Sleeper cell: Could Conan the Bacterium survive on Mars?

Even among the bacterial superheroes, this one stands out.

PREMIUM

Conan the Bacterium has a great origin story, complete with humble beginnings. The multicelled, bright orange species first came to the attention of scientists in cow and elephant dung, when it refused to die in food sterilisation processes. It then survived escalating bombardments by harmful radiation waves and exposure to extreme temperatures.

Officially known as Deinococcus radiodurans — Latin for “strange berry that withstands radiation” — its nickname is a reference to the 1955 Robert E Howard series of stories, which also inspired the 1982 Arnold Schwarzenegger film, Conan the Barbarian.

That is a tale about a powerful being who lives by no rules but his own. Conan the Bacterium would appear to do the same. It has even survived in outer space.

In 2015, Japanese researchers took pellets of dried Deinococcus radiodurans bacteria out into space, and stuck them to the exterior of the International Space Station, sandwiched between aluminium plates. Three years later, they found the bacteria still alive.

In a study based on this experiment, published in 2020 in the journal Frontiers in Microbiology, the Japanese researchers concluded that panspermia, or the theory that microbes could pass from one planet to another, was plausible.

Now, a paper by researchers at Northwestern University, published in the journal Astrobiology in October, offers more detail on just how hardy this bacteria is.

In a laboratory setting, Deinococcus radiodurans was tested with desiccation (the removal of moisture), freezing, and simulated cosmic radiation, all of which was meant to simulate the hostile environment of Mars.

Buried just 10 cm below the Martian surface, the findings suggest, Conan the Bacterium could have survived for about 1.5 million years. Buried 10 metres below the surface, the pumpkin-coloured bacteria could survive 280 million years. The tests have proven, researchers say, that some terrestrial microorganisms could potentially survive on Mars.

The experiments also revealed some of what enables Deinococcus radiodurans to survive extreme conditions as it does. One secret revealed is a unique cellular mechanism for DNA repair and protection.

Deinococcus radiodurans is now being studied for possible applications in space exploration and astrobiology, genetic engineering and biotechnology, and even food preservation.