FIG 2.

Survival of H. pylori cells upon exposure to air. H. pylori cell suspensions in PBS were incubated at 37°C under normal atmospheric conditions (21% partial-pressure O₂). Samples were removed at the times indicated on the x axis and were used for plate count determinations after incubation in a 5% oxygen environment. The data are the means from three experiments, with standard deviations as indicated. Symbols: square, wild type; triangle, hp119::cat; circle, hp119 complementation strain. Based on statistical analysis (Student t test), the cell survival differences between the WT and the mutant strains are significant (P < 0.01) for all the data points except for the 2-h time point.