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2001 Fiscal Year Final Research Report Summary

Reconsideration of the mechanism for shellfish to accumulate paralytic shellfish poisoning toxins

Research Project

Project/Area Number 10460096
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Fisheries chemistry
Research InstitutionKitasato University

Principal Investigator

KODAMA Masaaki  Kitasato University, School of Fisheries Sciences, Professor, 水産学部, 教授 (40050588)

Co-Investigator(Kenkyū-buntansha) KOTAKI Yuichi  Kitasato University, School of Fisheries Sciences, Associate Professor, 水産学部, 助教授 (30113278)
SATO Shigeru  Kitasato University, School of Fisheries Sciences, Associate Professor, 水産学部, 助教授 (20170748)
OGATA Takehiko  Kitasato University, Professor, 水産学部, 教授 (00104521)
Project Period (FY) 1998 – 2001
Keywordsparalytic shellfish toxin / gonuautoxin / saxitoxin / thiol / protein / scallop / thiol-toxin conjugate
Research Abstract

We have pointed out in the field survey that bivalves often accumulate PSP toxins during absence of the causative dinoflagellates. The purpose of the present study is to reconsider the mechanism for bivalves to accumulate toxins by the laboratory experiments. Feeding experiments of cultured cells of Alexandrium tamarense to bivalves showed that bivalves released accumulated PSP toxins to the environmental water. However, curious phenomena were observed, that is, 1) bivalves accumulate toxins more than supplied, 2) After the cessation of toxin supply, the sum of accumulated toxins in bivalve and those in the environmental water once decreased, and then increased again. These phenomena are similar to those observed in the field survey. In the reaction in which 11-O-sulfate of gonyautoxins (GTX) is reductively removed by thiols such as glutathione (GSH), stable conjugates of toxins and thiols are found to form. The phenomenon 2) suggests that GTXs bind with GSH of bivalves to form GS-STXs … More which cannot be detected by PSP analysis, and then the toxins are released from the conjugates again. However, no significant GS-STXs was detected. It was revealed to be due to a series of the reactions in which GS-STXs is digested by gGTP to form the conjugate of STXs with cysteinyl glycine, and the amino group of cystein decomposes STXs to fluorescent compounds similar to those in alkaline treatment of toxins. When the thin section of toxic scallop digestive gland was stained with antibody against SIX, cytosol of amoebarcytes and membranes surrounding nutrient cells were stained, suggesting that toxins are bound with proteins in these tissues. Protein fractions prepared from the digestive gland by gel filtration gave STXs by treatment with mercaptoethanol, showing that toxins are bound with amino group of cystein residues of proteins in these fractions; On the other hand, GTXs were released when the protein fractions described above are digested with protease, showing that some GTXs are bound with proteins in a different manner from that involved in thiol of cystein residue. Furthermore, fluorescent substances are also observed in the digested protein fractions with protease, indicating that STXs bound with cystein residue are decomposed by digestion ofproteins with protease. These are the first finding on the decomposition of toxins in bivalves in which the enzymes of bivalves are involved. The results of the present study could give a clue for the future study on metabolism of PSP toxins. Less

  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] S.Sato: "Trace amounts of saxitoxins in the viscera of chum salmon Oncorhynchus keta"Marine Ecology Progress Series. 175. 295-298 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Sato: "Frequent occurrence of paralytic shellfish poisoning toxins as dominant toxins in marine puffer from tropical water"Toxicon. 38. 1101-1109 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Sakamoto: "Formation of intermediate conjugates in the reductive transformation of gonyautoxins to saxitoxins by thiol compouns"Fisheries Science. 66. 136-141 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Sato: "Identification of thioether intermediates in the reductive transformation of gonyautoxins into saxitoxins by thiols"Bioorg.Med.Chem.Lett.. 10. 1787-1789 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 児玉正昭: "麻ひ性貝毒とチオール化合物の複合体-有毒渦鞭毛藻の補食による貝類の毒化機構に新たな視点"化学と生物. 39. 502-503 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 児玉正昭: "麻痺性貝毒の化学と生物学"月刊海洋. 33. 705-709 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Sekiguchi: "Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells"Fisheries Science. 67. 301-305 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Sekiguchi: "Accumulation and depuration kinetics of paralytic shellfish toxins in the scallop Patinopecten yessoensis fed Alexandrium tamarense"Mar.Ecol.Prog.Ser.. 220. 213-218 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Sekiguchi: "Accumulation of paralytic shellfish toxins in the scallop Patinopecten yessoensis caused by the dinoflagellate Alexandrium catenella in Otsuchi Bay, Iwate Prefecture, northern Pacific coast of Japan"Fisheries Science. 67. 1157-1162 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] G.J.Doucette: "Physiological Ecology of Harmful Algal Blooms"D. M. Anderson, A. D. Cembella and G. M. Hallegraef. 652 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Kodama: "Seafood and Freshwater Toxin"L. M. Botana. 798 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 関口勝司: "北里大学水産学部博士論文(水産学)麻ひ性貝毒による貝類の毒化機構に関する研究"関口勝司. 102 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] G. J. Doucette, M. Kodama, S. Franca and S. Gallacher: "Bacterial interactions with harmful algal bloom species: Bloom ecology, toxigenesis, and cytology"Physiological Ecology of Harmful Algal Blooms, NATO ASI Series, Vol. G41 (ed. By D. M. Anderson, A. D. Cembella and G. M. Hallegraeff), Springer, Berlin. 619-647 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S. Sato, T. Ogata and M. Kodama: "Trace amounts of saxitoxins in the viscera of chum salmon Oncorhynchus keta"Marine Ecology Progress Series. 175. 295-298 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S. Sato, T. Ogata, V. Borja, C. Gonzales, Y. Fukuyo and M. Kodama: "Frequent occurrence of paralytic shellfish poisoning toxins as dominant toxins in marine puffer from tropical water"Toxicon. 38. 1101-1109 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S. Sakamoto, S. Sato, T. Ogata and M. Kodama: "Formation of intermediate conjugates in the reductive transformation of gonyautoxins to saxitoxins by thiol compouns"Fish. Sci.. 66. 136-141 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S. Sato, R. Sakai and M. Kodama: "Identification of thioether intermediates in the reductive transformation of gonyautoxins into saxitoxins by thiols"Bioorg. Med. Chem. Lett.. 10. 1787-1789 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Kodama: "Ecology, classification, and origin"Seafood and Freshwater Toxin (ed. By L.M.Botana), Marcel Dekker, New York. 125-149 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Sekiguchi: "Studies on the mechanism for shellfish to accumulate paralytic shellfish toxins (in Japanese)"Ph. D. Thesis of Kitasato University. 1-102 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Kodama and S. Sato: "Conjugates of paralytic shellfish poisoning toxins and thiols - a new insight for the toxin-accumulating mechanism in shellfish (in Japanese)"Kagaku to Seibutu. 39. 502-503 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Kodama: "Chemistry and biology of paralytic shellfish toxins (in Japanese)"Monthly Kaiyou. 33. 705-709 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Sekiguchi, S. Sato, S. Kaga, T. Ogata and M. Kodama: "Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells"Fish. Sci.. 67. 301-305 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Sekiguchi, S. Sato, T. Ogata, S. Kaga and M. Kodama: "Accumulation and depuration kinetics of paralytic shellfish toxins in the scallop Patinopecten yessoensis fed Alexandrium tamarense"Mar. Ecol. Prog. Ser.. 220. 213-218 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Sekiguchi, T. Ogata, S. Kaga, M. Yoshida, Y. Fukuyo and M. Kodama: "Accumulation of paralytic shellfish toxins in the scallop Patinopecten yessoensis caused by the dinoflagellate, Alexandrium catenella in Otsuchi Bay, Iwate Prefecture, northern Pacific coast of Japan"Fish. Sci.. 67. 1157-1162 (2001)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2003-09-17  

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