Pyrimidine Dimer Excision Repair of DNA in Bacteroides fragilis Wild-type and Mitomycin C-sensitive/UV-sensitive Mutants

Abstract

An enzyme preparation purified from Micrococcus luteus was shown to be specific for UVinduced pyrimidine dimers and was suitable for the detection of DNA excision repair systems. The wild-type Bacteroides fragilis Bf-2 strain and a mitomycin C-sensitive mutant (MTC25) had constitutive dimer excision systems which functioned efficiently under anaerobic and aerobic conditions. A UV-sensitive mutant (UVS9) had markedly reduced levels of the constitutive dimer excision systems under anaerobic and aerobic conditions. Since liquid holding recovery under aerobic conditions was inhibited by chloramphenicol whereas the final level of excision repair in B. fragilis Bf-2 was not affected, it is concluded that pyrimidine dimer removal is not the process responsible for increased physiological aerobic liquid holding recovery.

Bacteroides fragilis RecA protein overexpression causes resistance to metronidazole

“…Denaturing gel electrophoresis was performed to investigate DNA strand breaks (Abratt et al., 1986) and the gel was visualised with short wavelength UV light using GelDoc (BioRad) and photographed.…”