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有害渦鞭毛藻Heterocapsa circularisquamaに関する生理生態学的研究(2)
https://fra.repo.nii.ac.jp/records/2010800
https://fra.repo.nii.ac.jp/records/2010800eefb08b3-9da1-47de-8df8-01409319513b
| 名前 / ファイル | ライセンス | アクション |
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fra_k_9_13.pdf (38.3 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2024-10-02 | |||||
| タイトル | ||||||
| タイトル | 有害渦鞭毛藻Heterocapsa circularisquamaに関する生理生態学的研究(2) | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Physiological and ecological studies on harmful dinoflagellate Heterocapsa circularisquama - Ⅱ Clarification on toxicity of H. circularisquama and its mechanisms causing shellfish kills | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | Heterocapsa circularisquama; dinoflagellate; bivalve; mortality; toxicity | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | open access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||
| その他（別言語等）のタイトル | ||||||
| その他のタイトル | H. circularisquamaの毒性および貝類斃死機構の解明 | |||||
| 言語 | ja | |||||
| 著者 |
松山, 幸彦
× 松山, 幸彦 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Heterocapsa circularisquama Horiguchi (Dinophyceae) is a causative agent of red tide organism, appeared in 1988 in first time and then rapidly dispersed off the coastal waters of western Japan. The red tide due to H. circularisquama was associated with massive killing of commercially important bivalve species: pearl oyster Pinctada fucata martensii, Pacific oyster Crassostrea gigas, manila clam Ruditapes philippinarum, blue mussel Mytilus galloprovincialis, etc. Until 2000, 31 cases of H. circularisquama red tide (including 16 incidences leading to fisheries damage) had been recorded in western Japan. Economic losses in shellfish aquaculture by direct killing of marketable products were estimated about at least 10 billion-yen in the last decade. Although the recurrent blooms of H. circularisquama had damaged the shellfish aquaculture, no harmful effects on wild and cultured finfish, other marine vertebrates, and public health hazard were recorded. Therefore, this phenomenon is referred to as "novel red tide." The red tide due to H. circularisquama has devastates shellfish aquaculture in most of the region, in terms of mass mortality in farming organism, cost of measures to prevent the damage, adversely affects the development of shellfish aquaculture, and secondary damage, i.e. decline of demand due to misinformation. Incidence of this species has increased recently, and the economic losses in aquaculture have been a cause for concern for the industry and society. In the present study, mechanism of damage caused to shellfish aquaculture, toxicity of the organism were conducted, in order to clarify the mechanism to be causing shellfish death due to H. circularisquama red tide. In field observations, pearl oysters exposed to 4,000-6,000cells/mL of H. circularisquama resulted in death within several days although the level of dissolved oxygen was not critical for their survival. The dead individuals were characterized by various negative symptoms: valve closure, marked shrinkage of the mantle, decrease of glycogen lobe attached to the mantle, gut discoloration, cardiac disorder, paralytic etc.. The symptoms caused by the H. circularisquama exposure clearly showed a potent cytotoxic effect on bivalve physiology. The consist cytotoxicity to the bivalve molluscs was also confirmed in laboratory-reared experiment. Further, laboratory exposure experiments revealed that various marine animals such as bivalves, gastropods, ascidians, jellyfish, ciliates, and some naked phytoflagellates are affected by H. circularisquama unlike vertebrates, crustaceans, starfish, and sea urchins, and mouse. According to survival experiments using various culture condition of H. circularisquama, toxicity of H. circularisquama on the mussel were increased in the high water temperature and high salinity culture conditions, but markedly decreased in nitrogen-limited conditions. These results suggested that toxicity of this dinoflagellate was considerably affected by environmental conditions in nature. Further, comparative studies on toxicity of H. circularisquama cells showed that toxicity of this algae clearly varied among strains which isolated from various locatities in Japan. The toxicity of H. circularisquama to bivalves molluscs was clearly mediated by a chemical agent. The toxic effect of H. circularisquama on bivalves was not due to extracellular metabolites, cell exudates, and "naked cells" prepared by sonication and centrifugation. Furthermore, SDS (sodium dodecyl sulfate), triethanolamin, and trypsin treatments were found to decrease drastically the toxicity of H. circularisquama cells. The metabolism inhibitor for protein and glycochains also reduced the toxicity of H. circularisquama. Therefore, labile glycoprotein-like complex localized on the cell surface of H. circularisquama presumably exerts a detrimental effect on bivalves. Furthermore, H. circularisquama did not affect on the anterior byssus retractor muscle of the mussel M. galloprovincialis but significantly affects on the radula retractor muscle of rapa whelk Rapana venosa, having various chemical receptors against peptide and other related substances. These results indicated that H. circularisquama does not synthesize monoamines such as dopamine and acetyl-cholin, alternating bivalve physiology. Some bivalve species resulted in gill damage and cardiac disorder in early periods of the exposure experiment. Histological study on manila clam exposed to H. circularisquama demonstrated that marked collaps of the mitocondria and muscle fiber occurred in several minuts. This is considered as a potencial factor causing short-term death in shellfish species. Further, H. circularisquama showed lethal effects on the early stage of bivalve species. Exposure of H. circularisquama to non-fertilized eggs of bivalve causes rapid collapse of vitelline envelope of eggs. These results indicated that a receptor destroying enzyme or related substances in the cell surface of H. circularisquama is the causative agent of shellfish kills. Further, affected larval stage of R. philippinarum by the H. circularisquama showed drastic increases of intracellular calcium concentration. Therefore, detrimental effects of H. circularisquama cells to the targeted organs (gills and mantle etc) led significant increases the concentration of intracellular calcium at critical level, that is probably brought about collapse of bivalve homeostasis. The toxicity of H. circularisquama can easily lost by the simple mechanical disturbance such as centrifugation of their cells. Further, the toxicity of H. circularisquama cells has been dropped by gently treatments of SDS (sodium dodecyl sulfate), triethanolamine, and trypsin. These detoxicated cell are readily cleared by the filter-feeding bivalve without any negative responses. Therefore, physiological and chemical treatments can be apply to prevent the detrimental effect of H. circularisquama in future. However, widespread application of these procedures for marine environments may exert a secondary harmful effect on the other valuable aquatic organisms. It is necessary to improve the economically cost and to asses risk management. Biological control of H. circularisquama; i. e. diatoms growth promoting due to silicate conditioning in coastal waters and clearances of H. circularisquama cells by the other filter-feeder such as dense population of ascidians is likely to be low cost and environmentally acceptable techniqus for mitigation in future. | |||||
| 言語 | en | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 渦鞭毛藻Heterocapsa circularisquama は1988年に日本で初めて赤潮を形成し，その後急速に西日本全域に拡大して貝類養殖業に甚大な漁業被害をもたらすようになった新興赤潮生物である。本研究はH.circularisquama 赤潮が二枚貝や巻貝に及ぼす毒性を明らかにするために取り組まれたものである。まず，H. circularisquama の水産生物に与える影響を調べたところ，本種は二枚貝や巻貝に致死的な作用を及ぼすものの，魚類，甲殻類，その他の生物に対する影響は全く認められなかった。貝類の斃死は酸素欠乏や硫化水素などの発生が認められなくとも起こり，貝類の組織とH. circularisquama が接触する際に悪影響が生じていた。二枚貝に対する致死活性は1,000cells/mL以上で認められ，4,000～6,000 cells/mLを越えると数日中に半数の個体が斃死する。培養株を用いた試験でも同様の結果が得られ，H. circularisquama が貝類に対して直接毒性を示すことが判明した。 H. circularisquama の毒性は超音波や遠心分離で容易に失われることから，毒素は細胞表層に含まれ，物理化学的に不安定な物質であると考えられた。また，界面活性剤であるSDSやトリエタノールアミン，タンパク質分解酵素であるトリプシンなどに感受性を示し，タンパク質や糖鎖の合成阻害剤も毒性を有意に低下させた。このことから，毒性は糖蛋白質様物質に由来するものと推察された。H. circularisquama は化学的レセプターを多数有している巻貝の筋肉に作用すること，二枚貝未受精卵外皮を短時間で崩壊させることなどから，原因物質はレセプターや膜の構造を破壊する分解酵素のようなものではないかと推察された。影響を受けた貝類は細胞内に多量のカルシウムが流入しており，これにより生理的なかく乱が生じて細胞や組織の恒常性が崩壊しているものと考えらる。H. circularisquama の毒性を低減する方法としては，遠心力負荷などによる物理学的処理，SDSを用いた化学的処理などが有効であったが，コストと環境負荷の点から改良が必要であった。また，珪酸塩の散布によって競合者である珪藻を賦活させる方法も特定の条件下では有効であった。生物学的な防除法としては，ホヤなどろ過食性付着生物を利用した防除法が有望であると判断された。 | |||||
| 言語 | ja | |||||
| 書誌情報 |
ja : 水産総合研究センター研究報告 en : Bulletin of Fisheries Research Agency 巻 9, p. 13-117, ページ数 105, 発行日 2003-09 |
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| 出版者 | ||||||
| 出版者 | 水産総合研究センター | |||||
| 言語 | ja | |||||
| ISSN | ||||||
| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 1346-9894 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AA11589591 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | fra_k_9_13 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010690838 | |||||
| 関連名称 | 日本農学文献記事索引（AgriKnowledge） | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
