Figure 1

SYTO9 staining analyzed with microplate reader. Relative fluorescence intensity (RFU) at 528 nm is shown for different live/dead proportions of S. aureus (a) and P. aeruginosa (b). Values were measured after staining with SYTO9 for 15 minutes (green diamonds) and after additional 15 minutes counterstaining with PI (red circles). As a control 0.9% NaCl solution (NS) was added (green circles) instead of PI to consider dilution and bleaching effects of SYTO9. Cell optical densities (OD) of 0.25 for S. aureus and 0.12 for P. aeruginosa were used. Error bars represent 3 individual repeats with 3 replicas for P. aeruginosa and S. aureus, respectively. The error bars for some data points are too small to be seen (hidden behind the symbols).