Yield of radiation-induced DNA single-strand breaks in Escherichia coli and superinfecting phage lambda at different dose rates. Repair of strand breaks in different buffers

Journal Article · Wed Dec 01 04:00:00 EST 1976 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574331· OSTI ID:7234083

Boye, E ^[1]; Johansen, I; Brustad, T

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1. Norwegian Radium Hospital, Oslo

Cells of E. coli K-12 strain AB 1886 were irradiated in oxygenated phosphate buffered saline at 2/sup 0/C with electrons from a 4-MeV linear accelerator. The yield of DNA single-strand breaks was determined as a function of the dose rate between 2.5 and 21,000 krad/min. For dose rates over 100 krad/min the yield was found to be constant. Below 10 krad/min the yield of breaks decreases drastically. This is explained by rejoining of breaks during irradiation. Twenty percent of the breaks induced by acute exposure are repaired within 3 min at 2/sup 0/C. Superinfecting phage lambda DNA is repaired at the same rate as chromosomal DNA. In contrast to the results obtained with phosphate-buffered saline, an increase in the number of breaks after irradiation is observed when the bacteria are suspended in tris buffer. It is suggested that buffers of low ionic strength facilitate the leakage through the membrane of a small-molecular-weight component(s) necessary for DNA strand rejoining.

• OSTI ID: 7234083
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 68:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560112* -- Radiation Effects on Biochemicals-- In Microorganisms-- (-1987)
560131 -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BUFFERS
DNA
DOSE RATES
ELECTRONS
ELEMENTARY PARTICLES
ESCHERICHIA COLI
FERMIONS
IRRADIATION
LEPTONS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIOINDUCTION
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
STRAND BREAKS