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THE PHOTODYNAMIC INACTIVATION OF PHAGE PRECURSOR BY METHYLENE BLUE

A P Krueger1, E J Scribner, T Mecracken

  • 1Department of Bacteriology, University of California, Berkeley.

The Journal of General Physiology
|October 30, 2009
PubMed

Insights

Methylene blue and light inactivate Staphylococcus phage precursors without killing bacteria. A 15-minute lag phase occurs before light exposure triggers prompt inactivation.

Area of Science:

  • Photochemistry
  • Microbiology
  • Molecular Biology

Background:

  • Staphylococcus bacteria are significant pathogens.
  • Phage precursors are essential for bacteriophage replication.
  • Methylene blue is a photosensitizing dye.

Purpose of the Study:

  • To investigate the photodynamic inactivation of phage precursors in Staphylococcus.
  • To determine the effect of methylene blue and light on bacterial viability.

Main Methods:

  • Suspensions of activated staphylococci were treated with methylene blue.
  • Methylene blue was added at a concentration of 1 x 10^5 molecules/bacterium.
  • Mixtures were exposed to strong light (4000-8000 A).
  • Bacterial viability and phage precursor inactivation were assessed.

Main Results:

  • Methylene blue and light effectively inactivated phage precursor content.
  • Bacterial cell death was not observed under these conditions.
  • A lag phase of approximately 15 minutes preceded prompt inactivation.
  • The lag phase is attributed to an initial cell-dye reaction.

Conclusions:

  • Methylene blue-mediated photodynamic therapy can specifically target phage precursors in Staphylococcus.
  • This method offers a potential strategy for controlling phage propagation without harming bacteria.
  • Further research into the initial cell-dye interaction may elucidate precise mechanisms.

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