ABSTRACT
Oxygen free radicals and reactive oxygen species (ROS) damage the DNA both in the mitochondria that power the cell and in the chromosomes in the nucleus of the cells. They also damage other structures in the cells, especially the membrane that is exceptionally susceptible to oxidation damage due to its high concentration of lipids. Accumulated debris in the cell is a message to the cell to speed up duplication, or to self-destruct. This chapter explains how the rate of destruction of the mitochondria and the accumulation of debris in the cell speeds up cell reproduction that leads to premature aging. Science is now revising our knowledge of the principal causes of oxidative stress. It is known that plasma membranes and mitochondria are a major source of free radicals. Recent studies have identified small chemical compounds that modulate sirtuins, and these modulators have enabled a greater understanding of the biological function and molecular mechanisms of sirtuins.
