Washington, March 11 : Experimental payload aboard the space shuttle Endeavor will continue studies on the ability of germs to become more infectious due to spaceflight and thus adversely affect the health of astronauts.
The new experiment, called "Microbial Drug Resistance Virulence" is part of the STS-123 space shuttle Endeavor mission, which will continue the research studies of Cheryl Nickerson, project leader and scientist in the institute's Center for Infectious Diseases and Vaccinology.
Last fall, Nickerson completed a multi-institutional study that showed for the first time that microbes could be affected by spaceflight, making them more infectious pathogens. The results were from a payload flown onboard space shuttle Atlantis in 2006.
Spaceflight not only altered bacterial gene expression but also increased the ability of these organisms to cause disease, or virulence, and did so in novel ways.
Compared to identical bacteria that remained on earth, the space-traveling Salmonella, a leading cause of food-borne illness, had changed expression of 167 genes. In addition, bacteria that were flown in space were almost three times as likely to cause disease when compared with control bacteria grown on the ground.
Now, Nickerson's research team will have an extraordinarily rare opportunity to fly a repeat experiment of their NASA payload to confirm their earlier results.
"We saw unique bacterial responses in flight and these responses are giving us new information about how Salmonella causes disease," said Nickerson.
"NASA is giving us the opportunity to independently replicate the virulence studies of Salmonella typhimurium from our last shuttle experiment and to do a follow-up experiment to test our hypothesis about new ways this bacteria causes disease in this unique environment," she added.
In the new experimental wrinkle, the team will test a hypothesis that may lead to decreasing or preventing the risk for infectious diseases to astronauts.
The experiment will determine if the modulation of different ion (mineral) concentrations may be used as a novel way to counteract or block the spaceflight-associated increase in the disease-causing potential that was seen in Salmonella.
In addition, the project will support three other independent investigators to determine the effect of spaceflight on the gene expression and virulence potential of other model microorganisms.
"We now have a wide variety of supportive evidence that the unique low fluid shear culture environment the bacteria encounter in space is relevant to what pathogens encounter in our body, including during Salmonella infection in the gut, and there may be a common regulatory theme governing the microbial responses," said Nickerson.