Gliding Arc Discharge in the Potato PathogenErwinia carotovorasubsp.atroseptica: Mechanism of Lethal Action and Effect on Membrane-Associated Molecules

Abstract

. This prototype also decreases the required duration of treatment by 50%. The study of the time course effect of the process on bacterial morphology suggests that glidarc induces major alterations of the bacterial membrane. We showed that glidarc causes the release of bacterial genomic DNA. By contrast, an apparent decrease in the level of extractible lipopolysaccharide was observed; however, no changes in the electrophoretic pattern and cytotoxic activity of the macromolecule were noted. Analysis of extractible proteins from the outer membrane of the bacteria revealed that glidarc discharge induces the release of these proteins from the lipid environment, but may also be responsible for protein dimerization and/or aggregation. This effect was not observed in secreted enzymatic proteins, such as pectate lyase. Analysis of the data supports the hypothesis that the plasma generated by glidarc discharge is acting essentially through oxidative mechanisms. Furthermore, these results indicate that, in addition to effectively destroying bacteria, glidarc discharge should be used to improve the extraction of bacterial molecules.Industrial guidelines prescribing the use of nonchemical techniques of decontamination have evolved to avoid traces of antibacterial agents in the final product; consequently, this has encouraged research into physical techniques that kill bacteria, such as advanced oxidation processes.Systems based on electric discharge, especially those that generate nonthermal plasma, appear to be very promising because of their low equipment and energy costs, their efficiency on diverse surfaces or media, and even their possible application to heatsensitive materials (25). Producing nonthermal plasma requires specific conditions. Plasmas can be classified according to their energy level and proportion of light (electrons) and heavy species (e.g., molecules, atoms, radicals, and ions). Thermal plasmas, usually formed at high pressure (Ն1 atm), are media in which the energies of the two species are similarly high. By contrast, the mean energy of the electrons at low pressure is much higher than that of the heavy species, and the resulting plasma is designated "cold plasma." There are intermediate conditions at atmospheric pressure which allow for the formation of the nonthermal plasmas. Among the various techniques able to generate nonthermal plasma, we decided to study gliding arc, or "glidarc," discharge. We chose glidarc particularly because of its high industrial potential and its efficiency for decontamination. This technique was previously used for treating Escherichia coli (35), Staphylococcus epidermidis (4), and various species of the potato pathogen, Erwinia (26). Glidarc has been shown to totally destroy Erwinia carotovora subsp. atroseptica, Erwinia chrysanthemi, and Erwinia carotovora subsp. carotovora cultures (26). Bacterial killing using glidarc was achieved directly in the liquid medium at room temperature and was not accompanied by the formation of viable but noncultivable forms. However, thi...

Retraction: Plasma Acid: Water Treated by Dielectric Barrier Discharge

“…[20][21][22][23] It has been reported that water treated by various plasma discharges becomes acidic, [9][10][11][20][21][22][23][24] which leads to antimicrobial effects. [9][10][11][24][25][26][27] The important question is which acid is created in water treated by plasma. Oehmigen et al [28] suggested that the acid created in water is nitric/nitrous acid and the antimicrobial properties observed are the result of synergetic action between H 2 O 2 and nitric/nitrous acid.…”

Nonthermal Atmospheric Plasma Rapidly Disinfects Multidrug-Resistant Microbes by Inducing Cell Surface Damage

“…However, since EthD-2 carries a net positive charge, we cannot rule out the possibility that EthD-2 may be recruited to the cell surface via electrostatic interaction with negatively charged species deposited by plasma (15). Alternatively, EthD-2 may stain nucleic acids leaking from the periphery of NTP-treated cells, as we and others have shown that plasma rapidly permeabilizes cell membranes and extracts intracellular nucleic acids (18). Prior to the onset of visible membrane damage, we observed only minor increases in DNA damage and protein oxidation, indicating that genetic damage and oxidative stress do not play primary roles in NTP-mediated microbial sterilization, consistent with the findings of other groups (7,26,27).…”

Inhibitory effect of silver nanoparticles mediated by atmospheric pressure air cold plasma jet against dermatophyte fungi

“…The hydroxyl radicals generated from APACP may contribute to membrane lipid peroxidation, causing an increase in membrane permeability (Ryu et al, 2013;Mai-Prochnow et al, 2014). It is evident from several related studies that the direct permeabilization of the cell membrane or wall is one of the modes of action in the toxicity of cold plasma for microbial cells (Kvam et al, 2012;Moreau et al, 2007).…”