Washington State Magazine

Fall 2004

Fall 2004

In This Issue...


A Little Bronze—Strategically Placed :: Although it might be better known for wine and wheat, Walla Walla is also home to one of the most prominent fine-art foundries. For a short time this fall, 32 sculptures cast at the Walla Walla Foundry will reside at 13 locations across the Pullman campus.

{ WEB EXCLUSIVE–Gallery: A little bronze—Strategically placed Photos by George Bedirian. }

Tracking Trucks :: One heavily-loaded eighteen-wheeler can cause the same highway damage as 7,000 cars. Ken Casavant and other transportation economists are trying to make sense of the effects of trucks on the state's highways.

{ WEB EXCLUSIVE–Gallery: Truck Drivin' Man Photos by Rajah Bose of the romance of trucking. }

No Hollow Promise :: Half of all new public-school teachers quit within five years, and the best and brightest are often the first to go. Worse, the attrition rate at high-needs schools is even greater. The CO-TEACH program at WSU decided to change this situation.

An Exquisite Scar :: The beauty of the channeled scablands comes from unimaginable catastrophe.

{ WEB EXCLUSIVE–Gallery: Images of Washington's Channeled Scabland Photos by Robert Hubner. }

Carlton Lewis—Still Building Bridges :: The early 1970s were tumultuous years on the WSU campus. As student body president, Carlton Lewis helped keep things from boiling over. Now he presides over Devcorp Consulting Corporation, a project management company with teeth.



:: SEASONS/SPORTS:Big little man Bill Tomaras


Cover: Edison Elementary teacher Jacqui Fisher '00 with students Dillon Skedd, Alejandrina Carreño, Jorge Herrera, Kylee Martinez. Photograph by Laurence Chen.

Brenda Schroeder and Michael Kahn in a nitrogen-producing pea field.


Brenda Schroeder and Michael Kahn in a nitrogen-producing pea field. Robert Hubner

A library of rhizobial genes

by | © Washington State University

All living things require nitrogen for building many important molecules, including DNA, RNA, and proteins. Animals get their nitrogen through other animals and, ultimately, through plants. However, even though the atmosphere is 78-percent nitrogen, it is too stable for plants to use directly. It must be "fixed." Non-leguminous plants depend on nitrogen that has built up in the soil by leguminous plants, through other less dependable processes, or through nitrogen fertilizer. The more enterprising legumes get their nitrogen through a symbiotic relationship with bacteria called rhizobia.

The rhizobia split the paired nitrogen molecules, then convert each to ammonia, which is more chemically reactive and thus usable to plants.

Understanding this beneficial relationship is the research focus in the laboratory of Michael Kahn, a professor in Washington State University's School of Molecular Biosciences, Center for Integrated Biotechnology, and Institute of Biological Chemistry.

Kahn and his team have nearly completed a monumental step in understanding nitrogen fixation. Under the direction of his postdoctoral assistant, Brenda Schroeder, graduate and undergraduate WSU students have cloned over 6,000 of one nitrogen-fixing bacterium's genes in less than one year. This means they've made copies of each gene that codes for proteins, isolated the gene copies, and put each into its own small piece of DNA, creating a library of all the genes in the species S. meleloti. Scientists can now use the gene library to begin identifying exactly what each fragment does. "The premise of the project was to share the clones and send out copies for further research," says Schroeder. "With this library, researchers can work with the whole genome and figure out which genes are turned on under what circumstances."

Their work adds a "predictive" aspect to DNA sequencing, according to Schroeder. When scientists find the DNA sequence of an organism's entire genome, as they have for humans and fruit flies, they usually don't know what most of it means. Kahn's lab has taken the first step in putting biological meaning to the nitrogen-fixing bacteria's DNA sequence.

"I can't say enough about the dedication, hard work, and diligence of the team," says Schroeder. The achievement stands out. For example, the genes of the intensively-studied bacteria E. coli have not been entirely cloned.

At this point, the research findings and applications stemming from the creation of this gene library can only be imagined. Perhaps scientists could identify the group of genes that convert free nitrogen into fixed nitrogen, and then put extra copies of those genes into new bacteria. The new bacteria could be introduced to soil in lieu of fertilizer, not only increasing the size of your tomatoes, but perhaps also helping to ensure the world's food supply.

Categories: Agriculture, Biological sciences | Tags: Nitrogen, Genetics, Bacteria

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