Nitrate Reduction Stimulates and Is Stimulated by Phenazine-1-Carboxylic Acid Oxidation by Citrobacter portucalensis MBL.
Nitrate Reduction Stimulates and Is Stimulated by Phenazine-1-Carboxylic Acid Oxidation by Citrobacter portucalensis MBL.
复制标题
硝酸盐还原刺激并通过柠檬酸杆菌portucalensis mbl刺激苯嗪-1-羧酸氧化。
DOI：
10.1128/mbio.02265-21
复制
发表时间：
2021-08-31
期刊：
影响因子：
6.4
通讯作者：
Newman DK
中科院分区：
文献类型：
--
作者：
Tsypin LM;Newman DK
促瑞苯烷是分泌的代谢产物，从法定人数的敏感性到抗微生物战争，到能量保存都可以促进这些活性，因为它们的氧化还原活性是广泛的，但它是广泛研究的。通过其减少生产者这个终端电子依赖性的PCA氧化活性与其他几个具有硝酸盐的能力的γ杆菌。通过C. portucalensis mbl降低硝酸盐除了将电子从PCA到硝酸盐的化学计量交换之外，我们将其归因于C. portucalensis MBL还可以减少氧化PCA的能力，从而催化了完整的PCA氧化还原循环。
Phenazines are secreted metabolites that microbes use in diverse ways, from quorum sensing to antimicrobial warfare to energy conservation. Phenazines are able to contribute to these activities due to their redox activity. The physiological consequences of cellular phenazine reduction have been extensively studied, but the counterpart phenazine oxidation has been largely overlooked. Phenazine-1-carboxylic acid (PCA) is common in the environment and readily reduced by its producers. Here, we describe its anaerobic oxidation by Citrobacter portucalensis strain MBL, which was isolated from topsoil in Falmouth, MA, and which does not produce phenazines itself. This activity depends on the availability of a suitable terminal electron acceptor, specifically nitrate. When C. portucalensis MBL is provided reduced PCA and nitrate, it oxidizes the PCA at a rate that is environmentally relevant. We compared this terminal electron acceptor-dependent PCA-oxidizing activity of C. portucalensis MBL to that of several other gammaproteobacteria with various capacities to respire nitrate. We found that PCA oxidation by these strains in a nitrate-dependent manner is decoupled from growth and strain dependent. We infer that bacterial PCA oxidation is widespread and genetically determined. Notably, oxidizing PCA enhances the rate of nitrate reduction to nitrite by C. portucalensis MBL beyond the stoichiometric exchange of electrons from PCA to nitrate, which we attribute to C. portucalensis MBL’s ability to also reduce oxidized PCA, thereby catalyzing a complete PCA redox cycle. This bidirectionality highlights the versatility of PCA as a biological redox agent.