Molecular biologists Matt Kaeberlein, Brian Kennedy, Stanley Fields, and colleagues at the University of Washington, reported in the November 18, 2005, issue of the journal Science that by decreasing the function of nutrient-responsive pathways such as TOR and Sch9, the life span of yeast is extended. Fields is a Howard Hughes Medical Institute investigator at the University of Washington.
The results of the studies are important because they begin to provide an explanation for the "life extension" effect seen in laboratory animals when food is restricted. So the studies could offer new clues about the molecular mechanisms that living organisms employ when food is scarce, said Fields.
Although it seems counterintuitive, experiments showed long ago that severely restricting food intake leads to an increase in longevity by as much as 40 percent -- in some animals. Although the longevity phenomenon was well documented in laboratory animals, researchers remained unsure about how it happened.
Now, the experiments by Kaeberlein, Kennedy, Fields and their colleagues are uncovering some of the molecular pathways that are involved in controlling longevity in yeast, and thus probably in more complex organisms.
"Through a large-scale screening process we have identified a set of genes
that slows aging in yeast." Kaeberlein explained. He and his colleagues are
hoping to use that model to expand their understanding of longevity higher up
the evolutionary ladder, even into humans. "We speculate that it is important
in higher organisms," Fields added, since very similar genes are found in
most other species, from worms to fruit flies, mi
Contact: Jim Keeley
Howard Hughes Medical Institute