FIG. 5.

3-oxo-C₁₂-HSL inhibits sarA expression at sub-growth-inhibitory concentrations. (A) Growth of S. aureus RN6390 in shake flask cultures in the absence of 3-oxo-C₁₂-HSL (▪) or in the presence of 3-oxo-C₁₂-HSL at a concentration of 5 μM (⧫) or 15 μM (○). (B) Northern blot analysis of sarA transcripts prepared from S. aureus RN6390 grown for 4, 6, or 9 h in the absence of 3-oxo-C₁₂-HSL (lanes 0) or in the presence of 3-oxo-C₁₂-HSL at a concentration of 5 μM (lanes 5) or 15 μM (lanes 15). The top panel shows the loading gel with the positions of the 23S and 16S rRNAs indicated; the bottom panel shows the Northern blot.