Photosensitization of Wild and Mutant Strains ofEscherichia colibymeso-Tetra (N-methyl-4-pyridyl)porphine

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• 作者：Valduga ; Giuliana ; Breda ; Barbara ; Giacometti ; Giorgio M. ; Jori ; Giulio ; Reddi ; Elena
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：1999
• 出版时间：March 5, 1999
• 年：1999
• 卷：256
• 期：1
• 页码：84-88
• 全文大小：102 K

文摘

Wild typeEscherichia colicells as well as some mutant strains lacking specific DNA repair systems are efficiently killed upon visible light-irradiation after 5 min-incubation withmeso-tetra(4N-methyl-pyridyl)porphine (T₄MPyP). The presence of oxygen is necessary for cell photoinactivation. The porphyrin appears to exert its phototoxic activity largely by impairing some enzymic and transport functions at the level of both the outer and cytoplasmic membrane. Thus, SDS–PAGE electrophoresis shows a gradual attenuation of some transport protein bands as the irradiation proceeds, while a complete loss of lactate and NADH dehydrogenase activities is caused by 15 min-exposure to light. On the other hand, DNA does not represent a critical target of T₄MPyP photosensitization as suggested by the closely similar photosensitivity of the wildE. coliandE. colistrains defective for two different DNA repair mechanisms, as well as by the lack of any detectable alteration of the pUC19 plasmids extracted from photosensitizedE. coliTG1 cells.