title: delta-Aminolaevulinic acid-induced porphyrin synthesis and photodynamic inactivation of Escherichia coli B.
abstract: The possibility and conditions for the induction of porphyrin synthesis by exogenous delta-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 degrees 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 are 10-15 min of incubation of a bacterial culture of 2 x 10(7) 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.
authors.affiliation: Institute of Biophysics, Semmelweis University of Medicine, Budapest, Hungary.
authors.forename: K
authors.initials: K
authors.lastname: Szocs
authors.forename: F
authors.initials: F
authors.lastname: Gabor
authors.forename: G
authors.initials: G
authors.lastname: Csik
authors.forename: J
authors.initials: J
authors.lastname: Fidy
mesh_terms: D000622:Aminolevulinic Acid / Q000494:pharmacology*; D003306:Coproporphyrins / Q000096:biosynthesis; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D008652:Mesoporphyrins / Q000096:biosynthesis; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011166:Porphyrins / Q000096:biosynthesis*; D011524:Protoporphyrins / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D003306:Coproporphyrins; D008652:Mesoporphyrins; D017319:Photosensitizing Agents; D011166:Porphyrins; D011524:Protoporphyrins; C026971:coproporphyrin III; C031468:mesoporphyrin IX; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX