title: A study on the bacterial photo-toxicity of phenothiazinium based photosensitisers.
abstract: "Comet assay" showed light activated (3.15 Jcm-2 over 30 min) phenothiazinium based photosensitisers (PhBPs) to induce photo-damage of Staphylococcus aureus DNA, as indicated by DNA "tails" between 80 and 120 microm. In general, PhBPs exhibited significant singlet oxygen yields (Phi(DeltaPhBP)>0.7), suggesting the use of type II mechanisms of photo-oxidation. However, the photodynamic action of PhBPs on DNA showed generally insignificant production of 7,8-dihydro-8-oxo-2'-deoxyguanosine, normally a major product of type II DNA photo-oxidation. These combined results show DNA to be a major site of action of PhBPs and suggest that this action may involve type II attack on a nucleoside(s) other than guanosine.
authors.affiliation: Department of Forensic and Investigative Science, University of Central Lancashire, Preston, PR1 2HE, England, UK.
authors.forename: Zia
authors.initials: Z
authors.lastname: Sayed
authors.forename: Frederick
authors.initials: F
authors.lastname: Harris
authors.forename: David A
authors.initials: DA
authors.lastname: Phoenix
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D010582:Bacteriophage lambda / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects; D020552:Comet Assay; D004249:DNA Damage; D004269:DNA, Bacterial / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects; D004279:DNA, Viral / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D010084:Oxidation-Reduction; D010640:Phenothiazines / Q000494:pharmacology*; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000737:chemistry / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004279:DNA, Viral; D010640:Phenothiazines; D017319:Photosensitizing Agents; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine