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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

Leucocins 4010 from Leuconostoc carnosum cause a matrix related decrease in intracellular pH of Listeria

Weihuan Fang1, Birgitte Bjørn Budde, Henrik Siegumfeldt

  • 1College of Animal Sciences, Zhejiang University, Zhejiang, China.

FEMS Microbiology Letters
|April 28, 2006
PubMed

Insights

Leuconostoc carnosum 4010 inhibits Listeria monocytogenes growth. Bacteriocins like leucocin 4010 and nisin dissipate the pH gradient in L. monocytogenes, with faster effects observed in liquid media compared to agar.

Area of Science:

  • Microbiology
  • Food Safety
  • Bacteriocin Research

Background:

  • Listeria monocytogenes is a significant foodborne pathogen.
  • Bacteriocins, such as those produced by Leuconostoc carnosum, show potential for controlling bacterial growth.

Purpose of the Study:

  • To investigate the antimicrobial effect of Leuconostoc carnosum 4010 on Listeria monocytogenes.
  • To determine the impact of bacteriocins (leucocin 4010 and nisin) on the intracellular pH (pHi) of Listeria monocytogenes.

Main Methods:

  • Co-culturing Listeria monocytogenes with Leuconostoc carnosum 4010.
  • Exposing Listeria monocytogenes to purified bacteriocins in liquid and agar matrices.
  • Measuring intracellular pH using fluorescence ratio imaging microscopy.

Main Results:

  • Co-culture demonstrated growth inhibition of L. monocytogenes, but intracellular pH remained unaffected.
  • Leucocin 4010 and nisin caused significant dissipation of the pH gradient in L. monocytogenes.
  • The matrix influenced bacteriocin efficacy, with faster pHi decrease in liquid compared to agar.

Conclusions:

  • Bacteriocins effectively disrupt the pH gradient in L. monocytogenes, impacting its physiology.
  • The physical state of the medium (liquid vs. agar) significantly affects bacteriocin activity and speed of action.

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