Exopolysaccharide visualization enabled us to assess the accumulation pattern (Figure 5A) and exopolysaccharide biovolume per base area (Figure Sapitinib mw 5B). Furthermore, the exopolysaccharide production was normalized to the levels of DAPI-labeled P. gingivalis cells in the biofilms and expressed as the

exopolysaccharide/cell ratio (Figure 5C). Interestingly, a unique pattern of exopolysaccharide accumulation was observed in the Rgp mutant KDP133 in vertical sections (x-z plane) of biofilms (Figure 5A). In contrast to the other strains, exopolysaccharide accumulated in the middle layer, and the biofilm surface was not covered with exopolysaccharide. It was also notable that the long fimbria mutant KDP150 developed a biofilm enriched with exopolysaccharide (Figure 5A), reflecting Selleck SC79 a significantly higher exopolysaccharide/cell ratio (Figure 5C). The gingipain null mutant KDP136 produced the most abundant exopolysaccharide per unit base area (Figure 5B). The minor fimbria

mutant MPG67, long/short fimbriae mutant MPG4167 and Rgp mutant KDP133 also accumulated significantly larger amounts of exopolysaccharide than wild type; however, exopolysaccharide/cell ratio in KDP133 and MPG4167 was significantly lower than wild type because biofilms of these strains consisted of larger numbers of cells (Figure 5C). Figure 5 Exopolysaccharide production by P. gingivalis wild-type strain and mutants in dTSB. A) Visualization of exopolysaccharide production in biofilms formed by P. gingivalis strains after staining with FITC-labelled concanavalin A and wheat germ agglutinin (green). Bacteria were stained with DAPI (blue). Fluorescent

images were Quisinostat purchase obtained using a CLSM. The z stack of the x-y sections was converted to composite images with the “”Volume”" function using Imaris software, after which a y stack of the x-z sections was created and is presented here. B) Fluorescent images were quantified isothipendyl using Imaris software and average of total exopolysaccharide biovolume per field was calculated. C) Exopolysaccharide levels are expressed as the ratio of exopolysaccharide/cells (FITC/DAPI) fluorescence. The experiment was repeated independently three times. Data are presented as averages of 8 fields per sample with standard errors of the means. Statistical analysis was performed using a Scheffe test. *p < 0.05 and **p < 0.01 in comparison to the wild-type strain. Autoaggregation Bacterial autoaggregation has been reported to play an important role in initial biofilm formation [24], thus the autoaggregation efficiencies of the mutants were assessed (Table 2). Deletion of long fimbriae significantly reduced the autoaggregation efficiency, which agreed with the previous report that long fimbriae were required for autoaggregation [25].