Comparison of ripA promoter activity in C. glutamicum WT and the Δpup mutant using the reporter plasmid pJC1-PripA-crimson. The two strains were cultivated under iron limitation, and samples were taken after 0, 2, 4, 6, and 24 h. A total of 100,000 cells of each sample were analyzed by flow cytometry for crimson fluorescence. The fluorescence intensities of individual cells are plotted against the forward scatter (FSC). Dotted lines were inserted at 103 and 104 arbitrary units (AU) of fluorescence to allow comparison of the two samples. The median crimson fluorescence for each sample is indicated on top of each scatter plot.