FIG 3.

Sporulation frequency and glucose uptake in B. subtilis. (A) Sporulation frequencies and uptake rates for different strains of B. subtilis under various carbon-excess stationary-phase conditions. The TF8A genetic background strain (25) used for the majority of this work was compared to other standard lab strains, 168trpC2 and 1A747 (38), as well as the prototrophic strain BSB168trp+ (37) and strain QB5448 (36), which was used as a control for the ptsG overexpression strains. While all strains sporulated at near-100% rates under nitrogen starvation (blue) and carbon starvation (not shown), there was more variability in sporulation frequency under phosphate (aqua) and sulfate (yellow) starvation. In some cases, stationary-phase physiology could be separated into early and late stages, in which case the two stages are shown as separate points. Biological replicates are also shown as separate points. (B) Comparison of stationary-phase physiology for the wild type (TF8A) and the sporulation-deficient ΔsigF mutant under phosphate limitation.