(Press-News.org) Microbes that live in rice paddies, northern peat bogs and other previously unexpected environments are among the bacteria that can generate highly toxic methylmercury, researchers at Oak Ridge National Laboratory and the Smithsonian Environmental Research Center have learned.
This finding, published in Environmental Science and Technology, explains why deadly methylated mercury is produced in areas where the neurotoxin's presence has puzzled researchers for decades. Methylmercury — the most dangerous form of mercury — damages the brain and immune system and is especially harmful to developing embryos. Certain bacteria transform inorganic mercury into toxic methylmercury.
The discovery also validates the recent finding that two genes are essential for the methylation of mercury. Previously, only a narrow range of microbes were recognized as mercury methylators, said co-author Dwayne Elias of the Department of Energy laboratory's Biosciences Division.
"We showed for the first time that many different types of bacteria are able to produce this potent neurotoxin," Elias said. "The newly identified microbes include methane-producing organisms that live in rice paddies, anaerobic wastewater treatment plants, northern peat lands and possibly within our bodies."
Elias and colleagues are testing a bacterium from the human intestine that they predict will also methylate mercury. Other bacteria able to transform inorganic into methylmercury include those used in biological dechlorination and metal treatment systems. All of these organisms are anaerobic, which means they grow in habitats without oxygen, including aquatic sediments and wetland soils.
By identifying these organisms, the researchers may have explained why methylmercury is accumulating in unexpected places. The discovery may also help clarify how methylmercury is produced in the open ocean, according to co-author Cindy Gilmour of the Smithsonian Environmental Research Center. Gilmour noted that the newly identified fermentative bacteria may be common in the low oxygen zones of the ocean where methylmercury production occurs. Ocean fish are the primary source of methylmercury in human diets worldwide.
Gilmour and Elias believe this work will have far-reaching implications for understanding the global mercury cycle. Scientists can now use the mercury-methylating organisms and their genes as global biomarkers and develop detection techniques to assess and eventually predict the extent of methylmercury production in a given environment.
"Based on the substantially expanded diversity of organisms and environments for methylation, a number of important habitats deserve further attention," Gilmour said. "We now have a way to identify and track the abundance of mercury-methylating organisms within these environments, and we hope that the information can be used to devise strategies to minimize methylmercury production."
Mercury is a global pollutant, released to the atmosphere through coal burning and other industrial uses, and through natural processes. Most of the harm comes from methylmercury bioaccumulation, which is the buildup of the element in tissue that occurs when moving up the food chain.
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Other authors of the paper, titled "Mercury methylation by novel microbes from new environments," are Mircea Podar, Richard Hurt, Steven Brown, Anil Somenahally, Alex Johs and Kathryn Bailey of ORNL, Allyson Bullock of the Smithsonian Environmental Research Center and Andrew Graham of Grinnell College. The paper is available at http://pubs.acs.org/doi/abs/10.1021/es403075t. Funding was provided by DOE's Office of Science, the National Science Foundation and the Smithsonian Postdoctoral Fellowship Program.
UT-Battelle manages ORNL for DOE's Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov/.
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Alexandria, VA – One tornado can be damaging enough; severe weather systems that spawn hundreds of deadly tornadoes in super-outbreaks pose special challenges to the scientific and emergency management communities. Now, scientists have identified certain conditions in the Pacific Ocean that may lead to super-outbreaks over the U.S.' tornado alley.
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People ...
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The study, led by VIMS graduate student Gina Ralph, appeared recently ...
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The MODIS instrument aboard NASA's Terra satellite captured a visible image of Hurricane Humberto that showed it's eye was cloud-filled. Humberto was moving away from the Cape Verde Islands in the Atlantic Ocean.
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LOUISVILLE, Ky. - Does gum disease indicate future joint problems? Although researchers and clinicians have long known about an association between two prevalent chronic inflammatory diseases - periodontal disease and rheumatoid arthritis (RA) - the microbiological mechanisms have remained unclear.
In an article published today in PLOS Pathogens, University of Louisville School of Dentistry Oral Health and Systemic Diseases group researcher Jan Potempa, PhD, DSc, and an international team of scientists from the European Union's Gums and Joints project have uncovered how ...
TheSkyNet is celebrating its two year anniversary today with the official launch of a new research project, as well as a range of improvements and new features to make contributing to astronomical research at home more enjoyable, and even easier.
Launched on September 13th 2011, theSkyNet is a community computing project dedicated to astronomy, initiated by the International Centre of Radio Astronomy Research (ICRAR) in Perth, Western Australia.
By using the idle processing power of thousands of computers connected to the Internet, theSkyNet simulates a powerful single ...
Sexually transmitted infection researchers potentially have reached a milestone in vaccine treatment for genital herpes, according to a report to be presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Denver, Colo., on today, Sept. 12.
Kenneth H. Fife, M.D., is the principal investigator for the IU School of Medicine clinical study of the vaccine for herpes simplex virus type 2 called GEN-003. According to an interim analysis, the experimental protein subunit vaccine made by Genocea Biosciences of Cambridge, Mass., effectively reduces ...
