Pyrimidine dimer excision in surviving and nonsurviving cells of ultraviolet-irradiated cultures of Escherichia coli

Journal Article · Sat May 01 04:00:00 EDT 1976 · J. Bacteriol.; (United States)

OSTI ID:7286087

Schenley, R L; Fisher, W D; Swenson, P A

We compared dimer excision in viable and nonviable cell fractions separated from Escherichia coli B/r cultures exposed to ultraviolet (uv) irradiation. For cells grown on minimal medium with glycerol as a carbon source, both fractions from the irradiated (20 J/m/sup 2/, 5 percent survival) culture excised 60 to 70 percent of the thymine dimers from prelabeled DNA within 120 min. This percentage was, within experimental error, the same as that obtained from unseparated cultures. When isolated viable and nonviable populations were given a second uv exposure (20 J/m/sup 2/), both types of cells were again able to excise dimers. The uv survival curve for the isolated viable population indicates that these cells are no more sensitive to radiation than exponentially growing cells not previously exposed to uv. The extent of dimer excision after uv irradiation was also the same in viable and nonviable cells separated from cultures grown on a glucose minimal medium in which both populations excised about 85 percent of the dimers within 120 min. These results show that the extent of removal of pyrimidine dimers from deoxyribonucleic acid is not precisely correlated with survival of repair-competent bacterial cells after exposure to uv light. (auth)

• Research Organization: Oak Ridge National Lab., TN
• OSTI ID: 7286087
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 126:2; ISSN JOBAA
• 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.
AZINES
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CULTURE MEDIA
DIMERS
DNA
ELECTROMAGNETIC RADIATION
ESCHERICHIA COLI
HETEROCYCLIC COMPOUNDS
IRRADIATION
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
ULTRAVIOLET RADIATION