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Following Cell-fate in E. coli After Infection by Phage Lambda
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Following Cell-fate in E. coli After Infection by Phage Lambda

Published on: October 14, 2011

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Phage liquid crystalline droplets form occlusive sheaths that encapsulate and protect infectious rod-shaped bacteria

Abul K Tarafder1,2, Andriko von Kügelgen1,2, Adam J Mellul3

  • 1Sir William Dunn School of Pathology, University of Oxford, OX1 3RE Oxford, United Kingdom.

Proceedings of the National Academy of Sciences of the United States of America
|February 20, 2020
PubMed

Insights

Pseudomonas aeruginosa uses filamentous phage Pf4 to form protective compartments, enhancing antibiotic tolerance. This phage-mediated biophysical occlusion offers a novel survival strategy for bacteria.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biophysics

Background:

  • * *Pseudomonas aeruginosa* is an opportunistic pathogen causing antibiotic-tolerant infections.
  • * Bacterial biofilms enable *P. aeruginosa* to evade antibiotics via filamentous phage Pf4.
  • * The mechanism of phage-mediated antibiotic tolerance requires investigation.

Purpose of the Study:

  • * To elucidate the mechanism of Pf4-mediated antibiotic tolerance.
  • * To determine the structural basis of Pf4 assembly and compartment formation.
  • * To explore the role of biophysical occlusion in bacterial survival.

Main Methods:

  • * Biochemical reconstitution of phage-mediated protection.
  • * Electron cryomicroscopy for atomic structure determination of Pf4.
  • * Optical microscopy and electron cryotomography for studying Pf4 assembly and droplet formation.
  • * Cellular imaging to observe compartment formation around bacteria.

Main Results:

  • * Atomic structures of Pf4 with and without its DNA genome were resolved.
  • * Pf4 assembles into liquid crystalline droplets, forming phase-separated occlusive compartments around bacteria.
  • * These compartments significantly increase bacterial survival, even with inanimate rod-shaped mimics.
  • * Shape and size complementarity are crucial for encapsulation efficiency.

Conclusions:

  • * Phage liquid crystalline droplets create protective compartments, conferring antibiotic tolerance to *P. aeruginosa*.
  • * Biophysical occlusion by filamentous molecules like Pf4 is a general bacterial survival strategy.
  • * This mechanism is relevant to other Gram-negative pathogens harboring similar prophages.
Keywords:
Pseudomonas aeruginosaantibiotic tolerancecryo-EMphagephase separation

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