Bacteria Frozen for 32,000 Years Comes to Life

HUNTSVILLE, Alabama, February 24, 2005 (ENS) - An undiscovered species of bacteria that was frozen in the Alaskan ice for 32,000 years came to life in a laboratory when thawed out, NASA scientists reported Wednesday.

The new organism was found in an ice core taken five years ago from a research tunnel near Fox, Alaska, just north of Fairbanks by NASA astrobiologist Dr. Richard Hoover.

The bacterium - the first fully described, validated species ever found alive in ancient ice - is NASAís latest discovery of a "psychrotolerant" organism, one capable of enduring deep cold that resumes normal activity when temperatures rise.

NASA and its partner organizations study the life forms found in environmentally extremes zones to help prepare robotic probes and, eventually, human explorers to search other planets for signs of life.

In 1999 and 2000, Hoover, a researcher at NASA's Marshall Space Flight Center in Huntsville, took ice samples from the U.S. Armyís Cold Regions Research and Engineering Laboratory (CRREL) tunnel. The research site was excavated in the mid-1960s to enable scientists to study permafrost in preparation for construction of the Trans-Alaska Oil Pipeline.


Dr. Richard Hoover, a NASA astrobiologist, and Dr. Elena Pikuta, a University of Alabama scientist, lead a team of researchers who discovered the new bacterium. (Photo courtesy NASA)
When Hoover returned with the samples to Alabama, he and collaborator, microbiologist Dr. Elena Pikuta of the University of Alabama in Huntsville, studied the samples at the National Space Science and Technology Center, the research consortium operated by NASA and Alabama universities.

They found the samples contained anaerobic bacteria that grew on sugars and proteins in total absence of oxygen.

The bacteria had frozen near the end of the Pleistocene Age, which extended from about 1.8 million years ago to 11,000 years ago. It is named after its origin in that Age - Carnobacterium pleistocenium.

"Astrobiologists ask, 'Is life strictly terrestrial in origin, or is it a cosmic imperative, an undeniable, universal biological truth?' That possibility is central to our desire to explore the universe," Hoover said.

"The existence of microorganisms in these harsh environments suggests - but does not promise - that we might one day discover similar life forms in the glaciers or permafrost of Mars or in the ice crust and oceans of Jupiterís moon Europa."

There are some 7,000 described species of bacteria, though many more are believed to exist. The vast majority are harmless to humans, Hoover says. Less than one percent of all known species are dangerous.


Carnobacterium pleistocenium, active once again after 32,000 years on ice. (Photo courtesy NASA)
Many bacteria, Hoover observed, are valuable to human life - culturing wine, dairy products and other foods; assisting in the biological extraction of gold and other precious metals from ore wastes; and aiding production of valuable proteins and lifesaving drugs.

Carnobacterium pleistocenium could offer new medical breakthroughs. "The enzymes and proteins it possesses, which give it the ability to spring to life after such long periods of dormancy, might hold the key to long-term, cryogenic - or very low temperature - storage of living cells, tissues and perhaps even complex life forms," Hoover said.

"Life is far more diverse, and far more resistant to conditions we consider hostile, than was thought possible only a decade or two ago," he adds. "Studying these organisms helps us understand that life may be far more widespread in the cosmos than we previously imagined."

Living cultures of the new bacterium have been deposited in the American Type Culture Collection, in the Microbial Collection at the Pasteur Institute in Paris, and in the Japan Collection of Microorganisms in Saitama, Japan.

Hoover and Pikuta have discovered other microscopic forms of life in extreme environments such as the bacterium Spirochaeta americana in California's Mono Lake, and ancient, still unnamed microorganisms at the South Pole.