The expression of different gene constructs in Escherichia coli SM lux biosensor after exposure to drugs.

The research used bacterial biosensors containing bacterial luciferase genes to monitor changes in the environment in real-time. In this work to express four different gene constructs: recA:luxCDABE, soxS:luxCDABE, micF:luxCDABE, and rpoB:luxCDABE in Escherichia coli SM lux biosensor after exposure to three different antibiotics (nalidixic acid, ampicillin, kanamycin) and diclofenac was determined. It was found that incubation of the E. coli SM strain in various concentrations of analytes results in differentiation in gene expression at each of the tested concentrations (from 0.625 to 10 µg/mL) and during all three measurements, in "time 0", after 30 min. and after 1 h. The measurable signal is created as a result of the action of reporter genes (bacterial luciferase genes luxCDABE), present in genetically modified bacterial cells. E. coli luminescent bioreporters in the stationary phase were used. In the analysis of the induction of the promoter (regulatory proteins) to the control (0 µg/ml), the highest biosensor response was shown in the case of kanamycin concentration equal to 0.625 µg/mL after 1-h incubation. The highest increase express gene construct was found for micF:luxCDABE in E. coli SM343 lux biosensor, where the micF promoter induction relative to the control at a concentration of 0.625 µg/mL is 73.9%.