Expression and regulation of the <i>mer</i> operon in <i>Thermus thermophilus</i>

Norambuena, Javiera; Miller, Maximilian; Boyd, Jeffrey M.; Barkay, Tamar

doi:10.1111/1462-2920.14953

Cited by 9 publications

(2 citation statements)

References 39 publications

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“…The mer and chr operons confer resistance to mercury and chromium, respectively. The mer operon is widely distributed in bacteria and has a complex composition [32,33]. MerC, MerP, and MerT are the key components for the recognition and uptake of Hg 2+ .…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

Hu,

Wei,

Liu

et al. 2024

BMC Biotechnol

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Background Removal of heavy metals from water and soil is a pressing challenge in environmental engineering, and biosorption by microorganisms is considered as one of the most cost-effective methods. In this study, the metal-binding proteins MerR and ChrB derived from Cupriavidus metallidurans were separately expressed in Escherichia coli BL21 to construct adsorption strains. To improve the adsorption performance, surface display and codon optimization were carried out. Results In this study, we constructed 24 adsorption engineering strains for Hg2+ and Cr6+, utilizing different strategies. Among these engineering strains, the M’-002 and B-008 had the strongest heavy metal ion absorption ability. The M’-002 used the flexible linker and INPN to display the merRopt at the surface of the E. coli BL21, whose maximal adsorption capacity reached 658.40 μmol/g cell dry weight under concentrations of 300 μM Hg2+. And the B-008 overexpressed the chrB in the intracellular, its maximal capacity was 46.84 μmol/g cell dry weight under concentrations 500 μM Cr6+. While in the case of mixed ions solution (including Pb2+, Cd2+, Cr6+ and Hg2+), the total amount of ions adsorbed by M’-002 and B-008 showed an increase of up to 1.14- and 4.09-folds, compared to the capacities in the single ion solution. Conclusion The construction and optimization of heavy metal adsorption strains were carried out in this work. A comparison of the adsorption behavior between single bacteria and mixed bacteria systems was investigated in both a single ion and a mixed ion environment. The Hg2+ absorption capacity is reached the highest reported to date with the engineered strain M’-002, which displayed the merRopt at the surface of chassis cell, indicating the strain’s potential for its application in practical environments.

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Section: Introductionmentioning

confidence: 99%

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

Hu,

Wei,

Liu

et al. 2024

BMC Biotechnol

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“…In addition to the sulfate reducing bacteria in the natural environment can make MeHg demethylation [12] , it is also found that selenium compounds can regulate the abundance of sulfate reducing bacteria in the intestinal tract of MeHg poisoned rats, thereby promoting the demethylation of MeHg in vivo [13][14] . Genetically, it was found that the hgcAB gene cluster and the mer operon is responsible for demethylation of MeHg [15] . Anaerobic microorganisms possessing these genes, such as sulfate-reducing bacteria and pseudomonas have been found to degrade MeHg [16][17] .…”

Section: Introductionmentioning

confidence: 99%

Fecal microbiota transplantation in treating methylmercury-poisoned rats: Reconstruction of gut microbiome and modulation of gut-brain axis related metabolites

Zhang,

Xie,

Lin

et al. 2023

Preprint

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Background Methylmercury (MeHg) can bring devastating neurotoxicity to animals and human beings. Gut microbiota has been found to demethylate MeHg while MeHg exposure was found to destroy the diversity and abundance of gut microbiota. Besides, some neurotransmitters such as GABA, glutamate and other metabolites were altered due to MeHg exposure. Fecal microbiota transplantation (FMT) has been successfully applied to treat a series of diseases like Tourette syndrome, irritable bowel syndrome, necrotizing enterocolitis and to treat ulcerative coliti. The objective of this study was to investigate the effects of FMT in treating MeHg-poisoned rats. Results: It was found that FMT for 14 days promoted body weight gain, enhanced demethylation of MeHg and increased fecal excretion of Hg in MeHg-poisoned rats. Furthermore, the gut microbial bacteria associated with demethylation, such as sulfate-reducing bacteria were restored and some metabolites related to neuroactivity through gut-brain axis were increased after FMT, there is also repair of brain derived neurotrophic factor(BDNF)-related factor levels in the intestine, brain and serum. Conclusions: In all, it was showed that FMT can be a effective way in treating MeHg-poisoned rats through the reconstruction of gut microbiota, especially the bacteria that are associated with the demethylation of MeHg. Furthermore, the modulation of metabolites that are related to gut-brain axis after FMT also contributed to the treating of MeHg-poisoning. This study provides a novel way to treat MeHg-poisoning, which may contribute to the health promotion of mercury exposed population and shed lights on the treatment of other neurological diseases like Parkinson’s disease.

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Effect of exogenous and endogenous sulfide on the production and the export of methylmercury by sulfate-reducing bacteria

Barrouilhet

Monperrus²,

Tessier³

et al. 2022

Environ Sci Pollut Res

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Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg) is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sul des are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two forms can be endogenously converted by microorganisms into sul de. Here, we explore the effect of sul de (produced by the cell or supplied exogenously) on Hg methylation. For this purpose, Pseudodesulfovibrio hydrargyri BerOc1 was cultivated in non-sul dogenic conditions with addition of cysteine and sul de as well as in sul dogenic conditions. We report that Hg methylation depends on sul de concentration in the culture rather than on the initial form of sulfur (cysteine, sul de or sulfate) added, and was independent of hgcA expression. Interestingly, MeHg production was maximal at 0.1-0.5 mM of sul des. Besides, a strong positive correlation between MeHg in the extracellular medium and the increase of sul de concentrations was observed, suggesting a facilitated MeHg export with sul de and/or higher desorption from the cell. We demonstrate that sul des (exogenous or endogenous) play a key role in controlling mercury methylation, and should be considered when investigating the impact of Hg on natural environments.

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Expression and regulation of the mer operon in Thermus thermophilus

Cited by 9 publications

References 39 publications

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

Fecal microbiota transplantation in treating methylmercury-poisoned rats: Reconstruction of gut microbiome and modulation of gut-brain axis related metabolites

Effect of exogenous and endogenous sulfide on the production and the export of methylmercury by sulfate-reducing bacteria

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