CR Reduces Yeast Lifespan in Anaerobic Conditions

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" ............ under .......... strictly anaerobic conditions, yeast

lifespan was shorter .................... and further reduced by

caloric restriction. .............. " :

" Methionine sulfoxide reductase regulation of yeast lifespan reveals

reactive oxygen species-dependent and -independent components of aging

" Aging is thought to be caused by the accumulation of damage,

primarily from oxidative modifications of cellular components by

reactive oxygen species (ROS). Here we used yeast methionine sulfoxide

reductases MsrA and MsrB to address this hypothesis. In the presence

of oxygen, these antioxidants could increase yeast lifespan and did so

independent of the lifespan extension offered by caloric restriction.

However, under ROS-deficient, strictly anaerobic conditions, yeast

lifespan was shorter, not affected by MsrA or MsrB, and further

reduced by caloric restriction. In addition, we identified changes in

the global gene expression associated with aging in yeast, and they

did not include oxidative stress genes. Our findings suggest how the

interplay between ROS, antioxidants, and efficiency of energy

production regulates the lifespan. The data also suggest a model

wherein factors implicated in aging (for example, ROS) may influence

the lifespan yet not be the cause of aging. "

Rodney.