[Electrochemical gradient of H+ ions as an immediate source of energy during bacteria movement]

An uncoupler of oxidative phosphorylation causes an instantaneous cessation of movement of bacteria Rhodospirillum rubrum in the presence and in the absence of oligomycin. It is concluded that such cessation is not due to a decrease in the ATP concentration but to the elimination of deltamicron-H+ by the uncoupler. The mobility of the bacteria does not practically change in the presence of acetate and is, to some extent, decreased after addition of valinomycin or penetrating cation of tetraphenyl phosphonium. Under a combined action of acetate and valinomycin the movement is depleted. It is concluded that both constituents of deltamicronH+-transmembrane difference of electric potentials and the pH gradient--may serve as energy sources for the bacteria movement. Inhibitory analysis data suggest that the bacteria movement may be maintained by any of the deltamicronH+ sources, e.g. light-dependent cyclic electron transfer, respiration, ATPase and membrane pyrophosphatase.