Monday, August 27, 2007

Ancient bacteria could point to life on Mars

Finding: Harsh conditions ok for the survival of Bacteria
Ancient bacteria are able to survive nearly half a million years in harsh, frozen conditions, researchers said on Monday in a study that adds to arguments that permafrost environments on Mars could harbor life. The findings also represent the oldest independently authenticated DNA to date obtained from living cells and could offer clues to better understand ageing.

How long can it live?
"When it can live half a million years on Earth it makes it very promising it could survive on Mars for a very long time," Willerslev said. "Permafrost would be an excellent place to look for life on Mars."

Where did the bacteria live?
The international team, which also included researchers from the United States, Canada, Russia and Sweden, tested the microbes living up to 10 meters deep in permafrost collected from Northern Canada, the Yukon, Siberia and Antarctica.

Repair operations
When a cell dies, its DNA fragments into pieces but the samples studied were all very long strands -- evidence the cells were able to continuously repair genetic material and remain alive.

These cells are active cells repairing DNA to deal with continuous degradation of the genomes. It is the same thing with humans.

What is the mechanism of repair
The scientists do not yet know the mechanism driving the continuous repair but the cells survived by eating nutrients like nitrogen and phosphate lodged in the permafrost.
This is interesting because the temperature on Mars is much colder with more stable temperatures, representing an even better environment to sustain this kind of life, he added.
While most scientists think our neighbor in the solar system is lifeless, the discovery of microbes on Earth that can exist in environments previously thought too hostile has fuelled debate over extraterrestrial life.

Researchers had known these microbes could survive for a long time without food but until now there was little agreement on how long they could live. Knowing this, and eventually pinpointing the key to this longevity, may also help scientists better understand the ageing process, he added.

It is interesting to see why some cells can survive for a very long time, that can be a key for understanding ageing.

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