The heady odor of yeast paste partially counteracts the life-lengthening effects of nutrient restriction on fruit flies leading Baylor College of Medicine researchers to believe that the flys perception that there is still food around may trigger a different metabolic state than one that exists when nutrients are limited.
In a report that appears online today in the journal Science Express, Dr. Scott Pletcher, assistant professor in the Huffington Center on Aging and Department of Human and Molecular Genetics at BCM, and his colleagues found that when the calorie-restricted flies were exposed to the odor of yeast paste (although they did not eat it), they did not live as long as insects who were on identical diets but who were not exposed to the odor.
Odorants limit the benefits of calorie restriction, Pletcher said.
Calorie restriction is a manipulation that has been shown to lengthen the lives of many different organisms, but the mechanisms through which this is achieved remains largely unknown. Moreover, the fact that reduced calories extend lifespan seems counterintuitive.
However, said Pletcher, dietary restriction does extend the lives of mice, and some data suggest that it also works in primates as well. How it works is not understood. Many feel that it works through reduced energy, said Pletcher. Our work argues that reduced perception plays a role as well.
There may be a signaling mechanism that makes the organism operate more robustly when there are few resources (such as food), said graduate student Sergiy Libert, who is lead author of the Science Express study. Activating that signaling might be enough to provide the advantage and extend longevity.
In his study, he said, Flies that could smell rich food in the environment lived shorter lives than flies who ate the same amount of food but were not exposed to the odorant. The perception of a rich environment was sufficient to shorten the l
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Contact: Laura Madden-Fuentes
maddenfu@bcm.edu
713-798-4710
Baylor College of Medicine
1-Feb-2007