Dissimilatory Fe(III) Reduction Controls on Arsenic Mobilization: A Combined Biogeochemical and NanoSIMS Imaging Approach.
Dissimilatory Fe(III) Reduction Controls on Arsenic Mobilization: A Combined Biogeochemical and NanoSIMS Imaging Approach.
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异化铁（III）还原控制砷的动员：生物地球化学和纳米模拟成像相结合的方法。
DOI：
10.3389/fmicb.2021.640734
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发表时间：
2021
影响因子：
5.2
通讯作者：
Lloyd JR
中科院分区：
文献类型：
--
作者：
Lopez-Adams R;Newsome L;Moore KL;Lyon IC;Lloyd JR
微生物代谢在控制有毒地下水污染物（如砷）的命运方面起着关键作用。地下细菌催化的异化金属还原可以通过还原溶解含As（V）的Fe（III）矿物组合促进砷的活化。释放的As（V）的流动性然后可以通过As（V）呼吸细菌还原为更可溶的As（III）而放大。本研究的重点是还原溶解的As（V）吸附到Fe（III）-（oxyhydr）氧化物的模型Fe（III）-和As（V）-还原细菌，阐明这些过程的基础机制在单细胞规模。希瓦氏菌属ANA-3野生型（WT）细胞[能够呼吸Fe（III）和As（V）]的无菌培养物使用13 C标记的乳酸盐在含砷的Fe（III）-（oxyhydr）氧化物薄膜上生长，定植后，使用纳米级二次离子质谱（NanoSIMS）评估固相中Fe和As的分布，并辅以含水地球化学分析。使用arrA突变体进行平行实验，该突变体能够呼吸Fe（III）但不能呼吸As（V）。NanoSIMS成像显示，大多数代谢活跃的细胞不与Fe（III）矿物质直接接触。两种菌株均释放黄素，表明这些细胞分泌的电子穿梭介导细胞外Fe（III）-（oxyhydr）oxide还原，但不促进细胞外As（V）还原，这通过arrA缺失突变菌株的上清液中存在黄素但缺乏As（III）来证明。NanoSIMS深度轮廓单细胞的3D重建显示，在WT细胞中，As和Fe与细胞表面相关，而对于arrA突变体，只有Fe与生物量相关。这些数据与希瓦氏菌ANA-3在多步骤过程中呼吸As（V）一致;首先，Fe（III）矿物质的还原溶解释放As（V），一旦在溶液中，As（V）被细胞呼吸为As（III）。以及突出Fe（III）还原作为砷的主要释放机制，我们的数据还确定了意想不到的细胞As（III）保留机制，需要进一步研究。
Microbial metabolism plays a key role in controlling the fate of toxic groundwater contaminants, such as arsenic. Dissimilatory metal reduction catalyzed by subsurface bacteria can facilitate the mobilization of arsenic via the reductive dissolution of As(V)-bearing Fe(III) mineral assemblages. The mobility of liberated As(V) can then be amplified via reduction to the more soluble As(III) by As(V)-respiring bacteria. This investigation focused on the reductive dissolution of As(V) sorbed onto Fe(III)-(oxyhydr)oxide by model Fe(III)- and As(V)-reducing bacteria, to elucidate the mechanisms underpinning these processes at the single-cell scale. Axenic cultures of Shewanella sp. ANA-3 wild-type (WT) cells [able to respire both Fe(III) and As(V)] were grown using 13C-labeled lactate on an arsenical Fe(III)-(oxyhydr)oxide thin film, and after colonization, the distribution of Fe and As in the solid phase was assessed using nanoscale secondary ion mass spectrometry (NanoSIMS), complemented with aqueous geochemistry analyses. Parallel experiments were conducted using an arrA mutant, able to respire Fe(III) but not As(V). NanoSIMS imaging showed that most metabolically active cells were not in direct contact with the Fe(III) mineral. Flavins were released by both strains, suggesting that these cell-secreted electron shuttles mediated extracellular Fe(III)-(oxyhydr)oxide reduction, but did not facilitate extracellular As(V) reduction, demonstrated by the presence of flavins yet lack of As(III) in the supernatants of the arrA deletion mutant strain. 3D reconstructions of NanoSIMS depth-profiled single cells revealed that As and Fe were associated with the cell surface in the WT cells, whereas for the arrA mutant, only Fe was associated with the biomass. These data were consistent with Shewanella sp. ANA-3 respiring As(V) in a multistep process; first, the reductive dissolution of the Fe(III) mineral released As(V), and once in solution, As(V) was respired by the cells to As(III). As well as highlighting Fe(III) reduction as the primary release mechanism for arsenic, our data also identified unexpected cellular As(III) retention mechanisms that require further investigation.
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影响因子：
12.8
作者：
Biswas, Ashis;Gustafsson, Jon Petter;Bhattacharya, Prosun
通讯作者：
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影响因子：
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通讯作者：
Clarke TA