ΔVNG0258His impaired for growth and survival upon exposure to hydrogen peroxide (H2O2). (A) Comparison of ΔVNG0258H and Δura3 parent growth rates under standard conditions across all experiments (n = 63, see also Additional file 3: Table S1). (B) Mean growth rates for 4 biological replicate cultures treated with H2O2 in lag phase. Blue bars represent Δura3 cultures; red bars represent ΔVNG0258H cultures. Concentration of H2O2 added is indicated on the x-axis. (C) Representative growth curves (1 of 4 biological replicates) for cultures treated with H2O2 at beginning of growth (OD600 ≈ 0.05). Line colors are as in (B). Thin, medium, and thick lines indicate H2O2 added to a final concentration of 0, 5, or 6 mM, respectively (see legend; 7 mM curves omitted for clarity). Downward arrow indicates time of H2O2 addition. Bracket indicates period for which mean growth rates were calculated. (D) Mean growth rates for 7 biological replicate cultures treated with H2O2 in mid-logarithmic growth phase. (E) Representative growth curves for cultures treated with H2O2 in mid-logarithmic phase (OD600 ≈ 0.3). Thin, medium, and thick lines indicate H2O2 added to a final concentration of 0, 18.75, or 25 mM, respectively (curves for 6.25 and 12.5 mM conditions are omitted for clarity). Downward arrow indicates time of treatment. Bracket indicates period for which mean growth rates were calculated. In all bar graphs, error bars represent standard deviation. Asterisks represent statistically significant differences between ΔVNG0258H and parent strain Δura3 under the same growth conditions, where single asterisk indicates a p-value < 0.01, double asterisk indicates p < 0.001, and triple asterisk indicates p < 0.0001. All raw data are given in Additional file 3: Table S1.
Sharma et al. BMC Genomics 2012 13:351 doi:10.1186/1471-2164-13-351