Microarray Analysis of Transcriptomic Response of <i>Escherichia coli</i> to Nonthermal Plasma-Treated PBS Solution

Abstract

We developed a technique of generating nonthermal atmospheric plasma-activated solution that had broad-spectrum antibacterial properties. Plasma-activated phosphate-buffered saline (PBS) causes rapid inactivation of bacteria following generation of oxidative stress. However, dose optimization requires understanding of cellular mechanisms. The objective of this study was to explore genome-wise response to develop gene expression profile of Escherichia coli using DNA microarray following exposure to plasma-activated PBS solution. Upon exposure to plasma-treated PBS solution, E. coli cells had differentially expressed genes involved in oxidative stress, and cell envelope and membrane associated porin and transporters. The genes involved in house-keeping and metabolism, energy generation, motility and virulence were conversely downregulated. This is the first report which demonstrates a severe oxidative stress induced in E. coli cells in response to an exposure to nonequilibrium nonthermal dielectric-barrier discharge plasma-activated PBS solution, and the genes that are responsive to reactive oxygen species appeared to play a role in cellular stress. Such studies are important to identify targets of inactivation, and to understand plasmatreated solution and bacterial cell interactions.

Atmospheric Nonthermal Plasma-Treated PBS Inactivates Escherichia coli by Oxidative DNA Damage

“…The amount of hydrogen peroxide retained in each sample was measured by a commercially available Hydrogen Peroxide Detection Kit (National Diagnostics, Atlanta, GA), following their protocol [ 6 ]. A working solution of 20mL, combining the two reagents given in the kit, was added to a 96-well plate at 90μL per well.…”

“…coli was performed using the established protocol and Affymetrix Genechip® E . coli Genome 2.0 array system (Affymetrix, Santa Clara, CA) as described [ 6 ], and the relevant oxidative stress mediating gene responses are discussed here.…”

“…Bacteria have evolved mechanisms to combat ROS bursts, and protect themselves by decomposing ROS, using enzymes such as catalase, glutathione peroxidase, superoxide dismutase, and other cellular antioxidants [ 6 ]. Conversely, small amounts of ROS can stimulate cells to produce defensive enzymes and proteins that allow them to tolerate relatively high doses of ROS.…”

Cold Physical Plasmas in the Field of Hygiene—Relevance, Significance, and Future Applications

“…Moreover, the inactivation of bacteriophages and viruses by plasma has been demonstrated . Plasma‐treated solutions exhibit microbicidal effects as well . Up to now, no development of microorganisms resistant to the plasma's cytotoxicity was observed.…”

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

“…Inhibition of biofilm formation with other plasma‐treated solutions and down‐regulation of genes involved in motility and adherence have been showed recently through other studies by our group (Joshi et al . , ; Ercan et al . ).…”