A Better Way to Study Microbes

Oct 14, 11:07 AM

Current Headlines: By Ron Seely, The Wisconsin State Journal

Oct. 14--Seven years ago, Jo Handelsman 's mother died after her body became resistant to the antibiotics that were holding her illness at bay.

Today, working in her lab on the UW-Madison campus, hardly a day goes by that Handelsman doesn 't think of her mother 's death and the frustrating and ultimately failed struggle of doctors to find drugs that would keep her alive.

Handelsman is a molecular biologist who studies microbes in soil and in other interesting places, such as the stomachs of gypsy moths. Microbes are microscopic life forms, agents of chemical change that drive photosynthesis and, in the human body, help digest food and fight off infection. It is from soil microbes that we have derived most of our antibiotics.

As the Howard Hughes Medical Institute Professor in the Department of Bacteriology, Handelsman heads a laboratory that is pioneering a new way of searching for useful microbes, primarily those that might be commandeered as antibiotics to replace drugs that are fast becoming useless because of the growing resistance of many infectious illnesses.

Seven years removed from that difficult year when her mother 's health failed, Handelsman has entered upon a time when the potential for the discovery of new antibiotics is greater than it has ever been.

Handelsman, a slight and intensely energetic woman, becomes as enthusiastic when she talks about microbes and the work she directs in labs on the sixth floor of the UW-Madison 's new $121-million Microbial Sciences Building.

So prevalent and crucial are microbes to life on Earth, Handelsman points out, that without them we would not be able to breathe, plants would not be able to convert light to energy and, worst of all for Wisconsin, we wouldn 't have cheese.

Trillions of microbes live and work in the human body, 1,000 species alone in the human gut.

The problem to which Handelsman has applied most of her energy is the difficulty of scanning the billions of microbes around us to find those which might be useful. In the past, scientists have been forced to study microbes one at a time, culturing them in the lab to find out their capabilities.

But Handelsman has come up with a new approach called metagenomics, which she has applied mostly to soil microbes. Using this technique, Handelsman collects the DNA from an entire community of microbes instead of an individual microbe and then studies the genes looking for their function. Looking for an antibiotic-producing gene, for example, the researchers noticed one gene with a brown coloration instead of the more usual white. Studying it further, they discovered that it produced an antibiotic.

Such an approach holds the promise of studying billions more microbes much more efficiently than before. Some say it offers the greatest opportunity, perhaps since the discovery of the microscope, to better understand the natural world.

"This is the most exciting time in science I 've experienced, ' ' said Handelsman.

OTHER DISCOVERIES NEWS:

Boggy lakes may increase global warming

Are boggy northern Wisconsin lakes contributing to global climate change?

Researchers at the UW-Madison are finding that such lakes, which are scattered across Wisconsin's North Woods, break down organic matter in a way that may indeed create more carbon dioxide, which contributes to the warming of the climate.

"There's a lot of concern that, as the climate changes, more carbon will be turned into carbon dioxide in these kinds of lakes," said Katherine McMahon, a UW-Madison assistant professor of civil and environmental engineering.

Specifically, McMahon and other researchers are trying better to understand how the lakes break down organic matter such as fallen leaves, tree limbs and other debris and convert it to carbon dioxide.

The research, paid for with $1.5 million from the National Science Foundation, may enable researchers to better predict carbon or nutrient flow. And it may also result in such carbon-dioxide producing lakes being given more weight in the computer models that scientists use to study climate change.

Canary grass control

More effective methods to control reed canary grass, an invasive plant that chokes more than a half-million acres of the state's wetlands, may be discovered in research under way at the UW Arboretum.

The research is being conducted by more than 60 students in UW-Madison's general ecology class.

The students will continue work started by Joy Zedler, a botany professor and Arboretum research director. For the past decade, Zedler has tried numerous tactics to fight the invasive grass, including restoration of the prairie where it is most prominent and treatment with a grass-specific herbicide.

The work had mixed results though it provided important clues about what might work to stem the advance of the grass.

The student researchers will test a combination of burning, herbicide treatments and seeding of native plants.

The work is important because reed canary grass is spreading rapidly through the state's wetlands, crowding out and destroying native species. When the native plants go, important habitats for native wildlife are destroyed, according to Brad Herrick, Arboretum ecologist.

-- Ron Seely

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