Fig. 4.

Temperature and time effects on 2OG pool during filtration and wash. (A) Wild-type strain NCM3722 was inoculated in glycerol medium with 11.5 mM NH₄⁺. Samples were collected during the exponential phase of growth, when the concentration of NH₄⁺ left in the culture was 10 ± 0.2 mM. Wash medium equilibrated either in a 37°C culture room or in ice water contained different concentrations of NH₄⁺. (B) Strain NCM3722 was inoculated in glycerol medium with 20 mM NH₄⁺. Samples were collected during the exponential phase of growth, when the OD₆₀₀ was between 0.3 and 0.4. Wash medium was identical to the starting medium, with 20 mM NH₄⁺ and equilibrated at 37°C. N, normal handling speed of filtration and wash that lasted ∼15 s; N + 30", cells were held in a pipette tip for 30 s after the culture was withdrawn from the vessel and before filtration; N + 60", hold for 60 s. The error bars are minimal and maximal values for two different OD points.