High‐yield synthesis of milligram amounts of isotopically enriched methylmercury (CH<sub>3</sub><sup>198</sup>HgCl)

Bancon-Montigny, Chrystelle; Yang, Lu; Sturgeon, Ralph E.; Colombini, Vanessa; Mester, Zoltán

doi:10.1002/aoc.572

Cited by 44 publications

(39 citation statements)

References 31 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Explicit detection limits are in Table S1. Spent medium controls averaged 0.12 ± 0.03% methylation, and fresh, uninoculated medium controls averaged 0.05 ± 0.02%.Stable isotope enriched Me 199 Hg was synthesized in-house with 199 HgCl 2 (Oak Ridge National Laboratories, 91.95% enriched in 199 Hg) with methylcobalamin 21 …”

Section: Methodsmentioning

confidence: 99%

Mercury Methylation by Novel Microorganisms from New Environments

Gilmour

Podar²,

Bullock

et al. 2013

Environ. Sci. Technol.

607

539

View full text Add to dashboard Cite

Microbial mercury (Hg) methylation transforms a toxic trace metal into the highly bioaccumulated neurotoxin methylmercury (MeHg). The lack of a genetic marker for microbial MeHg production has prevented a clear understanding of Hg-methylating organism distribution in nature. Recently, a specific gene cluster (hgcAB) was linked to Hg methylation in two bacteria.1 Here we test if the presence of hgcAB orthologues is a reliable predictor of Hg methylation capability in microorganisms, a necessary confirmation for the development of molecular probes for Hg-methylation in nature. Although hgcAB orthologues are rare among all available microbial genomes, organisms are much more phylogenetically and environmentally diverse than previously thought. By directly measuring MeHg production in several bacterial and archaeal strains encoding hgcAB, we confirmed that possessing hgcAB predicts Hg methylation capability. For the first time, we demonstrated Hg methylation in a number of species other than sulfate- (SRB) and iron- (FeRB) reducing bacteria, including methanogens, and syntrophic, acetogenic, and fermentative Firmicutes. Several of these species occupy novel environmental niches for Hg methylation, including methanogenic habitats such as rice paddies, the animal gut, and extremes of pH and salinity. Identification of these organisms as Hg methylators now links methylation to discrete gene markers in microbial communities.

show abstract

Section: Methodsmentioning

confidence: 99%

Mercury Methylation by Novel Microorganisms from New Environments

Gilmour

Podar²,

Bullock

et al. 2013

Environ. Sci. Technol.

607

539

View full text Add to dashboard Cite

show abstract

“…The 198 HgCl 2 from Oak Ridge National Laboratory; the synthesis method was modified from the work of Bancon-Montigny et al [2]). Samples were withdrawn over time for measurement of unfiltered and filter (0.2 m)-passing THg and MeHg in the medium.…”

Section: Methodsmentioning

confidence: 99%

Detailed Assessment of the Kinetics of Hg-Cell Association, Hg Methylation, and Methylmercury Degradation in Several Desulfovibrio Species

Graham

Bullock

Maizel

et al. 2012

Appl Environ Microbiol

125

View full text Add to dashboard Cite

. We tested the hypothesis that differences in Hg(II) i sorption and/or uptake rates drive observed differences in methylation rates among Desulfovibrio species. Hg(II) i associated rapidly and with high affinity to both methylating and nonmethylating species. MeHg production by Hg-methylating strains was rapid, plateauing after ϳ3 h. All MeHg produced was rapidly exported. We also tested the idea that all Desulfovibrio species are capable of Hg(II) i methylation but that rapid demethylation masks its production, but we found this was not the case. Therefore, the underlying reason why MeHg production capability is not universal in the Desulfovibrio is not differences in Hg affinity for cells nor differences in the ability of strains to degrade MeHg. However, Hg methylation rates varied substantially between Hg-methylating Desulfovibrio species even in these controlled experiments and after normalization to cell density. Thus, biological differences may drive crossspecies differences in Hg methylation rates. As part of this study, Microbial mercury methylation is the main driver of risk associated with Hg pollution. Methylmercury production is an anaerobic process that occurs in saturated soils and wetlands (26,44,45,53), decaying periphyton mats (1, 14, 31), aquatic bottom sediments (16,27,33,36), and anaerobic bottom waters (56). Early investigations, prior to the advent of modern methylmercury (MeHg) analyses, reported a wide variety of aerobic and anaerobic Gram-positive and Gram-negative bacteria (30,49,55,58) and fungi (55) to be capable of MeHg production. However, subsequent studies with pure cultures have conclusively demonstrated a role only for sulfate-reducing bacteria (SRB) (4,8,11,13,20,23,38,50) and iron-reducing bacteria (FeRB; principally Geobacter spp.) (21, 37), all belonging to the Deltaproteobacteria. Many field studies, using selective microbial stimulants (1, 10, 26, 44, 57), inhibitors (1, 16, 24, 26, 59), and biogeochemical correlates (6,39,40,45), have buttressed the paradigm of SRB and FeRB as the dominant Hg methylators in natural aquatic systems (16,24,59), though recent studies have hypothesized that methanogens may be significant in some systems (31).Only a subset of SRB and FeRB are capable of Hg methylation (11,23,37,50), but why this is the case remains unclear. Early work by Choi and Bartha (13) suggested that Hg methylation was a "metabolic mistake" of SRB utilizing the acetyl coenzyme A (acetyl-CoA) pathway for carbon metabolism. Subsequent studies, however, indicated that Hg methylation capability is not restricted to SRB possessing the acetyl-CoA pathway (20). At present, it is not possible to conclusively identify the methyltransferase or methyl donor in SRB (or other Deltaproteobacteria) responsible for in vivo Hg methylation. Hg methylation occurs intracellularly (23), and significant effort has therefore been devoted to elucidating the mechanism(s) of Hg uptake by Hg-methylating bacteria.Passive diffusion of neutral HgS species has been hypothesized to control Hg uptak...

show abstract

“…Hg(II)), held in deionized water, was synthesized in our laboratory from Hg(II) using a method described by Imura et al (1971), Rouleau &Block (1997), andBancon-Montigny et al (2004). Experimental radioisotope additions were in µl quantities, and equimolar volumes of sodium hydroxide (NaOH) were added to neutralize the acid added during radiolabeling.…”

Section: Methodsmentioning

confidence: 99%

Intraspecific comparisons of metal bioaccumulation in the juvenile Atlantic silverside Menidia menidia

Dutton¹,

Fisher²

2010

Aquat. Biol.

View full text Add to dashboard Cite

High‐yield synthesis of milligram amounts of isotopically enriched methylmercury (CH₃¹⁹⁸HgCl)

Cited by 44 publications

References 31 publications

Mercury Methylation by Novel Microorganisms from New Environments

Mercury Methylation by Novel Microorganisms from New Environments

Detailed Assessment of the Kinetics of Hg-Cell Association, Hg Methylation, and Methylmercury Degradation in Several Desulfovibrio Species

Intraspecific comparisons of metal bioaccumulation in the juvenile Atlantic silverside Menidia menidia

Contact Info

Product

Resources

About

High‐yield synthesis of milligram amounts of isotopically enriched methylmercury (CH3198HgCl)

Cited by 44 publications

References 31 publications

Mercury Methylation by Novel Microorganisms from New Environments

Mercury Methylation by Novel Microorganisms from New Environments

Detailed Assessment of the Kinetics of Hg-Cell Association, Hg Methylation, and Methylmercury Degradation in Several Desulfovibrio Species

Intraspecific comparisons of metal bioaccumulation in the juvenile Atlantic silverside Menidia menidia

Contact Info

Product

Resources

About

High‐yield synthesis of milligram amounts of isotopically enriched methylmercury (CH₃¹⁹⁸HgCl)