A soil-borne Mn(II)-oxidizing bacterium of Providencia sp. exploits a strategy of superoxide production coupled to hydrogen peroxide consumption to generate Mn oxides.
A soil-borne Mn(II)-oxidizing bacterium of Providencia sp. exploits a strategy of superoxide production coupled to hydrogen peroxide consumption to generate Mn oxides.
复制标题
普罗维登斯菌 (Providencia sp.) 土传锰 (II) 氧化细菌。
DOI：
10.1007/s00203-022-02771-7
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发表时间：
2022
影响因子：
2.8
通讯作者：
Ding Li
中科院分区：
文献类型：
--
作者：
Sha Chen;Zhexu Ding;Jinyuan Chen;Jun Luo;Xiaofang Ruan;Zongpei Li;Fengfeng Liao;Jing He;Ding Li
涉及活性氧（ROS）的细菌非酶促Mn（II）氧化（即，间接氧化），最初发现于海洋α-变形杆菌，被认为在控制海洋地球化学循环中具有重要意义。然而，对于土传细菌，间接Mn（II）氧化的证据仍不清楚。在这项研究中，间接锰（II）氧化证明在土壤中传播的细菌，普罗维登西亚普。LLDRA 6.首先，对于LLDRA 6，在有和没有50 mM Mn（II）暴露的情况下，通过转录组测序发现300个差异表达的基因与Mn（II）暴露相关。其中，操纵子，负责苯乙酸催化剂，在转录急剧上调，提请我们特别注意，因为它的转录上调最近被证明是重要的承受ROS。接着，使用荧光探针2′，7 ′-二氯荧光素二乙酸酯（DCFDA）定性检测来自细胞的ROS，显示在Mn（II）暴露期间ROS的荧光强度明显增加。此外，超氧化物和过氧化氢从细胞的浓度进行了检测，分别与和没有锰（II）曝光，表现出当锰（II）氧化发生，超氧化物浓度显着增加，但过氧化氢浓度显着下降。特别地，由LLDRA 6产生的超氧化物被证明是Mn（II）在Mn氧化物形成中的氧化剂。最后，我们预测苯乙酸代谢途径和活性氧在锰（II）曝光之间的联系，提出过量的活性氧，在响应锰（II）曝光，转录激活苯乙酸catalysts推测通过增加浓度的高活性氧杂卓。
Bacterial non-enzymatic Mn(II) oxidation involving reactive oxygen species (ROS) (i.e., indirect oxidation), initially discovered from a marine alpha-proteobacterium, is believed to be of importance in controlling biogeochemical cycles. For soil-borne bacteria, however, evidence of indirect Mn(II) oxidation remains unclear. In this study, the indirect Mn(II) oxidation was evidenced in a soil-borne bacterium,Providenciasp. LLDRA6. First, with and without 50 mM of Mn(II) exposure for LLDRA6, 300 differentially expressed genes were found to be linked to Mn(II) exposure via transcriptome sequencing. Among them, an operon, responsible for phenylacetic acid catabolism, was sharply upregulated in transcription, drawing us a special attention, since its transcriptional upregulation has recently shown to be important for withstanding ROS. Next, a fluorometric probe, 2′,7′-Dichlorofluorescin diacetate (DCFDA), was used to qualitatively detect ROS from cells, showing a distinct increase in fluorescence intensities of ROS during Mn(II) exposure. Furthermore, concentrations of superoxide and hydrogen peroxide from cells were detected, respectively, with and without Mn(II) exposure, exhibiting that when Mn(II) oxidation occurred, superoxide concentration significantly increased but hydrogen peroxide concentration significantly decreased. Particularly, superoxide produced by LLDRA6 was proven to be the oxidant for Mn(II) in the formation of Mn oxides. Finally, we predicted links between phenylacetic acid metabolism pathway and ROS during Mn(II) exposure, proposing that the excessive ROS, generated in response to Mn(II) exposure, transcriptionally activate phenylacetic acid catabolism presumably by increasing concentrations of highly reactive oxepins.