Date of Award
Doctor of Philosophy
Molecular, Cellular, and Developmental Biology
The mutations mit-376 and ngr-374 are described which effect genetic recombination and the apurinic/apyrimidinic (AP) endonuclease, respectively, in Staphylococcus aureus NCTC 8325. The mit-376 mutation was isolated from the Rec('-) mutant RN81. When transformed to other strains of S. aureus, this mutation caused sensitivity to DNA alkylating agents, mitomycin C, and UV irradiation. In addition, mit-376 caused a marked reduction in genetic recombination, the severity of which was related to the prophage content of the recipients. The ngr-374 mutation was also isolated from RN981 and caused an increase in sensitivity to DNA alkylating agents, nitrous acid, and UV irradiation. Bioassays for AP endonuclease activity showed that strains carrying ngr-374 have reduced levels of this endonuclease. Furthermore, the UV sensitivity of ngr-372-carrying strains suggests that S. aureus has an AP endonuclease-dependent DNA repair mechanism for UV-generated lesions. By protoplast fusion analysis and genetic transformations the chromosomal locations of these mutations were determined. mit-376 was in the linkage group purA102 - nov-142 - mit-376 - hisG15, and ngr-374 was in the linkage group (OMEGA) chr: :Tn551 42 - ngr-374 - thrB106.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Jeffrey Ernest Tam
Tam, Jeffrey Ernest, "Genetics and biology of mutations affecting genetic recombination, sensitivity to alkylating agents, and apurinic endonuclease in Staphylococcus aureus " (1984). Retrospective Theses and Dissertations. 7891.