FIG 1.

Respiration-arresting conditions impair S. aureus ypfP proliferation. (A) CFU of WT or ypfP mutant cells grown on TSA supplemented with 5 μg mL⁻¹ of gentamicin (gent) or tobramycin (tob) were enumerated after 24 h at 37°C. Values are percentages of the WT value, where the number of CFU of the ypfP mutant was divided by the number of CFU of the WT and the WT value was set to 100% (dotted line). Data are means from at least five independent experiments. Error bars represent one standard deviation from the mean. (B) Zones of inhibited growth generated by colonies of P. aeruginosa spotted on top of S. aureus WT or ypfP mutant lawns were measured after 24 h at 37°C. Data are means from three independent experiments performed in triplicate. Statistical significance was determined by an unpaired two-tailed t test for unequal variance. P < 0.0001. Error bars represent one standard deviation from the mean. (C) The zone of reduced growth generated by HQNO on lawns of WT or ypfP mutant cells was measured after 24 h at 37°C. Data are means from three independent experiments performed in triplicate. Error bars represent one standard deviation from the mean. Statistical significance was determined by an unpaired two-tailed t test for unequal variance. P < 0.01. (D) CFU of WT and ypfP, gtrR or gtrR ypfP mutant strains were quantified after 24 h (for respiring colonies) or 48 h (for respiration arrest colonies) of growth on TSA or TSA supplemented with ALA at 37°C. Error bars represent one standard deviation for three independent experiments. Statistical significance was determined by two-way analysis of variance (ANOVA) with a Šidák method for multiple comparisons. **, P < 0.01.