Fluorescence induction of photosynthetic bacteria
- 84 Downloads
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.
Additional keywordsbacterial photosynthesis electron transfer fluorescence transients intact cells
minimal fluorescence yield of the dark-adapted state
maximal fluorescence yield of the light-adapted state
Unable to display preview. Download preview PDF.
- Comayras F., Jungas C., Lavergne J.: Functional consequences of the organization of the photosynthetic apparatus in Rhodobacter sphaeroides. I. Quinone domains and excitation transfer in chromatophores and reaction center antenna complexes.–J. Biol. Chem. 280: 11203–11213, 2005.CrossRefPubMedGoogle Scholar
- Maróti P.: Induction and relaxation of bacteriochlorophyll fluorescence in photosynthetic bacteria.–In: Pessarakli M. (ed): Handbook of Photosynthesis, 3rd ed. Pp. 463–483. CRC Press, Boca Raton–London–New York 2016.Google Scholar
- Sambrook J., Fritsch E.F., Maniatis T.: Molecular cloning: a laboratory manual, 2nd ed. Page A.1. Cold Spring Harbor Laboratory Press, New York 1989.Google Scholar