EFFECTS OF RETINOIC ACID AND DIMETHYLSULFOXIDE ON THE MORPHOGENESIS OF THE SEA-URCHIN EMBRYO

Sea urchin embryos of the species Paracentrotus lividus were treated c ontinuously with different concentrations of all-trans retinoic acid ( RA) or dimethylsulfoxide (DMSO) at different developmental stages. A d elay in embryonic development was observed when embryos were cultured in the presence of 2x10(-5) M RA, between 1 and 12 hours of developmen t Hence, at 48 hours of development, while control embryos had reached the pluteus stage, RA-treated embryos were at the prism stage. At 72 hours of development RA-treated embryos recovered and continued normal development reaching the pluteus stage. No effect was observed when t reatment was performed before 1 hour or after 12 hours of developmet. DMSO treatment had no effect on normal sea urchin embryo development, although we observed that pigment cells, clearly visible at the pluteu s stage, become visible earlier with respect to control embryos. This report confirms the advantages that the sea urchin embryo offers for t he study of problems in cellular and developmental biology.