FIG 5.

Real-time efflux assays using the different piperazine arylideneimidazolones as fluorescent membrane probes and the acrAB-overexpressing strain 3-AG100. After dye loading for 30 min, the deenergized cells were washed once in PPB, and efflux was triggered by addition of 50 mM glucose at 50 s. Identical conditions were used for all dyes (OD₆₀₀ of 0.25, near-infrared emission maximum as given in Table 1, and slit width of 10 nm). The 3-AG100 ΔacrB strain demonstrated that BM-27 efflux in the 3-AG100 strain is mediated mainly by the AcrAB-TolC pump.