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Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes
12:50

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Published on: August 9, 2011

Listeria monocytogenes mutants lacking phosphatidylinositol-specific phospholipase C are avirulent

A Camilli1, H Goldfine, D A Portnoy

  • 1Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104.

The Journal of Experimental Medicine
|March 1, 1991
PubMed

Insights

Listeria monocytogenes secretes phosphatidylinositol-specific phospholipase C (PI-PLC), crucial for its virulence. A PI-PLC-deficient mutant showed significantly reduced growth and pathogenicity in mice, highlighting PI-PLC

Area of Science:

  • Microbiology
  • Pathogenesis Research
  • Bacterial Molecular Biology

Background:

  • Phosphatidylinositol-specific phospholipase C (PI-PLC) is secreted by various bacterial species.
  • Listeria monocytogenes is a facultative intracellular bacterial pathogen.
  • The gene plcA in L. monocytogenes predicts a PI-PLC polypeptide.

Purpose of the Study:

  • To investigate the role of PI-PLC in Listeria monocytogenes pathogenesis.
  • To characterize the PI-PLC secreted by L. monocytogenes.
  • To determine if PI-PLC is essential for L. monocytogenes virulence.

Main Methods:

  • Gene identification and characterization (plcA).
  • Construction of a plcA-deficient mutant in L. monocytogenes.
  • Assessment of PI-PLC activity in wild-type and mutant strains.
  • Virulence studies in a mouse model.
  • In vitro growth assays in macrophages.

Main Results:

  • L. monocytogenes secretes PI-PLC activity, mediated by the plcA gene.
  • A plcA mutant lacked detectable PI-PLC activity.
  • The PI-PLC-deficient mutant exhibited a three-log reduction in virulence in mice.
  • The mutant failed to grow in host tissues and showed defective in vitro growth in macrophages.

Conclusions:

  • PI-PLC is an essential virulence factor for Listeria monocytogenes.
  • The secreted PI-PLC plays a critical role in L. monocytogenes pathogenesis.
  • Further research is needed to identify the specific substrate(s) of L. monocytogenes PI-PLC.

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