FIG 4 .
Enzyme digestion of biofilm matrix. Prior to inoculation of the culture medium with P. multocida, 0.1 mg/ml α-amylase or proteinase K was added; this was followed by incubation for 48 h. Biofilms were rinsed, stained with CV, and solubilized with ethanol, and the A562 was determined. White bars, no treatment; light gray bars, treatment with proteinase K; dark gray bars, treatment with α-amylase. Significance values are based on comparison to the sample with no enzyme added. *, P ≤ 0.05; **, P ≤ 0.01; ****, P ≤ 0.0001; ns, not significant.