University Of Minnesota Research May Help Fight Yeast Infections

Fostering Sexual Reproduction Makes Genetic Work Easier

Tom Majeski

Staff Writer

At first glance, it sounds a bit frivolous. Scientists at the University of Minnesota have found a way to manipulate a common variety of yeast so that it sexually mates.

But the discovery, reported in today's edition of the journal Science, could lead to more effective treatments for widespread and potentially fatal infections, the scientists say.

``This is a nice basic tool that we've been looking for for 20 years,'' said Beatrice Magee, a research scientist in the university's genetics, cell biology and development department and senior author of the study.

The yeast, called Candida albicans, lives in the bodies of about 60 percent of all humans. ``It's not a real problem unless something happens,'' Magee said. Then the yeast can infect either the skin or the blood of patients.

For instance, women who take antibiotics can experience a chemical imbalance in their systems and develop vaginal yeast infections. Infants can come down with thrush, another form of yeast infection. AIDS patients can develop an esophageal yeast infection that prevents them from swallowing.

In addition, patients with compromised immune systems -- those undergoing chemotherapy, taking immunosuppressive drugs after an organ transplant or battling AIDS -- can develop a devastating and often deadly yeast infection in their blood.

Yeast infections also can be picked up in hospitals, particularly by patients who undergo catheterizations.

``The problem is that there aren't very many effective drugs'' to treat the infections, Magee said. One of the best drugs produces a lot of unwanted side effects while a common anti-fungal treatment keeps the yeast under control but cannot kill it completely. This, in turn, can permit the organism to become resistant to the drug, she said.

To develop better treatments, pharmaceutical companies need better targets -- a unique gene or a molecule in the cell wall. Once a target is found, company scientists can design drugs to zero in on the target and kill the yeast without harming human cells.

Unfortunately, Candida albicans multiplies by simple cell division, which gives scientists little if any opportunity to experiment genetically with the organism. To get around that roadblock, Magee and her husband, Paul ``Pete'' Magee, a professor in the genetics, cell biology and development department, found a way to maneuver the organism in a way that prompts it to mate sexually.

``What we found is that there are ways to manipulate the organism so that we can make it have sex,'' Beatrice Magee said. This achievement -- the first step in a long discovery process -- will allow scientists to experiment with the organism's genes and, in the process, eventually pinpoint key enzymes and molecules in cell walls involved in the yeast's life cycle.

``We're trying to find basic mechanisms to study the organism,'' Magee said. ``The better we can work with it, the more likely we are to find these drug targets.''

Magee said she and her husband will continue their basic research into the yeast's life cycle and probably will not become involved in developing more effective drug therapies.

``Drug companies are taking our information to make the perfect drug, which is OK with us because we can't do everything,'' Magee said.

Tom Majeski, who covers medical news, can be reached at tmajeski@pioneerpress.com or (651) 228-5583.

Copyright © 2000 PioneerPlanet / St. Paul (Minnesota) Pioneer Press.

This article posted July 23, 2000.