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Monalysin, a novel ß-pore-forming toxin from the Drosophila pathogen Pseudomonas entomophila, contributes to host

Onya Opota1, Isabelle Vallet-Gély, Renaud Vincentelli

  • 1Global Health Institute, Ecole Polytechnique Fédérale Lausanne-EPFL, Lausanne, Switzerland. onya.opota@epfl.ch

Plos Pathogens
|October 8, 2011
PubMed

Insights

Researchers discovered Monalysin, a novel pore-forming toxin (PFT) from Pseudomonas entomophila. This toxin contributes to bacterial virulence by damaging the insect gut, highlighting PFTs as a common entomopathogen strategy.

Area of Science:

  • Microbiology and Molecular Biology
  • Insect Pathology
  • Biochemistry

Background:

  • Pseudomonas entomophila is an insect pathogen that causes lethal damage to the Drosophila gut.
  • The bacterium's virulence is associated with its ability to disrupt gut epithelium renewal and repair.

Purpose of the Study:

  • To identify novel virulence factors contributing to Pseudomonas entomophila pathogenicity in Drosophila.
  • To characterize the function and mechanism of a newly identified pore-forming toxin (PFT).

Main Methods:

  • Identification and biochemical characterization of the novel toxin, Monalysin.
  • In vitro assays to assess oligomerization and pore formation in lipid membranes.
  • Analysis of Monalysin expression regulation and activation by other bacterial factors.
  • Assessment of virulence in a Drosophila infection model using a Monalysin-deficient mutant.

Main Results:

  • A novel PFT, Monalysin, was identified and shown to require N-terminal cleavage for full activity.
  • Monalysin forms oligomers and induces pores in artificial membranes, consistent with a β-type PFT.
  • Monalysin expression is regulated by GacS/GacA and Pvf systems; its activation is promoted by AprA protease.
  • A mutant lacking Monalysin exhibited reduced virulence and intestinal cell damage, confirming its role in pathogenesis.

Conclusions:

  • Monalysin is a key virulence factor of Pseudomonas entomophila, contributing to gut damage via pore formation.
  • The findings suggest that PFT production is a conserved strategy among entomopathogens to disrupt insect gut homeostasis.
  • This study expands our understanding of bacterial toxin mechanisms in insect-pathogen interactions.

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