Study offers important new insights into the behavior of organisms

by William G. Gilroy

A new study by researchers from the University of Notre Dame that offers insights into the behavior of organisms could have important potential implications for the field of metabolic engineering.p. The paper by Albert-Laszlo Barabasi, Emil T. Hofman Professor of Physics, and Eivind Almaas, a postdoctoral physics researcher, is the cover article in today’s (Feb. 26) edition of the prestigious journal Nature.

Barabasi and Almaas analyzed computer models of the Escherichia coli (E. coli) bacterium’s metabolic pathways. They chose to study the E. coli bacterium because it has been extensively researched by biologists and also offers a good model for understanding the behavior in cells of other organisms.

The researchers found that the bacterium’s use of the various metabolic pathways resembles human use of complex road systems, in that a few large chemical pathways (the cellular “highway” systems) incur more traffic than “suburban” roads. Changes in the bacterium’s environment, such as increased sugar level, prompt changes in traffic flow. Small “roads” are largely unaffected while larger “main” roads experience huge shifts in activity.

The study suggests that shifts in the balance between major pathways may be a common feature of how many biological systems cope with change. Although no data yet exists for humans, the behavior Barabasi and Almaas uncovered likely represents a universal feature of metabolic activity in all cells. The finding could prove to be an important advance in the field of metabolic engineering, which involves altering cellular pathways to achieve higher efficiency, which, in turn, could result in improved biomedical substances and agricultural products.

“This study helps us map the network of chemical pathways that cells use to convert food into the building blocks and energy needed for growth,” said John Whitmarsh, a biophysicist at the National Institute of General Medical Sciences, which partially supported the research. “Understanding these interacting pathways could one day help scientists manipulate them in order to make improved medicines, food and materials.”

Baldvin Kovacs and Tamas Vicsek of Eotvos University, Budapest, Hungary, and Zoltan Oltvai of Northwestern University also contributed to the paper.

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