Figure 2

Characteristics of strains APEC40, APEC40-ΔyqeH, and APEC40-CΔyqeH. A Growth curves of APEC40, APEC40-ΔyqeH, and APEC40-CΔyqeH in LB broth. Growth rates of APEC40, APEC40-ΔyqeH, and APEC40-CΔyqeH were monitored by measuring their OD₆₀₀ values in LB medium at 2 h intervals for 24 h. During culture for 24 h, there was no significant difference in the growth rates of APEC40, APEC40-ΔyqeH, and APEC40-CΔyqeH grown in LB broth (P > 0.05). Each value is the average of three independent experiments. B Bacterial motility. Swimming motility of strain APEC40-ΔyqeH was significantly lower than that of the wild-type APEC40 strain, whereas the swimming motility of complemented strain APEC40-CΔyqeH was restored. The experiment was repeated three times and all samples were measured in triplicate. C Biofilm formation by APEC strains as determined with crystal violet (CV) staining. APEC40-ΔyqeH showed significantly lower biofilm formation than wild-type strain APEC40 after crystal violet staining (**P < 0.01 for the WT vs. mutant).