FIG 4.

Effects of DNase I, proteinase K, and sodium periodate on preformed ΔarsS and ArsR-D52N biofilms. DNase I, proteinase K, and sodium periodate were tested against preformed biofilms of ΔarsS (A) and ArsR-D52N (B) mutant strains. At the time points indicated, biofilms were treated with the indicated enzyme or chemical and incubated for another 24 h at 37°C. The means from the three biologically independent experiments are plotted; error bars indicate the standard errors of the means. *, P < 0.05; ***, P < 0.001.