title: Sensitive detection of genes by sandwich hybridization and time-resolved fluorometry.
abstract: Europium has been used as a non-radioactive marker in immunoassays as this metal can be detected with high sensitivity by time-resolved fluorometry. In this work streptavidin labeled with europium was used to detect biotinylated probes in a sandwich nucleic-acid hybridization assay with microtitration strips as the solid phase. pBR 322 plasmids were detected with a sensitivity of 4 x 10(5) molecules. As the sample is added in solution in sandwich hybridization, fast and simple sample pre-treatment can be used without encountering background problems. The method was applied to test bacterial samples of uropathogenic Escherichia coli strains for the presence of the beta-lactamase gene.
authors.affiliation: Wallac Oy, Turku, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Dahlén
authors.forename: A C
authors.initials: AC
authors.lastname: Syvänen
authors.forename: P
authors.initials: P
authors.lastname: Hurskainen
authors.forename: M
authors.initials: M
authors.lastname: Kwiatkowski
authors.forename: C
authors.initials: C
authors.lastname: Sund
authors.forename: J
authors.initials: J
authors.lastname: Ylikoski
authors.forename: H
authors.initials: H
authors.lastname: Söderlund
authors.forename: T
authors.initials: T
authors.lastname: Lövgren
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D001710:Biotin; D004247:DNA / Q000032:analysis; D004926:Escherichia coli; D005063:Europium; D005470:Fluorometry / Q000379:methods*; D005796:Genes; D005820:Genetic Testing; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D019809:Streptavidin; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D005063:Europium; D001710:Biotin; D004247:DNA; D019809:Streptavidin; D001618:beta-Lactamases