FIG 4.

CpAL control of C. perfringens biofilms. Strain CN3685 or mutant derivatives were inoculated in 96-well plates containing THY, and biofilms were incubated for 3, 6, or 24 h at 37°C. (A) Biofilms (24 h) were stained with SYTO9, and their biomass was obtained using a fluorometer. (B) Micrographs of fluorescence-stained biofilms at 3 or 6 h postinoculation were obtained using an Evos inverted microscope. In another set of experiments, strain CN3685 or CPJV21 (ΔagrB) was incubated at 37°C, whereas strain CN3685 or CPJV32 (ΔagrB/agrB) was incubated at 30°C. (C) SYTO9-stained biofilms were quantified by fluorescence. *, Statistical significant (P < 0.05), as evaluated by the Mann-Whitney U test. (D) The macroscopic aspect of these strains was photographed, and micrographs were also obtained with a fluorescence microscope. Where shown, error bars indicate the standard errors of the mean calculated using data from three independent experiments.