. It is suggested that these may be of relay character, that is, each transformed cell induces the same transformation in the adjacent one. The cytological transformations are correlated with metabolic ones described elsewhere.