(A) Effects of FCS concentrations in the biofilm growth medium on TK1402 biofilm formation. Strain TK1402 biofilms in Brucella broth supplemented with various concentrations of FCS (7%: lane 1, 3.5%: lane 2, 1.75%: lane 3 and 0: lane 4) were examined. Quantification of biofilms (percent) was calculated relative to that of strain TK1402 in Brucella broth supplemented with 7% FCS, which was set equal to 100%. The values for the biofilms under these conditions are shown as in Fig. 1A. (B) The OMV were fractionated from different medium conditions for TK1402 cultures and the OMV-fractions were separated by SDS-PAGE (lane 1, 7% FCS; lane 2, 3.5%; lane 3, 1.75% lane 4, Brucella broth only) and compared to controls (medium without the organism, FCS concentrations were 7%: lane 5, 3.5%: lane 6, 1.75%: lane 7 and 0: lane 8). (C) Western blotting of OMV-fraction from different medium conditions using anti-H. pylori antibody. M: Molecular weight marker. Lanes: 1, 7% FCS; 2, 3.5%; 3, 1.75%; 4, 0; 5, 7% FCS without organism (negative control). (D to G) SEM observation of TK1402 biofilms under different medium conditions. D: Brucella broth only (without FCS, 0); E: with 1.75% FCS; F: with 3.5% FCS; G: with 7% FCS. *significantly different (p < 0.05). ** significantly different (p < 0.005).