[Inhibitory effect of blue and ultraviolet light on photoinduced changes in the pH of a suspension of Halobacterium halobium cells].
It was found that when switching on blue and UV light with the green one at the background decreased the acidification of Halobacterium suspension sensitized with bacterirhodopsin. Three facts are responsible for the acidification decrease. 1. At high intensity of the background green light (above 10(2)/Wt/m2) the effect predominates, which is conditioned by the action of blue light on the intermediate of the photochemical cycle of bacteriorhodopsin P419 (M412). Phototransformation of the latter prevents the transmembrane transfer of H+. 2. At high intensities of shortwave light (10(3)Wt/m2) alkalization of the suspension sensitized with unidentified pigment is observed. 3. At low intensities of blue and UV light (10 Wt/m2) the effect with the maximum in the action spectrum at 390 nm predominates. It is increased after preillumination of Halobacteria with green light and after short-term incubation (to 1-2 hours at 20 degrees C) of the cells with dicyclohexylcarbodiimide. It is inhibited with dinitrophenol. The effect is suggested to result from the photo-induced increase of cell membrane permeability for H+. Judging by the action spectrum it may be involved in the phototaxis of Halobacteria.
D001436:Bacteriorhodopsins / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000528:radiation effects; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D006217:Halobacterium / Q000528:radiation effects*; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008027:Light; D010777:Photochemistry; D014466:Ultraviolet Rays
D004140:Dinitrophenols; D001436:Bacteriorhodopsins; D004024:Dicyclohexylcarbodiimide; D006859:Hydrogen
Ingibiruiushchee deĭstvie sinego i ul'trafioletovogo sveta na fotoindutsirovannye izmeneniia pH suspenzii kletok Halobacterium halobium.