DURHAM, N.C. -- Duke University researchers studying primitive worms have found that as many as 31 different genes may react to the metal cadmium, an industrial additive and contaminant that is toxic to humans and animals. Twenty-two are unknown genes with no previous links to cadmium exposure.

The findings, by assistant professor Jonathan Freedman and doctoral student Vivian Hsiu-Chuan Liao of Duke's Nicholas School of Environment, are published in the Nov. 27 issue of the Journal of Biological Chemistry. Their work was funded by the Nicholas School's Marine/Freshwater Biomedical Center.

"The important thing is that these new genes serve as starting points for studies in higher organisms," Freedman said in an interview. "They can serve as a model to start investigating how cadmium can be a carcinogen in humans. We can define brand new pathways in terms of toxicology that have never been seen before.

"They can be used to define brand new regulatory pathways in organisms. For example, how does cadmium get picked up by a cell and then turn on all these different genes? These genes can serve as tools to define those pathways."

Another option is to engineer living "biomarkers" that could be used to monitor for cadmium contamination by testing for responses by certain genes, he added.

Cadmium is ranked seventh on the U.S. Environmental Protection Agency's and Agency for Toxic Substances' "Top 20 Hazardous Substances Priority List," the authors' article notes. Cadmium is used in metal coatings, nickel-cadmium batteries and pigments, and is released into the atmosphere from ore smelting and fossil fuel combustion.

Humans exposed to cadmium continually accumulate the metal in their livers, lungs and kidneys, and cadmium exposure has been linked to kidney damage, respiratory diseases and neurological disorders. It is also known to cause various cancers in rodents, and population studies sugge
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Contact: Monte Basgall
monte@dukenews.duke.edu
919-681-8057
Duke University Medical Center
24-Nov-1998