Journal article


Possible involvement of the membrane potential in the gravitactic orientation of Euglena gracilis


Publication Details
Author(s): Richter P, Lebert M, Korn R, Häder DP
Publisher: Elsevier
Publication year: 2001
Volume: 158
Pages range: 35 - 39
ISSN: 0176-1617

Abstract

Euglena gracilis, a unicellular photosynthetic flagellate, uses light and gravity as environmental hints to reach and stay in regions optimal for growth and reproduction. The current model of gravitaxis (the orientation with respect to the earth's gravitational field) is based on the specific density difference between cell body and medium. The resulting sedimentation of the cell body applies a force to the lower membrane. This force activates mechano-sensitive ion channels. The resulting ion flux changes the membrane potential, which in turn triggers reorientational movements of the trailing flagellum. One possibility for recording the predicted membrane potential changes during reorientation is the use of potential-sensitive dyes, such as Oxonol VI. The absorption changes of the dye indicating potential changes were recorded with a custom-made photometer, which allows a high precision measurement with a high temporal resolution. After a gravitactic stimulation, a short period of hyperpolarization was detected, followed by a massive depolarization of the cell. The membrane potential returned to initial values after a period of approximately 200s. Parallel measurements of the precision of orientation and the membrane potential showed a close relationship between both phenomena. The obtained results support the current model of gravitaxis of Euglena gracilis.



How to cite
APA: Richter, P., Lebert, M., Korn, R., & Häder, D.-P. (2001). Possible involvement of the membrane potential in the gravitactic orientation of Euglena gracilis. Journal of Plant Physiology, 158, 35 - 39. https://dx.doi.org/10.1078/0176-1617-00194

MLA: Richter, Peter, et al. "Possible involvement of the membrane potential in the gravitactic orientation of Euglena gracilis." Journal of Plant Physiology 158 (2001): 35 - 39.

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