Atmospheric Nonthermal Plasma-Treated PBS Inactivates Escherichia coli by Oxidative DNA Damage.
Atmospheric Nonthermal Plasma-Treated PBS Inactivates Escherichia coli by Oxidative DNA Damage.
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DOI：
10.1371/journal.pone.0139903
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Joshi SG
中科院分区：
文献类型：
--
作者：
Yost AD;Joshi SG
我们最近报道，经非热介质阻挡放电等离子体（等离子体）处理的磷酸盐缓冲盐水（PBS）具有很强的抗菌特性，但细菌灭活的潜在机制尚不清楚。本研究的目的是了解大肠杆菌的细胞反应，并研究等离子体激活的PBS的特性。等离子体激活的PBS在大肠杆菌细胞中诱导严重的氧化应激，活性氧清除剂α - 生育酚和过氧化氢酶可保护大肠杆菌免于细胞死亡。在此我们表明，大肠杆菌对等离子体激活的PBS的反应受OxyR和SoxyRS调节子调控，且主要通过katG的表达来介导，katG可使等离子体产生的氧化剂失活。在缺乏katG和katE的情况下大肠杆菌进行补偿时，暴露于等离子体处理的PBS的样本中sodA和sodB显著过表达。基因芯片分析发现，参与DNA修复的基因上调，表达recA::lux融合蛋白的大肠杆菌在暴露于等离子体处理的PBS时对SOS反应极其敏感。细胞变化包括大肠杆菌膜电位和膜完整性迅速丧失、脂质过氧化、8 - 羟基 - 脱氧鸟苷（8OHdG）积累以及严重的氧化性DNA损伤；最终显示DNA解体和细胞死亡。总之，这些数据表明，等离子体处理的PBS含有过氧化氢和超氧化物等活性物质或/和它们的产物，这些物质导致细胞成分发生氧化变化，并最终导致细胞死亡。
We recently reported that phosphate-buffered saline (PBS) treated with nonthermal dielectric-barrier discharge plasma (plasma) acquires strong antimicrobial properties, but the mechanisms underlying bacterial inactivation were not known. The goal of this study is to understand the cellular responses of Escherichia coli and to investigate the properties of plasma-activated PBS. The plasma-activated PBS induces severe oxidative stress in E. coli cells and reactive-oxygen species scavengers, α-tocopherol and catalase, protect E. coli from cell death. Here we show that the response of E. coli to plasma-activated PBS is regulated by OxyR and SoxyRS regulons, and mediated predominantly through the expression of katG that deactivates plasma-generated oxidants. During compensation of E. coli in the absence of both katG and katE, sodA and sodB are significantly overexpressed in samples exposed to plasma-treated PBS. Microarray analysis found that up-regulation of genes involved in DNA repair, and E. coli expressing recA::lux fusion was extremely sensitive to the SOS response upon exposure to plasma-treated PBS. The cellular changes include rapid loss of E. coli membrane potential and membrane integrity, lipid peroxidation, accumulation of 8-hydroxy-deoxyguinosine (8OHdG), and severe oxidative DNA damage; reveal ultimate DNA disintegration, and cell death. Together, these data suggest that plasma-treated PBS contains hydrogen peroxide and superoxide like reactive species or/and their products which lead to oxidative changes to cell components, and are eventually responsible for cell death.