Figure 1. CLS shortening under amino acid restriction is reverted by removing the non-limiting nitrogen source (ammonium or glutamine) from the culture medium and no beneficial effect could be observed by further imposing caloric restriction.

Glucose consumption (dashed lines) and survival (CFU counts, %; solid lines) of S. cerevisiae BY4742 cultured in SD media buffered to: pH 3.4 (A and C) or pH 6.0 (B and D), with 2% (A and B) or 0.5% (C and D) glucose and supplemented with: high and low concentrations of auxotrophy-complementing amino acids (HAA and LAA, respectively), and with (w/) or without (w/o) NH₄⁺ [05%, (NH₄)₂SO₄] or glutamine [700 mg/L, GLN] supplementation. In all the cultures, starting cell density was about 3.8 × 10⁷ cells/ml. Day -3 represents the day of culture inoculation and day zero represents the beginning of aging experiments. Values are means ± SEM (n=3).