There is no walk in the park a year in space. Ask American astronaut Scott Kelly, who spent a year on the International Space Station (ISS) in 2015.
Her DNA, telomeres, and gut microbiome were altered by her long stay in space, she lost bone density, and still had pain in her legs three months later.
But the whole other thing is to survive in the naked state outside the protection of the ISS, where UV radiation, vacuum, extreme fluctuations in temperature and microgravity are all close dangers.
Therefore, it is a feat that a species of bacterium was first found in a meat can, Dinococcus radioiodurans, He lived and kicked even after living on a specially designed platform outside the ISS pressure module for a year.
Researchers have been investigating these powerful microbes for some time; Back in 2015, an international team set up the Tenpopo Mission, outside the Japanese experimental module Kibo, to test hard bacterial species.
Now, d. Radiodurans Passed with flying colors.
Bacterial cells were dehydrated, sent to the ISS, and placed in an exposed facility, a platform that constantly exposed the space environment; In this case, the cells were behind a glass window that blocked UV light at a wavelength of less than 190 nanometers.
The team from Austria, Japan and Germany wrote in their new paper that “the results presented in this study may raise awareness of planetary safety concerns, for example, the Martian atmosphere which absorbs UV radiation below 190-200 nm,” And the German team has written in their new paper.
“To mimic this situation, our experimental setup on the ISS includes a silicon dioxide glass window.”
This is not the longest time D radiodurans In these conditions – last August, we wrote about a bacterium sample that has a full three years left.
But the team wasn’t trying for a world record, instead trying to figure out what they were making. D. Radiodurans Just so good to survive in this extreme situation.
SEM images of D. Radiodurans Control (left), and after contact with LO (right). (Tt et al., Microbiome, 2020)
So, after a year of radiation, freezing and boiling temperatures and no gravity, the researchers retrieved the spacefaring bacteria back to Earth, redeemed the control they had spent years on the Earth and Low Earth Orbit (LEO) sample, and compared their results.
The survival rate for the Leo bacteria was much lower than for the control version, but even if the germs living bacteria are slightly different from their Earth-bound brethren, it is doing just fine.
The team found that LEO bacteria were covered with small lumps or vesicles on the surface, several repair mechanisms were provoked, and some proteins and mRNAs became more abundant.
The team isn’t exactly sure why the vesicles (which you can see in the picture above) are designed for, but they do have some ideas.
“Post-recovery vesticulation after LEO exposure can respond to rapid stress, which will increase cell survival by withdrawing stress products,” the team wrote.
“In addition, nutrient acquisition in the outer membrane vesicles, DNA transfer, transport of toxins and quorum-sensing molecules may be important proteins for activation of immune mechanisms after contact with space.”
This kind of study helps us understand whether bacteria can survive in another world, and perhaps even the journey between them, which we take with humans and microbes, will become even more important in our solar system than our moon begins to travel. , And one day maybe even beyond that.
“This investigation helps us understand the mechanisms and processes by which life exists outside of Earth, expanding our knowledge of how to survive and adapt to the hostile environment of outer space.”
“The results indicate that it exists D. Radiodurans Longer is possible due to its efficient nuclear response system in Lyo and suggests that even longer journeys can be achieved for organisms with such capabilities. “
Research has been published in Microbiome.
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