FIG 2.

Uptake of NaH¹⁴CO₃ by strain sets grown in ambient air (A; solid lines and symbols) and 5% CO₂ conditions (CO₂; dashed lines and symbols). The bicarbonate-responsive strains (A) JE2 and (B) MRSA 11/11 showed significantly higher H¹⁴CO₃ uptake when grown in ambient air than in CO₂. **, P = 0.0092; ***, P = 0.0003. The H¹⁴CO₃ uptake for cells grown in ambient air and 5% CO₂ was not significantly different in the nonresponsive strains (C) BMC1001 (ns, not significant [P = 0.7847]) and (D) COL (P = 0.6652). Each point represents the mean and SD from three independent biological replicates. Statistical significance between the uptake in ambient air and CO₂ was calculated using Student’s t test from the AUC values for each strain set.