Near-ultraviolet mutagenesis in superoxide dismutase-deficient strains of Escherichia coli

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Environmental Health Perspectives; (United States)

DOI:https://doi.org/10.1289/ehp.9410288· OSTI ID:6820442

Knowles, R L ^[1]; Eisenstark, A ^[2]

---

1. Univ. of Missouri, Columbia, MO (United States)
2. Cancer Research Center, Columbia, MO (United States)

We compared mutagenic spectra induced by polychromatic near-ultraviolet radiation (near-UV; 300-400 nm) with superoxide anion (O[sub 2][sup [minus]])-dependent mutagenesis using a set of Escherichia coli tester strains. Near-UV radiation produced increased frequencies of G:C to A:T transitions, G:C to T:A and A:T to T:A transversions, and small increases in frameshift mutations in wild-type cells. Tester strains lacking superoxide dismutase (SOD) activity (sodAsodB double mutants) demonstrated high spontaneous mutation frequencies and increased near-UV sensitivity. The double mutants also showed increased mutations induced by near-UV sensitivity. The double mutants also showed increased mutations induced by near-UV compared to either isogenic wild type, sodA or sodB single mutants. Futhermore, these mutants had an unusual spontaneous mutation spectrum, with a predominance of A:T to T:A transversions, followed by G:C to T:A transversions and frameshifts generated in runs of adenines and frameshifts generated in runs of adenines in both the +1 and -1 direction. Other frameshifts were detected to a lesser degree. The oxygen dependency and the type of mutations spontaneously induced in SOD-deficient cells indicated that this mutagenic spectrum was caused by oxidative DNA damage. However, no apparent synergistic action between near-UV radiation and an increased flux of O[sub 2][sup [minus]] could be detected. From the frequency and types of mutations induced by the two agents, we speculate that near-UV-induced mutagenesis and O[sub 2][sup [minus]]-dependent mutagenesis involve, in part, different lesion(s) and/or mechanism(s). The nature and possible mutagenic pathways of each are discussed. 41 refs., 5 figs., 3 tabs.

• OSTI ID: 6820442
• Journal Information: Environmental Health Perspectives; (United States), Journal Name: Environmental Health Perspectives; (United States) Vol. 102:1; ISSN EVHPAZ; ISSN 0091-6765
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560152* -- Radiation Effects on Animals-- Animals
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BIOLOGICAL PATHWAYS
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
MICROORGANISMS
MUTAGENESIS
MUTATIONS
NEAR ULTRAVIOLET RADIATION
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTEINS
RADIATIONS
RESPONSE MODIFYING FACTORS
SENSITIVITY
SPONTANEOUS MUTATIONS
SUPEROXIDE DISMUTASE
ULTRAVIOLET RADIATION