Mastodon remains yield oldest life.

Scientists have isolated living, 11,000-year-old bacteria from what appear to be the intestinal contents of a mastodon. Partially preserved remains of the elephantine animal that harbored the microbes turned up more than a year ago as golf-course developers excavated a pond near Newark, Ohio.

Paleontologists recovered the mastodon's largely skeletal remains from portions of a peat bog that remained a chilly 45[degrees]F year-round. A three-foot cap of clay had sealed the site. "We think the conditions of the peat bog slowed down the growth of the bacteria, putting them into a state of suspended animation," says Gerald Goldstein, the Delaware, Ohio-based researcher who cultured them. "These could be the oldest living organisms ever found."

Goldstein, of Ohio Wesleyan University, obtained the microbes from a reddish-brown cylinder of malodorous material found near the mastodon's ribs. He determined that the bacteria did not come from the surrounding soil by searching for them in 12 soil samples from the excavation site. All 12 turned up negative; a second "blind" analysis at Lyle Laboratories in Columbus, Ohio, confirmed those results.

Investigation disclosed that the ancient bacteria were Enterobacter cloacae, a distant ancestor of microbes that aid digestion in many animals today. They were found amidst bits of vegetation -- such as swamp grass, leaves, and seeds -- that Goldstein says others have traced back to the last ice age, 11,000 years ago. Carbon dating indicates that wood embedded in the material also dates from the last ice age.

Goldstein presented his findings last week at the annual meeting of the American Society for Microbiology in Dallas. He is now working under the direction of the Licking County (Ohio) Archeology and Landmarks Society to isolate the ancient microbe's DNA for comparison with DNA isolated from modern bacteria.