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Fluorescence induction of photosynthetic bacteria
- Sipka, G., Kis, M., Smart, J. L., Maróti, P.
- Photosynthetica 2018 v.56 no.1 pp. 125-131
- Rhodobacter sphaeroides, bacteriochlorophyll, chemical treatment, diodes, electron transport chain, fluorescence, lighting, photochemistry, photosynthetic bacteria, wavelengths
- The kinetics of bacteriochlorophyll fluorescence in intact cells of the purple nonsulfur bacterium Rhodobacter sphaeroides were measured under continuous and pulsed actinic laser diode (808 nm wavelength and maximum 2 W light power) illumination on the micro- and millisecond timescale. The fluorescence induction curve was interpreted in terms of a combination of photochemical and triplet fluorescence quenchers and was demonstrated to be a reflection of redox changes and electron carrier dynamics. By adjustment of the conditions of single and multiple turnovers of the reaction center, we obtained 11 ms–¹ and 120 μs–¹ for the rate constants of cytochrome c₂³⁺ detachment and cyclic electron flow, respectively. The effects of cytochrome c₂ deletion and chemical treatments of the bacteria and the advantages of the fluorescence induction study on the operation of the electron transport chain in vivo were discussed.