W Briegleb

Learn 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)
Aboard the German-Spacelab-Mission D-2 the project "Gravity Perception and Neuronal Plasticity (STATEX II)" was performed. STATEX is for STATolith EXperiment. Objects were growing tadpoles of the South African Toad (Xenopus laevis D.) and a juvenile cichlid fish (Oreochromis mossambicus). The results give a broader base for the understanding of how(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)
Cellular signal processing in multi-, as well as in unicellular organisms, has to rely on fundamentally similar mechanisms. Free-living single cells often use the gravity vector for their spatial orientation (gravitaxis) and show distinct gravisensitivities. In this investigation the gravisensitive giant ameboid cell Physarum polycephalum (Myxomycetes,(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)
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)
Aquatic animals have almost no body weight related proprioception for spatial orientation. Xenopus larvae, like fish, maintain their attitude in water by continuous correction with their fin(s). For these reasons a special performance of the equilibrium system compared to terrestrial animals is necessary. Evidently fish therefore have more compact(More)
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)
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)