FIG. 5.

Effects of PCP (a), CA (b), and DCA (c) on the internal pH of membrane vesicles of L. salivarius subsp. salicinius JCM 1044. An artificial ΔpH was established by the addition of 28 μl of 2 N KOH to the membrane vesicle suspension in 2 ml of 150 mM potassium phosphate buffer, which altered the external pH from 6.5 to about 6.8. The chemical compounds were added at the indicated final concentrations. Nigericin (100 nM) was added to dissipate the preexisting ΔpH.