Researchers at Washington University School of Medicine in St Louis have shown for the first time that zebrafish can be raised in a germ-free environment. Zebrafish are transparent until they reach adulthood. Thus, these fish are providing researchers with unique opportunities to watch the gut develop with and without the beneficial effects of symbiotic bacteria.

"To untangle the complex interactions between humans and their friendly gut bacteria, we need simple animal models that can function as living test tubes," explains principal investigator Jeffrey I. Gordon, M.D. "These models are key to identifying the genes and chemicals that allow friendly bacteria to enhance our health."

Gordon is the Dr. Robert J. Glaser Distinguished University Professor and head of the Department of Molecular Biology and Pharmacology. The first author is John F. Rawls, Ph.D., a postdoctoral fellow in Gordon's laboratory. The study, which will be published online the week of March 15 in the Proceedings of the National Academy of Sciences, also is the first to describe which bacteria normally reside in the zebrafish gut.

"Thanks to John's painstaking work, we now have a new model for studying the molecular details of how symbionts affect animal development and physiology," Gordon says.

Germ-free zebrafish arrive 50 years after scientists announced a similar biological feat: a viable strain of mice with no bacteria in their bodies. Gordon's team believes zebrafish provide a nice complement to ongoing mouse research for several reasons. First, the zebrafish gut is organized in ways similar to the mammalian gut, and an international effort to sequence the zebrafish ge
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Contact: Gila Z. Reckess
reckessg@wustl.edu
314-286-0109
Washington University School of Medicine
15-Mar-2004