| Project/Area Number |
14560143
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TAKEDA Shigenobu The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (20334328)
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| Co-Investigator(Kenkyū-buntansha) |
KOTAKI Yuichi Kitasato University, School of Fisheries Scences, Associate Professor, 水産学部, 助教授 (30113278)
FUKUYO Yasuwo The University of Tokyo, Asian Natural Environmental Science Center, Professor, 教授 (10165318)
FURUYA Ken The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (30143548)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Iron / Domoic Acid / Amnesic Shellfish Poisoning / Diatom / Pseudo-nitzschia / Organic ligand / Growth rate / Iron limitation stress / 記憶喪失性毒 / Domoic acid / 欠乏ストレス / 無菌株 |
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| Research Abstract |
Batch culture experiments were performed to investigate iron requirement for growth of a coastal diatom Pseudo-nitzschia multiseries, which id known to produce domoic acid, a causative toxin of amnestic shellfish poisoning. Specific growth rates of P.multiseries showed a 50% decrease when dissolved inorganic iron concentration [Fe'] in the media was about 0/1 nM. P.multiseriesi required relatively high dissolved inorganic iron concentration for the maximum growth, that is similar to the other coastal phytoplankton. However, P.multiseriesi was still able to grow at [Fe']<0.02 nM, which limit the growth of most coastal species completely. Under iron-stressed condition, specific growth rates of P.multiseriesi were not affected by the addition of 2μM domoic acid, suggesting domoic acid itself does stimulate iron transport to support high growth rates. When iron availability was greatly reduced by the addition of a fungal siderophore desferrioxamine B(DFB), growth rates of P.multiseriesi significantly increased. Even under these strict iron stressed conditions, domoic acid concentrations in the cells showed little change compared with control without DFB. In addition, domoic acid concentrations in the media were always below the detection limit. These findings suggest that P.multiseriesi may utilize organically complexed iron under severe iron limitation and this iron transport system becomes active without production or release of domoic acid. Such iron uptake mechanism may allow this species to grow at the extremely low iron conditions.
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