1987 Fiscal Year Final Research Report Summary
A study on the changes in organophosphorus insecticide resistance of shrimp larvae at different stages
| Project/Area Number |
61560235
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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 |
Fisheries chemistry
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| Research Institution | Kyushu University |
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Principal Investigator |
KOBAYASHI Kunio Kyushu University, Faculty of Agriculture, 農学部, 教授 (30038195)
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| Co-Investigator(Kenkyū-buntansha) |
OSHIMA Yuji Kyushu University, Faculty of Agriculture, 農学部, 助手 (70176874)
IMADA Nobuyoshi Kyushu University, Faculty of Agriculture, 農学部, 助手 (60038247)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Tiger shrimp / Larvae / Organophosphorus insecticides / Toxicity / Metabolism / Acetylcholinesterase / 酵素阻害 |
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| Research Abstract |
The study has been performed to elucidate the cause for the occurrence of the remarkable changes in the toxicity of organophosphorus insecticides to tiger shrimp larvae at different stages (nauplius, zoea, mysis and postlarva).
1. The acute toxicity of fenitrothion (FS), its oxo-form (FO) and several organophosphorus insecticides was investigated. The abrupt increase in the toxicity to the larvae with the progress of the larval stages was occurred in the phosphorothionates such as FS, whereas the unchanged toxicity to the larvae throughout all stages was observed in the phosphates such as FO.
2. The FS absorbed by the larvae at early stages was found mostly as FS itself associated with a very small amount of its metabolites, but the amount of the metabolites including FO which displays much higher toxicity than FS, increased abruptly with the progress of the larval stages.
3. The susceptibility of larval acetylcholinesterase (AChE) to each organophosphorus insecticide was almost at the same level in the all stages. However, the larval AChE showed very high susceptibility to the phosphates, especially FO, as compared with that ot the phosphorothionates.
The study concluded that the abrupt increase in the toxicity of phosphorothionates to the shrimp larvae with the progress of the developmental stages is due to the increase in their oxidative desulfuration activity, resulting in the produce of the respective phosphates which display high toxicity.
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