| Project/Area Number |
15310042
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Risk sciences of radiation/Chemicals
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
SHIOMI Nobuyuki (2004-2005) Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Professor, 産学官連携機構, 教授 (90100198)
米澤 司郎 (2003) 大阪府立大学, 先端科学研究所, 教授 (80090463)
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| Co-Investigator(Kenkyū-buntansha) |
YAGI Takashi Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Professor, 産学官連携機構, 教授 (80182301)
MATSUDA Yatsuka Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Associate Professor, 産学官連携機構, 助教授 (70090438)
TANIGUCHI Ryoichi Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Associate Professor, 産学官連携機構, 助教授 (60155215)
SHIRAISHI Kazunori Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Assistant Professor, 産学官連携機構, 助手 (40347513)
KAWANISHI Masanobu Osaka Prefecture University, Organization for University-Industry-Government Cooperation, Assistant Professor, 産学官連携機構, 助手 (70332963)
汐見 信行 大阪府立大学, 先端科学研究所, 教授 (90100198)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,600,000 (Direct Cost: ¥15,600,000)
Fiscal Year 2005: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2004: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 2003: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Keywords | Background Radiation / Adaptive Response / Radiation Hormesis / Paramecium tetraurelia / Gamma Ray / Neutron / 放射線ホルミシス / 低線量放射線 / 生物影響 |
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| Research Abstract |
We constructed a radiation-shield box containing an apparatus for cell growth experiments. The box was made of 15 cm-thick iron surrounded by 10 cm-thick paraffin. Background natural radiation dose of gamma ray and neutron in the shield was decreased to 1/40 and 1/6, respectively, compared with that of outside the shield.
Paramecium tetraurelia mating type 4 was cultured for 10 days in and out of the shield box. The growth rate was not affected by the radiation shield in any experimental condition we adopted. This does not support the findings of Planell et al. The Paramecium tetraurelia was then cultured from autogamy to the end of proliferation (about 3 months) in and out of the shield box. The growth rate was decreased significantly by the shield, and recovered by a ^<60>Co gamma ray (0.018 μGy/h) source put in the box.
Mouse lymphoma L5178Y cells were cultured for 10 days in and out of the shield box. The growth rate of the cells was significantly reduced by the shield of the background radiation. This result is consistent to the findings of Takizawa et al. The reduction of the growth rate by radiation shielding was not found in the radiosensitive mutant M10 cells that lack XRCC4 protein, which means that XRCC4 has an important role for this phenomenon.
Our results can be explained as follows. Organisms live under low background radiation that may become stimuli for gene expression to proliferate cells of the organisms.
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