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Airdate: Jul 29, 2010
Scientist: Prof. Derek Lovley

Geobacter - Strain 121

Geobacter - Strain 121
A recently discovered group of microorganisms have the ability to clean up contaminated groundwater.

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Scientists used to think that no organism could survive at temperatures above 121 degrees centigrade. And then they discovered a microbe which was soon dubbed "strain 121," and the way we think about life on earth was changed forever. I'm Jim Metzner and this is the Pulse of the Planet.

"Strain 121 is a microorganism that can grow at very high temps, using iron in a way that is unusual for most life forms. This organism uses iron much the way that we humans use oxygen to gain our energy."

Derek Lovely is a professor of microbiology at the University of Amherst.

"Strain 121 lives in environments known as hydrothermal vents. These are areas at the bottom of the ocean where there's hot water gushing from deeper in the earth to the surface. This water typicially contains a lot of hydrogen. These fluids also contain a lot of iron. Strain 121 combines hydrogen and iron in order to gain energy to support its growth. "

"For a human, a hydrothermal vent would be extremely toxic. The temperatures can range up easily to 350 degrees centrigrade. But it's an environment that strain 121 enjoys. It's adapted itself to grow at high temperatures. It can grow at a temperature higher than any other life form has ever been known to exist."

For the record, 121 degrees centrigrade is about 250 degrees Farenheit. How important is it that an organism can survive at this temperature?

"The ability to grow at 121 degrees centigade is significant because this is the temp that's been used for over a hundred years to sterilize equipment for medical purposes, for microbiological purposes. This is the temperature that was always thought to kill all life forms. Strain 121 thrives at that temperature."

In our next program, we'll hear how the discovery of strain 121 could effect our search for life on other planets and our understanding of how life evolved on earth. Pulse of the Planet is presented by the National Science Foundation. I'm Jim Metzner.