Figure 4

Detection of EtBr efflux in E. coli K-12 AG100. The bacteria were loaded with EtBr at 1 μg/ml in the presence of CPZ (20 μg/ml) for a period of 60 minutes at 25°C. After replacing the buffer with EtBr-free PBS with or without glucose, the efflux was assessed by: (A) the semi-automated fluorometric method, performed at 37°C for 15 minutes; and (B) flow cytometry, represented by an histogram overlay corresponding to the data selected for analysis (2^nd gate) for E. coli K-12 AG100 immediately after replacing the buffer with EtBr-free PBS (t = 0) and 15 minutes after incubation at 37°C with or without glucose.