CORRELATION BETWEEN PORPHYRIN BIOSYNTHESIS AND PHOTODYNAMIC INACTIVATION OF PSEUDOMONAS-AERUGINOSA AFTER INCUBATION WITH 5-AMINOLEVULINIC ACID

The porphyrin biosynthesis of Pseudomonas aeruginosa was examined with respect to porphyrin and porphyrinogen formation using fluorescence s pectroscopy and high performance liquid chromatography (HPLC) techniqu es. The porphyrin and porphyrinogen profiles, as well as the fluoresce nce spectra, were determined for different growth phases and after inc ubation with 5-aminolaevulinic acid (5-ALA). The fluorescence maxima w ere attributed to coproporphyrin (618 nm and 685 nm) or protoporphyrin (635 nm and 703 nm). Incubation of Pseudomonas aeruginosa with 5-ALA led to enhanced protoporphyrin accumulation as confirmed by fluorescen ce measurements and HPLC analyses. In addition to protoporphyrin synth esis, 5-ALA was mainly converted into non-fluorescing and photodynamic ally inactive porphyrinogens. Coproporphyrinogen was found to be the p redominant substance. In addition, uroporphyrinogen, 7-carboxyporphyri nogen, 6-carboxyporphyrinogen and 5-carboxyporphyrinogen were determin ed. Consequently, the photodynamic inactivation of Pseudomonas aerugin osa was almost negligible after incubation with 5-ALA and irradiation with laser light at 630 nm. (C) 1997 Elsevier Science S.A.