Machemer-Röhnisch S, Machemer H, Bräucker R (1996) Activation and relaxation of gravikinesis in Didinium


Experiments at the Japan Microgravity Center (JAMIC) at Kamisunagawa/Hokkaido, spring 1996, confirmed and extended previous results of free fall experiments obtained with Didinium in the drop tower of Bremen. Sedimentation stops immediately with the onset of microgravity. However, the gravikinetic relaxation takes some time. The swimming velocity changed in a manner of a damped oscillation. After 4 s of microgravity the steady-state swimming rate is higher than seen in horizontally swimming cells under 1g-conditions. The observed transient oscillation suggests that step transition from 1g to µg includes a relaxation of gravikinesis superimposed by a transient gravikinetic activation.