Fig. 3: Kinetics of phosphate uptake into different C. crescentus strains.

Shown are the kinetics of phosphate uptake into wild-type (CB15N), ΔpstS (JK158) and ΔpstS^pitA (MAB215) cells. Cells were pre-grown in PYE medium with xylose, washed and incubated for 6 h in M2G^-P medium with xylose prior to the measurements. To determine the rates of phosphate uptake over time, cells were incubated with the indicated concentrations of radioactively labeled phosphate. Subsequently, samples of the cultures were harvested by filtration at regular time intervals, and the amount of phosphate taken up was determined by scintillation counting. The uptake rates determined at the different phosphate concentrations were fitted to a Michaelis-Menten equation. The resulting v_max and K_M values are indicated in the graphs. Data represent the mean of three independent measurements (± SD), unless indicated otherwise.