Increased Life Span due to Calorie Restriction in Respiratory-Deficient Yeast

Calorie restriction (CR) is a moderate reduction of energy intake for organisms. The response to CR has been shown to slow aging in many species like yeast, worms, flies and rodents. One of the potential mechanisms is that CR will cause a metabolic shift of yeast from fermentation to respiration. As a result, it activates a NAD+-dependent histone desacetylase Sir2, and Sir2 further slows down aging. In this study they found that life span extension by CR in both long life span and short life span strain yeast is independent of respiration.

An alternative mechanism is that CR decreases the expression level of Sir2 inhibitor nicotinamide. This study found that addition of nicotinamide to the medium will dramatically shortens the life span of wild type cells, but only partially prevent life span extension in cells lacking both Sir2 and replication fork block protein Fob1 by CR.

Yi-Lin Cheng
42134932