FIG. 3.

The role of VPS in biofilm-induced infectivity. (A) Ectopic expression of VpsT leads to dramatically increased biofilm formation. Differentially marked V. cholerae bacteria containing pVpsT or empty vector (WT), as well as a vpsR negative control, were assayed for biofilm formation under static conditions by crystal violet staining. Both in the presence and in the absence of 0.1 mM IPTG, the pVpsT strain produced significantly more biofilm than the vector control strain, indicating increased VPS production (*, P < 0.05 by Student's t test). Bars indicate the mean A₅₇₀; error bars show standard deviations. (B) Ectopic expression of VpsT does not result in increased infectivity. Differentially marked strains containing pVpsT or vector control were grown in shaking culture, with or without 0.1 mM IPTG. The strains were assessed for colonization of the mouse small intestine using a competition assay. In vitro competitions were done in parallel. Symbols represent data for individual mice or in vitro control samples; horizontal lines indicate the median CI.