Skip to main content
. 2024 Aug 14;9(9):e00372-24. doi: 10.1128/msystems.00372-24

Fig 8.

Bar graphs of β-galactosidase activity for PcupB-lacZ and PcupC-lacZ in different strains, including WT, ΔcbrA, Δcrc, and ΔcbrAΔcrc. Diagram of pathways showing the effect of high quorum and varying CrcZ levels on biofilm surface coverage and height.

Crc promotes the transcription of cupB and cupC fimbrial operons. (A and B) β-Galactosidase assays of PcupB-lacZ transcriptional (A) or PcupC-lacZ transcriptional (B) fusions for background genotypes indicated on the x-axis and grown in tryptone broth with no addition (black), 50 mM pyruvate (light gray), or 50 mM glucose (dark gray). Error bars represent SEM of three biological replicates. Only pairwise comparisons that had P value < 0.05 are denoted. Statistical significance was determined using Welch’s ANOVA with Dunnett’s T3 multiple comparisons test in GraphPad Prism software. ***P < 0.001, *P < 0.05. (C) Model for Crc-dependent activation of biofilm matrix components. At high population density, RhlR-mediated quorum sensing activates the expression of Pel exopolysaccharide while Crc, depending on the abundance of CrcZ small RNA, promotes the expression of Pel, CupB, and CupC fimbriae components of the biofilm matrix. The arrow indicates activation and T-bar indicates inhibition.