title: Near-UV-induced radicals in Propionibacterium acnes, studied by electron spin resonance spectrometry at 77 K.
abstract: Suspensions of Propionibacterium acnes were UV irradiated and the induced radicals were measured at 77 K by electron spin resonance (ESR) spectrometry. Two types of radical were formed during irradiation and stabilized in the frozen suspensions. The relative yield of each radical was studied as a function of irradiation wavelength. The first radical, which was a singlet with a peak-to-peak width of 20 G, was insensitive to the deoxygenation of the samples and to the exchange of solvent water by heavy water. The action spectrum was similar to the absorption spectrum of NADPH. The second type of radical was not formed in deoxygenated samples and the shape of the ESR spectrum was characteristic of the superoxide radical. This radical was only formed at wavelengths below 340 nm.
authors.affiliation: Department of Physics/AVH, University of Trondheim, Dragvoll, Norway.
authors.forename: B
authors.initials: B
authors.lastname: Kjeldstad
authors.forename: T B
authors.initials: TB
authors.lastname: Melø
authors.forename: A
authors.initials: A
authors.lastname: Johnsson
mesh_terms: D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers; D005615:Freezing; D009249:NADP / Q000737:chemistry; D011425:Propionibacterium acnes / Q000378:metabolism / Q000528:radiation effects*; D013535:Suspensions; D014466:Ultraviolet Rays
chemical_list: D016166:Free Radical Scavengers; D013535:Suspensions; D009249:NADP