δ-aminolaevulinic acid-induced porphyrin synthesis and photodynamic inactivation of Escherichia coli B.

K. Szocs, F. Gabor, G. Csik, J. Fidy

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The possibility and conditions for the induction of porphyrin synthesis by exogenous 6-aminolaevulinic acid (ALA) and its applicability for the inactivation of Gram-negative bacteria Escherichia coli B. by photodynamic therapy (PDT) have been studied. The bacteria are supplemented with ALA in the log phase of growth, and are grown in a synthetic medium at 37°C in the dark. The efficiency of porphyrin synthesis is detected by fluorescence spectroscopy performed on the isolated bacterial cells and the medium, respectively, and compared with results of high-performance liquid chromatography (HPLC) analysis. ALA stimulates the synthesis of protoporphyrin in the bacteria by a factor of five to six, and an increased amount of the more hydrophilic derivatives with a significant contribution of mesoporphyrin by a factor of two to three is observed in the culturing medium. The optimal conditions of ALA treatment with respect to PDT an 10-15 min of incubation of a bacterial culture of 2 x 107 cells ml-1 with (5-9) x 10-3 mol l-1 ALA. The ALA-treated cells are irradiated by white light of 80 mW cm-2 under growth conditions and a decrease to 0.6% of the number of colony-forming units (CFUs ml-1) is observed after 90 min of irradiation.

Original languageEnglish
Pages (from-to)8-17
Number of pages10
JournalJournal of Photochemistry and Photobiology B: Biology
Volume50
Issue number1
DOIs
Publication statusPublished - May 1 1999

Keywords

  • Endogenous porphyrins
  • Escherichia coli B. inactivation
  • Photodynamic therapy (PDT)
  • δ-aminolaevulinic acid

ASJC Scopus subject areas

  • Radiation
  • Radiological and Ultrasound Technology
  • Biophysics
  • Radiology Nuclear Medicine and imaging

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