Fig. 2.

GOGAT⁻ SK3062 (ΔgltB824) in an NH₄⁺-limited chemostat. The diluted minimal medium (0.2 × N⁻C⁻DB) contained 2 mM NH₄⁺ as the limiting N-source, and 0.2% glycerol as the C-source. Five dilution rates were chosen from 0.52 h⁻¹ (close to maximal growth rate, doubling time of 81 min, day 2) to 0.25 h⁻¹ (about half of the maximal growth rate, doubling time of 168 min, days 1 and 6), with each interval corresponding to a change in doubling time of ≈20 min. After each overnight equilibration, two to three samples were collected several hours apart. (Upper) Cell doubling time calculated from dilution rate measurement after each sample collection. (Lower) Cell density (○) and free NH₄⁺ concentration in the medium (▴).