Figure 6.

Effect of the addition of copper ions on the defect of biofilm formation by cbiO null mutant. The cbiO null mutant CFSa36ΔcbiO/pYH4, complementary strain (CFSa36ΔcbiO/pYH4-cbiO), and their parental control CFSa36/pYH4 were incubated in CDM supplemented with 5 μg/mL erythromycin at 37 °C overnight with shaking at 220 rpm. The cultures were re-inoculated in CDM with Erm⁵ and the different concentrations of CuSO₄, and incubated in a 96-well format at 37 °C overnight without shaking. Four repeats were included for each strain. (A) Effect of the addition of extra copper ions on the biofilm defect phenotype of cbiO null mutant, and (B) quantitatively determine the effect of the addition of copper ions on biofilm formation. The data were statistically analyzed with a T.TEST. The results are representative of at least three independent repeats. The symbol *** represents p < 0.001.