Related Experiment Video

Updated: May 31, 2025

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

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The Fem cell-surface signaling system is regulated by ExsA in Pseudomonas aeruginosa and affects pathogenicity

Yanqi Li1, Anjali Bhagirath1,2, Sara Badr3

  • 1Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0W2, Canada.

Iscience
|January 24, 2025
PubMed

Insights

The Pseudomonas aeruginosa Fem system, regulated by ExsA, influences virulence and pathogenicity. Deleting femA increased host survival, while overexpressing femI decreased it in a Galleria mellonella model.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Bacterial interspecies interactions are crucial in polymicrobial infections.
  • The FemI-FemR-FemA system in Pseudomonas aeruginosa mediates mycobactin uptake.
  • Mycobactin is an iron-chelator produced by Mycobacterium spp.

Purpose of the Study:

  • To investigate the regulation of the Fem system by ExsA, a master regulator of the type three secretion system (T3SS).
  • To determine the role of the Fem system in Pseudomonas aeruginosa virulence and pathogenicity.

Main Methods:

  • Analysis of the femA-PA1909 operon regulation by ExsA.
  • Assessment of Fem system influence on quorum sensing, pyocyanin production, biofilm formation, and type six secretion systems (T6SSs).
  • Evaluation of bacterial pathogenicity using a Galleria mellonella infection model.

Main Results:

  • The femA-PA1909 operon is positively regulated by ExsA, linking the Fem system to T3SS.
  • The Fem system impacts P. aeruginosa virulence factors, including quorum sensing and T6SSs.
  • FemA deletion in PAO1 increased host survival, while FemI overexpression decreased it in vivo.

Conclusions:

  • The Fem system is a target of ExsA, connecting it to T3SS regulation.
  • The Fem system plays a significant role in P. aeruginosa pathogenicity.
  • Modulating the Fem system can alter P. aeruginosa virulence and host-pathogen interactions.
Keywords:
MicrobiologyMolecular biology

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