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Escherichia coli cellular responses to exposure to atmospheric‐pressure dielectric barrier discharge plasma‐treated N‐acetylcysteine solution

Ercan, U.K., Sen, B., Brooks, A.D., Joshi, S.G.
Journal of applied microbiology 2018 v.125 no.2 pp. 383-397
DNA damage, Escherichia coli, acetylcysteine, atmospheric pressure, bacteria, cell death, disinfectants, genes, glutathione, membrane potential, oxidation, reactive nitrogen species, solvents, transcriptomics
AIM: To understand the underlying cellular mechanisms during inactivation of Escherichia coli in response to antimicrobial solution of nonthermal plasma‐activated N‐acetylcysteine (NAC). METHODS AND RESULTS: The recommended techniques were used to demonstrate E. coli cellular and transcriptomic changes caused associated with peroxynitrite and compared with plasma‐treated NAC solution. The findings demonstrate that E. coli cells respond to plasma‐treated NAC and undergo severe oxidative and nitrosative stress, and leading to stress‐induced damages to different components of bacterial cells, which includes loss of membrane potential, formation of oxidized glutathione (GSSG), formation of nitrotyrosine (a known marker of nitrosative stress), DNA damage, and generated a prominent pool of peroxynitrite. Reverse‐transcriptase (RT)‐polymerase chain reaction analysis of reactive nitrogen species (RNS) responsive genes indicated their differential expressions. CONCLUSION: For the first time, we report that the plasma‐treated NAC solution activates predominantly nitrosative stress‐responsive genes in E. coli and is responsible for cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: The reactive species generated in solutions by nonthermal plasma treatment depends on the type of solution or solvent used. The plasma‐treated NAC solution rapidly inactivates E. coli, mostly involving highly RNS generated in NAC solution, and has high potential as disinfectant.