A5018779020- Mercury impact and mitigation studies
- Microbial Community Ecology and Physiology
- Water Treatment and Disinfection
- Heavy Metal Exposure and Toxicity
- Heavy metals in environment
- Analytical chemistry methods development
- Chromium effects and bioremediation
- Methane Hydrates and Related Phenomena
- Bacteriophages and microbial interactions
- Geochemistry and Elemental Analysis
- Microbial Fuel Cells and Bioremediation
- Microbial bioremediation and biosurfactants
- bioluminescence and chemiluminescence research
- Radioactive element chemistry and processing
- Toxic Organic Pollutants Impact
- Pharmaceutical and Antibiotic Environmental Impacts
- Marine animal studies overview
- Genomics and Phylogenetic Studies
- Isotope Analysis in Ecology
- Environmental Toxicology and Ecotoxicology
- Indigenous Studies and Ecology
- Chemical Analysis and Environmental Impact
- Environmental DNA in Biodiversity Studies
- Animal Genetics and Reproduction
- Advanced biosensing and bioanalysis techniques
Rutgers, The State University of New Jersey
2013-2022
Rutgers Sexual and Reproductive Health and Rights
2005-2020
Aarhus University
2010-2013
Pacific Northwest National Laboratory
2009
University of Michigan–Ann Arbor
2007-2008
Princeton University
2007
University of Manitoba
2007
Fisheries and Oceans Canada
2007
McGill University
2007
Université de Montréal
2007
Biosensors for the detection of pollutants in environment can complement analytical methods by distinguishing bioavailable from inert, unavailable forms contaminants. By using fusions well-understood Tn21 mercury resistance operon (mer) with promoterless luxCDABE Vibrio fischeri, we have constructed and tested three biosensors Hg(II). Bioluminescence specified pRB28, carrying merRo/pT, pOS14, mediating active transport Hg(II), pOS15, containing an intact mer operon, was measured rich minimal...
Mercury methylation and demethylation rates were measured in periphyton biofilms growing on submerged plants from a shallow fluvial lake located along the St. Lawrence River (Quebec, Canada). Incubations performed situ within macrophytes beds using low-level spikes of (199)HgO Me(200)Hg stable isotopes as tracers. To determine which microbial guilds are playing role these processes, methylation/demethylation experiments absence presence different metabolic inhibitors: chloramphenicol...
Mercuric mercury (Hg[II]) is a highly toxic and mobile element that likely to have had pronounced adverse effect on biology since Earth's oxygenation ~2.4 Gy ago due its high affinity for protein sulfhydryl groups, which upon binding destabilizes structure decreases enzyme activity, resulting in decreased organismal fitness. The central the microbial detoxification system mercuric reductase (MerA) protein, catalyzes reduction of Hg2+ volatile Hg0. In addition MerA, mer operons encode...
Hypotheses that dissolved organic carbon (DOC) and electrochemical charge affect the rate of methylmercury [CH3Hg(I)] synthesis by modulating availability ionic mercury [Hg(II)] to bacteria were tested using a mer-lux bioindicator (O. Selifonova, R. Burlage, T. Barkay, Appl. Environ. Microbiol. 59:3083-3090, 1993). A decline in Hg(II)-dependent light production was observed presence increasing concentrations DOC, this more pronounced at pH 7 than 5, suggesting DOC is factor controlling...
ABSTRACT Alasan, a high-molecular-weight bioemulsifier complex of an anionic polysaccharide and proteins that is produced by Acinetobacter radioresistens KA53 (S. Navon-Venezia, Z. Zosim, A. Gottlieb, R. Legmann, S. Carmeli, E. Ron, Rosenberg, Appl. Environ. Microbiol. 61:3240–3244, 1995), enhanced the aqueous solubility biodegradation rates polyaromatic hydrocarbons (PAHs). In presence 500 μg alasan ml −1 , apparent solubilities phenanthrene, fluoranthene, pyrene were increased 6.6-, 25.7-,...
Mercury (Hg) undergoes systematic stable isotopic fractionation; therefore, signatures of Hg may provide a new tool to track sources, sinks, and dominant chemical transformation pathways in the environment. We investigated fractionation by Hg(II) resistant (HgR) bacteria expressing mercuric reductase (MerA) enzyme. The composition both reactant added growth medium volatilized product (Hg(0)) was measured using cold vapor generation multiple collector inductively coupled plasma mass...
The curious phenomenon of similar levels methylmercury (MeHg) accumulation in fish from contaminated and pristine environments may be explained by the observation that proportion total mercury (HgT) present as MeHg is inversely related to HgT natural waters. We hypothesize this "MeHg paradox" quantitative induction bacterial enzymes are encoded resistance (mer) operon, organomercury lyase (MerB), mercuric reductase (MerA) inorganic Hg (Hg[II]). tested hypothesis two ecosystems New Jersey:...
The dissimilatory metal reducing bacterium (DMRB) Shewanella oneidensis MR-1 reduces ionic mercury (Hg[II]) to elemental (Hg[0]) by an activity not related the MerA mercuric reductase. In S. oneidensis, this is constitutive and effective at Hg(II) concentrations too low induce mer operon functions. Reduction of required presence electron donors acceptors. occurred with oxygen or fumarate, but had highest rate when ferric oxyhydroxide was used as a terminal acceptor. Geobacter sulfurreducens...
We investigated microbial methylmercury (CH3Hg) production in sediments from the South River (SR), VA, an ecosystem contaminated with industrial mercury (Hg). Potential Hg methylation rates samples collected at nine sites were low late spring and significantly higher summer. Demethylation of 14CH3Hg was dominated by 14CH4 spring, but switched to producing mostly 14CO2 Fine-grained originating erosion river banks had highest CH3Hg concentrations potential hot spots for both demethylation...
Mercury (Hg) is a highly toxic element, and its contamination of groundwater presents significant threat to terrestrial ecosystems. Understanding the geochemical processes that mediate mercury transformations in subsurface necessary predict fate transport. In this study, we investigated redox transformation mercuric Hg (Hg[II]) presence Fe(II)/Fe(III) mixed valence iron oxide mineral magnetite. Kinetic spectroscopic experiments were performed elucidate reaction rates mechanisms. The...
Mercury (Hg) stable isotope fractionation has recently been developed as a tool in biogeochemistry. In this study, the extent of Hg during reduction ionic mercury [Hg(II)] by two Hg(II)-resistant strains, Bacillus cereus 5 and thermophile Anoxybacillus sp. FB9 [which actively detoxify Hg(II) mer system] Hg(II)-sensitive metal-reducing anaerobe, Shewanella oneidensis MR-1 reduces at low concentrations], was investigated. all cases, barring suppression that is likely due to lower...
Microbial methylation and demethylation are two competing processes controlling the net production bioaccumulation of neurotoxic methylmercury (MeHg) in natural ecosystems. Although mercury (Hg) by anaerobic microorganisms aerobic Hg-resistant bacteria have both been extensively studied, little attention has given to MeHg degradation bacteria, particularly iron-reducing bacterium Geobacter bemidjiensis Bem. Here we report, for first time, that strain G. Bem can mediate a suite Hg...
ABSTRACT Methylmercury (MeHg), a neurotoxic substance that accumulates in aquatic food chains and poses risk to human health, is synthesized by anaerobic microorganisms the environment. To date, mercury (Hg) methylation has been attributed sulfate- iron-reducing bacteria (SRB IRB, respectively). Here we report methanogen, Methanospirillum hungatei JF-1, methylated Hg sulfide-free medium at comparable rates, but with higher yields, than those observed for some SRB IRB. Phylogenetic analyses...
The biological production of monomethylmercury (MeHg) in soils and sediments is an important factor controlling mercury (Hg) accumulation aquatic terrestrial food webs. In this study we examined the fractionation Hg stable isotopes during methylation nongrowing cultures anaerobic bacteria Geobacter sulfurreducens PCA Desulfovibrio desulfuricans ND132. Both organisms showed mass-dependent, but no mass-independent methylation. Despite differences rates, two had similar factors (αr/p = 1.0009...