Fig. 6

Comparison of the σ⁷⁰ expression systems to the toehold versions controlling the expression of the lux operon in E. coli using pCOLE1 and pSC101 derived plasmids. Architecture of the synthetic gene circuits controlling the luxCDABE genes with and without the THS in A, B σ⁷⁰V2TcR system & C-D σ⁷⁰V3-2LacI system. Time course of bioluminescence production by the E pσ⁷⁰V2TcR & F pσ⁷⁰V3-2LacI expression systems; each bar represents the bioluminescence measurement every 3 h from time 0 to 18 h (bars in each set, left to right, are 0 h, 3 h, 6 h, 9 h, 12 h, 15 h, and 18 h). Difference in bioluminescence production between the ON and OFF states in G pσ⁷⁰V2TcR & H pσ⁷⁰V3-2LacI expression systems. Fold-change difference in the luminescence emission of the recombinant cells containing the I pσ⁷⁰V2TcR and J pσ.⁷⁰V3-2LacI expression systems vs the wild type DH10B. The cultures were induced after 3 h of growth with aTc or IPTG accordingly. For all samples, the bioluminescence mean was normalized by the cell density (OD₆₀₀). Error bars are ± S.D., n = 3. Relative Luminescence Units (RLU)