Fan Jin’s team form SIAT first quantitatively measured the transcription of PprB downstream control-related genes by constructing a fluorescent reporter strain, and found that P. aeruginosa significantly increased the expression of downstream genes of PprB in a carbon starvation environment. Further, the researchers found that the sigma factor RpoS in bacteria mediates this process by up-regulating the intracellular expression of PprB protein, and proved that the transcriptional regulatory activity of PprB does not depend on its own phosphorylation. Using a combination of microfluidics and microscopy techniques, the researchers found that the overexpression of PprB greatly enhanced the adhesion between bacteria and surfaces, and between bacteria and bacteria, thus causing the strain to produce a dense, thick super biofilm . In addition, BapA adhesion protein and CupE pilus both contributed to the adhesion of PprB overexpressing strains, while type IV pilus b had little effect on bacterial adhesion. In the natural environment, Pseudomonas aeruginosa is often colonized in some nutrient-poor environments. The above findings suggest that the PprB system is likely to play an important role in the formation of bacterial biofilms in a carbon-poor environment, and to prevent this Biofilm-like membranes provide possible targets (BapA and CupE).
The achievement was recently published on the topic of "Carbon starvation induces the expression of PprB-regulated genes in Pseudomonas aeruginosa" in Applied Environmental Microbiology (10.1128 / AEM.01705-19). This research is supported by the National Natural Science Foundation of China.
Figure: Schematic representation of the effect of the RpoS-PprB-Flp / CupE / Bap system on carbon source starvation signal and bacterial adhesion phenotype in P. aeruginosa
References:
[1], de Bentzmann S, Giraud C, Bernard CS, Calderon V, Ewald F, Plesiat P, Nguyen C, Grunwald D, Attree I, Jeannot K, Fauvarque MO, Bordi C. 2012. Unique Biofilm Signature, Drug Susceptibility and Decreased Virulence in Drosophila through the Pseudomonas aeruginosa Two-Component System PprAB. PLoS Pathog 8:15.