Designer microbe shows promise for reducing mercury absorption from seafood

An engineered gut microbe can detoxify methylmercury, reducing the amount that passes into the brain and developing fetuses of mice fed a diet rich in fish, UCLA and UC San Diego's Scripps Institution of Oceanography scientists have discovered.

In the ocean, mercury transforms into a toxic form called methylmercury. It also biomagnifies, meaning that methylmercury concentrations in animal tissues increase up the food chain from algae-eaters to top predators like humans.

Researchers modified Bacteroides thetaiotaomicron, a naturally abundant bacterium in the human digestive tract, by inserting DNA-encoding mercury detoxification enzymes from a mercury-resistant soil bacterium.

They then tested pregnant mice and found lower levels of methylmercury in both maternal and fetal tissues, and lower signs of mercury toxicity in the fetal brain.

"By reducing dietary methylmercury in the intestine, the gut bacteria helped to eliminate it from the body before it could enter the maternal bloodstream and access the developing offspring," said first author and UCLA research scientist Kristie Yu.

Image source: Unsplash/CC0 Public Domain.