Comparative studies on gravisensitive protists on ground (2D and 3D clinostats) and in microgravity

Abstract

In order to prepare and support space experiments, 2D and 3D clinostats are widely applied to study the influence of simulated weightlessness on biological systems. In order to evaluate the results, a comparison between the data obtained in simulation experiments and in real microgravity is necessary. We are currently analyzing the gravity-dependent behaviour of the protists Paramecium biaurelia (ciliate) and Euglena gracilis (photosynthetic flagellate) on these different experimental platforms. So far, first results are presented concerning the behaviour of Euglena on a 2D fast rotating clinostat and a 3D clinostat as well as under real microgravity conditions (TEXUS sounding rocket flight), of Paramecium on a 2D clinostat and in microgravity. Our data show similar results during 2D and 3D clinorotation compared to real microgravity with respect to loss of orientation (gravitaxis) of Paramecium and Euglena and a decrease of linearity of the cell tracks of Euglena. However, the increase of the mean swimming velocities, especially during 3D clinorotation (Euglena) and 2D clinoratation of Paramecium might indicate a persisting mechanostimulation of the cells. Further studies including long-term 2D and 3D clinostats exposition will enable us to demonstrate the qualification of the applied simulation methods.