FIG 3.

RNAIII expression (A to C) and agrA expression (D to F) of S. aureus MW2 in a pure culture (black) and in mixed cultures with L. lactis LD61 (gray). Cells were cultured under reference conditions (CDM at a constant pH of 6.6 under microaerobic conditions) (A and D), under reference conditions with the addition of potassium ferricyanide (B and E), and in CDM at a constant pH of 6.6 and with pO₂ at 50% (C and F). The expression levels of RNAIII and agrA were determined by RT-qPCR during the exponential (exp) and stationary (stat) phases of growth and are expressed relative to those of RNAIII and agrA in the stationary phase in a pure culture (100%), respectively. Significant changes of expression levels in pure versus mixed cultures were determined for each time point by using one-way analysis of variance and are indicated by asterisks (*, P < 0.05; **, P < 0.01; ***, P < 0.001).