Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
Department of Infectious Disease, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
J Bacteriol. 2019 Oct 4;201(21). doi: 10.1128/JB.00474-19. Print 2019 Nov 1.
rapidly kills by producing membrane-permeable hydrogen peroxide (HO). The mechanism by which -produced HO mediates killing was investigated. An model that mimicked - contact during colonization of the nasopharynx demonstrated that killing required outcompeting densities of Compared to the wild-type strain, isogenic Δ and Δ, both deficient in production of HO, required increased density to kill While residual HO activity produced by single mutants was sufficient to eradicate , an Δ Δ double mutant was unable to kill A collection of 20 diverse methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains showed linear sensitivity ( = 0.95) for killing, but the same strains had different susceptibilities when challenged with pure HO (5 mM). There was no association between the clonal complex and sensitivity to either or HO To kill , produced ∼180 μM HO within 4 h of incubation, while the killing-defective Δ and Δ Δ mutants produced undetectable levels. Remarkably, a sublethal dose (1 mM) of pure HO incubated with Δ eradicated diverse strains, suggesting that bacteria may facilitate conversion of HO to a hydroxyl radical (OH). Accordingly, killing was completely blocked by incubation with scavengers of OH radicals, dimethyl sulfoxide (MeSO), thiourea, or sodium salicylate. The OH was detected in cells by spin trapping and electron paramagnetic resonance. Therefore, produces HO, which is rapidly converted to a more potent oxidant, hydroxyl radicals, to rapidly intoxicate strains. strains produce hydrogen peroxide (HO) to kill bacteria in the upper airways, including pathogenic strains. The targets of -produced HO have not been discovered, in part because of a lack of knowledge about the underlying molecular mechanism. We demonstrated that an increased density of kills by means of HO produced by two enzymes, SpxB and LctO. We discovered that SpxB/LctO-produced HO is converted into a hydroxyl radical (OH) that rapidly intoxicates and kills We successfully inhibited the toxicity of OH with three different scavengers and detected OH in the supernatant. The target(s) of the hydroxyl radicals represents a new alternative for the development of antimicrobials against infections.
迅速杀死 通过产生膜通透性的过氧化氢 (HO)。研究了产生的 HO 介导 杀伤的机制。一种模拟 在鼻咽定植过程中接触的 模型表明，杀伤需要竞争密度 与野生型菌株相比，同源缺失 HO 产生的 和 突变体需要增加密度才能杀死 虽然单突变体产生的残留 HO 活性足以消灭 ，但 双突变体无法杀死 收集了 20 株不同的耐甲氧西林金黄色葡萄球菌 (MRSA)和耐甲氧西林金黄色葡萄球菌 (MSSA)菌株，对 杀伤表现出线性敏感性（= 0.95），但相同的菌株在受到纯 HO（5 mM）挑战时具有不同的敏感性。 克隆复合体与对 或 HO 的敏感性之间没有关联。在孵育 4 小时内产生约 180 μM HO，而杀伤缺陷型 和 突变体未检测到 HO 水平。值得注意的是，用纯 HO 孵育亚致死剂量 (1 mM)的 根除了多种 菌株，表明 细菌可能有助于将 HO 转化为羟基自由基 (OH)。因此，用 OH 自由基清除剂二甲亚砜 (MeSO)、硫脲或水杨酸钠孵育完全阻断了 杀伤。通过自旋捕获和电子顺磁共振检测到 细胞中的 OH。因此， 产生 HO，HO 迅速转化为更有效的氧化剂羟基自由基，迅速使 菌株中毒。菌株在上呼吸道中产生过氧化氢 (HO)以杀死细菌，包括致病性 菌株。尚未发现 -产生的 HO 的靶标，部分原因是缺乏对潜在分子机制的了解。我们证明，通过两种酶 SpxB 和 LctO，增加的 密度通过 HO 杀死 。我们发现 SpxB/LctO 产生的 HO 转化为羟基自由基 (OH)，迅速使 中毒并杀死 我们成功地用三种不同的清除剂抑制了 OH 的毒性，并在上清液中检测到 OH。羟基自由基的靶标代表了开发针对 感染的抗菌药物的新选择。
