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Phage-host interactions during pseudolysogeny: Lessons from the Pid/dgo interaction

William Cenens1, Angella Makumi, Mehari Tesfazgi Mebrhatu

  • 1Laboratory of Food Microbiology; Department of Microbial and Molecular Systems (M2S); Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium.

Bacteriophage
|July 3, 2013
PubMed

Insights

Researchers discovered phage carrier cells in Salmonella Typhimurium, supporting pseudolysogeny. A novel phage protein (Pid) expressed in these cells impacts host metabolism.

Area of Science:

  • Microbiology
  • Bacteriology
  • Virology

Background:

  • Bacteriophage P22-Salmonella Typhimurium interactions are crucial for understanding bacterial genetics and evolution.
  • Pseudolysogeny, a state where phage DNA persists without immediate lysis, has been historically challenging to study.
  • Recent findings suggest a more intricate role for phages beyond simple infection or lysogeny.

Purpose of the Study:

  • To provide molecular and genetic evidence for pseudolysogenic development in the Salmonella Typhimurium-phage P22 system.
  • To investigate the role of a newly discovered P22 ORFan protein (Pid) in pseudolysogenic cells.
  • To explore the impact of pseudolysogeny on both bacterial and phage biology.

Main Methods:

  • Utilized the Salmonella Typhimurium-phage P22 model system.
  • Employed molecular and genetic analyses to identify phage carrier cells.
  • Observed the behavior of episomal phage elements during cell division.
  • Analyzed the expression of the P22 ORFan protein (Pid) and its effect on the host dgo operon.

Main Results:

  • Confirmed the existence of phage carrier cells harboring an episomal P22 element in Salmonella Typhimurium.
  • Demonstrated asymmetric segregation of the episomal P22 element during bacterial cell division.
  • Identified a novel P22 ORFan protein (Pid) specifically expressed in phage carrier cells.
  • Showed that Pid can derepress a host metabolic operon (dgo), indicating phage influence on bacterial metabolism.

Conclusions:

  • Pseudolysogenic development is a viable phenomenon in the Salmonella Typhimurium-phage P22 system.
  • The P22 ORFan protein Pid plays a significant role in mediating phage-host interactions during pseudolysogeny.
  • Pseudolysogeny has demonstrable effects on bacterial metabolism and potentially influences bacterial and phage evolution.
Keywords:
Salmonella Typhimuriumphage P22phage carrier statephage–host interactionspseudolysogeny

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