Posts Tagged ‘microbe’

Life As We Don’t Know It

Posted by Petra on 3rd December 2010 in Exogeology, Petra's Blog

What if someone found a creature that wasn’t like any other, a creature which wasn’t made of the same chemicals as anything else on Earth? Wouldn’t it ROCK to find something so different? That’s exactly what geomicrobiologist Felisa Wolfe-Simon discovered in California’s Mono Lake.

Extremophiles are organisms which can survive in extreme environments, such as intense heat or lack of light. An extremophile bacteria was found recently in California’s salty, alkaline Mono Lake. This extremophile, known as GFAJ-1, can survive high amounts of normally poisonous arsenic.

By weight, the human body contains 65% oxygen, 18.5% carbon, 9.5% hydrogen, 3.3% nitrogen, 1% phosphorus, 0.3% sulfur, and small amounts of several other elements. Even though there is so much oxygen in the human body, most of that is in the form of water, so we say that humans are carbon based. Most life on Earth has a similar composition. While GFAJ-1 is tolerant of arsenic, it’s not exactly an arsenic based life form. However, it does replace one of the basic ingredients for life. This unusual microbe is not only tolerant of arsenic, but is able to incorporate it into its cells.

Yesterday, NASA held a press conference explaining this surprising extremophile. Among the presenters was astrobiologist Pan Conrad, interviewee in Exogeology ROCKS! Episode 3.

Science fiction and real science have often considered replacing important elements with chemically similar ones, but until now, there haven’t been any real life examples. When given no phosphorus and a lot of arsenic, GFAJ-1 replaces the phosphorus in its body with arsenic and continues to grow. None of the bacteria have yet entirely gotten rid of the phosphorus originally in them, but I personally think that replacing most of it is exciting enough.

This discovery changes what we know about life. There are so many possible places a life form can survive on Earth alone. Maybe life on other worlds is more common than previously thought. I sure hope so.