| Project/Area Number |
14340170
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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 |
地球化学
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| Research Institution | Yokohama National University |
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Principal Investigator |
KOBAYASHI Kensei Yokohama National University, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (20183808)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKO Takeo Yokohama National University, Faculty of Engineering, Assistant, 大学院・工学研究院, 助手 (50191987)
HASHIMOTO Hirofumi University of Tsukuba, Institute of Engineering Mechanics and Systems, Lecturer, 大学院・システム情報工学研究科, 講師 (50272175)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2003: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2002: ¥7,500,000 (Direct Cost: ¥7,500,000)
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| Keywords | Origins of Life / Interstellar organic compounds / Complex organic compounds / Amino acids / Cosmic rays / Hyper-velocity bombardment / Submarine hydrothermal systems / Meteorites / 地球外有機物 / 重粒子線 / カルボン酸 / 核酸塩基 / 光学活性 / 紫外線 |
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| Research Abstract |
Objectives of the present study are to perform integrated experiments including formation, alteration (evolution) and delivery of interstellar organic compounds, and to evaluate the roles of extraterrestrial organic compounds in chemical evolution toward origins of life.
A mixture of methanol (or carbon monoxide), ammonia and water was irradiated with high energy protons, γ-rays, or heavy ions. It was proved that the resulting products were "complex organic compounds" with molecular weights of several thousands by gel filtration chromatography and by pyrolysis-GC/MS. A wide variety of amino acids were detected when the products were acid-hydrolyzed. Heavy ions gave higher G-values (energy yields) of glycine than γ-rays. The G-value of glycine from frozen mixture of methanol, ammonia and water at 77 K was almost the same as that from the liquid mixture at room temperature.
Free amino acids and bounded amino acids (protein (HSA) and abiotically-formed amino acid precursors (CAW)) were irradiated with γ-rays or heavy ions. Bounded amino acids showed much higher stability than free amino acids against radiation. The molecular weight of CAW changed little after irradiation, which showed high stability of interstellar complex organic compounds in space environments. The CAW also showed higher stability against high-velocity impact with a rail gun, and against heat with a supercritical water flow reactor than free amino acids.
It was concluded that (i)complex amino acid precursors with high molecular weight can be formed in interstellar environments, (ii)they were more stable than free amino acids against radiation, shock and heat, and (iii)such complex organics were probable sources for generation of life on the Earth. We are planning to study possible evolution of such complex interstellar molecules in meteorite matrix.
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