Along
with the six-member crew, space shuttle Atlantis,
scheduled for liftoff this Sunday, will be carrying some very small passengers
to the International
Space Station: three common microbes.
Scientists
plan to study the ability of Salmonella
typhimurium, Pseudomonas aeruginosa and Candida albicans, all microbes
identified as potential threats to the health of space crews, to adapt to
microgravity and to infect astronauts in the space environment.
Such
understanding will help to evaluate risks for longer-duration missions when
astronauts will be far from the medical luxuries of Earth.
"Our
microbe experiment will be the first to investigate the effects of spaceflight
on the disease-causing potential and gene expression profiles of
disease-causing microbes," said the experiment's principal investigator Cheryl
A. Nickerson, a researcher at the Biodesign Institute at the Arizona State University.
Less
immunity
Studies
have shown that spaceflight weakens the immune
system of humans and animals.
Additionally, with longer missions where water and air will be recycled and
contamination becomes a risk, astronauts
could be even more vulnerable to infections caused by these
microbes:
- Salmonella
typhimurium, are
rod shaped bacteria known to cause Salmonellosis. Symptoms of this
infectious disease include nausea,
diarrhea,
and fever. The illness can become much worse for those with weakened
immune systems.
- Pseudomonas
aeruginosa, a
potential water contaminant on spacecrafts, was responsible for a
crewmember's urinary tract infection aboard the Apollo 13 mission.
- Candida
albicans, is a
naturally occurring yeast in the human body and can overgrow if microbial
communities are altered in space causing yeast infections and oral
diseases.
"Spaceflight
has been shown to induce key changes in both human and microbial cells that are
directly relevant to infectious disease, including changes in immune system
function, microbial growth rates, antibiotic resistance, and cell surface
properties," said Nickerson. "It is exciting to think of the potential
benefit that research in space holds for translation to the clinical bedside by
providing a better understanding of how pathogens cause disease that will lead
to new ways to treat, prevent and diagnose infectious disease."
Raising microbes
The
microbes will be flown in self-contained chambers activated by the astronauts.
A crewmember can turn a hand crank to release the growth media onto the culture
media.
The
microbes will be allowed to grow for 24 hours in ambient temperatures before
the astronauts stop the procedure.
"This
experiment requires only the minimum of space shuttle resources, but it has
the potential to greatly advance infectious disease research in space and on
the ground," said the experiment's project manager Steven Hing, from NASA Ames
Research Center. Because the microbes will be contained in hardware that provides three
levels of containment, they will pose no threat of exposure to the astronauts.
Once the
shuttle lands on Earth, some of the
samples will be examined for disease causing potential while the rest will be
frozen. Differences in growth rates, genetic changes, and their ability
to infect will be studied. This knowledge can advance
the treatment of infectious diseases in space and on Earth.
advertisement
advertisement
