Tamar Barkay Professor Rutgers University Dept. of Biochemistry and Microbiology Lipman Hall. Room 333 School of Env & Biol Sciences New Brunswick. N. J. 08903-0231 (732) 932-9763. ext. 333 FAX - 8965 barkay@aesop.rutgers.edu

Microbial ecology of the interactions of microbes with toxic metals

Research in my laboratory is focused on the microbial ecology of the interactions of microbes with toxic metals. Specifically. we are looking at microbial transformations of metals and how they affect metal toxicity and accumulation patterns in the environment and at the genetics and physiology of metal resistance and transformations in bacteria. This research supports efforts in bioremidiation of metal contaminated environments. Our research relies heavily on the application of molecular tools. such as cloning. gene probing. mRNA transcript analysis. sequencing. PCR amplification. and phylogenetic analyses in microbial ecology.

Several on-going research projects are focused on the role of microbes in the formation and accumulation of methylmercury in aquatic environments. Methylmercury is the most toxic form of mercury. which is accumulated and biomagnified in fish and shellfish. posing a risk to predators (including humans) that rely on the aquatic food chain for sustenance. Our studies are focused on environments with elevated mercury concentrations as a result of man activities or geothermal enrichments. Current projects are conducted in the Meadowlands. NJ. the Adirondacks. NY. and in deep-sea hydrothermal vents.

A third project examines the evolutionary pathways of metal homeostasis among microorganisms. In particular. we are interested in the role of horizontal gene transfer in the evolution of metal resistance in microbial communities that inhabit metal and radionuclei impacted subsurface (below the root zone) soils. Such genetic spread might facilitate microbial survival and activities in metal contaminated environments.

Selected Publications

Wiatrowski HA, Das S, Kukkadapu R, Ilton ES, Barkay T, Yee N. (2009) Reduction of Hg(II) to Hg(0) by magnetite. Environ Sci Technol. 43(14):5307-13.

Crespo-Medina M, Chatziefthimiou A, Cruz-Matos R, Pérez-Rodríguez I, Barkay T, Lutz RA, Starovoytov V, Vetriani C. (2009) Salinisphaera hydrothermalis sp. nov., a mesophilic, halotolerant, facultatively autotrophic, thiosulfate-oxidizing gammaproteobacterium from deep-sea hydrothermal vents, and emended description of the genus Salinisphaera. Int J Syst Evol Microbiol. 59(Pt 6):1497-503.

Kritee K, Blum JD, Barkay T. (2008) Mercury stable isotope fractionation during reduction of Hg(II) by different microbial pathways. Environ Sci Technol. 42(24):9171-7.

Boyd ES, King S, Tomberlin JK, Nordstrom DK, Krabbenhoft DP, Barkay T, Geesey GG. (2009) Methylmercury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming. Environ Microbiol. 11(4):950-9.

Wang Y, Freedman Z, Lu-Irving P, Kaletsky R, Barkay T. (2009) An initial characterization of the mercury resistance (mer) system of the thermophilic bacterium Thermus thermophilus HB27. FEMS Microbiol Ecol. 67(1):118-29.

Atamna-Ismaeel N, Sabehi G, Sharon I, Witzel KP, Labrenz M, Jürgens K, Barkay T, Stomp M, Huisman J, Beja O. (2008) Widespread distribution of proteorhodopsins in freshwater and brackish ecosystems. ISME J. 2(6):656-62.

Cardona-Marek T, Schaefer J, Ellickson K, Barkay T, Reinfelder JR. (2007) Mercury speciation, reactivity, and bioavailability in a highly contaminated estuary, Berry's Creek, New Jersey Meadowlands. Environ Sci Technol. 41(24):8268-74.

Golding GR, Kelly CA, Sparling R, Loewen PC, Barkay T. (2007) Evaluation of mercury toxicity as a predictor of mercury bioavailability. Environ Sci Technol. 41(16):5685-92.

Kritee K, Blum JD, Johnson MW, Bergquist BA, Barkay T. (2007) Mercury stable isotope fractionation during reduction of Hg(II) to Hg(0) by mercury resistant microorganisms.
Environ Sci Technol. 41(6):1889-95.

Chatziefthimiou AD, Crespo-Medina M, Wang Y, Vetriani C, Barkay T. (2007) The isolation and initial characterization of mercury resistant chemolithotrophic thermophilic bacteria from mercury rich geothermal springs. Extremophiles. 11(3):469-79.

Poulain AJ, Ní Chadhain SM, Ariya PA, Amyot M, Garcia E, Campbell PG, Zylstra GJ, Barkay T.
(2007) Potential for mercury reduction by microbes in the high arctic.
Appl Environ Microbiol. 73(7):2230-8. Erratum in: Appl Environ Microbiol. Jun;73(11):3769.

Barkay T, Poulain AJ. (2007) Mercury (micro)biogeochemistry in polar environments.
FEMS Microbiol Ecol. 59(2):232-41. Review.

Ní Chadhain, S., J.K. Schaefer, S. Crane, G.J. Zylstra, and T. Barkay. (2006) Analysis of mercuric reductase (merA) gene diversity in an anaerobic mercury–contaminated sediment enrichment. Environ. Microbiol. 8: 1746-1752.

Martinez RJ. Wang Y. Raimondo MA. Coombs JM. Barkay T. Sobecky PA. (2006) Horizontal gene transfer of PIB-type ATPases among bacteria isolated from radionuclide- and metal-contaminated subsurface sSoils. Appl Environ Microbiol. 72(5):3111-8.

Smets BF. Barkay T. (2005) Horizontal gene transfer: perspectives at a crossroads of scientific disciplines. Nat Rev Microbiol. 3(9):675-8.

Barkay T. Wagner-Dobler I. achievements in controlling mercury toxicity in the environment. Adv Appl Microbiol. (2005) Microbial transformations of mercury: potentials. challenges. and achievements in controlling mercury toxicity in the environment. Adv Appl Microbiol. 57:1-52.

Wiatrowski HA. Barkay T. (2005) Monitoring of microbial metal transformations in the environment.
Curr Opin Biotechnol. 16(3):261-8.

Vetriani C. Chew YS. Miller SM. Yagi J. Coombs J. Lutz RA. Barkay T. (2005) Mercury adaptation among bacteria from a deep-sea hydrothermal vent. Appl Environ Microbiol. 71(1):220-6.

Schaefer JK. Yagi J. Reinfelder JR. Cardona T. Ellickson KM. Tel-Or S. Barkay T. Role of the bacterial organomercury lyase (MerB) in controlling methylmercury accumulation in mercury-contaminated natural waters. Environ Sci Technol. (2004) 38(16):4304-11.

Coombs. J.M.. and Barkay. T. (2004). Molecular evidence for the evolution of metal homeostasis genes by lateral gene transfer in bacteria from the deep terrestrial subsurface. Appl. Environ. Microbial. 70:1698-1707. Barkay. T.. Miller. S. and Summers. A.O. (2003). Bacterial mercury resistance from atoms to ecosystems. FEMS Microbiol. Rev. 27:355-384.

Benyehuda. G.. Coombs. J.. Ward. P.M.. Balkwill. D. and Barkay. T. (2003). Metal resistance among aerobic chemoorganotrophic bacterial isolates from the deep terrestrial subsurface. Can. J. microbial. 49:151-156.

Schaefer. J.K.. J. Letowski. and T. Barkay. (2002). mer-mediated resistance and volatilization of Hg(II) under anaerobic conditions. Geomicrobiol. J. 19:87-102.

de Lipthay. J.R. . J. Aamand . and T. Barkay. (2002). Expression of the tfdA gene in aquatic microbial communities during degradation of 2,4-dichlorophenoxyacetic acid. FEMS Microbiol. Ecol. 40:205-214.

Golding G.R.. C.A Kelly. R. Sparling. P.C. Loewen. J.W.M. Rudd. and T. Barkay. (2002). Demonstration of facilitated uptake of Hg(II) by Vibrio anguillarum and Escherichia coli under anaerobic and aerobic conditions. Limnol. Oceanog. 47:967-975.