Figure 6. Increase in reactive oxygen species (ROS) levels associated with Δagr deficiency.

Flow cytometry measurements. S. aureus LAC wild-type (WT, BS819) and Δagr mutant (BS1348) were grown overnight, diluted, cultured in Tryptic Soy Broth (TSB) medium for 1 hr, and treated with carboxy-H2DCFDA (10 µM) for 5 min. Relative cell number is on the vertical axis. Unst. indicates samples containing LAC wild-type cells not treated with carboxy-H2DCFDA. (B) Five replicate experiments gave similar results (‘fold change’ indicates the mean wild-type or Δagr ROS level divided by the mean autofluorescence background signal; lines connect results in replicate experiments).