RESPIRATION-LINKED PROTON TRANSLOCATION COUPLED TO ANAEROBIC REDUCTION OF MANGANESE(IV) AND IRON(III) IN SHEWANELLA-PUTREFACIENS MR-1

An oxidant pulse technique, with lactate as the electron donor, was used to study respiration-linked proton translocation in the manganese- and iron-reducing bacterium Shewanella putrefaciens MR-1. Cells grown anaerobically with fumarate or nitrate as the electron acceptor translocated protons in response to manganese (IV), fumarate, or oxygen. Cells grown anaerobically with fumarate also translocated protons in response to iron(III) and thiosulfate, whereas those grown with nitrate did not. Aerobically grown cells translocated protons only in response tooxygen. Proton translocation with all electron acceptors was abolished in the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone (20 μM) and was partially to completely inhibited by the electron transport inhibitor 2-n-heptyl-4-hydroxyquinoline N-oxide (50 μM).