8-methoxypsoralen effects on survival and repair of Escherichia coli after ultraviolet irradiation: action spectra

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

DOI:https://doi.org/10.2307/3575123· OSTI ID:5571118

Hass, B S; Webb, R B

The action spectra of two strains of Escherichia coli over the wavelength range of 254 to 390 nm has been obtained in the presence of 8-methoxypsoralen (8-MOP). Strains WP2 (wild-type) and WP2Hcr(uvrA) showed greatly enhanced (10/sup 2 -/ to 10/sup 3/-fold) photosensitivity from 390 to 310 nm, the greatest effect appearing at 320 to 335 nm. At wavelengths from 300 to 254 nm the presence of 8-MOP produced no effect on lethal sensitization with WP2Hcr cells, but the WP2 strain exhibited a two-fold protection when 8-MOP was present. 8-MOP has a major absorption peak at 304 nm, the region of the least biological effect. The large shoulders on the survival curves of untreated cells of both strains irradiated at wavelengths above 300 nm was significantly diminished by the presence of 8-MOP. If such shoulders are caused by fluence-dependent repair processes, using the reciprocal of the shoulder fluence, F/sub q/, as a measure of the rate of production of sublethal damage, it appears that 8-MOP-sensitized damage is not repaired as efficiently as damage induced in the absence of 8-MOP. Two small regions in the action spectra were exceptions to this generality: the region of 300 to 315 nm for the WP2Hcr strain and of 300 to 285 nm for the WP2 strain.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5571118
• 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

560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION SPECTRA
ANTICOAGULANTS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL KILLING
COMPARATIVE EVALUATIONS
DATA
DATA FORMS
DNA
DRUGS
ELECTROMAGNETIC RADIATION
ESCHERICHIA COLI
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
IRRADIATION
ISOLATED VALUES
LETHAL IRRADIATION
MICROORGANISMS
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PSORALEN
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RESPONSE MODIFYING FACTORS
SPECTRA
SURVIVAL CURVES
ULTRAVIOLET RADIATION