Fig. 5.

Bacteria regulate their sensory diversity based on growth rate. (a) (Top) Concentration of Tar proteins as a function of growth rate. Protein concentration in batch cultures (hollow points) is defined as the mean fluorescence between two time points during growth divided by the mean biomass (OD) at the same two time points. Carbon sources used to supplement minimal media are indicated as: Gro: 0.5% v/v glycerol; Pyr: 20 mM pyruvate; Fru: 20 mM fructose; Suc: 15 mM succinate; Lac: 20 mM lactose; Ara: 20 mM arabinose; Mal: 20 mM maltose; and Glc: 0.4% v/v glucose. For all minimal media experiments, expression levels were extracted between OD 0.2 and 0.8, during which growth rate remained approximately constant. Protein concentration is also measured at the single-cell level via fluorescence microscopy (filled points). Filled points represent the means of the Tar concentration distributions shown in EDF 4. Hollow points are the means of 8 technical replicates for each carbon source in minimal media or 40 technical replicates for each OD in rich media. Solid lines are fits to the data. Growth rate, OD, and batch fluorescence levels were assessed in the same batch cultures using a plate reader. (Bottom) Same as the top panel, but for Tsr concentration. Filled points represent the means of the Tsr concentration distributions shown in EDF 4. Inset: growth rate as a function of OD. Points represent growth rates extracted at the same culture phases as expression levels (see methods). (b) Scaling of mean Tar/Tsr receptor ratio as a function of growth rate for cells grown in rich (circles) and minimal (squares) media. Same color coding as figure 2c and e. Error bars indicate 95% confidence intervals of the mean $K_{1/2}$ obtained via bootstrap resampling and are typically on the order of the data point size. (c) Scaling of mean L-serine (black) and L-aspartate (blue) $K_{1/2}$ as a function of growth rate for cells grown in rich and minimal media. Error bars indicate 95% confidence intervals of the mean $K_{1/2}$ obtained via bootstrap resampling and are typically on the order of the data point size. (d) Coefficient of variation (CV) of L-serine (black) and L-aspartate (blue) $K_{1/2}$ as a function of growth rate. Error bars indicate 95% confidence intervals of the CV obtained via bootstrap resampling. (e) CV of tumble bias (green) and run speed (brown) as a function of growth rate. Error bars indicate 95% confidence intervals of the CV obtained via bootstrap resampling and are typically on the order of the data point size.