NASA’s Arsenic Thingy: What It Is, Why It Matters

In case you missed it, NASA announced Dec. 2 that researchers have discovered the first organism that can survive and reproduce using arsenic – an extremely toxic element. First things first: it is NOT extraterrestrial and they did NOT find it. They sort of created it. That said, it’s still incredibly cool.

In short, a NASA-funded research team trained bacteria to use arsenic, instead of phosphorus, for its biological functions. It did this by “starving” the bacteria of phosphorus. Arsenic is toxic because it mimics phosphorus very well, but doesn’t have the same chemical properties that phosphorus does in a biological context. So, essentially, arsenic slots into places where phosphorus should go and disrupts biological functions. Arsenic is bad.

Here’s what we know for sure (or as sure as we can be): these bacteria (a strain of Gammaproteobacteria called GFAJ-1) are incorporating arsenic into their cellular makeup and thriving. GJAJ-1 were culled from the arsenic-rich environment of California’s Mono Lake, so were already adapted to high levels of arsenic before the researchers began their phosphorus-starvation project (the project would likely not have worked with just any old bacteria).

“This tells us an organism is capable of dealing what is normally an extremely toxic environment, and expands our ideas of which environments are capable of supporting life,” says Dr. Amy Grunden, a microbiology researcher at NC State. “Conservatively, this is the first demonstration of an organism being able to deal with what should be very toxic levels of arsenic.

“The big implication,” Grunden explains, “is that this may direct people to look for life [on other worlds] in areas they otherwise would have overlooked as being too toxic. Our chances of finding life are thereby increased.”

But the research holds the potential to be an even bigger deal, because it remains unclear as to whether arsenic is replacing phosphate bonds in the bacteria’s DNA – and phosphates are an essential component in the DNA of all known life (so far).

If the researchers can ultimately show that arsenic is being incorporated into the DNA, “that would be incredibly exciting,” Grunden says. “It would show that there are substitutes for the elements that we thought were essential for creating life. That would open up whole vistas of different chemistries that may support life.”

And Grunden’s not alone in her conclusions. “Research results like these indicate that there are many different pathways that life can take,” says Dr. Chris Brown, a research administrator at NC State, and director of the North Carolina Space Grant, who developed the Space Biology lab at Kennedy Space Center in the early 1990s. “Coupled with the large number of habitable planets, in my opinion there is a good chance that life exists elsewhere in the universe.”

So, while they are not aliens, these bacteria are really no less amazing.