Fig. 3.

Phenotypes of rcs mutants and substitutions. “Δ” indicates deletion; “-pe” and “-pstb” denote Y. pestis and Y. pseudotuberculosis alleles. ΔrcsD-pe experiments used the empty plasmid vector pET-32a(+); p-rcsD-pstb denotes the Y. pseudotuberculosis allele cloned into this plasmid under its native promoter. Congo red (CR) colony color phenotypes: −, white; +/−, pink; +, red; ++, dark red. Colony size and morphology are described in the Fig. 2 legend. In vitro biofilms grown on polystyrene culture dishes were quantified by staining with crystal violet (Methods); data are mean ± SD of two to four trials. Biofilms on C. elegans were photographed after overnight incubation on Y. pestis lawns; rare animals on rcsA-pstb acquired traces of biofilm (data not shown). Numbers are percentage of worms that grew to L4 stage in 2 d; data are aggregate of two to four trials in which a minimum of 1,100 worms were scored for each bacterial genotype.