Differential gene expression in Escherichia coli following exposure to nonthermal atmospheric pressure plasma.
OBJECTIVE
Nonthermal atmospheric-pressure plasmas offer significant advantages as an emerging disinfection approach. However the mechanisms of inactivation, and thus the means of optimizing them, are still poorly understood. The objective of this study, therefore, was to explore differential gene expression on a genome-wide scale in Escherichia coli following exposure to a nonthermal atmospheric-pressure argon plasma plume using high-density oligonucleotide microarrays.


RESULTS
Plasma exposure was found to significantly induce the SOS mechanism, consisting of about 20 genes. Other genes involved in regulating response to oxidative stress were also observed to be up-regulated. Conversely, the expression of several genes responsible for housekeeping functions, ion transport, and metabolism was observed to be down-regulated.


CONCLUSIONS
Elevated yet incomplete induction of various DNA damage repair processes, including translesion synthesis, suggests substantial DNA damage in E. coli. Oxidative stress also appeared to play a role. Thus it is proposed that the efficacy of plasma is due to the synergistic impact of UV photons and oxygen radicals on the bacteria.


CONCLUSIONS
This study represents the first investigation of differential gene expression on a genome-wide scale in an organism following plasma exposure. The results of this study will help enable the design of safe and effective plasma decontamination devices.
Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO, USA.
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Sharma
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Collins
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Pruden
D001128:Argon; D001426:Bacterial Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D020869:Gene Expression Profiling; D007501:Iron / Q000378:metabolism; D046228:Microarray Analysis; D012329:RNA, Bacterial / Q000235:genetics; D013242:Sterilization / Q000379:methods*; D013696:Temperature
D001426:Bacterial Proteins; D012329:RNA, Bacterial; D001128:Argon; D007501:Iron