To elucidate the mechanism of graviperception and signal transduAction, both cell types were investigated under varying accelerations and their behavior analyzed using computer-controlled image analysis. Methods used to apply varying accelerations were hypergravity, simulated weightlessness achieved using fast-rotating clinostats, and microgravity in sounding rockets (TEXUS 27, 28, 39 und MAXUS 2), the Space Shuttle (D1, IML-1, IML 2, STS-69, S/MM-06) and parabolic flights (www.novespace.fr). In addition, cells were examined in density-modified media and after destruction of receptor candidates.
Experiments concerning graviresponses of ciliates are also perfomed in the DLR_School_Lab Köln-Porz durchgeführt.
Present Models of Gravity Perception
Hemmersbach, R. & Bräucker, R. (2002). Gravity-related behaviour in ciliates and flagellates, in Cell Biology and Biotechnology in Space. Ed., A. Cogoli. Elsevier, Amsterdam, pp. 59-75.Hemmersbach, R. & Häder, D.-P. (1999). Graviresponses of certain ciliates and flagellates. FASEB J., 13, S69-S75.Hemmersbach, R., Volkmann, D. & Häder, D.-P. (1999). Graviorientation in protists and plants. J. Plant Physiol., 154, 1-15.Hemmersbach, R., Voormanns, R., Briegleb, W., Rieder, N. & Häder, D.-P. (1996). Influence of accelerations on the spatial orientation of Loxodes and Paramecium. J. Biotechnol., 47, 271-8.Hemmersbach, R., Voormanns, R. & Häder, D.-P. (1996). Graviresponses in Paramecium biaurelia under different accelerations: Studies on the ground and in space. J. Exp. Biol., 199, 2199-205.
Block, I., Briegleb, W. & Wohlfarth-Bottermann, K.-E. (1986). Gravisensitivity of the acellular slime mold Physarum polycephalum demonstrated on the fast-rotating clinostat. Eur. J. Cell Biol., 41, 44-50.Block, I., Rabien, H. & Ivanova, K. (1998). Involvemement of the second messenger cAMP in the gravity-signal transduction in Physarum. Adv. Space Res., 21, 1311-4.Block, I., Freiberger, N., Gavrilova, O. & Hemmersbach, R. (1999). Putative graviperception mechanisms of protists. Adv. Space Res., 24, 877-82.