title: Mutation frequency of plasmid DNA and Escherichia coli following long-term space flight on Mir.
abstract: To elucidate the biological influence of space radiation, we studied the effects of long-term space flight on mutation of the bacterial ribosomal protein L gene (rpsL). We prepared dried samples of plasmid DNA and repair-deficient and wild type cells of Escherichia (E.) coli. After a 40-day space flight on board the Russian space station Mir, the mutation frequencies of the rpsL gene were estimated by transformation of E. coli and by assessment of conversion of rpsL wild type phenotype (SmS) to its mutant phenotype (SmR). The experimental findings indicate that mutation frequencies of space samples were not significantly different from those of ground control samples in plasmid DNA and both E. coli strains. It may suggest that space radiation did not influence mutation frequency.
authors.affiliation: Department of Biology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Takahashi
authors.forename: Ken
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Yokota
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Kumagai
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Nakano
authors.forename: Takeo
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D004247:DNA / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005787:Gene Frequency; D009154:Mutation; D010957:Plasmids / Q000528:radiation effects*; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins / Q000235:genetics; D012426:Russia; D013026:Space Flight; D013997:Time Factors
chemical_list: D029968:Escherichia coli Proteins; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins; C000717190:RpsI protein, E coli; D004247:DNA