A probiotic containing the protective bugs may offer a potential therapy for preventing the disease, researchers say.

We each have trillions of microbial hitchhikers living in and on our bodies. These symbiotic organisms have co-evolved with us over millions of years and increasingly are being seen as essential to our health and well being, researchers said at the 2012 Abelson Symposium at AAAS.

The effort to understand the human microbiome—the full complement of 4 million or more genes contained in the microbial community we each harbor—is one of the hottest fields of scientific research.

Two new reports show that a bacterium, known as GFAJ-1, requires small amounts of phosphate to grow—and that it cannot substitute arsenic for phosphorus to survive, as a 2010 report in Science had suggested.

The GFAJ-1 bacterium, which was discovered in the arsenic-rich sediments of California’s Mono Lake, became the center of a controversy last year after Felisa Wolfe-Simon of the NASA Astrobiology Institute and the U.S. Geological Survey and colleagues reported that the microorganism could incorporate arsenic into its DNA when phosphorus wasn’t available.

Chemically speaking, you become a different person when you run, according to new research in Science Translational Medicine that maps how chemicals change in the blood during exercise.

The study, by Gregory Lewis and colleagues from Massachusetts General Hospital, identified chemical switches in the body that are distinctly different during exercise in more-fit people versus less-people.