FIG 1.

Growth curves and oxygen levels of R. sphaeroides wild-type 2.4.1 and 2.4.1 ΔrpoHI. Strains were grown under microaerobic conditions, and the optical density at 660 nm (OD₆₆₀) was determined over time; growth is indicated as a black line (wild type) or gray line (2.4.1 ΔrpoHI). The cultures were diluted 28 h (dashed line) after inoculation (early stationary phase) or 72 h after inoculation (late stationary phase) into fresh medium to an OD of 0.2. Oxygen saturation in the wild-type culture (blue) was similar to that in the mutant (not shown). RNA samples were taken at different time points (red dots). Both data sets represent the means of results from at least three independent experiments, and the error bars indicate the standard deviation.