Development and performance evaluation of an antioxidant gene-knockout microbial sensor for active monitoring of DNA damage effects
Objective The oxidative damage of DNA can be caused by excessive levels of Reactive oxygen species(ROS).Monitoring of DNA oxidative damage enables effective evaluation of ROS damage effects.Although the detection of DNA damage effects based on microbial sensor allows quantitative analysis of oxidative damage,the ROS clearance mechanism existed in bacterial will affect the sensitive of detection.The work of this article is to knockout the key genes of ROS clearance mechanism and construct an antioxidant gene-knock-out microbial sensor.The microbial sensor can realize sensitive monitoring of DNA damage effects and then evaluates the damage effects of cells by ROS.Methods The antioxidant damage genes of bacterial ahpCF,katE and katG were knocked out by λ-Red homologous recombination and antioxidant gene-knockout microbial sensor was constructed.The nalidixic acid sodium salt and UV irradiation were used to characterize the performance for monitoring of DNA damage effects.Results The antioxidant gene-knockout microbial sensors ΔahpC,ΔahpCF/ΔkatEG and ΔahpCF/ΔkatE/ΔkatG were constructed successfully.The results showed that the microbial sensor ΔahpCF/ΔkatE/ΔkatGl had the highest sensitive of damage effects and the limit of detection for nalidixic acid sodium salt was 0.40 μmol/L.In addition,1.80 min of UV irradiation(254 nm)was sufficient to induce a significant fluorescent expression effect in the engineered bacteria.Conclusion In this article,antioxidant gene-knockout microbial sensors had been constructed to realize active and sensitive monitoring of DNA damage effects such as DNA damage reagents and UV irradiation.The sensors could provide an active,effective,and sensitive potential monitoring method for future evaluation of radiation effects in space.
DNA damage effectgene knockoutmicrobial sensorspace radiationnalidixic acid sodium saltUV irradiation
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