Robustness of Heterologous ECF Switches in B. subtilis
The four three-dimensional scatterplots show the behavior of the ECF switches upon the imposed alterations. Each plot corresponds to one ECF: BL00106 and BL04030 of B. licheniformis, ECF105 of B. cereus, and SVEN_0399 of S. venezuelae. The x axis corresponds to the baseline value of the switch; the y axis corresponds to the maximum output level of the switch, and the z axis corresponds to the maximal fold-induction. Baseline refers to the output observed in the absence of inducer, maximal output refers to the output value upon induction with the maximal concentration of inducer, and fold-induction refers to the ratio between maximal output and baseline values. Baseline and maximal output level are shown as relative luminescence units (RLU) normalized by the optical density at 600 nm (OD600 nm). All data points represent averages of three independent experiments in which cells were grown to exponential phase, the expression of the ECF was induced by 0.5% xylose (or 10 μg/mL of bacitracin for PliaI-driven switches), and the values used were obtained 90 min after induction. The legend at the bottom of the figure shows the correspondence between the symbols and the performed alterations.