pylori strains TK1402 (C) and SS1 (D) biofilm formation and their growth. The biofilm mass of these strains are shown as black bars and the lines depict the OD600 absorbances of these strains. All of the results were expressed as the means ± standard deviations from at least three independent experiments. *significantly different (p < 0.05) relative level of biofilm formation (strain TK1402 versus other strains). Morphological analysis of biofilms The biofilms were stained
with a selleck chemical BacLight LIVE/DEAD 3MA bacterial viability kit solution which could differentiate between live cells (green) and dead cells (red). Strain TK1402 formed strong biofilms covering the entire visible area (Fig. 2A) but the other strain SS1 formed relatively poor biofilms (Fig. 2B). In the biofilms of both strains, the majority of the biofilm cells were stained green (Fig. 2A, and 2B). In order to confirm that the TK1402 biofilm cells were viable, the 2-day and 3-day biofilms cells were scrapped into PBS and the optical densities Avapritinib and the CFU values of
the mixtures were evaluated (Table 1). The 2-day and 3-day cultures of this strain in Brucella broth supplemented with 7% FCS were also measured as controls. The optical densities and CFU of the 3-day biofilm cells showed increases compared to those of 2-day biofilm cells. Further, the CFU values were normalized to optical densities. The values for the 2-day biofilm cells were similar compared to the controls (broth culture). However, the normalized values for 3-day biofilm cells tended to be decreased, although there was no significant difference in the normalized values, suggesting that 3-day biofilm cells might contain some dead cells or morphologically altered cells. Table 1 Optical densities and CFU measurements in the strain TK1402 biofilm cells and broth cultures OD600 CFU (×109) CFU/OD600 (×109) 2-Day biofilma 0.141 ± 0.037
0.259 ± 0.202 1.860 ± 1.487 3-Day biofilma 0.258 ± 0.027 0.340 ± 0.230 1.614 ± 0.695 2-Day broth cultureb 0.939 ± 0.012 1.847 ± 0.318 1.966 ± 0.387 3-Day broth cultureb 1.075 ± 0.044 2.248 ± 1.170 2.151 ± 1.180 a) the biofilm cells were scrapped by mechanical treatment into PBS. The cell suspensions were examined by optical densities and CFU were also calculated. Ketotifen b) the standard broth cultures of strain TK1402 in Brucella broth supplemented with 7% FCS were examined by optical densities and CFU. Data are shown as the mean value of the 3-independent experiments ± standard deviations. Figure 2 CLSM images of H. pylori strains TK1402 (A) and SS1 (B) biofilms in Brucella broth containing 7% FCS. Each image represents the layer in the Z-stack that has the maximum bacterial coverage. The 3-day biofilms of each strain were stained with BacLight LIVE/DEAD stain. Viable cells are colored green and nonviable cells are colored red. x-z and y-z reconstructions of each biofilm are shown on the right and upper sides of each x-y image. The scale bars equal 50 μm in both panels.