Oxygen-dependent sensitization of irradiated cells. [Role of OH radicals]
Attention is focused primarily on O/sub 2/ effects in three biological systems, all tested in suspension: bacterial spores, vegetative bacterial cells, and mammalian cells. Information from these systems shows that O/sub 2/ has more than one process through which it can act. Studies with bacterial spore suspensions provide clear evidence that multiple components to oxygen-dependent radiation sensitization exist. Studies with mammalian cell suspensions also show that at least two oxygen-dependent sensitization processes can be distinguished. Similar studies with vegetative bacteria in suspension have not resolved oxic sensitization into components. The roles of water-derived radicals in radiation sensitivity and, specifically, in sensitization by O/sub 2/ were examined. OH radicals are clearly implicated in damage in all three biological test systems. However, the specific roles proposed for OH radicals are different in these organisms. In bacterial spores, OH radical removal in itself does not protect in anoxia or in high concentrations of O/sub 2/. OH radical removal over a limited intermediate range of O/sub 2/ concentrations will, however, protect. OH radical scavenging probably results in the formation of the actual protector. In bacteria, the supposition is that OH radical removal will protect both in anoxia and in the presence of O/sub 2/. OH radicals probably react with a cellular target molecule and leave a radicalsite; this is the site which can then react with O/sub 2/ to cause damage; DNA is the likely cellular target. In mammalian cells, a reaction scheme, similar to that proposed for bacteria, has been suggested for O/sub 2/-dependent sensitization. (ERB)
- Research Organization:
- Hahnemann Medical Coll. and Hospital, Philadelphia, PA (USA); Texas Univ., Austin (USA). Lab. of Radiation Biology
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- EY-76-S-05-3408
- OSTI ID:
- 5732066
- Report Number(s):
- CONF-790229--4
- Country of Publication:
- United States
- Language:
- English
Similar Records
Radiation-induced damage in Escherichia coli B: the effect of superoxide radicals and molecular oxygen. [. gamma. irradiation of bacterial suspensions]
Laboratory of Radiation Biology progress report, August 15, 1975--August 14, 1976
Related Subjects
560121 -- Radiation Effects on Cells-- External Source-- (-1987)
560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
AQUEOUS SOLUTIONS
BACTERIA
BACTERIAL SPORES
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BIOLOGICAL RADIATION EFFECTS
COMPARATIVE EVALUATIONS
CRYOGENIC FLUIDS
DATA
DATA FORMS
DISPERSIONS
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
HYDROXYL RADICALS
INFORMATION
ISOLATED VALUES
MICROORGANISMS
MIXTURES
NONMETALS
NUMERICAL DATA
OXYGEN
RADIATION EFFECTS
RADICALS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
SOLUTIONS
SPORES