Bacteria in space take scientists back to Earth
NASA missions give insight into bacteria, which could lead to advanced vaccines to fight infection
Scientists aboard the space shuttle are gaining a better understanding of how infectious disease occurs in space and their research could someday improve astronaut health and provide new treatments for people on Earth.
The research involves Pseudomonas aeruginosa, the same bacterium that caused astronaut Fred Haise to become sick during the Apollo 13 mission to the moon in 1970.
The scientists believe their research could lead to advanced vaccines and therapies to fight infections. The findings are based on flight experiments with microbial pathogens on NASA shuttle missions to the International Space Station and appear in a recent edition of the journal Applied and Environmental Microbiology.
‘For the first time, we're able to see that two very different species of bacteria – Salmonella and Pseudomonas – share the same basic regulating mechanism, or master control switch, that micro-manages many of the microbes' responses to the spaceflight environment,’ said Cheryl Nickerson, associate professor at the Center for Infectious Diseases and Vaccinology, the Biodesign Institute at Arizona State University (ASU) in Tempe.
‘We have shown that spaceflight affects common regulators in both bacteria that invariably cause disease in healthy individuals [Salmonella] and those that cause disease only in people with compromised immune systems [Pseudomonas].’
During the initial study in 2006, two bacterial pathogens, Salmonella typhimurium and Pseudomonas aeruginosa, and one fungal pathogen, Candida albicans, were launched to the International Space Station aboard shuttles. They were allowed to grow in appropriately contained vessels for several days. Nickerson's team was the first to evaluate global gene and protein expression (how the bacteria react at the molecular level) and virulence changes in microbes in response to reduced gravity.
‘We discovered that aspects of the environment that microbes encountered during spaceflight appeared to mimic key conditions that pathogens normally encounter in our bodies during the natural course of infection, particularly in the respiratory system, gastrointestinal system and urogenital tract,’ Nickerson said.
The initial study and follow-on space experiments show that spaceflight creates a low fluid shear environment, where liquids exert little force as they flow over the surface of cells. This affects the molecular genetic regulators that can make microbes more infectious. These same regulators might function in a similar way to regulate microbial virulence during the course of infection in the human body.
‘We have now shown that spaceflight conditions modified molecular pathways that are known to be involved in the virulence of Pseudomonas aeruginosa,’ said Aurelie Crabbe, a researcher in Nickerson's lab at ASU and the lead author of the paper. ‘Future work will establish whether Pseudomonas also exhibits increased virulence following spaceflight as did Salmonella.’