Radiation-induced damage in E. coli B: The effect of superoxide radicals and molecular oxygen. Progress report, December 1, 1978--November 30, 1979

Technical Report · Thu Nov 01 04:00:00 EST 1979

DOI:https://doi.org/10.2172/5932727· OSTI ID:5932727

Samuni, A; Czapski, G

The roles of superoxide radicals and of molecular oxygen in the radiodamage of E. coli B suspended in dilute phosphate buffer were studied. The presence of high concentrations of polyethylene glycol in the ..gamma..-irradiated cell suspensions, had no effect on bacterial radiosensitivity. This indicates that the damage was primarily endogenous, i.e. originated intracellularly. Saturation of the cell suspensions with N/sub 2/O doubled the radiosensitivity, thus indicating that OH radicals are responsible for the majority of the damage (indirect radiation effect). The presence of oxygen either in the absence or presence of N/sub 2/O brought about roughly a three-fold increase in the radiosensitivity. Since in the presence of N/sub 2/O all e/sup -//sub aq/ are scavenged by the nitrous oxide rather than by oxygen, this shows that superoxide radicals play no role in the bacterial radiodamage. Our results substantiate the attribution of the oxygen effect to a direct interaction of O/sub 2/ with the hydroxyl-radical-damaged sites on vital biomolecules, and exclude any significant contribution of e/sup -//sub aq/ and superoxide radicals to the cellular radiodamage.

• Research Organization: Hebrew Univ., Jerusalem (Israel)
• Sponsoring Organization: USDOE
• OSTI ID: 5932727
• Report Number(s): COO-3221-56
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560112 -- Radiation Effects on Biochemicals-- In Microorganisms-- (-1987)
560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BUFFERS
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CRYOGENIC FLUIDS
DATA
DATA FORMS
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ESCHERICHIA COLI
EXPERIMENTAL DATA
FERMIONS
FLUIDS
FORMATES
GAMMA RADIATION
HYDROXYL RADICALS
IN VITRO
INFORMATION
IONIZING RADIATIONS
IRRADIATION
ISOLATED VALUES
LEPTONS
MICROORGANISMS
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
POLYETHYLENE GLYCOLS
POLYMERS
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
SOLUTIONS
SOLVATED ELECTRONS
SUPEROXIDE RADICALS
SURVIVAL CURVES