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October 31, 2000
Media Contact: Herbert Levine (858) 534-4844

Physicists and biologists at the University of California, San Diego have been awarded $3-million from the National Science Foundation to collaborate in characterizing, in an integrated way, the development of the ameboid protozoan Dictyostelium discoideum, an organism popularly known as a slime mold.

The five-year award, which includes researchers at Cornell University, was one of 16 research grants announced this month by the NSF to foster a better scientific understanding of the interrelationships that arise when living things at all levels-from molecular structures to genes to ecosystems-interact with their environment.

"Past investments in molecular biology, remote sensing, information science, and mathematics have yielded tremendous advances and powerful new technologies and tools that now make biocomplexity research possible," said Rita Colwell, director of NSF. "The biggest, most exciting scientific questions are now at the interfaces of traditional disciplines, such as biological chemistry, computational ecology and environmental genetics."

In the biocomplexity award to UCSD, physicists, biologists and computational scientists from the two universities will attempt to connect the underlying genetic information about Dictyostelium to its morphology and multicellular organization. This should provide the scientists with a greater understanding of one of the central problems of modern biology: How to form an integrated picture of an organism that connects genetic information to its behavioral responses.

"Dictyostelium provides the simplest example of cellular biology mechanisms that go on everywhere," said Herbert Levine, a professor of physics at UCSD who heads the research collaboration. "Its motion and its response to cell signals is characteristic of the way your cells move, but Dictyostelium does it in a much more simple way and in a way you can investigate with genetics. In our investigations of the organism, we will try to bring a level of precision that will enable us to bridge the gap between genomics and multicellular organization."

Other UCSD researchers involved in the project include Jose N. Onuchic, professor of physics; William F. Loomis, professor of biology; Terence T.-L. Hwa, associate professor of physics; and Wouter-Jan Rappel, associate project scientist in the physics department. Researchers at Cornell, which will receive approximately $700,000 of the $3-million award over the next five years, will be led by Eberhard Bodenschatz, an associate professor of physics, who collaborated closely with Levine at UCSD last year when the two scientists proposed the project to the NSF.

Levine said Dictyostelium was chosen by the scientists because it's the simplest organism in which to study the complex phenomena they hope to investigate, such as the cell's response to external signals that coordinate multicellular development.

"Dictyostelium has a solitary lifestyle in which each individual cell is on its own," he added. "But the organisms also go through a developmental cycle in which they cooperate when food becomes scarce-sending each other signals, aggregating together and forming rudimentary multicellular organisms, one of which is a slug that can crawl around looking for a better environment. In the course of this transformation, the organism develops, in the simplest possible form, many of the fundamental mechanisms that work in all molecular biological systems-chemical signaling, cell differentiation in response to external signals. Besides being simple, everything takes place on the time scale of a day and you can genetically engineer all sorts of variations of the individual cells."

The UCSD scientists hope to first acquire a large base of genetic knowledge relevant to the development of Dictyostelium, then carry out a new generation of experiments focusing on the cell response to external signals that coordinate multicellular development. Finally, they plan to use computational simulations to tie the genetic with the developmental and behavioral information in a coordinated way.