Mercury Methylation Genes Identified across Diverse Anaerobic Microbial Guilds in a Eutrophic Sulfate-Enriched Lake.

Autor: Peterson BD; Environmental Science & Technology Program, University of Wisconsin - Madison, 660 N. Park Street, Madison, Wisconsin 53706, United States., McDaniel EA; Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States., Schmidt AG; Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States., Lepak RF; Environmental Science & Technology Program, University of Wisconsin - Madison, 660 N. Park Street, Madison, Wisconsin 53706, United States.; U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, Minnesota 55804, United States., Janssen SE; U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States., Tran PQ; Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States.; Department of Integrative Biology, University of Wisconsin - Madison, 250 N. Mills St. Madison, Wisconsin 53706, United States., Marick RA; Department of Biochemistry, University of Wisconsin - Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States., Ogorek JM; U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States., DeWild JF; U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States., Krabbenhoft DP; U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States., McMahon KD; Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States.; Department of Civil and Environmental Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison Wisconsin 53706, United States.
Jazyk: angličtina
Zdroj: Environmental science & technology [Environ Sci Technol] 2020 Dec 15; Vol. 54 (24), pp. 15840-15851. Date of Electronic Publication: 2020 Nov 23.
DOI: 10.1021/acs.est.0c05435
Abstrakt: Mercury (Hg) methylation is a microbially mediated process that converts inorganic Hg into bioaccumulative, neurotoxic methylmercury (MeHg). The metabolic activity of methylating organisms is highly dependent on biogeochemical conditions, which subsequently influences MeHg production. However, our understanding of the ecophysiology of methylators in natural ecosystems is still limited. Here, we identified potential locations of MeHg production in the anoxic, sulfidic hypolimnion of a freshwater lake. At these sites, we used shotgun metagenomics to characterize microorganisms with the Hg-methylation gene hgcA . Putative methylators were dominated by hgcA sequences divergent from those in well-studied, confirmed methylators. Using genome-resolved metagenomics, we identified organisms with hgcA (hgcA+) within the Bacteroidetes and the recently described Kiritimatiellaeota phyla. We identified hgcA+ genomes derived from sulfate-reducing bacteria, but these accounted for only 22% of hgcA+ genome coverage. The most abundant hgcA+ genomes were from fermenters, accounting for over half of the hgcA gene coverage. Many of these organisms also mediate hydrolysis of polysaccharides, likely from cyanobacterial blooms. This work highlights the distribution of the Hg-methylation genes across microbial metabolic guilds and indicate that primary degradation of polysaccharides and fermentation may play an important but unrecognized role in MeHg production in the anoxic hypolimnion of freshwater lakes.
Databáze: MEDLINE
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