title: RBE of HTO to 60Co gamma-rays for cell killing of a radioresistant E. coli harboring plasmid.
abstract: Radioresistant E. coli TGl harboring pUC 18 plasmid which was Ampicillin-resistant was exposed to 60Co gamma-rays or 3H beta-rays in saline to determine whether the relative biological effectiveness of 3H beta-rays is higher than one. After exposure to 60Co gamma-rays at a dose rate of 0.465 Gy/min, the D0 by colony formation was 145 Gy in the presence of Ampicillin in or absence from the agar medium; whereas, the D0 was calculated as 118 Gy with and without Ampicillin after exposure to 3H beta-rays at a dose rate of 0.431 Gy/min. The relative biological effectiveness established for 3H beta-rays to 60Co gamma-rays was 1.23. The reason for the higher effectiveness of 3H beta-rays as compared to the reference 60Co gamma-rays is discussed in terms of nascent 0 production.
authors.affiliation: Department of Biology, Faculty of Sciences, Hiroshima University, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Jo
authors.forename: M
authors.initials: M
authors.lastname: Sugiyama
authors.forename: T
authors.initials: T
authors.lastname: Itoh
mesh_terms: D001610:Beta Particles; D016923:Cell Death / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects; D005720:Gamma Rays; D011815:R Factors / Q000528:radiation effects*; D011836:Radiation Tolerance / Q000235:genetics*; D012062:Relative Biological Effectiveness; D014316:Tritium; D014867:Water
chemical_list: D003037:Cobalt Radioisotopes; D014867:Water; D014316:Tritium; C033961:tritium oxide