title: An assay for the detection of superoxide dismutase in individual Escherichia coli colonies.
abstract: A method for detecting superoxide dismutase activity in individual colonies of Escherichia coli was developed. The assay involves the lysis of individual cells in colonies on filter papers by a series of lysozyme, chloroform, and freeze-thaw treatments. Filters are placed on agar plates to allow diffusion of cellular enzymes into a solid matrix. A nitroblue tetrazolium overlay is applied to detect superoxide dismutase activity. Colonies possessing activity produce achromatic zones against a dark Formazan background. The assay can detect the presence of superoxide dismutase and the relative amount of enzyme as well. This assay provides a method for screening a population of cells for mutants deficient in or overproducing superoxide dismutase.
authors.affiliation: Department of Food Science, North Carolina State University, Raleigh 27695-7624.
authors.forename: J R
authors.initials: JR
authors.lastname: Schiavone
authors.forename: H M
authors.initials: HM
authors.lastname: Hassan
mesh_terms: D001431:Bacteriological Techniques; D004926:Escherichia coli / Q000201:enzymology; D009154:Mutation; D013482:Superoxide Dismutase / Q000032:analysis*
chemical_list: D013482:Superoxide Dismutase