Figure 1.

Effect of cadmium on C. metallidurans CH34 biofilm formation and c-di-GMP levels. (A) Cell attachment and cell viability after 15 h of incubation in LPTMS broth at 30°C. The means of three independent experiments and standard deviations are shown. (B) Macrocolonies grown on Congo Red LB agar plates at different cadmium concentrations. Images were taken after 5 days of incubation at room temperature. The red staining intensity of the macrocolony indicates the presence of EPS. The bar represents 1 cm. (C) c-di-GMP levels after 2 mM cadmium exposure during 45 min in LPTMS broth (planktonic) or on agar (biofilm). The c-di-GMP concentration was normalized with respect to total protein content in each sample. The means of three independent experiments and standard deviations are shown. Significant differences assessed by t-test: ^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗P < 0.001.