@article{oai:repo.qst.go.jp:00043165,
 author = {Sakashita, Tetsuya and Doi, Masahiro and Yasuda, Hiroshi and Takeda, Hiroshi and Fuma, Shoichi and Nakamura, Yuuji and P., Haeder Donat and 坂下 哲哉 and 土居 雅広 and 保田 浩志 and 武田 洋 and 府馬 正一 and 中村 裕二},
 issue = {11},
 journal = {International Journal of Radiation Biology},
 month = {},
 note = {Purpose: To study the effects of high-energy carbon ion irradiation on negative gravitaxis in the photosynthetic flagellate Euglena gracilis strain Z in a dose-response-dependent manner.
Materials and methods: Cells were exposed to 290 MeV amu-1 carbon ion from the Heavy Ion Medical Accelerator in Chiba (HIMAC) at 12 doses (0, 1, 5, 7.5, 10, 15, 20, 50, 75, 100, 150, 200 Gy for water). Gamma was used to quantify negative gravitaxis observed in a recently developed biomonitoring system.
Results: Negative gravitaxis of Euglena was significantly affected by irradiation at a dose > 7.5 Gy, 28 h after irradiation. Negative gravitaxis recovered after a few days. The rising phase of gamma during the first 30s of orientation was independent of irradiation dose. The recovery mechanism itself was damaged by 290 MeV amu-1 carbon ions at a dose > 50 Gy.
Conclutions: The results indicate that negative gravitaxis in Euglena may be affected by the radiation experienced during a space experiment especially during the occurrence of solar flares. The analyses of time needed to reorient to the gravitational vector suggest that the steering control of the flagellar apparatus is affected by exposure to the 290 MeV amu-1 carbon ion irradiation, resulting in an altered beating pattern of a flagellum and/or changes of the cell from during reorientation.},
 pages = {1055--1060},
 title = {High-energy carbon ion irradiation inhibits negative gravitaxis in Euglena gracilis Z.},
 volume = {78},
 year = {2002}
}