Microorganisms appear to pop up in Earth's harshest conditions, from the tropical deserts to the icy polar regions. And if that's the case, why doesn't it mean that life on other planets will do the same? So it's quite a feat that this bacterium called Deinococcus radiodurans, a bacterium species first discovered in a can of meat, proved itself to be alive and still kicking a year after experts placed a can of meat outside the International Space Station (ISS).
Researchers have researched these mighty microbes for a while; back in 2015, an international team set up the Tanpopo project to test hardy bacterial species outside of the Japanese Experimental Module Kibo.
D. Finally, the radiodurans passed the test with flying colors.
How did they conduct the test?
The bacterial cells were dehydrated, sent to the ISS and placed continuously exposed to the space environment in the Exposed Facility, a platform; in this case, the cells were behind a glass window blocking UV light at wavelengths of less than 190 nanometers.
"Results presented in this study may increase awareness regarding planetary protection concerns on, for instance, the Martian atmosphere which absorbs UV radiation below 190-200 nm," the team from Austria, Japan, and Germany wrote in their new paper.
It's not D's longest time. In these cases, radiodurans were preserved-a sample of the bacterium was left up there for three whole years.
But the team didn't try to set a world record, but instead wanted to discover what makes D. In these harsh environments, radiodurans are just so good at surviving.
So the researchers got the spacefaring bacteria back down to Earth after a year of radiation, freezing and boiling temperatures, and no gravity, then rehydrated both a control that had spent the year on Earth and the Low-Earth Orbit (LEO) sample, and compared their findings.
Compared to the control version, the survival rate was much lower for the LEO bacteria, but the bacteria that survived seemed to be doing well, even though they were a little different from their Earth-bound brethren.
The team found that tiny bumps or vesicles on the surface were covered with the LEO bacteria, a number of repair mechanisms had been activated, and certain proteins and mRNAs had become more abundant.
How did that come about?
The team isn't entirely sure why the vesicles were shaped (which you can see in the image above), but they have a few thoughts.
"Intensified vesiculation after recovery from LEO exposure can serve as a quick stress response, which augments cell survival by withdrawing stress products," the team wrote.
This kind of research allows us to understand whether other worlds can withstand bacteria, and maybe even the path between them which will become more and more important as humans and the germs we carry with us continue to migrate further into the solar system than our earth, and maybe even beyond that one day.
This kind of research allows us to understand whether other worlds can withstand bacteria, and maybe even the path between them which will become more and more important as humans and the germs we carry with us continue to migrate further into the solar system than our earth, and maybe even beyond that one day.
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