Journal article

Mercury methylation by metabolically versatile and cosmopolitan marine bacteria

Heyu Lin, David B Ascher, Yoochan Myung, Carl H Lamborg, Steven J Hallam, Caitlin M Gionfriddo, Kathryn E Holt, John W Moreau



Microbes transform aqueous mercury (Hg) into methylmercury (MeHg), a potent neurotoxin that accumulates in terrestrial and marine food webs, with potential impacts on human health. This process requires the gene pair hgcAB, which encodes for proteins that actuate Hg methylation, and has been well described for anoxic environments. However, recent studies report potential MeHg formation in suboxic seawater, although the microorganisms involved remain poorly understood. In this study, we conducted large-scale multi-omic analyses to search for putative microbial Hg methylators along defined redox gradients in Saanich Inlet, British Columbia, a model natural ecosystem with previously measured Hg..

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Awarded by National Health and Medical Research Council (NHMRC) of Australia

Awarded by Office of Science of the U.S. Department of Energy

Funding Acknowledgements

HL was supported by a postgraduate fellowship from The University of Melbourne Environmental Microbiology Research Initiative. HL and JWM designed the project and wrote the paper in consultation with all co-authors. DBA supervised the protein homology modelling, supported by an Investigator Grant from the National Health and Medical Research Council (NHMRC) of Australia [GNT1174405], and by the Victorian Government OIS Program. CHL thanks Woods Hole Oceanographic Institution for support and Tracy Mincer for help and inspiration. KEH co-advised meta-omics and phylogenetic analyses, supported by a Senior Medical Research Fellowship from the Viertel Foundation of Australia. HL, DBH, YM, RW, KEH and JWM gratefully acknowledge the use of data generated under the auspices of the US Department of Energy (DOE) Joint Genome Institute and Office of Science User Facility, supported by the Office of Science of the U.S. Department of Energy under Contract DE-AC02- 05CH11231, the G. Unger Vetlesen and Ambrose Monell Foundations, and the Natural Sciences and Engineering Research Council of Canada through grants awarded to SJH.