Scientists Map Out Ulcer Bacterium's Genetic Blueprint.

New treatment, maybe vaccine, possible.

Sept. '97 - Associated Press - New York.

Scientists have created the complete genetic blueprint for the bacterium that causes stomach ulcers generating a wealth of knowledge about how the organism works and suggesting new ways to stop it. Just a few years ago, many experts didn't even believe that the bacterium Heliobacter pylori causes ulcers.

But the complete genetic map published today graphically illustrates how the bacterium not only survives, but thrives and wreaks havoc in a place as caustic as a vat of sulfuric acid the human stomach. "It's a pretty phenomenal little machine," said Craig Venter, director of the Institute for Genomic Research in Rockville, Md. "This tells us a lot about how it lives with a human host and how it might even cause disease."

About half of the world's population is thought to be infected with some strain of Heliobacter pylori, although not everybody who has it develops an ulcer. Infection by the bacterium can also lead to stomach cancer.

Bacteria Mimics Human Cells, Creates Alkaline Proteins.

Although some of the microbes biological tricks are already understood, the genetic map published in the British journal Nature reveals a multitude of new ones. The genes show how Heliobacter pylori sticks to the stomach wall, evades the human immune system by rapidly evolving to mimic human cells, and partially protects its own insides from stomach acid by creating especially alkaline proteins. Other genes show how Heliobacter pylori captures iron in an environment where acidity makes the nutrient extremely hard to come by. "Those kinds of things will be "important" in developing new treatments, said Loren Laine, a professor of medicine at the University of Southern California School of Medicine.

Possible Ulcer Vaccine.

Ulcers currently are treated with antibiotics as well as acid fighting drugs. But the genetic blueprint suggests that an ulcer vaccine or some other revolutionary treatment might be possible Venter said. The blueprints reveal 1590 genes in Heliobacter pylori, a tiny number compared with the nearly 100,000 human genes that are thought to exist. About 70 percent of the ulcer bacterium's genes have known functions. What the other or 30 percent do is any body's guess.

Bacteria Discovered 15 Years Ago.

When two Australian doctors discovered Heliobacter pylori 15 years ago, most doctors though ulcers resulted from stress and poor diet. Ulcers were treated with acid neutralizing drugs such as cimetidine, known commercially as Tagament, and ranitidine, or Zantac. The drugs remain popular because they are useful for stomach aliments other than ulcers. "There was never great evidence that diet and stress cause ulcers per se," Laine said. Nevertheless, Barry Marshall and Robin Warren were nearly laughed out of medical meetings when they began suggesting in 1983 that Heliobacter pylori might be the true cause of ulcers. But later research, including a shocking experiment in which Marshall swallowed Heliobacter pylori to demonstrate its sinister effects, convinced their colleagues.

Computers Help Create Genetic Maps.

The gene map was created by scientists from the Institute for Geonomic Research and colleagues in the United States and Sweden. They made it by blasting multiple copies of Heliobacter pylori's DNA into manageable bits, reading the small pieces and then putting them back together with computers.