[Reversible effect of intensive light on photobiochemical properties of Rhodospirillum rubrum chromatophores]. / Obratimoe deistvie intensivnogo sveta na fotobiokhimicheskie svoistva khromatoforov Rhodospirillum rubrum.

The effect of high intensity (photosynthesis-saturating) light on the optical properties of the bacteriochlorophyll and the light-induced H+ uptake by R. rubrum chromatophores was studied. It was shown that under aerobic conditions illumination causes reversible inhibition (in the dark) of the chromatophore ability for the light-induced uptake of H+, a reversible inhibition of the photosynthetical reaction center function and irreversible bleaching of the antennal bacteriochlorophyll. A kinetic comparison of spectral effects and reversible changes in pH as well as the effects of atmospheric oxygen and exogenous electron donors suggests that inhibition of photoactivity of the chromatophores upon illumination is due to accumulation of oxidized bacteriochlorophyll in the reaction center.

[Activation and inhibition of photoinduced proton absorption in Rhodospirillum rubrum chromatophores by detergents and solvents]. / Aktivatsiia i ingibirovanie fotoindutsirovannogo pogloshcheniia protonov v khromatoforakh Rhodospirillum rubrum detergentami i rastvoriteliami.

The effects of detergents (Triton X-100) and solvents (diethyl ether, metanol) on the reversible light-induced proton uptake, photophosphorylation and band shift of the carotenoid in chromatophores from R. rubrum are described. All these compounds were found to stimulate the extent of light-induced proton uptake with subsequent inhibition when the concentrations were increased. Stimulation of proton uptake is accompanied by inhibition of both phosphorylation and carotenoid absorbance shift.

[Light-dependent uptake of hydrogen ions in chloroplasts and chromatophores: effects of hearing, solvents and detergents]. / Svetozavisimoe porloshchenie ionov vodoroda v khloroplastakh i khromatoforakh: deistvie nagrevaniia, rastvoritelei, detergentov.

The effects of heating, organic solvents and detergents on the light-dependent hydrogen ion uptake in chloroplasts and chromatophores and the coupled photophosphorylation were compared. It was shown that the membrane structure of the chromatophores is much more stable than that of the chloroplast thylacoids. The activation of the pH function in the chromatophores in the presence of low concentrations of diethyl ether and detergents was noted. The effects observed may be due to the changes in the physico-chemical properties of the membranes rather than to the direct effect on the photosynthetic electron transfer chain.