Comparative studies of the graviresponses of Paramecium and Loxodes
| Autor: | B. Bromeis, H. Rabien, R. Voormanns, Krassimira Ivanova, Ruth Hemmersbach, N. Schmidt |
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| Rok vydání: | 2001 |
| Předmět: |
Atmospheric Science
Paramecium Rotation Loxodes striatus Gravitaxis Aerospace Engineering Centrifugation Hypergravity Cellular level Behavioral study Orientation Animals Ciliophora Gravity Sensing Swimming biology Chemistry Weightlessness Astronomy and Astrophysics Paramecium biaurelia Space Flight biology.organism_classification Culture Media Geophysics Space and Planetary Science Negative gravitaxis Biophysics General Earth and Planetary Sciences Locomotion |
| Zdroj: | Advances in space research : the official journal of the Committee on Space Research (COSPAR). 21(8-9) |
| ISSN: | 0273-1177 |
| Popis: | Gravitactic protozoa offer advantages in studying how the gravity stimulus is perceived on the cellular level. By means of a slow rotating centrifuge microscope in space the acceleration thresholds for gravitaxis of Loxodes striatus and Paramecium biaurelia were determined: ≤ 0.15 × g for Loxodes and 0.3 x g for Paramecium, indicating different sensitivities of these species. Neutral-buyant densities of immobilized cells were determined using media of different densities, revealing densities of 1.03 to 1.035 g/cm3 for Loxodes and 1.04 g/cm3 to 1.045 g/cm3 for Paramecium. Behavioral studies revealed that gravitaxis of Loxodes persisted independent of the density of the medium. In contrast, negative gravitaxis of Paramecium was no longer measurable if the density of the medium approached the density of the cell. The results suggest that in the case of Loxodes gravity is perceived by an intracellular receptor and, in the case of Paramecium by its own mass via the pressure on the lower cell membrane. |
| Databáze: | OpenAIRE |
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