Figure 1.
Survival of indicated F. tularensis strains during heat and pH stress. Overnight grown bacteria were diluted in fresh growth media and subjected to stress at 50 °C for 30 min (A) or pH 4.5 for 1 h (B). Survival of each strain was monitored as viable bacteria and plotted as percentage of survival, setting wild-type strains survival as 100%. There was no significant killing of any wild-type strain during the treatment. Data are the average survival percentage for at least three independent experiments for each condition. Values are mean ± SD. **P < 0.01; *** indicates P < 0.001 vs. the corresponding wild-type strain.