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Using the Overlay Assay to Qualitatively Measure Bacterial Production of and Sensitivity to Pneumococcal Bacteriocins
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Bactericidal effect of bovine lactoferrin and synthetic peptide lactoferrin chimera in Streptococcus pneumoniae and

Nidia León-Sicairos1, Uriel A Angulo-Zamudio, Jorge E Vidal

  • 1Unidad de Investigación, Facultad de Medicina, Universidad Autónoma de Sinaloa, Cedros y Sauces, Fracc. Fresnos., C.P. 80246, Culiacán, Sinaloa, Mexico, nidialeon@uas.edu.mx.

Biometals : an International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
|July 24, 2014
PubMed

Insights

Bovine lactoferrin (bLF) and a chimeric peptide (LFchimera) show bactericidal effects against Streptococcus pneumoniae. These agents also reduce bacterial virulence by down-regulating key genes, offering potential for new pneumococcal infection treatments.

Area of Science:

  • Microbiology
  • Immunology
  • Biochemistry

Background:

  • *Streptococcus pneumoniae* (pneumococcus) causes nearly one million child deaths annually from infections like pneumonia and meningitis.
  • Lactoferrin (LF) is an antibacterial protein in the human immune system, but its efficacy against pneumococcus requires further study.

Purpose of the Study:

  • To evaluate the bactericidal activity of bovine lactoferrin (bLF) and synthetic lactoferrin-derived peptides against *S. pneumoniae*.
  • To investigate the mechanism of bacterial damage and the impact on virulence gene expression.

Main Methods:

  • Treatment of *S. pneumoniae* planktonic cells with bLF and LF-peptides.
  • Assessment of cell viability (CFU/ml), interaction via confocal microscopy and flow cytometry, structural damage via electron microscopy, membrane permeabilization, and gene expression (qRT-PCR).

Main Results:

  • bLF and LFchimera demonstrated significant bactericidal effects.
  • Interaction with bacteria caused morphological changes and membrane permeabilization.
  • LF treatment led to down-regulation of the *luxS* gene, a key virulence factor.

Conclusions:

  • bLF and LFchimera exhibit potent bactericidal activity against *S. pneumoniae*.
  • LF and LFchimera disrupt bacterial cell structure and membrane integrity.
  • LF's ability to down-regulate virulence genes highlights its potential as a novel therapeutic agent for pneumococcal infections.

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