RETURN OF THE LIVING DEAD?

By J. MADELEINE NASH

Through a teardrop of ancient amber -- fossilized tree sap as hard as plastic and as translucent as glass -- the scientists beheld their quarry: a small stingless bee that shared the earth with giant mastodons. With sterile instruments and gloved hands, microbiologist Raul Cano and his student Monica Borucki proceeded with an improbable experiment. First they delicately extracted the bee's diminutive digestive tract. Then they placed the tissues in nutrient-rich broth. Within a week the mixture turned cloudy, a sign that bacterial spores, dormant inside the bee for 25 million to 40 million years, had suddenly, miraculously surged back to life.

"As exciting as Jurassic Park," ventures Cano -- and maybe then some. For the stunt pulled off by scientists in Michael Crichton's novel and Steven Spielberg's movie -- retrieving strands of dinosaur DNA from amber, then using it to recreate monsters from the past -- belongs to the realm of fiction. By contrast, the article in which Cano and Borucki describe their achievement appeared last week in the pages of the journal Science. And while the Jurassic Park scientists cloned DNA to re-create approximations of dinosaurs and used frog DNA to fill in the genetic code, Cano's team claims to have revived the exact ancient organism, totally intact. The reactions from other scientists ranged from skepticism to astonishment and delight. "Wow!" exclaimed University of Chicago paleontologist David Jablonski. "It's marvelous to be able to reconstitute an organism from that long ago."

Already this bacterial Rip Van Winkle is being touted as a trailblazer for a new industry. Ambergene Corp. of San Carlos, California, a small biotech firm Cano helped start, claims to have used similar techniques to reanimate nearly 1,500 prehistoric microorganisms ranging from bacteria to yeast. Among the compounds these tiny creatures produce, Cano and his partners hope to identify unique drugs, industrial enzymes and natural pesticides. The company is already filing for patents on promising microbes.

The way Cano tells it, he did not set out to raise the dead but rather to study symbiosis, the mutually beneficial relationship that exists between complex organisms and their microbial fellow travelers. To that end, Cano, chairman of the microbiology department at California Polytechnic State University at San Luis Obispo, began working with insects fossilized in ancient amber and the microbes, presumably long dead, that their bodies contained. The problem, noted an exasperated Cano, was that live bacterial colonies kept popping up in the samples. And, oddly enough, the super-clean procedures followed by his laboratory appeared powerless to prevent the unwelcome intrusions.

Gradually an exciting hypothesis took shape. "I began to wonder," says Cano, "if I was not awakening ancient organisms that had been entombed in amber for millions of years." He knew scientists had revived hardy bacterial spores that were hundreds of years old, but they were youngsters compared with his alleged ancients.

If he's right, the secret may be amber. This semiprecious substance, observes Ward Wheeler, a molecular evolutionist at the American Museum of Natural History in New York City, provides a unique window on the history of life. Down through the ages, sudden flows of sticky, honey-colored tree resin have ensnared all manner of small life forms, including beetles, spiders, and even lizards and frogs. Moreover, as this natural polymer hardens, it becomes virtually airtight and waterproof. Not only are extinct organisms like Cano's bee preserved in exquisite anatomical detail, but biological molecules such as dna appear to be largely protected from deterioration. When something gets caught in amber, says Wheeler, it's like putting it into a time capsule.

But while amber seems to retard biochemical degradation, it does not prevent it entirely. "As remarkable as amber is," says David Grimaldi, a colleague of Wheeler's. "the DNA it contains is fragmented, which makes it astounding that viable spores could still be completely intact." And that is one reason why many scientists remain dubious about Cano's claims. Another ground for caution is the history of laboratory contamination that has haunted researchers working on ancient DNA. Though Cano took every precaution, laboratory samples can pick up extraneous material as easily as a jacket collects lint. Last year a team of British researchers disclosed that the DNA they thought had come from an extinct mammoth belonged to a lab technician.

According to University of Connecticut biochemist Peter Setlow, Cano is a long way from convincing critics "beyond a shadow of a doubt that the microbe he has isolated is an ancient one." Setlow agrees, however, that Cano has made the most compelling case possible. For instance, he has clearly established that his bacteria -- while related to Bacillus sphaericus, a living resident of apiarian digestive tracts -- are genetically distinct from known microbes. The catch is, something like 95% of the bacteria that populate today's world have not even been identified, much less analyzed by scientists.

Right or wrong, Cano's startling experiment could touch off an amber rush as scientists and companies alike try to get their hands on nuggets of the golden polymer. The leader of the pack is Ambergene, which has spent the past two years "mining" ancient amber from 15 locations around the globe, from Burma to the Baltic Sea. Already, says president and co-founder Robin Steele, Ambergene scientists have identified filamentous fungi similar to those that have produced a distinguished line of antibiotics. They have also brewed batches of ale with ancient yeast. Beer buff Cano was named official taster of the new brew, dubbed Jurassic Amber Ale (a slight misnomer since the yeast used to make it did not come from the Jurassic period, which ended 144 million years ago, but from more recent geological epochs.) Quipped Steele to Cano: "We're not going to drink this. We'll let you drink it and see if you survive the night."

Steele's wisecrack raises a serious question. Might some of these microorganisms be dangerous -- an ancient Andromeda Strain like the killer germ in another Crichton novel? Absolutely not, argues Steele, who stresses that Ambergene is very selective in the microbes it chooses to cultivate, carefully checking their genetic and ecological profiles to exclude possible pathogens. In addition, she notes, most of Ambergene's microbes are related to modern-day organisms of known habits. Still, experience with rabbits in Australia and kudzu in the Southern U.S. shows that seemingly innocuous plants and animals can misbehave when taken out of their original environments. And while most experts believe that the danger posed by ancient microbes is small, the idea that they have traveled from a time so distant is still unsettling to many people.

What few nonscientists realize is that nature is packed with all sorts of creatures that have changed little from ancient times. For that reason, some of Ambergene's potential competitors view the company's business strategy as something of a gimmick. There's hardly any need to prospect for ancient life forms in amber, says David Miller, vice president of research and development at EcoScience, based in Worcester, Massachusetts. Microbes that trace their roots back millions of years exist all over the place, even in suburban backyards. Moreover, as a source for discovering new, more effective drugs, amber is by no means a sure thing. Why not focus instead on compounds produced by the billions of living microbes still waiting to be identified?

Much more important than the commercial fate of Ambergene is the awesome scientific significance of what Cano may have done. If other laboratories confirm that microbes can survive over tens of millions of years, then humanity may gain new respect for the uncounted hordes of invisible organisms that dominate the world through the eons, even as bigger, supposedly smarter creatures come and go.

--Reported by David Bjerklie/New York

With reporting by David Bjerklie/New York