title: Enzymic chemical reaction under microgravity environment in space.
abstract: In recent years, some papers have reported synergism in the biological effects of space radiation and microgravity. However, there is no direct evidence for these phenomena. As one possible mechanism, we investigated whether DNA ligation in the final step of DSBs repair of DNA molecules induced by radiation is depressed by microgravity. Therefore, we have scheduled the space experiments of the effects of microgravity on repair activity of T4 DNA ligase for DSBs prepared with digestion of a restriction enzyme (Sma I) to plasmid DNA. As another possible mechanism, the high mutation frequency may be induced from abnormal base-incorporation during DNA replication under microgravity. Using the Taq polymerase and polymerase III, we have also scheduled whether mutation frequency is affected by microgravity during DNA replication for a damaged DNA base induced by an alkylating agent (N-methyl-N-nitrosourea, MNU).
authors.affiliation: Dept. of Biology, Nara Medical University, Kashihara, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohnishi
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: K
authors.initials: K
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Nakano
authors.forename: S
authors.initials: S
authors.lastname: Nagaoka
mesh_terms: D003359:Cosmic Radiation; D004249:DNA Damage; D011088:DNA Ligases / Q000737:chemistry* / Q000528:radiation effects; D004258:DNA Polymerase III; D004260:DNA Repair; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D013026:Space Flight; D019914:Taq Polymerase; D014893:Weightlessness
chemical_list: D019914:Taq Polymerase; D004258:DNA Polymerase III; D011088:DNA Ligases