Fig. 8.3.

Role for nitrogen assimilation in chronological longevity. a Nitrogen / ammonia assimilation pathway in S. cerevisiae. The TCA cycle intermediates are oxaloacetate (O), citrate (C), cis-aconitate (A), isocitrate (I), 2-ketoglutarate (2-kG), and succinate (S). Gene products are discussed in the text. AA, amino acids. P, purines and pyrimidines. Consumption of ATP, NAD⁺, and NADP⁺ are omitted for simplicity. Inhibition by TORC1 and Ure2p are diagrammed separately but participate in nitrogen catabolite repression (NCR). Interactions between NCR and the retrograde signaling pathway as well as negative regulation by Dal80p and Deh1p are not shown. b and c CLS measurements were done using deletion mutants in the BY4742 genetic background grown in SD minimal medium as described in Fig. 8.1. Viability is expressed in terms of colony forming units (CFU) per mL of culture and is plotted as the log of the percent viability on day three of the experiment. The results shown are representative of at least two independent experiments