Gravity masks some potentially significant factors in the spread of bacterial borne diseases, according to investigators who outlined research in the field under way aboard the International Space Station before the annual meeting of the American Association for the Advancement of Science in Boston this week.
NASA astronaut Tom Marshburn works with a capillary flow experiment aboard the International Space Station. Photo Credit: NASA
Two of those are the movement of fluid over the sensitive surface areas of bacterial cells, a force known as fluid shear, and the discovery of Hfq, an evolutionarily conserved protein that acts an a global regulator of gene responses to spaceflight conditions.
The findings have the potential to lead to treatments for terrestrial illnesses well beyond those caused by Salmonella, a particular focus of space research over the last few years, according to Cheryl Nickerson, a microbiologist from Arizona State University's Biodesign Institute and a principal investigator.
In the U. S. alone, more than 40,000 cases of food poisoning linked to Salmonella are reported annually. The actual number, though, is likely much higher. The economic impact of productive work time lost due to food poisoning is estimated at more than $2 billion annually, underscoring the benefits of an effective vaccine.
The Biodesign Institute provided a statement on the ISS research activities in conjunction with Nickerson's presentation.
Salmonella studies from a 2006 space shuttle mission revealed that Salmonella bacteria show a significant increase in their virulence in the absence of gravity. The fluid shear present in the weightless environment may trick the microbes into responding as though they were in the human digestive system.
Follow on studies by Nickerson and her collaborators examined the post-spaceflight state of the Salmonella microbe's circular chromosome. They detected alterations in 167 genes and 73 proteins cultured in the absence of gravity. The altered genes included those associated with virulence. One third of the altered gene pairs were under the control of Hfq.
Additional research identified Hfq as a regulator in spaceflight-induced responses to other pathogens, including Pseudomonas aeruginosa, a common bacterium responsible for sometimes fatal infections in humans.
Working in collaboration with the Biodesign Institute's Center for Infectious Diseases and Vaccinology, Anderson's team is hopeful the unveiling of subtle cellular mechanism will lead to new treatments.
Researchers are preparing a new investigation in the field that should reach the space station later this year. PHOENIX will feature the use of nematodes, or small round worms, as subjects. Investigators will follow along as the worms are infected with pathogens in the weightless realm.