Fig. 3.

Isotopic-labeling ratio methods and dynamic-labeling experiments with 34H revealing its metabolic pool sizes and metabolic behavior compared with E. coli. (A) Ratio of normal-growth 34H and E. coli metabolite pool sizes (Log₁₀ scale). (B) Comparison of metabolic-labeling responses of TCA metabolites in cold-stressed (4 °C, following acclimation at 4 °C for 1 h) E. coli, normal-growth (4 °C) 34H, and heat-stressed (room temperature, following acclimation for 1 h at room temperature) 34H in media pulsed with U-¹³C glucose. E. coli was not sampled at 48 h; citrate was not detected in 34H room-temperature samples at 24 h. For 10-s data (asterisk), cell metabolism may have been active during the 5-min centrifugation (0 °C) step. Error bars indicate SD of the mean (n = 2, except for 34H room temperature where n = 4).