In 2007, NASA discovered a brand new bacterium, named Tersicocus PhoenicisHidden inside two separate clean rooms – highly disinfected spacecraft manufacturing rooms – each located 2,500 miles (4,000 kilometers) apart. After years of not understanding how exactly it got there, a recently published paper in Environmental Microbiology finally provides an answer: It goes into hibernation, leading scientists to believe it is dead.
“It’s not dead. It was playing dead,” Madan Tirumalai, the study’s lead author and a microbiologist at the University of Houston, told National Geographic in October. “It’s just dormant.”
clean room is not clean
The reason spacecraft are built in special clean rooms is to prevent unexpected contamination during space missions – both for the astronauts and extraterrestrials. In the latter case, a rover searching for alien microbes would not want to carry earthly microbes.
For that purpose, scientists take some extreme measures, including, but not limited to, repeated heating, drying, chemical cleaning with microbe-killing gases, ultraviolet treatment, and radiation attacks. The microbiologist then performs another sterilization check to confirm that there is nothing living.
So even thinking like this is impressive-scary. T.phoenicis She not only survived this treatment but also managed to avoid sterilization tests. When NASA publicly announced the discovery of the bacterium in 2013, the agency clarified that the microbe posed no health risk. NASA scientists note that they will continue to study similar species, and that’s it.
Now you see them, now you don’t
Not content to leave it there, the team behind the new paper set out to learn more about the tiny germ and its apparent superpowers. For their experiment the team deprived T.phoenicis They were placed on sterile glass petri plates to dehydrate all nutrients to the maximum extent. They found that, within 48 hours of this “killing” process, the bacteria became inactive – silent and appearing to be dead based on their vital signs.
The bacteria remained intact for the next seven days, even after the researchers tried to wake them from dormancy by reintroducing food. But they certainly weren’t dead, the paper explained, because exposure to a certain protein “revived” their biological activities.
“The fact that this bacterium can deliberately suspend its metabolism makes survival on spacecraft surfaces or during deep space travel more plausible than previously thought,” Nils Eversh, a microbiologist at the University of Florida not involved in the study, explained in a university statement.
Did we accidentally contaminate Mars?
One of the clean rooms where scientists discovered T.phoenicis The first time was during preparations for NASA’s Phoenix Mars Lander, which successfully visited our neighboring planet. If these bacteria – and potentially others like them – are so good at hiding, is there any chance they reached Mars undetected?
The idea is scary to entertain, but experts believe the chances are low, because “[a]According to Eversh, anything directly exposed to the surface of Mars is unlikely to survive. There is also a possibility that T.phoenicis The paper explains that it has been developed specifically to adapt to spacecraft clean rooms, noting that it has not been found anywhere else in the world.
That said, the results also serve as alternative “cleaning” tips for cleanrooms. Now that scientists know how to bring the elusive bacteria out of dormancy, it could help enhance cleaning strategies for these spaces.
But most of all, this strange metabolic shutdown proves the incredible survival mechanisms of the smallest living forms known to us.
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