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USC scientists extend life of yeast 10-fold

January 19, 2008|Thomas H. Maugh II | Times Staff Writer

USC researchers have extended the life span of baker's yeast 10-fold through a combination of genetic manipulation and caloric restriction, marking the greatest increase in prolonging life ever achieved in the laboratory.

The team is now studying a human population with similar genetic mutations to determine whether they have a lower incidence of disease and whether they too live longer than normal.

Gerontologist Valter Longo and his team produced yeast that lived 10 weeks instead of the normal one by knocking out two genes, RAS2 and SCH9, and restricting the amount of nutrients the yeast received, they reported this week in the Journal of Cell Biology and the Public Library of Science's PLoS Genetics. The genes promote aging in yeast. Comparable genes in humans promote cancer.

Previous studies have shown that restricting calories can prolong life in a variety of species, including primates.

Longo believes that the mutations and the caloric restrictions push the organisms into a maintenance mode, enabling them to redirect energy from growth and reproduction into anti-aging systems until they can feed and breed again.

Ecuadorean researchers have identified a population of humans living in the mountains in the southern part of the country, people of Jewish descent who migrated from Spain a few hundred years ago, who carry similar mutations.

Those who receive the mutations from both of their parents are short -- no more than 4 feet tall -- and have a variety of health problems, including cardiovascular disease and obesity. Those probably occur because the genetic defects interfere with normal development early in life.

But, Longo said, "so far, we have seen very little cancer in them."

The team is studying those who receive the mutations from only one parent. If they are healthier and live longer than normal, he said, it might be possible to use drugs to shut off the genes in adulthood to extend life and prevent cancer.

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thomas.maugh@latimes.com

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