Fig 1.

Antibiofilm effect of G2cps and selection of mutants partially resistant to G2cps. (A) Crystal violet staining of biofilm formed by WT strain TG1-c in a PVC microtiter plate in the presence of increasing concentrations of G2cps extract. (B) Quantification of biofilm formed as shown in panel A by the WT in a PVC microtiter plate with increasing concentrations of G2cps. For the rest of the study, we chose to use 30 μg/ml G2cps, which cause a biofilm reduction of about 75%. (C) Quantification of the biofilm formed by the WT and the 26 mutants resistant to G2cps in the presence of 30 μg/ml G2cps. Biofilm quantities were standardized with the quantity of the biofilm formed by WT without G2cps (value, 100; white bar). ***, P ≤ 0.005. P values were determined with respect to the biofilm formed by the WT with G2cps (black bar). The seven mutants chosen for use in the rest of the study are in bold.