title: Nitrogen gas plasma treatment of bacterial spores induces oxidative stress that damages the genomic DNA.
abstract: Gas plasma, produced by a short high‑voltage pulse generated from a static induction thyristor power supply [1.5 kilo pulse/sec (kpps)], was demonstrated to inactivate Geobacillus stearothermophilus spores (decimal reduction time at 15 min, 2.48 min). Quantitative polymerase chain reaction and enzyme‑linked immunosorbent assays further indicated that nitrogen gas plasma treatment for 15 min decreased the level of intact genomic DNA and increased the level of 8-hydroxy-2'-deoxyguanosine, a major product of DNA oxidation. Three potential inactivation factors were generated during operation of the gas plasma instrument: Heat, longwave ultraviolet-A and oxidative stress (production of hydrogen peroxide, nitrite and nitrate). Treatment of the spores with hydrogen peroxide (3x2‑4%) effectively inactivated the bacteria, whereas heat treatment (100˚C), exposure to UV-A (75‑142 mJ/cm2) and 4.92 mM peroxynitrite (•ONOO‑), which is decomposed into nitrite and nitrate, did not. The results of the present study suggest the gas plasma treatment inactivates bacterial spores primarily by generating hydrogen peroxide, which contributes to the oxidation of the host genomic DNA.
authors.affiliation: Laboratory of Biometabolic Chemistry, School of Health Sciences, University of The Ryukyus, Nishihara, Okinawa 903‑0215, Japan.
authors.forename: Akikazu
authors.initials: A
authors.lastname: Sakudo
authors.affiliation: Laboratory of Biometabolic Chemistry, School of Health Sciences, University of The Ryukyus, Nishihara, Okinawa 903‑0215, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Toyokawa
authors.affiliation: Laboratory of Biometabolic Chemistry, School of Health Sciences, University of The Ryukyus, Nishihara, Okinawa 903‑0215, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Electrical and Electric Engineering, Sasebo National College of Technology, Nagasaki 857‑1193, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Yagyu
authors.affiliation: NGK Insulators, Mizuho‑ku, Nagoya, Aichi 467‑8530, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Imanishi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics; D004249:DNA Damage / Q000187:drug effects*; D004269:DNA, Bacterial / Q000235:genetics; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000235:genetics; D001411:Geobacillus stearothermophilus / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D050296:Microbial Viability / Q000187:drug effects; D009584:Nitrogen / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D058626:Plasma Gases / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects* / Q000235:genetics; D013242:Sterilization / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D058626:Plasma Gases; D000080242:8-Hydroxy-2'-Deoxyguanosine; D006861:Hydrogen Peroxide; D003849:Deoxyguanosine; D009584:Nitrogen