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  • W Briegleb
  • ASGSB bulletin : publication of the American…
  • 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 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)
Cultures of human lymphocytes were exposed to the mitogen concanavalin A in a low-G environment generated by a fast rotating clinostat. DNA-synthesis was determined by incorporation of 3H-thymidine as the parameter for activation, cell ultrastructure was analyzed by electron microscopy, and cell movements were recorded by a cinecamera. The results were(More)
Preparing the German Spacelab Mission D-2 project "Gravity Perception and Neuronal Plasticity"--STATEX II--ground based experiments have been performed with larvae of the amphibian vertebrate Xenopus laevis Daud. to study the reactions to different levels of acceleration forces and profiles. The larvae have been exposed to accelerations of up to 5 g for(More)
The paper sums up results of a 7-day space flight experiment (D-l-Mission-BW-STA 00-STATEX) using growing frog embryos and larvae (Xenopus laevis) as a model system. Evaluation of photographs taken from the surface of sectioned deep-frozen objects, and micrographs using TEM and SEM show no aberrations in the shape, size, position, or respective electron(More)
Gravitaxis of Paramecium at different oxygen concentrations is analyzed by means of a computer controlled image-analysis system. The gravitactic response depends on the oxygen tension: at low-oxic conditions Paramecium shows a precise negative gravitaxis which changes into a random distribution if the oxygen tension is increased. This response is(More)
During the 6 min-lasting "free-fall conditions" (4 x 10(-6) g) of the parabolic flight of a sounding rocket Paramecium aurelia cells showed an increase of 7.5 % in their mean swimming velocity. A detailed analysis revealed that the kinetic response was transient: after 3 min the velocity decreased to the speed of the former horizontal swimming at 1 g.(More)
A cell culture of Paramecium with a precise negative gravitaxis was exposed to 4 x l0(-6) g during a parabolic flight of a sounding rocket for 6 min. Computer image analysis revealed that without gravity stimulus the individual swimming paths remained straight. In addition, three reactions could be distinguished. For about 30 s, paramecia maintained the(More)
  • W Briegleb
  • Advances in space research : the official journal…
  • 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)