Researchers determined that a common marine bacterium produces a compound similar to man-made toxic flame-retardants.
These chemicals can be found in diverse habitats such as sea grasses and corals. They are an endocrine disruptor that mimics the body's most active thyroid hormone, the University of California-San Diego said.
The study was published in the June 29 online issue of Nature Chemical Biology.
"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 compounds are called polybrominated diphenyl ethers (PBDEs), they are used in foam, textiles and electronics to change the temperature at which these items will burn.
Researchers have long-recognized the "presence, persistence and ability" of these chemicals to accumulate in the fatty tissues of marine animals; in the past scientists thought PBDEs were anthropogenic in origin as a result of pollution. Recent research suggests the presence of the chemicals comes from both microbial and anthropogenic sources.
The recent study is the first to pinpoint the bacteria that synthesizes these compounds, which could help better-explain the distribution of PBDEs in the marine food chain.
The team identified a group of 10 genes responsible for the synthesis of 15 bromine-containing polyaromatic compounds. They have also performed a DNA sequencing analysis that will allow them to look for other biological sources of these chemicals and assess the risk they impose on human health.
"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.
