Cell motility empowers bacterial contact weapons.

Area of Science:

• Microbiology
• Bacterial Interactions
• Cell Motility

Background:

• Bacteria employ contact-dependent weapons, such as Type VI secretion systems and contact-dependent inhibition (CDI), to eliminate competitors.
• These weapons require direct cell-to-cell contact for toxin delivery, limiting their reach and effectiveness.

Purpose of the Study:

• To investigate the hypothesis that bacterial motility enhances the efficacy of contact-dependent weapons.
• To elucidate the mechanisms by which motility improves toxin delivery and competitive outcomes.

Main Methods:

• Development of individual-based and continuum models to simulate contact-dependent bacterial combat.
• Experimental validation using genetically engineered strains of Pseudomonas aeruginosa.
• Timelapse single-cell microscopy to observe and quantify bacterial interactions and motility-driven processes.

Main Results:

• Motility significantly increases the probability of contact between attacker and sensitive bacterial cells through genotypic mixing.
• Target switching, facilitated by motility, ensures continuous engagement with new competitors, preventing repeated attacks on the same cell.
• The combination of motility and CDI in Pseudomonas aeruginosa demonstrated a synergistic effect, increasing weapon efficacy by up to 10,000-fold compared to non-motile scenarios.

Conclusions:

• Bacterial motility is a crucial factor that potentiates the power of contact-dependent weapons.
• Motility enhances bacterial competition through genotypic mixing and effective target switching.
• The synergistic interaction between motility and weapons like CDI provides a significant advantage in bacterial warfare.