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Sato, Katsuya; Kikuchi, Masahiro; Oba, Hirofumi; Narumi, Issei
no journal, ,
To investigate the role of the RecFOR pathway in DNA double-strand break (DSB) repair in 
, we generated a 
disruptant strain and characterized the disruption effect. The disruptant strain exhibited hypersensitivity to 
rays than the wild-type strain. PFGE analysis showed that genome restitution ability following irradiation was severely impaired in the disruptant strain, suggesting that RecF has a crucial role in DSB repair. Furthermore, following irradiation, induction of RecA, which is essential protein for DNA recombination repair, was observed in the disruptant strain just as the wild-type strain. However a large amount of RecA protein in the disruptant strain remained inactive following irradiation. We suppose that the defect in RecA activation resulted in hypersensitivity to ionizing radiation and failure to repair radiation-induced DSB in the disruptant strain.
Sato, Katsuya; Kikuchi, Masahiro; Narumi, Issei; Oba, Hirofumi
no journal, ,
no abstracts in English
Wadachi, Hiroki*; Kunieda, Takekazu*; Abe, Wataru*; Nakahara, Yuichi*; Watanabe, Masahiko*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Kobayashi, Yasuhiko; Higashi, Seigo*; Okuda, Takashi*
no journal, ,
We collected some kinds of tardigrade to develop multi-cellular model oraganism for extremotolerant. Among four kinds of collected tardigrade, we found that a tardigrade at Sapporo-city feeded 
and could breed. The life-time of 
in an artificial culture condition is about 35 days and 5.7 days for hatching. During the whole life-time, one animal laids 8 eggs. In addition, it was observed that could enter an ametabolic dry state called anhydrobiosis in all stages of life-time. Furthermore, we observed a high surviving-rate even if exposed in various kinds of extreme environments.
Wadachi, Hiroki*; Kunieda, Takekazu*; Sakashita, Tetsuya; Kawai, Kiyoshi*; Iwata, Kenichi*; Nakahara, Yuichi*; Hamada, Nobuyuki*; Koseki, Shigenobu*; Yamamoto, Kazutaka*; Kobayashi, Yasuhiko; et al.
no journal, ,
We studied the effects of the exposure of extreme environments on life-time and breeding ability of tardigrade to reveal the possibility of multi-cellular organism existences in the outerspace. A life time of animals is the shortest in the heavy-ion exposed animals than any other stressors. There were significant decrease in the number of egg-laying and hatching rate between irradiated and non-irradiated animals. However, we found the next generation in all experimental conditions. Our findings suggest that tardigrades exposed to even any extreme environments could have a descendant.