Bacteria sent into space behave in mysterious ways

Colonies of bacteria grown aboard the Space Shuttle Atlantis behaved in ways never before observed on Earth, according to a new NASA-funded study from Rensselaer Polytechnic Institute, Troy, New York.

Recent findings provide important evidence of spaceflight's effect on the behavior of bacterial communities, and represent a key step toward understanding and mitigating the risk these bacteria may pose to astronauts during long-term space missions.

The research team, led by Rensselaer faculty member Cynthia Collins, sent the experiment into orbit aboard Space Shuttle Atlantis missions STS-132 on May 16, 2010 and STS-135 on July 8, 2011. Samples of the bacteria Pseudomonas aeruginosa were cultured for three days in artificial urine. The space-grown communities of bacteria, called biofilms, formed a "column-and-canopy" structure not previously observed on Earth. Additionally, biofilms grown during spaceflight had a greater number of live cells, more biomass, and were thicker than control biofilms grown under normal gravity conditions.

Biofilms are complex, three-dimensional microbial communities commonly found in nature. Most biofilms, including those found in the human body, are harmless. Some biofilms, however, have shown to be associated with disease.

"Biofilms were rampant on the Mir space station and continue to be a challenge on the ISS, but we still don't really know what role gravity plays in their growth and development," said Collins, assistant professor in the Department of Chemical and Biological Engineering at Rensselaer. "Our study offers the first evidence that spaceflight affects community-level behaviors of bacteria, and highlights the importance of understanding how both harmful and beneficial human-microbe interactions may be altered during spaceflight."