气候变化领域集成服务门户(CCPortal): Reduced sulphur sources favour HgII reduction during anoxygenic photosynthesis by Heliobacteria

CCPortal

DOI	10.1111/gbi.12364
	Reduced sulphur sources favour HgII reduction during anoxygenic photosynthesis by Heliobacteria
	Lavoie N.C.; Grégoire D.S.; Stenzler B.R.; Poulain A.J.
发表日期	2020
ISSN	14724677
起始页码	70
结束页码	79
卷号	18 期号:1
英文摘要	The consumption of rice has become a global food safety issue because rice paddies support the production of high levels of the potent neurotoxin, methylmercury. The production of methylmercury is carried out by chemotrophic anaerobes that rely on a diversity of terminal electron acceptors, namely sulphate. Sulphur can be a limiting nutrient in rice paddies, and sulphate amendments are often used to stimulate crop production, which can increase methylmercury production. Mercury (Hg) redox cycling can affect Hg methylation by controlling the delivery of inorganic Hg substrates to methylators in anoxic habitats. Whereas sulphur is recognized as a key substrate controlling methylmercury production, the controls sulphur exerts on other microbe-mediated Hg transformations remain poorly understood. To explore the potential coupling between sulphur assimilation and anaerobic HgII reduction to Hg0, we studied Heliobacillus mobilis, a mesophilic anoxygenic phototroph representative from the Heliobacteriacea family originally isolated from a rice paddy. Here, we tested whether the redox state of the sulphur sources available to H. mobilis would affect its ability to reduce HgII. By comparing Hg0 production over a redox gradient of sulphur sources, we demonstrate that phototrophic HgII reduction is favoured in the presence of reduced sulphur sources such as thiosulphate and cysteine. We also show that cysteine exerts dynamic control on Hg cycling by affecting not only Hg's bioavailability but also its abiotic photoreduction under low light conditions. Specifically, in the absence of cells we show that organic matter (as yeast extract) and cysteine are both required for photoreduction to occur. This study offers insights into how one of the most primitive forms of photosynthesis affects Hg redox transformations and frames Heliobacteria as key players in Hg cycling within paddy soils, forming a basis for management strategies to mitigate Hg accumulation in rice. © 2019 John Wiley & Sons Ltd
关键词	anoxic conditions bacterium bioavailability food safety mercury (element)methylmercury photosynthesis redox conditions reduction sulfate sulfur Heliobacillus mobilis mercury methylmercury derivative sulfur bacterium photosynthesis soil Bacteria Mercury Methylmercury Compounds Photosynthesis Soil Sulfur
语种	英语
来源机构	Geobiology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/133213
推荐引用方式 GB/T 7714	Lavoie N.C.,Grégoire D.S.,Stenzler B.R.,et al. Reduced sulphur sources favour HgII reduction during anoxygenic photosynthesis by Heliobacteria[J]. Geobiology,2020,18(1).
APA	Lavoie N.C.,Grégoire D.S.,Stenzler B.R.,&Poulain A.J..(2020).Reduced sulphur sources favour HgII reduction during anoxygenic photosynthesis by Heliobacteria.,18(1).
MLA	Lavoie N.C.,et al."Reduced sulphur sources favour HgII reduction during anoxygenic photosynthesis by Heliobacteria".18.1(2020).