Figure 7. In medium buffered to pH 6.0, ammonium inhibits a proper cell cycle arrest under caloric restriction only for cells cultured with low amino acid concentrations.

Cell cycle analysis of S. cerevisiae BY4742 cells cultured in SD media buffered to pH 6.0 with 0.5% glucose and supplemented with: high (A and B) and low (C and D) concentrations of auxotrophy-complementing amino acids (HAA and LAA, respectively) and with (w/) (A and C) or without (w/o) (B and D) NH₄⁺ [0.5%, (NH₄)₂SO₄] supplementation. Day -3 represents the day of culture inoculation and day zero represents the beginning of aging experiments. Values are means ± SEM (n=3).