title: The role of oxidative stress genes and effect of pH on methylene blue sensitized photooxidation of Escherichia coli.
abstract: In this study, the survival time of wild type E. coli W3110 and 11 mutants was analysed with a plate count method in methylene blue added or control groups under daylight fluoroscence illumination (4950 lux) at different pH values (5.0, 6.0, 7.0, and 8.0) in phosphate buffer. As a result, while the number of bacteria did not decrease under photooxidative stress at pH 5.0 and 6.0 during a 6-hour incubation, the wild type and all mutants decreased more than 2 log. at pH 8.0, and approximately one log. at pH 7.0. It was determined that a 2 log decrease in wild type E. coli takes 3.7 h according to t99 value at pH 8, these values were 2.39 h in the katE mutant, 2.64 h in the soxR mutant, 2.67 h in the oxyR mutant, 2.71 h in the sodB mutant, 3 h in the btuE mutant, 3.38 h in the zwf mutant and 3.40 h in the soxS mutant, respectively (p < 0.05). The roles of these genes were proved with complement tests. Finally, it is found that the effectiveness of photooxidative stress is in direct relation with pH, and the katE, soxR, oxyR, sodB, btuE, zwf, and soxS genes are important for the protection against this stress.
authors.affiliation: Faculty of Education, Amasya University , Amasya , Turkey.
authors.forename: Önder
authors.initials: Ö
authors.lastname: İdil
authors.affiliation: Department of Biology, Institute of Sciences, Amasya University , Amasya , Turkey.
authors.forename: İkbal
authors.initials: İ
authors.lastname: Macit
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Arts and Science, Bilecik Şeyh Edebali University , Bilecik , Turkey.
authors.forename: Özge
authors.initials: Ö
authors.lastname: Kaygusuz
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Arts and Science, Bilecik Şeyh Edebali University , Bilecik , Turkey.
authors.forename: Cihan
authors.initials: C
authors.lastname: Darcan
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D006863:Hydrogen-Ion Concentration; D008027:Light; D008751:Methylene Blue; D018384:Oxidative Stress / Q000235:genetics*
chemical_list: D008751:Methylene Blue
keywords: E. coli; katE; oxyS; photooxidation; sodB; soxRS