Engineered Fluorescent E. coli Lysogens Allow Live-Cell Imaging of Functional Prophage Induction Triggered inside...

Area of Science:

• Microbiology
• Immunology
• Virology

Background:

• Lysogenic bacteria, harboring integrated prophages, are prevalent in the human gut microbiome.
• Prophage activation may occur in stressful environments, such as within macrophages.
• The role of prophage activation in bacterial infection outcomes within macrophages is unknown.

Purpose of the Study:

• To investigate macrophage-triggered prophage induction and lysis of bacteria within phagosomes.
• To explore the dynamics of bacteria-phage interactions in a living cell model.

Main Methods:

• Utilized a tripartite system involving murine macrophages engulfing E. coli lysogenic for engineered bacteriophage λ.
• Incorporated a fluorescent lysis reporter into the bacteriophage λ genome.
• Investigated the role of the PhoP pathway in native λ phage induction within phagocytosed E. coli.

Main Results:

• Pre-induced prophages can lyse host bacteria and infect neighboring bacteria within the same phagosome.
• A non-canonical PhoP-mediated pathway is involved in native λ phage induction in phagocytosed E. coli.
• Prophage induction within macrophages influences bacterial infection dynamics.

Conclusions:

• Prophage activation within macrophages is a viable phenomenon.
• Induced prophages may contribute to macrophage bactericidal activity.
• Phage-host interactions within phagosomes offer potential mechanisms for controlling bacterial infections.