Pyocyanin mediated H₂O₂ generation and cells lysis.

<p>Increased H₂O₂ production as recorded in bacterial cell free supernatant in PAO1 mutant <i>phzSH</i> (A) and in PA14 wildtype (B) compared with strains producing less pyocyanin. The <i>P. aeruginosa</i> PAO1 (C, E and G) and PA14 (D, F and H) strains producing more pyocyanin (PAO1 <i>phzSH</i> mutant and PA14 wildtype) displayed accelerated decreases in optical density as cultures aged compared with pyocyanin deficient strains. Error bars represent standard deviation from the mean (n = 3). Asterisks indicate statistically significant (p<0.05) differences in H₂O₂ absorbance in comparison to the PAO1 wildtype and PA14 <i>phzA-G</i> mutant (A and B) and percentage of cells alive in comparison to max. cell number (E and F).Dashed line indicates the average decrease in percentage of cell number due to H₂O₂ generation in PAO1 <i>phzSH</i> and PA14 wildtype strains (G and H).