ISSN:
1550-7408
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Cells of Loxodes striatus were adjusted to defined culturing, experimental solution, O2-supply, temperature, and state of equilibration to be subjected to step-type transition of acceleration from normal gravity (1 g) to the weightless condition (μg) during free fall in a 500-m drop shaft. Cellular locomotion inside a vertical experimental chamber was recorded preceding transition and during 10 s of μg. Cell tracks from video records were used to separate cells gliding along a solid surface from free swimmers, and to determine gravitaxis and gravikinesis of gliding and swimming cells. With O2 concentrations ≥ 40% air saturation, gliders and swimmers showed a positive gravitaxis. In μg gravitaxis of gliders relaxed within 5 s, whereas gravitaxis relaxation of swimmers was not completed even after 10 s. Rates of horizontal gliders (319 μm/s) exceeded those of horizontal swimmers (275 μm/s). Relaxation of gravikinesis was incomplete after 10 s of μg. Analysis of the locomotion rates during the g-step transition revealed that gliders sediment more slowly than swimmers (14 versus 45 μm/s). The gravikinesis of gliders cancelled sedimentation effects during upward and downward locomotion tending to maintain cells at a predetermined level inside sediments of a freshwater habitat. At ≥ 40% air saturation, gravikinesis of swimmers augmented the speed of the majority of cells during gravitaxis, which favours fast vertical migrations of Loxodes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1550-7408.1998.tb05092.x
