title: Mutations of a shuttle vector plasmid, pZ189, in Escherichia coli induced by boron neutron captured beam (BNCB) containing alpha-particles.
abstract: A shuttle vector, pZ189, carrying a bacterial suppressor tRNA marker gene (supF) was dissolved in Tris-EDTA buffer containing 0.3 M 10B-enriched boric acid and then irradiated with boron neutron captured beam (BNCB) produced by the nuclear reaction 10B (n,alpha) 7Li with thermal neutrons. A DNA repair-deficient mutant, KS46 (uvrA-), of Escherichia coli was transformed with the plasmid DNA, and the transformants carrying mutations on the supF gene were selected as nalidixic acid-resistant colonies. The mutation frequency (2.4 x 10(-4)) of pZ189 at the D10 dose was about 70 times greater than the spontaneous rate (3.5 x 10(-6)). The plasmid mutations were analyzed using DNA sequencers; 88% of them were base substitutions. A few minus-one frameshifts (7%) and deletions (5%) were detected. Among these base substitutions, transversions of G:C to T:A (42%) and G:C to C:G (29%) predominated. Twenty-seven percent of the base substitutions were G:C to A:T transitions; no A:T to G:C transitions were detected.
authors.affiliation: PL Botanical Institute, PL Gakuen Women's Junior College, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakano
authors.forename: K
authors.initials: K
authors.lastname: Okaichi
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
authors.forename: R
authors.initials: R
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Akasaka
authors.forename: T
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D000512:Alpha Particles; D001483:Base Sequence; D001895:Boron; D004307:Dose-Response Relationship, Radiation; D004735:Energy Transfer; D004926:Escherichia coli / Q000235:genetics / Q000528:radiation effects*; D005798:Genes, Bacterial / Q000235:genetics / Q000528:radiation effects; D005822:Genetic Vectors / Q000235:genetics / Q000528:radiation effects*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics*; D009502:Neutrons; D010957:Plasmids / Q000235:genetics / Q000528:radiation effects*; D017354:Point Mutation; D012641:Selection, Genetic; D013489:Suppression, Genetic
chemical_list: D001895:Boron