Fruit Flies Shed Light on Microgravity Impact on Astronauts During Prolonged Space Travel

Although it has been long known that zero gravity negatively affects muscle, bone mass, and the immune system, scientists have not been able to figure out exactly why or how it happens. Fruit flies may help them provide some revealing answers, specifically the damaging of the immune system during prolonged space travel.

Fruit flies were chosen for this experiment because their immune systems are similar to humans'. They are frequently used as a model in basic studies of this nature.

The team of researchers at the University of California at Davis and the University of Central Florida have been studying this topic since 2006. UC biologist Deborah Kimbrell kicked off the research project when she bred fruit flies in space aboard Space Shuttle Discovery. The findings of the study were published in this month's issue of PLOS One, and are believed to provide insight into how the human immune system may be affected in outer space.

After the flies were bred in space, they developed into adults over the 12-day mission and were analyzed after the mission concluded. Researchers revealed that the flies were more prone to fungal infections because the "system" the flies used for detecting and defending fungal infection was deactivated. A positive finding was that the "system" used to defend bacterial infection was not affected.

"Our study showed that a biochemical pathway needed to fight fungal infections is seriously compromised in the flies after space flight," said Laurence Von Kalm, a UCF biologist, in this EurekAlert! article. "More work will be needed to determine if similar effects occur in humans, but this gives us some clues. Getting a better understanding is particularly important, especially as we look to engage in long-term missions such as interplanetary space flights."

The research teams, as well as their other contributors at the Lawrence Berkeley National Laboratory, Laverlam International in Butte, Montana, the University of Nevada Las Vegas, and Rice University, plan to carry out further research with the fruit flies aboard the International Space Station.