Designer microbe shows promise for reducing mercury absorption from seafood

Scientists inserted DNA-encoding methylmercury detoxification enzymes into the genome of an abundant human gut bacterium. The engineered bacterium detoxified methylmercury in the gut of mice and dramatically reduced the amount that reached other tissues, such as the brain and liver. Mice given an oral probiotic containing the engineered microbe and fed a diet high in bluefin tuna had much lower methylmercury levels than expected, suggesting that a probiotic might eventually make it safer for people to consume fish. Researchers performed the tests using pregnant mice and found lower levels of methylmercury in both maternal and fetal tissues, and lower signs of mercury toxicity in the fetal brain.