Fig. 1
Comparative analysis of Darobactin production by inducible genetic circuit modules. A Schematic representation of the pNOSO-darABCDE gene circuit (B) Darobactin concentration in the liquid medium (µg/mL) for the pNOSO-darABCDE construct in ClearColi BL21 DE3 strain after 24 h of incubation. The bacteria were induced with 500 µM of IPTG at OD600 = 0.4 in Formulated Media (FM) supplemented with 50 µg/mL kanamycin. The error bars represent standard deviation based on three independent measurements (****p < 0.0001 as calculated by paired t-test) (C) Schematic representation of the thermoresponsive darobactin gene circuits based on high—copy (pUC-Tlp-DarA) and medium-copy (p15A-Tlp-DarA) number replication origin. The thermosensitive repressor (TSR) represses PtlpA promoter at physiological temperature (37 °C) and is derepressed at temperatures beyond > 39 °C (D) Darobactin concentration in the liquid medium (µg/mL) for the p15A and pUC origin based Tlp-DarA gene circuits in ClearColi BL21 DE3 strains after 24 h of incubation at 37 °C and 40 °C. (###) represents darobactin concentration lower than the Limit of Detection (LOD) by ESI–MS. The error bars represent standard deviation based on three independent measurements (**p = 0.0016 as calculated by paired t-test)