Extended Data Fig. 5: Bismuth impairs the activity of the electron transport chain (ETC) and promotes intracellular antibiotic accumulation in P. aeruginosa.
a, Time-dependent oxygen consumption rate was quantified by a fluorescence probe in the presence of indicated concentrations of BSS. The decrease in the oxygen consumption rate by BSS suggests the inhabitation of ETC activities. b, BSS inhibits the activity of NADH dehydrogenase in vivo. The bacteria were treated with different concentrations of BSS (μM) for 2 hours, then the inner membrane was collected and membrane-bound NADH-quinone oxidoreductase activity was measured. c–f, BSS dose-dependent inhibition on the activity of NADH dehydrogenase from different gene mutant strains. The bacterial inner membrane was collected and treated with different concentrations of BSS (μM) for 2 hours, then the membrane-bound NADH-quinone oxidoreductase activity was measured. g, The fluorescence of calcein inside of P. aeruginosa under the treatment of indicated concentrations of BSS. h, The fluorescence of calcein inside of P. aeruginosa under the treatment of BSS in M9 medium without iron. The calcein-AM is not able to be quenched by bismuth or the change of metabolism and pH i, The fluorescence of calcein inside of P. aeruginosa under the treatment of different combinations of BSS (10 μM), iron(10 μM) or PVD (10 μM) in M9 medium. When cells were treated with iron and PVD, the fluorescence of calcein-AM was quenched, indicating that the iron was transported inside the cell and the calcein-AM was able be quenched by iron inside this bacterium. While the bacteria were treated with a combination of bismuth, iron, and PVD, iron could not be rapidly transported within the cells, suggesting that bismuth might bind to PVD to inhibit iron transport. For Fig. a–i, the data are presented as mean ± SEM of three biological replicates. For Fig. g and i, P values were determined using two-sided unpaired t-test, 95% confidence interval.
