Mechanism of delta pH maintenance in active and inactive cells of an obligately acidophilic bacterium.

摘要: The acidophilic bacterium PW2 possessed a delta pH of ca. 1.9 and psi 0 mV, corresponding to proton motive force (delta p) of--114 mV. Protonophore-treated cells little p but 1.5, as measured by salicylic acid distribution or measurement cell lysates. Starving continued possess 1.7, exhibited converse changes in p, with the former rising +80 +100 mV latter dropping essentially 0; progressive loss respiration, cellular ATP, culture viability accompanied these changes. Thus, protonophore-treated starving attained an H+ electrochemical equilibrium. Net influx resulting from declining respiration probably accounted for increased cells; indeed, when was progressively inhibited active cells, there increasing transient proportional increase psi. This sufficient lethally acidify cytoplasm, buffering capacity 85 nmol H+/mg protein per unit. linkage rise cytoplasmic play central roles acidophilism, it is conceivable that same impermeant macromolecule(s) accounts both. If so, would be Donnan potential offset energy-dependent extrusion.