FIG. 3.

Comparison of down-regulated lacZ fusion expression (strain PHL825) in attached and free-living bacteria during biofilm development on petri dishes (A) and in shaken liquid cultures under different osmolarity conditions (B). (A) Biofilm cultures were performed on petri dishes in M63-mannitol medium, and specific β-galactosidase activities in free-living (open squares) and sessile (filled squares) bacteria were measured as described in Materials and Methods. Results are means ± standard deviations of three independent measurements. (B) Cells were grown at 30°C in low-osmolarity MOPS-glycerol medium supplemented with increasing NaCl concentrations of 0 to 0.3 M. Two independent measurements of specific β-galactosidase activities were performed on mid-exponential-growth-phase cells. Results are means ± standard deviations of two independent measurements.