FIG. 1.

Growth curves for P. gingivalis strains. Overnight cultures were diluted in an anaerobic chamber to an OD₆₆₀ of 0.15 with Chelex-treated anaerobic medium (A) or saturated with 6% oxygen (B and C) growth medium. Cultures were incubated in the presence or absence of manganese anaerobically (A), aerobically (in the presence of 6% oxygen) (B), and anaerobically in the presence of peroxide (100 μM) (C) at 37°C. Growth was monitored as the increase in OD₆₆₀ versus time. Error bars indicate standard deviations for triplicate samples. feoB2, feoB2 mutant.