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 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 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.