Inducible reactivation of bacteriophage T7 damaged by methyl methanesulfonate or UV light
An examination was made of the effects of host mutations affecting ''SOS''-mediated UV light reactivation on the survival of bacteriophage T7 damaged by UV light or methyl methanesulfonate (MMS). Survival of T7 alkylated with MMS was not affected by the presence of plasmid pKM101 or by a umuC mutation in the host. The survival of UV light-irradiated T7 was similar in umuC/sup +/ and umuC strains but was slightly enhanced by the presence of pKM101. When phage survival was determined on host cells preirradiated with a single inducing dose of UV light, these same strains permitted higher survival than that seen with noninduced cells for both UV light- and MMS-damaged phage. The extent of T7 reactivation was approximately proportional to the UV light inducing dose inflicted upon each bacterial strain and was dependent upon phage DNA damage. Enhanced survival of T7 after exposure to UV light or MMS was also observed after thermal induction of a dnaB mutant. Thus, lethal lesions introduced by UV light or MMS are apparently repaired more efficiently when host cells are induced for the SOS cascade, and this inducible reactivation of T7 is umuC/sup +/ independent.
- Research Organization:
- Univ. of Tennessee, Oak Ridge
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6208848
- Journal Information:
- J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 156:1; ISSN JOBAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560302* -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIOPHAGES
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA REPAIR
DOSE-RESPONSE RELATIONSHIPS
ELECTROMAGNETIC RADIATION
ESTERS
METHYL METHANESULFONATE
MICROORGANISMS
MUTAGENS
MUTATIONS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PARASITES
PHOTOREACTIVATION
RADIATIONS
RECOVERY
REPAIR
SULFONIC ACID ESTERS
SURVIVAL CURVES
ULTRAVIOLET RADIATION
VIRUSES