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Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes
14:05

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Published on: September 19, 2013

Mode of action of antimicrobial peptide P45 on Listeria monocytogenes

Lisana Reginini Sirtori1, Amanda de Souza da Motta, Adriano Brandelli

  • 1Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.

Journal of Basic Microbiology
|August 15, 2008
PubMed

Insights

Antimicrobial peptide P45 from Bacillus sp. lysed Listeria monocytogenes by damaging cell membranes and walls. This peptide shows potential for food and clinical applications.

Area of Science:

  • Microbiology
  • Biochemistry
  • Peptide Research

Background:

  • Antimicrobial peptides (AMPs) are crucial for innate immunity.
  • Investigating AMPs from novel sources like fish gut microbiota is important.
  • Bacillus sp. P45 produces an AMP with potential antimicrobial activity.

Purpose of the Study:

  • To investigate the mode of action of antimicrobial peptide P45.
  • To determine the bactericidal and bacteriolytic effects of peptide P45 on Listeria monocytogenes.
  • To elucidate the molecular targets of peptide P45.

Main Methods:

  • Purification of antimicrobial peptide P45 from Bacillus sp. P45 culture supernatants using ammonium sulfate precipitation and gel filtration chromatography.
  • Determination of the EC(50) and minimum inhibitory concentration (MIC) against Listeria monocytogenes.
  • Analysis of cell lysis via optical density (OD) measurements.
  • Microscopic examination using transmission electron microscopy (TEM) to visualize cellular damage.

Main Results:

  • Peptide P45 exhibited bactericidal and bacteriolytic activity against Listeria monocytogenes.
  • A concentration of 800 AU/ml of peptide P45 was effective in killing all viable Listeria monocytogenes cells.
  • Transmission electron microscopy revealed significant damage to the cell envelope and loss of protoplasmic material in treated cells.
  • The study suggests peptide P45 interferes with bacterial cell membranes and cell walls.

Conclusions:

  • Antimicrobial peptide P45 from Bacillus sp. P45 demonstrates a potent bactericidal and bacteriolytic mechanism of action against Listeria monocytogenes.
  • The peptide's mode of action involves disruption of the bacterial cell envelope, specifically targeting cell membranes and the cell wall.
  • Understanding the mechanism of action of AMPs like P45 is essential for their potential application in food preservation and clinical settings.

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