FIG 6.

Internal pH decreases transiently upon addition of DCM. pJM40 expresses both the pH biosensor and DcmA. pJM41 contains only the biosensor and serves as a negative control. Internal pH upon addition of 5 mM DCM was measured in cell suspensions of dcmA-containing transconjugants using a pH-sensitive GFP translationally fused to a pH-insensitive mCherry (see Materials and Methods; also, see Fig. S5 in the supplemental material) (dead time before reliable fluorescence measurements, approximately 20 s).