Figure 4.

fsrB expression profile in OG1RF. For β-gal assays, samples were collected every hour from 3 to 8 hr, then at 10 and 24 hr after starting the culture (x axis). All sets of cultures presented were analyzed concurrently. The figure is a representative of at least two experiments. The growth curves are represented in brown for cells grown in BHI-air and purple for cells grown in TSBG (thin line when grown in air, dense line when grown in the presence of 5% CO₂/0.1 M NaHCO₃). OG1RF containing P_fsrB::lacZ was grown in BHI air (brown closed diamond), in TSBG- air (purple closed diamond) or in TSBG-5% CO₂/0.1 M NaHCO₃ (purple open diamond). A. OD_{600 nm} readings. B. β-gal assays (β-gal units = OD_{420 nm}/protein concentration in mg/ml).