This little bug may be the next best thing to immortality. Sheltered inside deeply buried salt crystals, the tiny Bacillus organism is thought to be 250 million years old, an astounding length of time for anything to keep on living.
Until now, the oldest known living thing was another microbe, 30-million-year-old yeast cells found in amber.
The discovery of life that could be 250 million years old is announced in today's issue of Nature by Russell Vreeland and William Rozensweig at West Chester University in Pennsylvania, and Dennis Powers, a consulting geologist in Anthony, Tex. DNA tests showed that the tiny organism is related to already-known bacteria called Bacillus marismortui and Virgibacillus pantothenticus.
"We believe," the scientists wrote, that the bacteria lived 250 million years ago and were "trapped inside a (salt) crystal at the time, and survived within the crystal until the present."
How the germs managed to live so long is not known, Vreeland and his colleagues said.
The microbe sample was found within a tiny fluid-filled cavity in salt dug from a deposit 1,850 feet underground near Carlsbad, N.M.
If the age is correct and not all scientists are convinced it will open new avenues for research. "It's giving us a new model to study how organisms can live that long," said microbiologist Raul Cano at Cal Poly State University in San Luis Obispo, Calif. For example, "What are the biological processes that determine long-term survival?"
Biologist John Parkes at the University of Bristol, England, wrote in a Nature commentary that there is also the question, "what energy source could last over such a long period?"
If the results are confirmed, Cano said, "it means we have access to much more ancient information than we thought" concerning "the history of life on this planet."
Cano added another caution. "Although I think it's feasible" such bacteria are really so old, "the trouble with all of these" experiments, "including mine, is the issue of contamination. So we need to have validation," someone else repeating the work. Tongue in cheek, Parkes added that "the next time you sprinkle salt on your food, think of what you might be eating."
It was Cano and his co-workers who isolated 30-million-year-old yeast cells in 1995. They proved the ancient yeast was alive and well by using it to brew beer.