Oxygen dependence of sensitization to 254-nm radiation by prior exposure to 365-nm radiation in strains of Escherichia coli K12 differing in DNA repair capability

Journal Article · Mon Oct 01 04:00:00 EDT 1979 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575117· OSTI ID:5571134

Webb, R B; Brown, M S

Near-ultraviolet radiaton (320 to 400 nm) can produce both lethal and mutagenic effects in bacteria and other biological systems. It has been proposed that biological effects associated with DNA lesions produced by far-uv, near-uv, and x radiation are enhanced by near-uv damage to the DNA repair systems. The relationships between oxygen dependence of enhancement of sensitivity to 254-nm radiation by prior irradiation at 365 nm and the oxygen dependence of inactivation by 365-nm radiation were investigated in strains of Escherichia coli K12 differing in DNA repair capability. The oxygen enhancement ratios (OER) of the four E. coli K12 strains tested, based on 365-nm F/sub 10/ values, were as follows: AB1157 (wild type), 3.9; AB1886 (uvrA rec/sup +/), 3.3; AB2463 (uvr/sup +/ recA), 4.6; and AB2480 (uvrA recA), 1.04. A large oxygen enhancement also was observed for the 365-nm induced increase in 254-nm lethality in strains AB1157 and AB1886. However, the oxygen enhancement for the recA strain AB2463 was complex: in stationary-phase cells with 365-nm fluences below 8.0 X 10/sup 5/ J m/sup -2/, no oxygen dependence was observed for the 365-nm-induced decrease in 254-nm inactivaton, while with 365-nm fluences greater than 8.0 x 10/sup 5/ J m/sup -2/, a strong oxygen enhancement of the increase in 254-nm inactivation was observed. In exponential-phase cells of strain AB2463, a large oxygen dependence occurred for both photoprotection and for the 365-nm-induced increase in sensitivity to 254-nm radiation. It is concluded that oxygen-dependent damage to repair processes contributes significantly to the oxygen-dependent lethality at 365 nm. These results do not exclude a contribution of oxygen-dependent DNA lesions to 365-nm lethality.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5571134
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 80:1; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560114 -- Radiation Effects on Biochemicals-- In Animals-- (-1987)
560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANOXIA
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL KILLING
COMPARATIVE EVALUATIONS
DATA
DATA FORMS
DNA REPLICATION
ELECTROMAGNETIC RADIATION
ESCHERICHIA COLI
EXPERIMENTAL DATA
INFORMATION
ISOLATED VALUES
MICROORGANISMS
NEAR ULTRAVIOLET RADIATION
NUCLEIC ACID REPLICATION
NUMERICAL DATA
OXYGEN ENHANCEMENT RATIO
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
SURVIVAL CURVES
ULTRAVIOLET RADIATION