title: Detection of bacteria using foreign DNA: the development of a bacteriophage reagent for Salmonella.
abstract: A phage-based reagent was developed for the detection of Salmonella in food samples. The parental phage was Felix 01, which lyses practically all Salmonella. Using data obtained about the molecular biology of the phage, a recombinant phage that carried the bacterial genes specifying luciferase was produced. The method involved the isolation of amber nonsense mutations and subsequent crosses to render doubly mutant phage with a very low reversion rate on strains lacking an amber suppressor. A plasmid was constructed that contained a segment of Felix 01 DNA with two adjacent genes, one dispensable and the other essential, and their flanking sequences. Recombinant DNA technology was used to remove the two genes and the luxA and luxB genes for luciferase, and a gene specifying a tRNA that recognizes amber codons (supF=tyrT) was put in their stead. This region could be transferred into the genome of the phage by homologous recombination. The recombinant phage cannot grow because it lacks an essential gene. However, it can grow in a host that synthesizes the missing protein. This technique allows the construction of "locked" recombinant phages that carry foreign DNA but which cannot propagate themselves in nature.
authors: Department of Biology Israel Institute of Technology, Technion, Haifa.
authors: Jonathan
authors: J
authors: Kuhn
authors: Mordechai
authors: M
authors: Suissa
authors: Joseph
authors: J
authors: Wyse
authors: Ilana
authors: I
authors: Cohen
authors: Irit
authors: I
authors: Weiser
authors: Sarah
authors: S
authors: Reznick
authors: Sharon
authors: S
authors: Lubinsky-Mink
authors: Gordon
authors: G
authors: Stewart
authors: Shimon
authors: S
authors: Ulitzur
mesh_terms: D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004274:DNA, Recombinant; D004279:DNA, Viral / Q000235:genetics; D005516:Food Microbiology; D017930:Genes, Reporter; D016680:Genome, Bacterial; D008156:Luciferases / Q000235:genetics*; D016296:Mutagenesis; D010957:Plasmids; D012343:RNA, Transfer / Q000235:genetics; D012475:Salmonella / Q000201:enzymology / Q000302:isolation & purification*; D012483:Salmonella Phages / Q000235:genetics*; D014161:Transduction, Genetic
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004279:DNA, Viral; D012343:RNA, Transfer; D008156:Luciferases