Quantification of gene expression patterns relevant to microbial mercury transformations
EMSL Project ID
50825
Abstract
Levels of toxic methylmercury (MeHg) in the environment are a net result of mercury (Hg) methylation and MeHg demethylation processes. Mercury methylation by anaerobic bacteria and archaea is the primary source of MeHg and has been linked to the gene cluster hgcAB expressing a protein complex HgcAB predicted to be associated with the cytoplasmic membrane. Recent studies suggest that MeHg production in these microorganisms depends on the exchange of Hg(II) between thiols in solution and cytoplasmic membrane-bound proteins (Liu et al., 2016). However, there is currently no experimental evidence for the subcellular localization of HgcAB, and it is essentially unknown what factors control hgcAB gene expression. We propose to use quantitative fluorescence in situ hybridization (FISH) combined with stochastic optical reconstruction microscopy (STORM) and photoactivated localization microscopy (PALM) to determine patterns of hgcAB expression in cells of the model methylator Desulfovibrio desulfuricans ND132 in response to growth stage and trace amounts of heavy metals. In addition, we have recently shown that methanotrophs are able to demethylate MeHg, which requires the expression of the metal-chelating agent, methanobactin. However, it is currently unknown if microbial interactions enhance or repress methanobactin production, and whether we can identify methanobactin-producing methanotrophs in mixed cultures. Thus, to fully understand the net Hg methylation potential, we also propose to use FISH to examine methanobactin gene expression (mbnAB) in artificial mixed cultures of known methanobactin and non-methanobactin producing methanotrophs, as well as methanotrophic enrichments from a Hg-contaminated site in Oak Ridge, TN.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2019-10-01
End Date
2021-12-31
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members