Researchers at the University of California, San Diego School of Medicine have discovered a widely distributed group of marine bacteria that produce compounds nearly identical to toxic man-made fire retardants.
The study is published in the June 29 online issue of Nature Chemical Biology.
A fire retardant is a substance that reduces flammability of fuels or delays their combustion. This includes chemical agents, but may also include substances that work by physical action, such as cooling the fuels, such as fire-fighting foams and fire-retardant gels. Fire retardants may also be coatings applied to an object, such as a spray retardant to prevent Christmas trees from burning. Fire retardants are commonly used in fire fighting.
Among the chemicals produced by the ocean-dwelling microbes, which have been found in habitats as diverse as sea grasses, marine sediments and corals, is a potent endocrine disruptor that mimics the human body’s most active thyroid hormone.
“We find it very surprising and a tad alarming that flame retardant-like chemicals are biologically synthesized by common bacteria in the marine environment,” said senior author Bradley Moore, PhD, a professor at the UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences and Scripps Institution of Oceanography.
The study is the first to isolate and identify bacteria that synthesize these compounds and whose presence may help explain the observed distribution pattern of PBDEs in the marine food chain.
In the study, the researchers identified a group of ten genes involved in the synthesis of more than 15 bromine-containing polyaromatic compounds, including some PBDEs. They have since conducted DNA sequencing analyses that will allow them to probe the ocean for other biological sources for these chemicals and to begin to assemble a complete picture of their human health risk.
“The next step is to look more broadly in the marine environment for the distribution of this gene signature and to document how these compounds are entering the food chain,” said Vinayak Agarwal, PhD, a postdoctoral researcher with the Scripps Center for Oceans and Human Health at UC San Diego.
Co-authors include Abrahim El Gamal, Kazuya Yamanaka, Roland Kersten, Dennis Poth, Michelle Schorn, and Eric Allen, all at UCSD.
Funding for this study was provided, in part, by the National Science Foundation (grant OCE-1313747) and National Institute of Environmental Health Sciences (grant P01-ES021921) through its Oceans and Human Health program.
Reference : www.sciencedaily.com