Effects Of PprM Gene Of Deinococcusradiodurans On Antioxidation And Radiation Resistance In Escherichia Coli

Objectives:The pprM gene plays an important role in the extreme antioxidant and radiation resistance of Radioactive Deinococcus(DR).The purpose of this study was to explore whether exogenous expression of pprM gene of DR bacteria could improve the antioxidant and radiation resistance of E.coli,and to provide a basis for the study of pprM gene function and the construction of E.coli engineering bacteria with high environmental stress resistance.Methods:1.Identify E.coli DH5_which is resistant to pprM gene of Radiococcus radiodurans,test the resistance of various types of E.coli to hydrogen peroxide,and study whether pprM gene can improve the antioxidant capacity of E.coli DH5_.ROS,GSH,SOD and CAT kits were used to detect free radicals,oxidase contents or activities of wild type E.coli DH5_,empty plasmid E.coli DH5_and transfected pprM E.coli DH5_after hydrogen peroxide treatment.The possible mechanism of pprM gene improving antioxidant capacity of E.coli was studied.2.pGEX-6p-1-pprM plasmid and pGEX-6p-1 plasmid were transformed into E.coli BL21 to observe the growth rate of E.coli BL21 with pprM gene after gamma irradiation,and to study whether pprM gene can improve the irradiation resistance of E.coli.By using ROS,GSH,SOD and CAT detection kits to detect free radicals and oxidase contents or activities in wild type E.coli BL21,empty plasmid E.coli BL21 and pprM-transfected E.coli BL21 after hydrogen peroxide treatment,the possible mechanism of pprM gene improving the radiation resistance of E.coli was studied.3.Detection of infrared spectra of pprM gene transfected Escherichia coli BL21,empty plasmid Escherichia coli BL21 and wild type Escherichia coli BL21 after hydrogen peroxide treatment,and study the changes of pprM gene on oxidative stress-related functional groups of E.coli.Results:1.Comparing the difference of bacteriostasis circle size of wild E.coli DH5_,empty plasmid E.coli DH5_and pprM-transformed E.coli DH5_in the experiment of hydrogen peroxide bacteriostasis circle,we found that pprM gene can improve the anti-hydrogen peroxide ability of E.coli after being transfected into E.coli.Compared with the control group,the content of ROS in E.coli transfected with pprM gene decreased,while the activity of superoxide dismutase and catalase increased,suggesting that pprM gene may play its antioxidant function by increasing the activity of antioxidant enzymes and scavenging free radicals in E.coli.2.E.coli BL21 containing pprM gene was successfully constructed.The growth of wild-type E.coli BL21,empty plasmid E.coli BL21 and pprM-transfected E.coli BL21,and the amount or activity of SOD,GSH and CAT in vivo were measured respectively after irradiation.The results showed that the growth rate of E.coli transfected into pprM was faster and the activities of superoxide dismutase and catalase were increased in vivo after irradiation compared with the control group.High,suggesting that pprM in E.coli may reduce the oxidative damage of E.coli by increasing the activity of antioxidant enzymes in E.coli.3.Comparing the infrared spectra of wild-type E.coli and pprM-transfected E.coli treated with hydrogen peroxide,we found that the peak values of amino and carboxyl groups of E.coli transfected with pprM gene changed after hydrogen peroxide treatment,which indicated that pprM gene could change the chemical properties of these groups of E.coli.Conclusions:Transgenic pprM gene of radiation-resistant azygococcus can significantly improve the antioxidant and radiation resistance of Escherichia coli,possibly through improving the antioxidant enzymes activity of Escherichia coli to play its role.