FIG 1.

(A) Uptake of NaH¹⁴CO₃ by bicarbonate-responsive strains (S. aureus JE2 and MRSA 11/11; red lines and symbols) and nonresponsive strains (S. aureus BMC1001 and COL; blue lines and symbols). Bacterial cultures grown in ambient air until mid-exponential phase were washed and adjusted to the same OD. Fluorocitrate was added to the cells and incubated for 30 min before the addition of NaH¹⁴CO₃ (50 μCi). Aliquots of cell suspensions were collected at the indicated time points, and the H¹⁴CO₃ uptake was determined by the ¹⁴C accumulation in cells, as measured by liquid scintillation counting. Each value is the mean and SD from three independent biological replicates. (B) The P values represent the significant differences in the AUC for the uptake of each strain, analyzed using one-way ANOVA followed by Tukey’s multiple-comparison test. The H¹⁴CO₃ uptake in the responsive strains JE2 and MRSA 11/11 was significantly higher than that in the nonresponsive strains BMC1001 and COL.