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Bacteria awakened after 250 million years

By
LIDIA WASOWICZ, UPI Science Writer

SAN FRANCISCO, Oct. 19 -- In a scene reminiscent of "Jurassic Park," scientists have awakened bacteria from a 250-million-year sleep.

Even before the finding was corroborated, the report of the oldest -- by far -- living organism ever discovered is fueling speculation of spores making inter-planetary odysseys across the galaxy and raising the specter of immortality.

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Like many of their kind, bacteria can form protective spores, a tough, compacted form in which nearly all metabolism ceases. From a spore encased inside rock salt before the dinosaurs evolved, the scientists revived what they think is a microbe that lived at a time when Earth's land mass was a single giant continent and the first reptiles were making their debut -- some 100 million years before the period evoked in "Jurassic Park."

The report, published in the British journal Nature,was written by biologists Russell Vreeland and William Rosenzweig of West Chester University in Pennsylvania and geologist Dennis Powers of Anthony, Texas.

If true, the bacterium they described easily disposes of previous longevity limits set by other organisms brought back from apparent suspended animation.

While fossils of long-departed prehistoric life forms are not uncommon -- some even dating back more than 3 billion years -- there has been only one other confirmed find of ancient living bacteria.

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Initially met with skepticism but subsequently widely accepted, that find was made in 1997 by California microbiologist Raul Cano who detected spores in the belly of a bee sealed in amber 25 million to 40 million years ago.

That's about 10 times younger than the newly found microbe, which passed the eons in a tiny, fluid-filled bubble in a stamp-sized salt crystal embedded in the wall of a giant cavern 1,850 feet underground, about 30 miles east of Carlsbad, N.M.

"This is a highly significant difference since it is at least 25 percent of the time needed for spores to survive in crystals on Mars," Vreeland told United Press International. "It even makes it possible for spores to survive inside meteorites moving between solar systems."

"The fact that something can survive this long is rather incredible," Vreeland said.

"The potential implications are profound," R. John Parkes, professor of earth sciences at the University of Bristol in England who wrote an accompanying commentary, told UPI.

"For instance, can spores effectively be immortal? Where else on Earth and to what depths might ancient bacterial life be lurking? And, given this startling example of bacterial durability, do spores in rocks even provide a mechanism for life to be transported between planets by 'panspermia,' as has been proposed?"

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The concept of panspermia -- spores of living organisms transported from planet to planet across the galaxy and over the ages -- is cited by some as a possible source of life on Earth.

Vreeland said he expected the report to raise more than a few eyebrows, "but that is part of science and why we have all of the supporting data to back our claim."

Some, indeed, have met the news with skepticism, pointing out there is no direct way to prove the microbe is as old as the authors claim and noting the possibility the sample may have leaked or been contaminated.

"We are very certain of the age and stability of the formation from which we obtained the crystal, we are very certain that the crystal used was high quality and had not been opened prior to our sampling. Also, we are very confidant that our sterilization techniques were adequate to eliminate contaminants," Vreeland said.

"In relation to reliability, we have repeated our sterilization experiments several times with different test organisms. Several different dating techniques used on the formation have consistently yielded a Permian age (250 million years ago), and the crystallographic techniques used to see if the crystals were primary have been widely accepted."

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"Given the care that Vreeland et. al. took...their results are the best evidence yet for extremely long-term survival of microorganisms," Parkes said.

While just exactly how the bacteria survived in suspended animation over the eons remains a mystery, the hardy spores are well known to resist heat, desication, or drying, and other elements that would contribute to their disintegration, scientists said.

Bacteria can thrive where few other lifeforms dare to tread: in searing springs, deep freeze ice cores, radioactive waste and toxic dumps. They can make their home where there is no light or oxygen, deep underwater or deep underground.

"Many people are asking the same question of modern spore formers, i.e. how are they able to survive," Vreeland said.

The bacteria have modern-day relatives, Virgibacillus pantothenticus and Bacillus marismortui, found in soil, water and dust near the Dead Sea and regarded as harmless, Rosenzweig said.

Since one in every 1,000 or so bacteria do more harm than good, odds are the recovered microbes served some noble purpose, perhaps biodegrading wastes and old dead materials, scientists speculated.

"This bacterium shows no sign of being harmful to anything, but then we haven't done some sort of extensive testing involving trying to infect things which we wouldn't want to do anyway," Vreeland said.

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What the scientists are testing is the nature of the organism's biochemistry and cell structures.

"We are learning more about them every day in (those) terms," Vreeland said. "I believe their function is primarily that of most other bacteria, waste breakdown and nutrient recycling."

"Now, we can ask biological questions that can't be asked of fossils," Vreeland said, noting the oldest living thing ever found persisted unchanged as Earth saw the drifting of continents, upthrusting of mountains, drying of ancient oceans and entire species come and go.

"These organisms can help us learn about the state of biology 250 million years ago, they can help us understand how rapidly evolution occurs in bacteria, otherwise known as calibrate evolutionary clocks."

The investigators sifted through 220 pounds of samples from an airshaft in the cavern deep beneath Earth's surface at the Waste Isolation Pilot Plant of the U.S. Department of Energy.

The researchers view the environment surrounding the bacteria's entombment as a key to its survival.

"It was stable, prevented intrusion of harmful radiation -- UV light -- and oxidizing gas (oxygen as in the browning of an apple)," Vreeland said. "Geologists have made a variety of inferences; now we have a living thing to examine as well."

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The isolated Bacillus bacteria like to live in salt water. So Vreeland's team suggested that the microbeds formed spores around which the salt water then crystallized, trapping the bacteria in a tiny brine pocket, as the sea evaporated all those eons ago.

The site, excavated by the Department of Energy, was opened in 1999 to store high-level radioactive waste from the U.S. nuclear weapons program. The cavern is within a thick rock salt layer called the Permian Salado Formation, which had been dated at some 250 million years old by Paul Renne and team from the Berkeley Geochronology Center, an independent research facility.

The investigators hope to start looking into even older formations, such as one near Vancouver, British Columbia, that may date back a billion years.

"You have to keep pushing to see how long life can last," Vreeland said.NEWLN:

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