... orientation. Cell profile measurements from microscope images suggest that the characteristic front–rear body asymmetry accounts for the observed orientation rates. Gravikinesis may result from interactions between the propelling cilia and the sedimentary flow around the cell, and it seems unlikely...

... by a negative gravikinesis. The graviresponse consists of a velocity-regulating physiological component (negative gravikinesis) and an additional orientational component. The latter is largely based on a physical mechanism but might, in addition, be affected by the frequency of ciliary reversals, which is under...

... (negative gravikinesis). In the mutant, only increases in propulsion were observed, although the orientation-dependent sensitivity of the gravikinetic response was the same as in the wild-type population. Observed swimming speed and sedimentation rates in the wild-type and mutant cells were linearly related...

...Richard Bräucker; Akira Murakami; Kazuko Ikegaya; Kenjiro Yoshimura; Keiichi Takahashi; Sigrun Machemer-Röhnisch; Hans Machemer ABSTRACT The kinetics of gravitaxis and gravikinesis in Paramecium caudatum were investigated by employing (1) step transitions from normal gravity (1 g...

... Limited 1996 Paramecium biaurelia gravitaxis gravikinesis hypergravity centrifuge microscope microgravity threshold As long ago as 1906, Jennings noted that at least some and probably many protozoa use gravity as an environmental stimulus for orientation. Some, such as Paramecium...

... functions of gravitational acceleration. Comparisons of cell populations from different cultures suggest that there is an age-dependent change in gravikinesis. In starved Paramecium caudatum (7-day cultures), the kinetic responses antagonizing sedimentation (negative gravikinesis) increased...

..., desensitization of mechanosensory channels and hyperactivation of ciliary activity in straight swimmers. * To whom reprint requests should be addressed. 23 9 1991 © 1992 by Company of Biologists 1992 Paramecium caudatum hypergravity swimming velocity gravikinesis gravitaxis...