Figure 4. Effects of CLS-extending growth conditions on extracellular acetic acid accumulation and resistance to exogenous acetic acid. (A) Accumulation of acetic acid in the media of CR, ade4∆, CR. conc. and INAM cultures was measured over the first 84 hours of the aging assays. (B) Cell viability was measured as colony forming units (CFU) following exposure to 300 mM acetic acid for 200 minutes. Exposures were performed at day 2 and day 5 of the aging assays. The fractions of viable cells in the treated cultures relative to untreated are plotted. (C) Assessment of ROS generation by long-lived cells using dihydrorhodamine (DHR 123) staining after 48 hr growth. Fluorescence intensity of the WT NR cells was normalized to 1.0.