title: Ergothioneine, histidine, and two naturally occurring histidine dipeptides as radioprotectors against gamma-irradiation inactivation of bacteriophages T4 and P22.
abstract: Bacteriophages P22, T4+, and T4os (osmotic shock-resistant mutant with altered capsids) were diluted in 0.85% NaCl and exposed to gamma irradiation (2.79 Gy/min) at room temperature (24 degrees C). T4+ was more sensitive to inactivation than was P22, and the T4os mutant was even more sensitive than T4+. Catalase exhibited a strong protective effect and superoxide dismutase a weaker protection, indicating that H2O2 or some product derived therefrom was predominant in causing inactivation of plaque formation. Low but significant (0.1-0.3 mM) reduced glutathione (GSH) enhanced phage inactivation, but a higher (1 mM) GSH concentration protected. A similar effect was found for the polyamine, spermidine. In contrast, 0.1 mM L-ergothioneine (2-thiol-L-histidine betaine) exhibited strong protection and 1 mM afforded essentially complete protection. L-Ergothioneine is present in millimolar concentrations in some fungi and is conserved up to millimolar concentrations in critical tissues when consumed by man. L-Histidine and two histidine-containing dipeptides, carnosine and anserine, protected at a concentration of 1 mM, a level at which they are present in striated muscles of various animals.
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
authors.forename: P E
authors.initials: PE
authors.lastname: Hartman
authors.forename: Z
authors.initials: Z
authors.lastname: Hartman
authors.forename: M J
authors.initials: MJ
authors.lastname: Citardi
mesh_terms: D000861:Anserine / Q000494:pharmacology*; D002336:Carnosine / Q000494:pharmacology*; D002588:Cesium Radioisotopes; D004151:Dipeptides / Q000494:pharmacology*; D004880:Ergothioneine / Q000494:pharmacology*; D005720:Gamma Rays; D006639:Histidine / Q000494:pharmacology*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012483:Salmonella Phages / Q000187:drug effects / Q000528:radiation effects*; D012486:Salmonella typhimurium; D013604:T-Phages / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D002588:Cesium Radioisotopes; D004151:Dipeptides; D011837:Radiation-Protective Agents; D006639:Histidine; D002336:Carnosine; D004880:Ergothioneine; D000861:Anserine