Fig. (2) Effect of hyperosmotic condition on (A)P. aeruginosa PAO1 growth, and on the extra-cellular production of (B) 3OC₁₂-HSL, (C) C₄-HSL, (D) HHQ, and (E) PQS. Bacteria were grown in PPGAS medium (squares), in PPGAS containing 0.5 M NaCl (triangles), or in PPGAS containing 0.5 M NaCl and 1 mM glycine betaine (circles). The signal molecules concentrations (in µM) were divided by the OD₆₀₀ values of the cultures at the sampling time. The points are averages of three experiments, and the standard deviations were lower than 10% of the mean values.