Effects of fast clinostat treatment and microgravity on Vicia faba L. mesophyll cell protoplast ubiquitin pools and actin isoforms

With parabolic rocket flights and fast clinostat treatments, the effect of microgravity on ubiquitin, ubiquitin-protein conjugates, and actin isoforms of Vicia faba mesophyll protoplasts was studied. Western immunoblotting with ubiquitin antibodies revealed that simulated and particularly, real microgravity influenced the amount of free ubiquitin and of 18, 19, and 40 kD ubiquitin conjugates by inducing strong oscillations in the proteins concentrations over time. Simulated microgravity and microgravity-phase during parabolic rocket flights resulted in a decrease of actin isoforms. Results obtained support the assumption, that microgravity and fast clinostat treatment have a direct effect on Vicia faba mesophyll protoplast metabolic activities.