Estimation of radiation tolerance to high LET heavy ions in an anhydrobiotic insect,

Watanabe, Masahiko*; Sakashita, Tetsuya; Fujita, Akihiko*; Kikawada, Takahiro*; Nakahara, Yuichi*; Hamada, Nobuyuki*; Horikawa, Daiki*; Wada, Seiichi*; Funayama, Tomoo; Kobayashi, Yasuhiko; Okuda, Takashi*

The aim of this study is to characterize the tolerance to high-LET radiations of. Larval survival and subsequent metamorphoses were compared between anhydrobiotic (dry) and non-anhydrobiotic (wet) samples after exposure to 1 to 7000 Gy of three types of heavy ions with LET values ranging from 16.2 to 321 keV/m. At all LET values measured, dry larvae consistently showed greater radiation tolerance than hydrated larvae, due to the disaccharide trehalose in anhydrobiotic animals. Relative biological effectiveness (RBE) values based on the median inhibitory doses reached a maximum at 116 keV/m (C). Anhydrobiosis potentiates radiation tolerance in terms of larval survival, pupation and adult emergence of exposed to high-LET radiations. larvae might have more efficient DNA damage repair after radiation than other chironomid species.