Space Research May Help Defeat Salmonella On Earth
Food-borne pathogens, like Salmonella, are pretty smart. According to researchers, the bugs “employ a startling array of techniques to skillfully outwit the body’s defense mechanisms and produce illness. Through their expression of genes—the fundamental building blocks of cellular physiology—the microbes ingeniously adapt to varied environments, continuously modifying their disease-causing potential or virulence.” Thus, if food-borne pathogens are outwitting us, how can we outwit them?
Research into the disease-causing potential of Salmonella from two recent NASA space missions may hold promise for improving ways to fight food-borne infections here at home. The studies were conducted because of NASA’s concern that astronauts might be more susceptible to food poisoning in space due to weakened immune systems – an unfortunate, but well-documented effect of microgravity. According to Julie Robinson, program scientist for the International Space Station at NASA's Johnson Space Center in Houston, "the research opens up new areas for investigations that may improve food treatment, develop new therapies and vaccines to combat food poisoning in humans, and protect astronauts in orbit from infectious disease."
Here at home, the studies are good news. Salmonella is a leading cause of food poisoning and related illnesses. According to the CDC, approximately 40,000 cases of Salmonella infections are reported in the United States each year.
The recent Salmonella experiments were flown on shuttle missions to the International Space Station. The experiments allowed researchers to identify a molecular "switch" that controlled Salmonella's response to spaceflight in ways not observed on Earth. The results showed that the space environment causes a short-term alteration in Salmonella virulence – the bacteria in space actually became more virulent than those on Earth.
Interestingly, researchers also discovered that a mechanical force known as "fluid shear," the motion that cells sense as fluid passes over their surface, has a dramatic effect on Salmonella's disease-causing potential. Lower fluid shear conditions, as it turns out, are found both in microgravity and in our intestines. In other words, space travel appears to have "tricked" the bacteria into behaving as though they were in the low fluid shear environment of the intestine, essentially turning on a switch inside the microbe that increases virulence.
The experiments have also helped researchers identify ways to “counter” the virulence effect. A research team led by Cheryl Nickerson, of the Biodesign Institute at Arizona State University in Tempe, found that by adjusting the ion content of the bacteria's environment, you can turn off the increased virulence caused by spaceflight. According to Nickerson, “no one had previously looked at a mechanical force like fluid shear on the disease-causing properties of a microorganism during the infection process." Armed with this discovery, researchers hope that additional research may lead to new interventions, therapies and vaccines for Salmonella and other pathogens.
Nickerson also hopes the benefits of space research will extend beyond infectious pathogens like Salmonella, eventually inspiring new clinical approaches to cancer, aging, bone and muscle wasting diseases, among other earthly afflictions.
Congrats to NASA -- and Nickerson -- for a job well done.
