Fig. 6. Colocalization of cardiolipin and ProP at the bacterial poles and septa. E. coli strains WG994 (cls+) and WG1008 (cls–), both expressing MVCCPGCC-ProP, were cultivated to exponential phase [an optical density (600 nm) of 1] or stationary phase (overnight) in low- or high-osmolality MOPS medium (0.15 or 0.7 mol kg-1) without arabinose. Cells were stained with DAPI (nucleoids, blue fluorescence) and NAO (CL, left panel, green or red fluorescence) or FlAsH-EDT2 (MVCCPGCC-ProP, right panel, green fluorescence) and fluorescence was recorded as described in Experimental procedures. Red NAO fluorescence, indicating high levels of CL, is shown for those preparations in which it was observed (cls+ bacteria cultivated under all conditions and cls– bacteria cultivated in high-osmolality medium to stationary phase). Green NAO fluorescence is shown where no red NAO fluorescence was observed (cls– bacteria cultivated at low osmolality or to exponential phase in high-osmolality medium).