Researchers have found that some extraordinarily resistant microorganisms can withstand the drastic influence of outer space: galactic cosmic and solar ultraviolet (UV) radiation, extreme vacuum, temperature fluctuations, desiccation, freezing, and microgravity.
After one year of exposure to low Earth orbit (LEO) outside the International Space Station, researchers found that the extremophilic bacterium Deinococcus radiodurans escaped morphological damage and produced numerous outer membrane vesicles.
A multifaceted protein and genomic responses were initiated to alleviate cell stress, helping the bacteria to repair DNA damage and defend against reactive oxygen species, said the study published in the journal Microbiome.
Processes underlying transport and energy status were altered in response to space exposure.
"These investigations help us to understand the mechanisms and processes through which life can exist beyond Earth, expanding our knowledge how to survive and adapt in the hostile environment of outer space," said corresponding author of the study Tetyana Milojevic from the University of Vienna in Austria.
"The results suggest that survival of D. radiodurans in LEO (low Earth orbit) for a longer period is possible due to its efficient molecular response system and indicate that even longer, farther journeys are achievable for organisms with such capabilities" Milojevic said.
The bacterium D. radiodurans used a primordial stress molecule polyamine putrescine as a reactive oxygen species scavenger during regeneration from space exposure, said the study.
