Astronauts
weren't the only living things aboard the space shuttle Endeavour that landed
safely this week – a precious payload of germs, grown and frozen in
zero-gravity, also returned to Earth.
Researchers
sent up sealed containers of Streptococcus pneumoniae bacteria,
the germs responsible for many diseases in patients with weakened immune
systems. David Niesel, a microbiologist at the University of Texas Medical Branch at Galveston, said the experiment will help scientists explore the risks
of getting sick in space.
"There's
a decline in people's immune function the longer they're in the space
environment, and it's been shown that other bacteria also alter their
properties in microgravity," Niesel said.
"They grow faster, they tend to be more virulent and resistant to
microbial treatment."
The S.
pneumoniae bacteria are normally harmless, but Niesel
said they never turn down opportunities to exploit weak immune systems
and turn into full-blown disease. For astronauts on long spaceflights, he said,
the germs could prove to
be dangerous.
"Strep
pneumoniae is a very potent pathogen in people who are immunosuppressed,"
he said. "It's the No. 1 cause of community-acquired pneumonia and a
leading mediator of bacteremia [bacterial blood infections] and meningitis."
Having no
well-equipped hospital in a small cabin millions of miles from Earth, Niesel
and his colleagues wanted to know how S. pneumoniae behaved in space, as
other
shuttle missions have explored with different germs.
To do so,
the researchers rocketed six refrigerated vials of bacteria into orbit, then
had the space
shuttle crew warm them up so that they could grow. After 15 hours and 30
minutes, the bacteria were chilled to -139 degrees Fahrenheit (-95 Celsius).
"That
locked the bacteria at whatever stage they were at ... so we get a picture of
what they were like in space at that time, which is the cool part," Niesel said. While the bacteria grew in space, Niesel and his team performed the same experiment on
the ground for comparison.
"We
should be able to see the differences that result when the bacteria see this
unique space environment," Niesel said of the two perfectly synced
experiments. "We think it will provide important information for
understanding the adaptation of bacteria to unique environments and begin to
answer the question of whether this species is a cause for concern for
long-duration space travelers."
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