FIG 1.

S. aureus expresses dacA but minimal gdpP during post-exponential and biofilm growth. (A to C) To assess dacA and gdpP promoter activity, fluorescence from a transcriptional reporter plasmid (divergent PdacA::DsRed and PgdpP::GFP) was monitored in S. aureus LAC during planktonic growth in TSB by using a TECAN fluorescent plate reader (black line indicates the OD₆₀₀; green reflects GFP fluorescence; red line indicates DsRed fluorescence) (A); at 4, 8, and 12 h in a flow cell biofilm grown in 50% TSB in a Bio-Flux system (B); or in a 5-day static biofilm grown in RPMI 1640 plus 1% Casamino Acids and examined using confocal microscopy (C). (D) Expression levels of dacA and gdpP in static biofilms grown for 1 to 6 days were analyzed using qRT-PCR. No significant changes in dacA expression were observed across the time points based on a one-way ANOVA with Tukey post hoc analysis. Results are representative of at least two independent experiments. ND, not detected.