Research Paper Volume 2, Issue 10 pp 709—726
Growth signaling promotes chronological aging in budding yeast by inducing superoxide anions that inhibit quiescence
Figure 1. Inhibition of growth signaling pathways prolongs CLS in concert with reduced O2- and more frequent growth of stationary phase cells in G0/G1. (A) Levels of O2- detected by dihydroethidium (DHE) fluorescence in exponential cultures and stationary phase wild type cells. In this and subsequent figures, dashed vertical line through flow cytometry histograms provides an arbitrarily chosen reference point for comparing related histograms. (B) Effects of caloric restriction and/or inactivation of Sch9p on CLS. (C) Effect of caloric restriction on levels of O2- detected by DHE fluorescence in exponential cultures of wild type cells. (D) Effects of caloric restriction and/or inactivation of Sch9p on levels of O2- detected by DHE fluorescence in stationary phase cells at day 3 of medium depletion. (E) Effects of caloric restriction and/or inactivation of Sch9p on the fraction of stationary phase cells that failed to arrest in G0/G1 as measured by counting cells with visible buds at day 3 of medium depletion. (F) Levels of H2O2 detected in stationary phase wild type and sch9Δ cells by dihydrorhodamine 123 (DHR) fluorescence at day 3. (G) Levels of H2O2 detected by DHR fluorescence and O2- detected by DHE fluorescence in rim15Δ cells at day 3.