Millisecond delayed light as a probe of membrane energization and redox poise in intact cells of photosynthetic bacteria

. This enhancement was modulated by proton-motive force (pmf), as demonstrated by sensitivity to protonophore carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP). Electron donor ferrocene quenched DL in all strains, consistent with perturbation of the redox equilibrium. Millisecond DL as an optical reporter of redox poise and membrane energization in intact photosynthetic bacteria offers valuable contribution to understanding energy dissipation pathways in bacterial photosynthesis and energization state of photosynthetic membranes.