[Photoinduced inhibition and stimulation of respiration in cells of Halobacterium halobiums kinetics, action spectra, relationship to photoinduction of deltapH]. / Fotoindutsirovannoe ingibirovanie i stimulirovanie dykhaniia v kletkakh Halobacterium halobiums: kinetika, spektry deistviia, sviaz' s fotoinduktsiei delapH.

Along with the inhibition illumination also causes the stimulation of the respiration of H. halobium R1 cells. When light is switched off photoinhibition of respiration (PIR) decays much faster (tau 1/2=12 sec) than photostimulation (PSR) (tau 1/2=60 sec). This allows the evaluation of the contribution of the each phase into the total change of the respiration rate. PIR prevails in neutral and alkaline media (at pH 6.8 the amplitude ratio of PSR/PIR=0.3). At the same conditions light induced alkalization of the medium is observed, which at high light intensities is followed by acidification. The half rise time of PIR is 0.5 divided by 0.8 sec under excitation with short light flashes at 18C and pH 6.8. When pH of the medium is reduced the rate of dark respiration decreases, PSR amplitude increases, PIR is almost not changed and light-induced alkalinization of the medium decreases. At pH 5.5 PSR prevails: at light of 10(5) erg/(cm(2).s) the ratio PSR/PIR=2. The maximum value of PIR and PSR at 18C reaches 20-30 percent of the dark respiration level. Uncouplers (CCCP, DNF) and inhibitor (DCCD) of phosphorylation suppress PIR and light induced alkalinization of the medium and significantly (5-7 times at Ph 6.8) increase PSR and light induced acidification. The action spectra show that bacteriorhodopsin is responsible for all the observed light induced changes of O2 and H+ exchange; carotinoids do not participate in sensibilization. It is suggested that photophosphorylation is necessary for PIR and that PSR is caused by the rise of internal pH due to light induced efflux of protons mediated by bacteriorhodopsin.

[The effect of uncouplers of oxidative phosphorylation on granule precipitation of neutral red in normal and tumor cells]. / Vliianie razobshchitelei okislitel'nogo fosforilirovaniia na granulootlozhenie neitral'nogo krasnogo v normal'nykh i opukholevykh kletkakh

A study of the effect of uncouplers of the oxidative phosphorylation on the interaction on neutral red with the normal mouse fibroblast and tumour L-cells showed the former to retain the capacity for the dye granule formation in the presence of 1x10 4 M 2,4-dinitrophenol (DNP). Another uncoupler of the oxidative phosphorylation - n-trifluoromethoxycarbonycyanidephenylhydrazone (FCCP) depressed the granule formation both in the tumour L-cells and in the mouse normal fibroblasts. The dye uptake in the normal fibroblasts and in the tumour L-cells was inhibited by both the DNP and the FCCR in the concentration which uncoupled the oxidative phosphorylation.