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Title: Methylmercury Uptake and Degradation by Methanotrophs

Methylmercury (CH 3Hg +) is a potent neurotoxin produced by certain anaerobic microorganisms in natural environments. While numerous studies have characterized the basis of mercury methylation, no studies have examined CH 3Hg + degradation by methanotrophs, despite their ubiquitous presence in the environment. We report that some methanotrophs (e.g., Methylosinus trichosporium OB3b) can take up and degrade CH 3Hg + rapidly, whereas others (e.g., Methylococcus capsulatus Bath) can take up but not degrade CH 3Hg +. Demethylation by M. trichosporium OB3b increases with increasing CH 3Hg + concentrations but is abolished in mutants deficient in methanobactin biosynthesis. Further, addition of methanol as a competing C1 substrate inhibits demethylation, suggesting that CH3Hg+ degradation by methanotrophs may involve an initial bonding of CH 3Hg + by methanobactin followed by cleavage of the C-Hg bond in CH 3Hg + by the methanol dehydrogenase. This new demethylation pathway by methanotrophs indicates possible broader involvement of C1-metabolizing aerobes in the environmental degradation of toxic CH3Hg+.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
  3. Iowa State Univ., Ames, IA (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 3; Journal Issue: 1; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Methylmercury production; uptake; demethylation; bioaccumulation; aquatic environments
OSTI Identifier:
1361357

Lu, Xia, Gu, Wenyu, Zhao, Linduo, Ul Haque, Muhammad Farhan, DiSpirito, Alan, Semrau, Jeremy D., and Gu, Baohua. Methylmercury Uptake and Degradation by Methanotrophs. United States: N. p., Web. doi:10.1126/sciadv.1700041.
Lu, Xia, Gu, Wenyu, Zhao, Linduo, Ul Haque, Muhammad Farhan, DiSpirito, Alan, Semrau, Jeremy D., & Gu, Baohua. Methylmercury Uptake and Degradation by Methanotrophs. United States. doi:10.1126/sciadv.1700041.
Lu, Xia, Gu, Wenyu, Zhao, Linduo, Ul Haque, Muhammad Farhan, DiSpirito, Alan, Semrau, Jeremy D., and Gu, Baohua. 2017. "Methylmercury Uptake and Degradation by Methanotrophs". United States. doi:10.1126/sciadv.1700041. https://www.osti.gov/servlets/purl/1361357.
@article{osti_1361357,
title = {Methylmercury Uptake and Degradation by Methanotrophs},
author = {Lu, Xia and Gu, Wenyu and Zhao, Linduo and Ul Haque, Muhammad Farhan and DiSpirito, Alan and Semrau, Jeremy D. and Gu, Baohua},
abstractNote = {Methylmercury (CH3Hg+) is a potent neurotoxin produced by certain anaerobic microorganisms in natural environments. While numerous studies have characterized the basis of mercury methylation, no studies have examined CH3Hg+ degradation by methanotrophs, despite their ubiquitous presence in the environment. We report that some methanotrophs (e.g., Methylosinus trichosporium OB3b) can take up and degrade CH3Hg+ rapidly, whereas others (e.g., Methylococcus capsulatus Bath) can take up but not degrade CH3Hg+. Demethylation by M. trichosporium OB3b increases with increasing CH3Hg+ concentrations but is abolished in mutants deficient in methanobactin biosynthesis. Further, addition of methanol as a competing C1 substrate inhibits demethylation, suggesting that CH3Hg+ degradation by methanotrophs may involve an initial bonding of CH3Hg+ by methanobactin followed by cleavage of the C-Hg bond in CH3Hg+ by the methanol dehydrogenase. This new demethylation pathway by methanotrophs indicates possible broader involvement of C1-metabolizing aerobes in the environmental degradation of toxic CH3Hg+.},
doi = {10.1126/sciadv.1700041},
journal = {Science Advances},
number = 1,
volume = 3,
place = {United States},
year = {2017},
month = {5}
}

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