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Arsenic: Research Studies Impact On Metabolism, Life on Other Planets

Potentially deadly arsenic might provide clues to changes in our metabolism as well as what life might look like on other planets.
Dr. John Stolz, director of Duquesne’s Center for Environmental Research and Education and a professor of microbiology, has found a possible link between arsenic and the mechanisms that impacts how food is metabolized in preliminary data.

Stolz, with the help of graduate student Rishu Dheeris, is focusing on changes in the microbial community in the digestive system as part of a larger study examining changes in cardiovascular and liver functions after short-term exposure to low levels of arsenic in drinking water.

The preliminary data reveal that the arsenic creates havoc for the microbes in the gut, disrupting their organization and metabolism. The balance of the microbes in the digestive systems of mice used in the study shifted dramatically. Firmicutes, microorganisms that are extremely efficient at metabolizing food, transform into spores and become inactive. Bacteroides, which are less efficient at processing food, become more prevalent.

Having more—and active—bacteroides could contribute to having a less efficient metabolic system—and, as a result, a leaner body. One possible implication of the research, Stolz said, is that by influencing the type of microbes in the digestive system, people might be able to change their metabolism and, as a result, their weight.

“It might help to explain why, when two people eat the same diet, one gains weight while the other doesn’t,” Stolz said.

This finding also might lead scientists to a path that could improve the overweight person’s metabolism.

This study is funded by a $244,920, two-year stimulus grant from the National Institutes of Environmental Health Sciences, an arm of the National Institutes of Health. It is being conducted as part of larger study led by Dr. Aaron Barchowsky at the University of Pittsburgh’s School of Public Health.

Another arsenic-related study by Stolz, sponsored by the National Aeronautics and Space Administration (NASA), is examining what life could look like in oxygen-deprived areas—possibly other planets. With the renewal of his NASA grant ($128,000 for four years), Stolz is studying volcanic Mono Lake in California, which is about three times saltier than sea water and about 80 times more alkaline than the ocean. This extreme yet accessible ecosystem is rich in arsenic.

While people worry about potentially toxic effects of arsenic, Stolz has found that some microbes actually thrive on arsenic. “We can actually create a whole ecology for a planet based on arsenic,” said Stolz, who is collaborating on this project with Ron Oremland at the U.S. Geological Survey.

Arsenic, Stolz said, may have been the key to life on early Earth, when oxygen was not plentiful—and may be the critical element for life on oxygen-deprived planets. “The premise of the grant is to look at the extreme environments on Earth, like Mono Lake, to see what life could possibly be like on other planets and their moons,” he said.

Duquesne University

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