FIG. 3.

Biofilm formation of S. mutans treated with FruA on saliva-coated polystyrene and hydroxyapatite surfaces. (A) Various units of FruA in the fructanase mixture were added and incubated with an S. mutans cell suspension in saliva-coated 96-well microtiter plates for 16 h in TSB with 0.25% sucrose and 1% inulin-DW. Fructanase activities in the cell suspension were measured as the fructose concentration after 2 h of incubation. (B) Effects of FruA in the fructanase mixture on biofilm formation of S. mutans GS-5 were analyzed on saliva-coated hydroxyapatite disks. Three hydroxyapatite disks were used: control (PBS), 1.25 unit/ml, and 6.0 unit/ml FruA. A biofilm photograph was taken as representative data from one of the three experiments. (C) Quantitative analyses were also performed for biofilm formation on hydroxyapatite The results are expressed as the means ± standard deviations of the absorbance obtained in triplicate assays in panel B. Representative data of three independent experiments are presented, and similar results were obtained in each experiment. The asterisks denote significantly different biofilm formation comparing the FruA treatment and control (P < 0.05).