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Physiological characterization of gravitaxis in Euglena gracilis
Peter Richter1, Maria Ntefidou, Christine Streb
1Institute of Botany and Pharmaceutical Biology, Chair of Plant Ecophysiology, Friedrich-Alexander University, Erlangen. prichter@biologie.uni-erlangen.de
Journal of Gravitational Physiology : a Journal of the International Society for Gravitational Physiology
|March 9, 2004
Summary
Euglena gracilis exhibits negative gravitaxis, swimming upward in darkness. This orientation relies on active physiological mechanisms, influenced by factors like calcium and membrane potential.
Area of Science:
- Microbiology
- Cell Biology
- Biophysics
Background:
- Euglena gracilis is a motile, unicellular freshwater flagellate.
- This organism uses external stimuli such as gravity, light, and oxygen pressure for orientation.
- In darkness, Euglena gracilis typically displays negative gravitaxis, moving upwards in the water column.
Purpose of the Study:
- To investigate the physiological mechanisms underlying gravitaxis in Euglena gracilis.
- To understand how Euglena gracilis utilizes gravity for orientation in its natural environment.
Main Methods:
- Analysis of Euglena gracilis behavior in response to gravitational stimuli.
- Investigation of cellular parameters potentially involved in gravitaxis, including calcium signaling, cyclic adenosine monophosphate (cAMP) levels, and membrane potential.
Main Results:
- Ground and space experiments indicate that gravitaxis in Euglena gracilis is an active physiological process.
- Key cellular components such as calcium ions, cAMP, and membrane potential are implicated in mediating gravitactic responses.
Conclusions:
- Gravitaxis in Euglena gracilis is a complex, physiologically regulated behavior.
- Understanding these mechanisms provides insights into cellular responses to environmental cues.