title: Quantification of ultraviolet-C irradiation induced cyclobutane pyrimidine dimers and their removal in Beauveria bassiana conidiospore DNA.
abstract: Ultraviolet (UV) radiation-induced DNA damage leading to entomopathogenic fungal inactivation is commonly measured by viability counts. Here we report the first quantification of UV-induced cyclobutane pyrimidine dimers (CPD) in DNA of the entomopathogenic fungus, Beauveria bassiana. Changes in the mobility of UV-C irradiated DNA were resolved with CPD specific bacteriophage T4 endonuclease V and alkaline agarose gel electrophoresis. The maximum number of CPD formed in B. bassiana DNA in vitro by UV-C irradiation was 28 CPD/ 10 kb after 720 J/m2 dose. The maximum number of CPDs formed in B. bassiana conidiospore DNA irradiated in vivo was 15 CPD/10 kb after 480 J/m2 dose and was quantified from conidiospores that were incubated to allow photoreactivation and nucleotide excision repair. The conidiospores incubated for photoreactivation and nucleotide excision repair showed decreased number of CPD/10 kb DNA and a higher percent survival of conidiospore populations than conidiospores not allowed to repair.
authors.affiliation: Department of Applied Microbiology and Food Science, College of Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8 Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Chelico
authors.forename: Janna L
authors.initials: JL
authors.lastname: Haughian
authors.forename: Adrienne E
authors.initials: AE
authors.lastname: Woytowich
authors.forename: George G
authors.initials: GG
authors.lastname: Khachatourians
mesh_terms: D015169:Colony Count, Microbial; D032661:Cordyceps / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D043224:Deoxyribonuclease (Pyrimidine Dimer) / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D011740:Pyrimidine Dimers / Q000378:metabolism*; D013172:Spores, Fungal / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D011740:Pyrimidine Dimers; D014764:Viral Proteins; C470698:endonuclease V, phage T4; D043224:Deoxyribonuclease (Pyrimidine Dimer)