Effects of microgravity and hypergravity on early development stages of Xeonopus laevis.

: The aim of this work is to evaluate the development of X.l. in modified gravity conditions. The simulation of hyper and microgravity was performed utilizing: an hyperfuge, a Clinostat and later on a Random Positioning Machine (RPM, 3d Clinostat). The effect of hypergravity on embryos is significantly higher than that of microgravity; the exposure of embryos to 3xg for 3 days before and after hatch causes an activation of HSP-60 and HSP-70. Embryos exposed to 3xg during the first 3 days of development are very sensitive and show a retard of development, with a lower content of DNA, neutral glycolipids and gangliosides compared to controls.