Fig. 4

The functional validation of ATP synthase under iron starvation conditions. a The H⁺-ATP synthase activity of A. hydrophila in a serial of DIP concentrations in 0, 150, 200 and 300 μM were measured spectrophotometrically at 340 nm using the H⁺-ATPase assay kit b The survival ratio of A. hydrophila when treated with 20 μg/mL DCCD in a serial dilution of DIP concentrations in 0, 150, 200 and 300 μM for 12 h and observed by colony counting, respectively. c Color grading of the effect of a serial of concentrations of DIP from 0 μM to 300 μM and DCCD from 0 μg/mL to 40 μg/mL. The colony amounts of bacteria without treatment were normalized to 100 as control