Leukotoxicity of pyoverdin, production of reactive oxygen species, and effect of UV radiation.
Pyoverdin was purified by solvent extraction, gel filtration, and ionic exchange chromatography. Assays of cytotoxic of pyoverdin were done with human leukocytes and macrophages from the peritoneum of mice. Both cell quantities showed a significant reduction. Death was followed by lysis in a dose-dependent form. The mechanism of action of pyoverdin involved the stimulation of reactive oxygen species (ROS) measured by Nitroblue Tetrazolium (NBT) reaction and chemiluminescence (CL). UV radiation at 368 nm increased the leukotoxicity; expositions of 5 min were enough to photostimulate the effect of pyoverdin on cellular oxydative metabolism, which increased between 35.4 and 53.2%. Genestein, an inhibitor of tyrosine kinases, counteracted the ROS stimuli of pyoverdin, suggesting endocytic mechanism of action for this pigment. The little chloroquine interference on oxydative stress indicated that intraphagosomal pH and the stimuli of reactive nitrogen intermediaries (RNI) seem to be of less importance than ROS in pyoverdin action on leukocytes.
Becerra
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Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Cuidad Universitaria, 5000 Córdoba, Argentina.
Albesa
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Eraso
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AJ
D001426:Bacterial Proteins / Q000302:isolation & purification / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003624:Darkness; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008163:Luminescent Measurements; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D009580:Nitroblue Tetrazolium; D009842:Oligopeptides; D010860:Pigments, Biological / Q000302:isolation & purification / Q000494:pharmacology*; D011551:Pseudomonas fluorescens / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000502:physiology*; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D009842:Oligopeptides; D010860:Pigments, Biological; D017382:Reactive Oxygen Species; D009580:Nitroblue Tetrazolium; C042453:pyoverdin; D019833:Genistein