Charoenlap Nisanart, Sornchuer Phornphan, Piwkam Anong, Srijaruskul Kriangsuk, Mongkolsuk Skorn, Vattanaviboon Paiboon
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand.
Can J Microbiol. 2015 May;61(5):343-50. doi: 10.1139/cjm-2014-0792. Epub 2015 Mar 6.
The exposure of Xanthomonas campestris pv. campestris to sublethal concentrations of a sodium hypochlorite (NaOCl) solution induced the expression of genes that encode peroxide scavenging enzymes within the OxyR and OhrR regulons. Sensitivity testing in various X. campestris mutants indicated that oxyR, katA, katG, ahpC, and ohr contributed to protection against NaOCl killing. The pretreatment of X. campestris cultures with oxidants, such as hydrogen peroxide (H2O2), t-butyl hydroperoxide, and the superoxide generator menadione, protected the bacteria from lethal concentrations of NaOCl in an OxyR-dependent manner. Treating the bacteria with a low concentration of NaOCl resulted in the adaptive protection from NaOCl killing and also provided cross-protection from H2O2 killing. Taken together, the results suggest that the toxicity of NaOCl is partially mediated by the generation of peroxides and other reactive oxygen species that are removed by primary peroxide scavenging enzymes, such as catalases and AhpC, as a part of an overall strategy that protects the bacteria from the lethal effects of NaOCl.
野油菜黄单胞菌野油菜致病变种暴露于亚致死浓度的次氯酸钠（NaOCl）溶液中会诱导OxyR和OhrR调控子内编码过氧化物清除酶的基因表达。对各种野油菜黄单胞菌突变体进行的敏感性测试表明，oxyR、katA、katG、ahpC和ohr有助于抵御NaOCl的杀伤作用。用过氧化物（如过氧化氢（H2O2）、叔丁基过氧化氢）和超氧化物生成剂甲萘醌对野油菜黄单胞菌培养物进行预处理，以OxyR依赖的方式保护细菌免受致死浓度NaOCl的伤害。用低浓度NaOCl处理细菌可导致对NaOCl杀伤的适应性保护，还能提供对H2O2杀伤的交叉保护。综上所述，结果表明NaOCl的毒性部分由过氧化物和其他活性氧的产生介导，这些过氧化物和活性氧会被主要的过氧化物清除酶（如过氧化氢酶和AhpC）清除，这是保护细菌免受NaOCl致死效应的整体策略的一部分。
