[meteorite-list] Ancient bacteria could point to life on Mars

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue, 28 Aug 2007 00:44:21 -0500
Message-ID: <042101c7e936$7c5883f0$2850e146_at_ATARIENGINE>

Hi, All,

    With the Phoenix Lander headed for Martian
permafrost territory, this is suddenly more interesting.

http://www.reuters.com/article/topNews/idUSL2733009920070827?feedType=RSS&feedName=topNews&sp=true

Ancient bacteria could point to life on Mars: Study

LONDON (Reuters) - 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, said Eske Willerslev, a researcher at the
University of Copenhagen who led the study.

"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."

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.

When a cell dies, its DNA fragments into pieces but
the samples the researchers studied were all very long
strands -- evidence the cells were able to continuously
repair genetic material and remain alive, said Willerslev,
whose findings were published in the Proceedings of
the Academy of Sciences.

"These cells are active cells repairing DNA to deal
with continuous degradation of the genomes, which
is the genetic material that is key to life," he said in
a telephone interview. "It is the same thing with humans."

The scientists do not yet know the mechanism driving
the continuous repair but Willerslev said 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, Willerslev said.

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," he said. "That can be a key
for understanding ageing."
Received on Tue 28 Aug 2007 01:44:21 AM PDT