Fig. 6.

Frequent sampling results in variance of acetyl-P measurements. ackA mutant cells (strain AJW1939) were grown in mMOPS supplemented with 0.8% pyruvate at 37°C, harvested at regular time intervals, lysates prepared and processed, subjected to 2D-TLC, and the signal corresponding to acetyl-P quantified. (A) A representative experiment in which relatively large samples (200 μL) were harvested from 2 mL cultures in 12 x 75 mm tubes, ensuring that the SA : vol ratio dropped below 20% shortly after the culture entered into stationary phase; this event occurred at an OD₆₀₀ of about 0.5. (B) An amalgamation of several replicate experiments in which samples were harvested during mid-exponential growth to early stationary phase, a several hour-long interval during which the acetyl-P pool of the ackA mutant tends to be relatively stable (18).