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The gravitactic ciliates Paramecium and Loxodes were cultivated for 15 days in space during the IML-2 spacelab mission. At dedicated times their behavioral responses to different accelerations between 10(-3) x g and 1.5 x g were investigated by using a slow rotating centrifuge microscope (NIZEMI). The threshold for gravitaxis of Paramecium was found to be(More)
  • W Briegleb
  • 1984
This paper speculates about the interplay between adaptational modifications with mutation and selection. Gravity effects are supposed to be very well suited to prove the role of direct adaptations for phylogenic processes. The speculation is based on strong hints that the cell in general reacts to accelerations (besides other mechanical stimuli) in the(More)
  • W Briegleb
  • 1992
In 1958 the geneticist H.J. Muller proposed an extension of the principle of the (slow) plant clinostat which --to a certain extent--abolishes g effects on plant growth (geotropism). Muller predicted that a feeling of weightlessness would be experienced by a human being attached to a clinostat platform, the rotation speed of which is enhanced compared to(More)
The acellular slime mold Physarum polycephalum was used to investigate a postulated general gravisensitivity of cells. Physarum was subjected i) to a rotation on the fast-rotating clinostat, which enables the simulation of weightlessness (0 g), and ii) to single horizontal turns of 180 degrees. On the fast-rotating clinostat the response consists of a(More)
We have investigated Physarum polycephalum, a unicellular organism with no special gravity receptors, on its ability to react to gravity. The first experiments were 0 g-simulation experiments on the fast-rotating clinostat conducted with plasmodial strands of this acellular slime mold. In these earth-bound experiments the observed parameters were(More)
When cell physiologists detect gravity related reactions of their objects it is often difficult to decide where the receptors for the observed effects are located. Answering this question is necessary for any further analysis of a detected gravity effect on cells. In previous papers we have discussed direct and indirect gravity effects in relation to the(More)
Organisms use gravity for spatial orientation, and differentiation into species during evolution follows geological processes which are caused by gravity. On the other hand, the task of most organismic functions which have or may have a relation to gravity is to compensate gravity. Furthermore, today it is very obvious that organisms do not disintegrate(More)
The structures and mechanisms involved in gravity perception and reaction are generally not known in animal cells, even in protozoa capable of gravitactic behaviour. To study the possible role of trichocysts in graviperception of Paramecium we analysed strains with a different set-up of trichocysts (absence, free floating or attached to the cell membrane)(More)