@article{oai:repo.qst.go.jp:00043207,
 author = {Sakashita, Tetsuya and Doi, Masahiro and Yasuda, Hiroshi and Fuma, Shoichi and P., Haeder Donat and 坂下 哲哉 and 土居 雅広 and 保田 浩志 and 府馬 正一},
 issue = {4},
 journal = {Advances in Space Research},
 month = {},
 note = {The effects of gamma-ray and high energy carbon ion irradiation on the swimming velocity of the photosynthetic flagellate Euglena gracilis strain Z were studied, focusing on a dose-effect relationship. Cells were exposed to Co60 gamma-rays at 6 doses of 10, 15, 20, 40, 100 and 200 Gy for water, and also to 290 MeV/amu carbon ions from the Heavy Ion Medical Accelerator in Chiba at 7 doses (5, 10, 15, 20, 50, 100 and 200 Gy for water). The swimming velocity was measured by a biomonitoring system, called ECOTOX. The swimming velocities of Euglena gracilis cells were significantly decreased by >40 Gy gamma-rays and >5 Gy carbon ions, respectively. The 50% effective doses for inhibitaion, 34+-4 Gy (gamma-rays) and 13+-1 Gy (290 MeV/amu carbon ions), were estimated from the best fit to data of the logistic model. The relative biological effectiveness (2.6+-0.4) was calculated by the ratio of 50% effective doses. The inhibitation of the swimming velocity of the cells irradiated with gamma-rays was still present after 3 days, while recovery of the cells irradiated with shown in the cells exposed to 290 MeV/amu carbon ions. It is suggested that ionizing radiation inhibits ATP production and/or increases frictional drag on beating of the flagellum, thus decreasing swimming velocity.},
 pages = {1023--1030},
 title = {Effects of gamma-ray and high energy carbon ion irradiation on swimming velocity of Euglena gracilis.},
 volume = {30},
 year = {2002}
}