| Formation of 8-oxoguanine in cellular DNA of Escherichia coli strains defective in different antioxidant defences. | |
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MedLine Citation:
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PMID: 9862189 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This paper examines the relationship in Escherichia coli between the in vivo content of 8-oxoguanine (8-oxoG) in chromosomal DNA and deficiencies of various key antioxidant defences. The structural genes for catalases (katG and katE), cytosolic superoxide dismutases (sodA and sodB) or formamidopyrimidine-DNA glycosylase (fpg) were inactivated to obtain bacterial strains lacking the scavenger enzymes for H2O2 or O2.- or the DNA repair protein for 8-oxoG. Wild-type bacteria showed 5-fold increased sensitivity to both lethality and mutagenesis by H2O2 in K medium (1% casamino acids and 1% glucose), as compared with nutrient broth. This higher sensitivity was associated with increased chromosomal oxidative damage, estimated as the 8-oxodG content, and with a marked decrease in both catalase and SOD activities. Bacteria lacking both cytosolic SODs (sodA sodB mutant) displayed increased 8-oxodG content in chromosomal DNA (2.8-fold that of the wild-type) when grown under standard aerated conditions. Comparatively, no significant difference in 8-oxodG content was observed in cells grown without aeration. Bacteria totally devoid of catalase activity (katG katE mutant) showed wild-type contents of 8-oxodG in chromosomal DNA when grown under aerated conditions. Nevertheless, the protective role of catalase in preventing formation of 8-oxodG in chromosomal DNA became evident under oxidative stress conditions: growth under hyperoxygenation and, particularly, following H2O2 exposure. Catalase deficiency resulted in a dramatic decrease in viability after H2O2 exposure. A deficiency of Fpg protein also sensitized E.coli to H2O2 lethality, though to lesser extent than a deficiency of catalase activity. However, the scavenger enzyme and the DNA repair protein protected equally against 8-oxoG formed in vivo upon H2O2 treatment. |
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Authors:
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J Alhama; J Ruiz-Laguna; A Rodriguez-Ariza; F Toribio; J López-Barea; C Pueyo |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Mutagenesis Volume: 13 ISSN: 0267-8357 ISO Abbreviation: Mutagenesis Publication Date: 1998 Nov |
Date Detail:
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Created Date: 1999-02-25 Completed Date: 1999-02-25 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8707812 Medline TA: Mutagenesis Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 589-94 Citation Subset: IM |
Affiliation:
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Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, España. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Alkaline Phosphatase
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chemistry,
metabolism Bacterial Proteins / genetics, metabolism Catalase / drug effects, genetics*, metabolism Cell Division / drug effects, genetics Culture Media DNA, Bacterial / chemistry, drug effects, metabolism* Escherichia coli / classification, drug effects, genetics* Guanine / analogs & derivatives*, biosynthesis Hydrogen Peroxide / pharmacology Hydrolysis Mutagenesis Oxidants / metabolism Oxidative Stress Peroxidases / drug effects, genetics, metabolism Species Specificity Superoxide Dismutase / drug effects, genetics*, metabolism |
| Chemical | |
Reg. No./Substance:
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0/Bacterial Proteins; 0/Culture Media; 0/DNA, Bacterial; 0/Oxidants; 0/SodA protein, Bacteria; 0/SodB protein, Bacteria; 5614-64-2/8-hydroxyguanine; 73-40-5/Guanine; 7722-84-1/Hydrogen Peroxide; EC 1.11.1.-/Peroxidases; EC 1.11.1.-/hydroperoxidase II; EC 1.11.1.6/Catalase; EC 1.11.1.6/catalase HPI; EC 1.15.1.1/Superoxide Dismutase; EC 3.1.3.1/Alkaline Phosphatase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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