Fig. 7

“Online” monitoring the dynamics of subtilin biosynthesis in B. subtilis W168. A The “online” reporter strain combines the subtilin-producing (spa-locus) and -reporting systems (P_psdA-lux) in one strain. Subtilin precursor (black and orange wavy line) is encoded by spaS and then modified and exported by SpaBTC. The N-terminal leader peptide (black wavy line) is cleaved off by proteases outside of the cell, resulting in bioactive subtilin. The TCS SpaRK is activated by subtilin and then induces subtilin gene expression. Meanwhile, the TCS PsdRS is also activated by active subtilin, inducing P_psdA and expression of luciferase. Thus, the dynamics of subtilin production can be real-time monitored in the producer itself. B “Online” record of subtilin biosynthesis. “Online” reporters were examined in LB and in mixed medium (50% LB + 50% Medium A). The genetic background and the corresponding color code of the strains are given at the bottom of the figure. The red arrows marked in the luminescence graphs indicate the point where the induction starts in TMB5723 strain, while the corresponding arrow in the growth curve indicates the growth status at the same time point. Data are shown as the mean of at least three replicates, with the error bars showing the standard deviations