Assessment of oxidative DNA damage in the oxyR-deficient SOS chromotest strain escherichia coli PQ300

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Environmental and Molecular Mutagenesis; (United States)

DOI:https://doi.org/10.1002/em.2850200408· OSTI ID:6526766

Mueller, J ^[1]; Janz, S ^[2]

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1. Leipzig Univ. (Germany)
2. National Cancer Institute, Bethesda, MD (United States)

The SOS chromotest is a simple short-term genotoxicity assay measuring the induction of gene sfiA in Escherichia coli K-12. The recent availability of SOS tester strains with additional mutations in DNA repair or protection systems allows testing of DNA damaging compounds for genotoxic specificity. E. coli PQ300 differs from the standard SOS tester strain PQ37 in that it contains an additional mutation in gene oxyR that renders it more sensitive to oxidative genotoxins. The generation of reactive oxygen intermediates (ROI) by hydroperoxides (H[sub 2]O[sub 2], t-butyl hydroperoxide, cumene hydroperoxide), [gamma]-radiation, glucose oxidase, and xanthine oxidase resulted in a more vigorous SOS response in strain PQ300 compared to strain PQ37. PQ300 was also more sensitive than PQ37 for the detection of reducing agents such as ascorbic acid, cysteine, and glutathione, which also alter the redox status of the bacterial cells. However, intercalating agents (adriamycin, bleomycin, and mitomycin C) and the UV- and radiomimetic compound 4-nitroquinoline-1-oxide whose DNA damaging potential are known also to involve ROI did not show significant differences between strains PQ37 and PQ300. It is concluded that the oxyR-deficient strain PQ300 is useful for detecting certain classes of genotoxins that change the oxidative/antioxidative balance of tester bacteria in the SOS chromotest. 70 refs., 4 figs., 1 tab.

• OSTI ID: 6526766
• Journal Information: Environmental and Molecular Mutagenesis; (United States), Vol. 20:4; ISSN 0893-6692
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ESCHERICHIA COLI
MUTAGENS
CHROMOSOMAL ABERRATIONS
DNA REPAIR
DNA REPLICATION
DNA SEQUENCING
DOSE-RESPONSE RELATIONSHIPS
GENE REGULATION
MUTAGEN SCREENING
MUTAGENESIS
SUPEROXIDE DISMUTASE
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
ELECTROMAGNETIC RADIATION
ENZYMES
MICROORGANISMS
MUTATIONS
NUCLEIC ACID REPLICATION
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTEINS
RADIATIONS
REPAIR
SCREENING
STRUCTURAL CHEMICAL ANALYSIS
550700* - Microbiology
550400 - Genetics