Tolerance of anhydrobiotic eggs of the tardigrade to extreme environments

Horikawa, Daiki*; Yamaguchi, Ayami*; Sakashita, Tetsuya; Tanaka, Daisuke*; Hamada, Nobuyuki*; Yukuhiro, Fumiko*; Kuwahara, Hirokazu*; Kunieda, Takekazu*; Watanabe, Masahiko*; Nakahara, Yuichi*; et al.

Astrobiology, 12(4), p.283 - 289, 2012/04

https://doi.org/10.1089/ast.2011.0669

We examined the hatchability of hydrated and anhydrobiotic eggs of the tardigrade to hatch after ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. Anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at high and low temperatures, but all of the hydrated eggs failed to hatch. After exposure to high vacuum conditions, the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.

Kinetic analysis of double-strand break rejoining reveals the DNA reparability of -irradiated tobacco cultured cells

Yokota, Yuichiro; Wada, Seiichi*; Hase, Yoshihiro; Funayama, Tomoo; Kobayashi, Yasuhiko; Narumi, Issei; Tanaka, Atsushi

Journal of Radiation Research, 50(2), p.171 - 175, 2009/04

https://doi.org/10.1269/jrr.08064

The rejoining efficiency of double-strand breaks (DSBs) was quantified in tobacco protoplasts and CHO-K1 cells following -ray irradiation in order to compare DNA reparability of higher plants with mammals. The DSB rejoining kinetics of tobacco protoplasts were well represented by a biphasic-exponential equation: half of initial-induced DSBs were rejoined for 1 h and the others were almost rejoined within 4 h. We found that the DSB rejoining kinetics of tobacco protoplasts at 27C are the same as those of CHO-K1 cells at 37C. These findings indicate that the DSB rejoining efficiency of tobacco protoplasts and CHO-K1 cells are comparable at their respective cell cultivation temperatures, suggesting that DSB rejoining efficiency is little responsible for the higher radiation-tolerance of tobacco protoplasts.

A Review on radiation tolerance mechanism of higher plants

Yokota, Yuichiro; Inoue, Masayoshi; Narumi, Issei; Funayama, Tomoo; Kobayashi, Yasuhiko; Tanaka, Atsushi

Hoshasen Seibutsu Kenkyu, 42(4), p.402 - 415, 2007/12

http://ci.nii.ac.jp/naid/40015788848

It has been known that many types of higher plants are several hundred times more radio-tolerant than mammals at an individual level. There was, however, no available information on the detail mechanism of radiation tolerance of higher plants. Thus, we have done the radiobiological studies using tobacco BY-2 cell line as a model plant cell. In their studies, we made clear that tobacco cells are ten times more radio-tolerant than mammalian cells, and that radioresistant tobacco cells can tolerate a large number of DNA double-strand breaks compared with mammalian cells. In this review, we discussed the radiation tolerant mechanism of higher plants by taking together the past findings with our latest data: tobacco cells are tolerant of radiation-induced chromosomal aberration although DNA double-strand break repair abilities of tobacco and mammalian cells are almost the same.

Biological effect of penetration controlled irradiation with ion beams

Tanaka, Atsushi; Shimizu, Takashi*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Yamashita, Takao*; Watanabe, Hiroshi

JAERI-Conf 97-003, p.323 - 326, 1997/03

no abstracts in English

Penetration controlled irradiation with ion beams for biological study

; Watanabe, Hiroshi; Shimizu, Takashi*; Inoue, Masayoshi*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Tano, Shigemitsu*

Nuclear Instruments and Methods in Physics Research B, 129(1), p.42 - 48, 1997/00

https://doi.org/10.1016/S0168-583X(97)00131-6

no abstracts in English

Ion beam irradiation apparatus for biological samples

; ; Kobayashi, Yasuhiko; ; Watanabe, Hiroshi

JAERI TIARA Annual Report, Vol. 1, 0, p.159 - 162, 1992/00

no abstracts in English

Study on 21/4Cr-1Mo steel for high temperature gas cooled reactor; Material characterization of forged low Si21/4Cr-1Mo steel

Oku, Tatsuo; Kodaira, Tsuneo; Fukaya, Kiyoshi; Suzuki, Masahide; *; *; *; *

Nucl. Eng. Des., 119, p.177 - 186, 1990/00

https://doi.org/10.1016/0029-5493(90)90159-U

no abstracts in English

Development of Bucket and Lambdatron Ion Sources

*; ; ; Araki, Masanori; ; ; ; ; Matsuda, Shinzaburo; ; et al.

JAERI-M 8740, 56 Pages, 1980/03

JAERI-M-8740.pdf:1.42MB

no abstracts in English

Effects of heavy ion irradiation on cellular and viral genes and induction of mutant cells resistant to virus infection

Hoshino, Hiroo*; Shimizu, Nobuaki*; Oue, Atsushi*; Tanaka, Atsushi*; Saha, M. N.*; Shinagawa, Masahiko*; Otsuki, Takahiro*; Hoque, A.*; Mori, Takahisa*; Wada, Seiichi*; et al.

no journal, , 

no abstracts in English

Characterization of a novel Cd sensitive mutant in Arabidopsis

Nakamura, Atsuko*; Ichikawa, Kazuki*; Kojima, Kazuaki*; Ono, Yutaka; Kobayashi, Yasuhiko; Tanaka, Shigeo*; Sakata, Yoichi*

no journal, , 

Phytochelatin (PC) has been shown to play an important role in heavy metal detoxification. However, Arabidopsis transgenic plants overexpressing the PC synthase gene failed to show an increase in Cd tolerance. To explore a novel heavy metal detoxification mechanism, we screened for an Arabidopsis Cd-sensitive mutant () by carbon ion beam mutagenesis, which causes large base pair deletions at random loci in the genome. Genetic analyses and GSH synthesis inhibitor studies revealed that the phenotype was different from those of PC synthesis mutants. Moreover, Cd content in shoots of cultured on Cd-containing media was similar to wild type, suggesting that Cd-sensitive phenotype of was not attributed to the Cd transport system from roots to shoots. In the rough mapping, was localized to approximately 300kbp region of chromosome 4. One of the genes was found to have a 2.5 kbp deletion in the promoter region.