Figure 5: Excessive Cap leads to decreasing biofilm formation and increasing aggregation rate of B. thuringiensis.

(a) Cell aggregation assay. Mid-logarithmic cultures grown in LB medium were divided into two groups. One group was directly applied for static incubation (Fig. 5a, left). The other was washed with PBS and re-suspended in the LB medium before static incubation (Fig. 5a, right). The interfaces of cell pellets and supernatant were indicated by white lines. (b) Representative photographs of biofilm formation assays for the ΔBc2, Δcap and BMB171 strains in glass bottles. Biofilm at the air-liquid-interface of the culture medium is indicated by arrows. (c) Quantification of biofilm formation by CV stain measured by UV spectrophotometer at 595 nm. Error bars depict SD of data from three independent experiments. *P < 0.05.