| Project/Area Number |
04640528
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
天然物有機化学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SUGA Takayuki Hiroshima University, Faculty of Science, Professor, 理学部, 教授 (00033811)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAGA Yoshikazu Hiroshima University, Faculty of Science, Research Associate, 理学部, 助手 (10238347)
EGUTI Shizuko Hiroshima University, Instrument Center for Chemical Analysis, Technical Officia, 機器分析センター, 教務員 (60090552)
OHTA Shinji Hiroshima University, Instrument Center for Chemical Analysis, Associate Profess, 機器分析センター, 助教授 (60185270)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Red Tides / Chattonella antiqua / Ichthyotoxicity / Fatty Acid / Ichthyotoxic Active / Autoxidation / Anti-oxidizing Reagent / Hydrophobic Interaction / ステアリドン酸 / パルミチン酸 / 含窒素化合物 / 培養条件 |
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| Research Abstract |
Saturated and unsaturated fatty acids present in the red tides alga Chattonella antiqua showed an ichthyotoxic activity when assayd against killifish. Among the unsaturated fatty acids, stearidonic acid (C_<18 : 4>) had the strongest activity (LC_<100> = 7 ppm). Other C_<18->unsaturated fatty acids assayd were less active, although their ichthyotoxic activities increased with increase of the unsaturation degree. However, the activity of these unsaturated fatty acids disappeared by addition of anti-oxidizing reagents (alpha-tocopherol and sodium ascorbate) at pH 8.1. These facts indicate that the ichthyotoxicity is due to damage caused to the biomembrane by radical species generated form the autoxidation of the unsaturated fatty acids.
Among the saturated fatty acids, myristic acid (C_<14 : 0>) and palmitic acid (C_<16 : 0>) had the strongest activity (LC_<100> = 10 ppm) at pH 8.1. The activities of myristic acid and palmitic acid decreased at pH 4.5 due to a diminished solubility in water. However, the activities of decanoic acid (C_<10 : 0>) and lauric acid (C_<12 : 0>) were stronger at pH 4.5 rather than at pH 8.1. At pH 4.5, decanoic acid and lauric acid are ionized to an extent of less than 30%. These facts indicate that the ichthyotoxicity ascribes to the hydrophobic interaction with the biomembrane by the non-ionic form of the saturated fatty acid.
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