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Yokota, Yuichiro; Shikazono, Naoya; Tanaka, Atsushi; Hase, Yoshihiro; Funayama, Tomoo; Wada, Seiichi; Inoue, Masayoshi*
Radiation Research, 163(5), p.520 - 525, 2005/05
Times Cited Count:20 Percentile:50.54(Biology)Higher plants are generally more tolerant to ionizing radiation than mammals. To explore the radiation tolerance of higher plants, the amount of DNA double-strand breaks (DSBs) induced by -rays was investigated in tobacco BY-2 cells and compared with that investigated in Chinese hamster ovary (CHO)-K1 cells as a reference. The resulting DNA fragments were separated by pulsed-field gel electrophoresis and stained with SYBR Green I. Initial DSB yield was then quantified from the fraction of DNA fragments shorter than 1.6 Mbp based on the assumption of random distribution of DSBs. The DSB yield in tobacco BY-2 cells (2.0 0.1 DSBs Gbp Gy) was only one-third of that in CHO-K1 cells. Furthermore, the calculated number of DSBs per diploid cell irradiated with -rays of mean lethal dose was five times greater in tobacco BY-2 cells (263.2 13.2) than in CHO-K1 cells. These results suggest that the radiation tolerance of tobacco BY-2 cells appears to be due to not only a lower induction of DNA damage but also a more efficient repair of the induced DNA damage.
Kobayashi, Yasuhiko
Hoshasen Seibutsu Kenkyu, 37(1), p.67 - 84, 2002/03
A single cell irradiation system has been developed for targeting cells individually with a precise number of high-LET heavy ions to elucidate radiobiological effects of exactly one particle and to investigate the interaction of damages produced by separate events. Using the heavy ion microbeam apparatus in TIARA, mammalian cells were irradiated in the atmosphere with a single or precise numbers of heavy ions, 13.0 MeV/u 20Ne or 11.5 MeV/u 40Ar, with a spatial resolution of a few microns.