Irradiation of Bacteroides fragilis cells with far-UV light resulted in the immediate, rapid and extensive degradation of DNA which continued for 40 to 60 min after irradiation. During the degradation phase, DNA synthesis was decreased but was never totally inhibited. DNA degradation after irradiation was inhibited by chloramphenicol and caffeine. DNA synthesis in irradiated cells was reduced by chloramphenicol but resumed after 100 min at the same exponential rate as in irradiated cells without chloramphenicol. Irradiated cells continued to synthesize DNA for 40 min in the presence of caffeine but after this time DNA synthesis was completely inhibited and never recovered. RNA and protein synthesis were decreased by UV irradiation and the degree of inhibition was proportional to the UV dose. Colony formation was not affected immediately by UV irradiation and continued for a dose-dependent period before inhibition. There was an inverse relationship between UV dose and inhibition of colony formation which occurred sooner in cells irradiated with lower doses of UV light. The characteristics of DNA synthesis in B. fragilis cells after UV irradiation differ from those in wild-type Escherichia coli cells, where DNA synthesis is stopped immediately by UV irradiation, but resemble those in E. coli recA mutant cells where extensive degradation occurs following UV irradiation.
BoyleJ. M., SetlowR. B.1970; Correlations between host-cell reactivation and pyrimidine dimer excision in the DNA of bacteriophage lambda. Journal of Molecular Biology 51:131–144
HallJ. D., MountD. W.1981; Mechanisms of DNA replication and mutagenesis in ultraviolet- irradiated bacteria and mammalian cells. Progress in Nucleic Acid Research and Molecular Biology 25:54–126
HoriiT., OgawaT., OgawaH.1980; Organization of the recA gene of Escherichia coli.. Proceedings of the National Academy of Sciences of the United States of America 77:313–317
JonesD. T., RobbF. T., WoodsD. R.1980; Effect of oxygen on Bacteroides fragilis survival after far-ultraviolet irradiation. Journal of Bacteriology 144:1179–1181
KelnerA.1953; Growth, respiration, and nucleic acid synthesis in ultraviolet-irradiated and in photoreactivated Escherichia coli. Journal of Bacteriology 65:252–262
KogomaT., LarkK. G.1970; DN A replication in Escherichia coli: replication in absence of protein synthesis after replication inhibition. Journal of Molecular Biology 52:143–164
KogomaT., LarkK. G.1975; Characterization of the replication of Escherichia coli DNA in the absence of protein synthesis: stable DNA replication. Journal of Molecular Biology 94:243–256
KogomaT., TorreyT. A., ConnaughtonM. J.1979; Induction of UV-resistant DNA replication in Escherichia coli: induced stable DNA replication as an SOS function. Molecular and General Genetics 176:1–9
LarkK. G., LarkC. A.1978; RecT-dependent DNA replication in the absence of protein synthesis: characteristics of a dominant lethal replication mutation, dnaT, and requirement for recA+ function. Cold Spring Harbor Symposia on Quantitative Biology 43:537–549
SancarA., StachelekC., KonigsbergW., RuppW. D.1980; Sequences of the recA gene and protein. Proceedings of the National Academy of Sciences of the United States of America 77:2611–2615
SattaG., GudasL. J., PardeeA. B.1979; Degradation of Escherichia coli DNA: evidence for limitation in vivo by protein X, the recA gene product. Molecular and General Genetics 168:69–80
SladeH.J.K., JonesD. T., WoodsD. R.1981; Effect of oxygen radicals and peroxide on survival after UV irradiation and liquid holding recovery of Bacteroides fragilis. Journal of Bacteriology 147:685–687
SladeH.J.K., SchumannJ. P., ParkerJ. R., JonesD. T., WoodsD. R.1983; Effect of oxygen on host cell reactivation in Bacteroides fragilis. Journal of Bacteriology 153:1545–1547
SmithK. C., O’LearyM. E.1968; The pitfalls of measuring DNA synthesis kinetics as exemplified in ultraviolet radiation studies. Biochimica et biophysica acta 169:430–438
StuyJ. H.1961; Studies on the radiation inactivation of microorganisms. VII. Nature of the X-ray induced breakdown of deoxyribonucleic acid in Haemophilus influenzae. Radiation Research 14:56–65
SwensonP. A.1976; Physiological responses of E. coli to far-UV radiation. . In Photochemical and Photobiological Reviews1 pp. 269–387SmithK. C. Edited by New York: Plenum Publishing Corp;
SwensonP. A., SetlowR. B.1966; Effects of ultraviolet radiation on macromolecular synthesis in Escherichia coli. Journal of Molecular Biology 15:201–219
TrgovcevicZ., PetranovicD., PetranovicM., Salaj-SmicE.1980; RecA gene product is responsible for inhibition of deoxyribonucleic acid synthesis after ultraviolet irradiation. Journal of Bacteriology 143:1506–1508
WillettsN. S., ClarkA. J.1969; Characteristics of some multiple recombination-deficient strains of Escherichia coli. Journal of Bacteriology 100:231–239
WilliamsJ.G.K., ShibataT., RaddingC. M.1981; Escherichia coli recA protein protects singlestranded DNA or gapped duplex DNA from degradation by recBC DNase. Journal of Biological Chemistry 256:7573–7582
YoungsD. A., BernsteinI. A.1973; Involvement of the recB-recC nuclease (exonuclease V) in the process of X-ray-induced deoxyribonucleic acid degradation in radiosensitive strains of Escherichia coli. Journal of Bacteriology 113:901–906