title: Analysis of mercuric reductase (merA) gene diversity in an anaerobic mercury-contaminated sediment enrichment.
abstract: The reduction of ionic mercury to elemental mercury by the mercuric reductase (MerA) enzyme plays an important role in the biogeochemical cycling of mercury in contaminated environments by partitioning mercury to the atmosphere. This activity, common in aerobic environments, has rarely been examined in anoxic sediments where production of highly toxic methylmercury occurs. Novel degenerate PCR primers were developed which span the known diversity of merA genes in Gram-negative bacteria and amplify a 285 bp fragment at the 3' end of merA. These primers were used to create a clone library and to analyse merA diversity in an anaerobic sediment enrichment collected from a mercury-contaminated site in the Meadowlands, New Jersey. A total of 174 sequences were analysed, representing 71 merA phylotypes and four novel MerA clades. This first examination of merA diversity in anoxic environments suggests an untapped resource for novel merA sequences.
authors.affiliation: Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Sinéad M
authors.initials: SM
authors.lastname: Ní Chadhain
authors.forename: Jeffra K
authors.initials: JK
authors.lastname: Schaefer
authors.forename: Sharron
authors.initials: S
authors.lastname: Crane
authors.forename: Gerben J
authors.initials: GJ
authors.lastname: Zylstra
authors.forename: Tamar
authors.initials: T
authors.lastname: Barkay
mesh_terms: D000693:Anaerobiosis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation / Q000502:physiology; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D006090:Gram-Negative Bacteria / Q000201:enzymology* / Q000235:genetics; D008628:Mercury / Q000378:metabolism*; D009515:New Jersey; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D014874:Water Pollutants, Chemical; D010088:Oxidoreductases; C021551:mercuric reductase; D008628:Mercury