Gradmann, D. and Ehlenbeck, S. and Hegemann, Peter (2002) Modeling light-induced currents in the eye of Chlamydomonas reinhardtii. JOURNAL OF MEMBRANE BIOLOGY, 189 (2). pp. 93-104. ISSN 0022-2631
Full text not available from this repository.Abstract
Rhodopsin-mediated electrical events in green algae have been recorded in the past from the eyes of numerous micro-algae like Haematococcus pluvialis, Chlamydomonas reinhardtii and Volvox carteri. However, the electrical data gathered by suction-pipette techniques could be interpreted in qualitative terms only. Here we present two models that allow a quantitative analysis of such results: First, an electrical analog circuit for the cell in suction pipette configuration is established. Applying this model to experimental data from unilluminated cells of C. reinhardtii yields a membrane conductance of about 3 Sm-2. Furthermore, an analog circuit allows the determination of the photocurrent fraction that is recorded under experimental conditions. Second, a reaction scheme of a rhodopsin-type photocycle with an early Ca2+ conductance and a later H+ conductance is presented. The combination of both models provides good fits to light-induced currents recorded from C. reinhardtii. Finally, it allowed the calculation of the impact of each model parameter on the time courses of observable photocurrent and of inferred transmembrane voltage. The reduction of the flash-to-peak times at increasing. light intensities are explained by superposition of two kinetically distinct rhodopsins and by assuming that the Ca2+-conducting state decays faster at more positive membrane voltages.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RHODOPSIN-TRIGGERED PHOTOCURRENTS; ALGA HAEMATOCOCCUS-PLUVIALIS; GREEN-ALGA; PHOTORECEPTOR CURRENT; BACTERIORHODOPSIN; PHOTOTAXIS; KINETICS; IONS; analog circuit; channelrhodopsin; photocycle; proton conductance; reaction kinetics; rhodopsin |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 01 Sep 2021 10:17 |
| Last Modified: | 01 Sep 2021 10:17 |
| URI: | https://pred.uni-regensburg.de/id/eprint/39875 |
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