title: Effect of free-radical scavengers on enumeration of thermally stressed cells of Staphylococcus aureus MF-31.
abstract: Exposure of crude cell lysates of Staphylococcus aureus MF-31 to 5 or 10 mM hydrogen peroxide resulted in a linear decrease in superoxide dismutase activity. Approximately 13% of the superoxide dismutase activity was lost after 16 min. Thermally stressed and nonstressed cells were exposed to a photochemically generated exogenous flux of superoxide radicals (O2.-). The death of thermally stressed cells was linear with time. Addition of superoxide dismutase or catalase to the O2.- generating system resulted in protection of thermally stressed and nonstressed cells, with the protective effect being greater for thermally stressed cells. Incorporation of O2-, hydroxyl radical, or singlet oxygen scavengers or antioxidants to tryptic soy agar containing 7.5% NaCl did not increase the enumeration of thermally stressed cells.
mesh_terms: D002374:Catalase / Q000494:pharmacology; D005609:Free Radicals; D006639:Histidine / Q000494:pharmacology; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D010100:Oxygen / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000201:enzymology / Q000254:growth & development*; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013481:Superoxides / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology
chemical_list: D005609:Free Radicals; D010879:Piperazines; D013481:Superoxides; D014810:Vitamin E; D006639:Histidine; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen; C007306:triethylenediamine