Figure 5.

Antibacterial mechanisms of DCA against E. coli. A) Percent survival of E. coli MG1655 and related knockout strains (△mdh, △cydB, △aceA, △katE, and △torA) after 4 h co‐treatment of DCA (50 × 10⁻³ m) and CIP (20‐fold MIC). B) Effect of DCA (50 × 10⁻³ m) on the mRNA expression of enzymes involved in TCA cycles. C,D) Intracellular C) NAD⁺ and NADH levels, and D) the ratio of NAD⁺/NADH in E. coli MG1655 in the absence or presence of DCA (50 × 10⁻³ m). E) The mRNA expression levels of electron transport chain (ETC)‐related genes in E. coli MG1655 after exposure to DCA (50 × 10⁻³ m). F) ROS levels of E. coli MG1655 in response to the increasing concentration of DCA, and NaHS (30 × 10⁻³ m) was served as the direct H₂S donor, which functions as the defense gas protecting bacteria from oxidative damage. G) Growth curves of E. coli MG1655 within 10 h in the presence of DCA with or without NAC (10 × 10⁻³ m), a ROS scavenger. H) Membrane permeability of E. coli MG1655 under the stimulation of varying concentrations of DCA for 1 h, probed by propidium iodide (10 × 10⁻⁹ m). I) Intracellular ATP levels of E. coli MG1655 in response to the increasing concentration of DCA ranged from 0 × 10⁻³ to 80 × 10⁻³ m. Data were displayed as mean ± SEM, and statistical significance was determined by unpaired t‐test (*p < 0.05; **p < 0.01; ***p < 0.001; ns, not significant). Experiments were performed with three biological replicates.