2008-01-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/663023摘要：二次世界大戰後，有機合成工業發達，各種合成農藥大量使用，帶動農業的蓬勃發展；然卻也造成環境的嚴重破壞，物種滅絕，甚至嚴重影響人類健康，因而降低有機化學合成農藥的使用，提高產品安全性的需求日殷，使得生物農藥之發展愈顯迫切。 幾丁質是普遍存在昆蟲的外骨骼 (exoskeleton)之成分，也是地球上含量僅次於纖維素的胺基醣型式的多醣，開發利用潛力無窮；昆蟲除了外骨骼，腸道中的圍食膜亦含有幾丁質成分，圍食膜具有保護昆蟲腸道上皮絨毛細胞，避免直接受到食物磨擦及微生物接觸，因此圍食膜為昆蟲攝食後與食物直接接觸的構造，適合作為以幾丁質為標的的生物殺蟲劑標靶。我們先前研究已證實Galectin(一種源自哺乳類之醣類結合蛋白)具有殺蟲活性，並可能破壞昆蟲圍食膜之構造；我們也證實galectin可與chitin直接產生結合作用；我們也成功地將galecitn基因轉殖至阿拉伯芥植株，並初步證實具有殺蟲作用；本計畫擬深入探討galectin的阿拉伯芥轉殖株之殺蟲活性與機制，並計畫進一步將galectin基因轉殖表現於阿拉伯芥植株之篩管，以測試對刺吸式口器害蟲之毒性及毒性機制。最終將galectin轉殖至經濟作物後，作為害蟲防制之依據。此種以幾丁質(chitin)為標的的生物性殺蟲劑，具有下述之優點(1) galectin源自哺乳類本身，安全性高， (2) galectin為蛋白質，可分解，無環境殘留問題，(3)幾丁質為昆蟲共同具有之構造，適用性廣。第一年目標將繼續探討galectin的阿拉伯芥轉殖株之殺蟲活性與機制，研究galectin於小菜蛾及斜紋夜盜蟲體內之分佈，並了解其腸道結構與galecitn結合作用之機制。長程目標則擬發展一種以幾丁質為作用標的的生物性殺蟲劑，並探討其作用機制，建立其基因轉殖植株，發展為生物殺蟲劑之可行性。 <br> Abstract: Chitin is one of the most abundant amino biopolymer found in nature and it has the potential to be utilised as an alternative source of organic pesticides. Chitin makes up the structural elements of the exoskeletons and peritrophic membranes in various insects. The peritrophic membrane is the first tissue that comes into contact with ingested food and thus, it represents a potential target for selective bio-insecticidal use in controlling fungi-borne diseases and insect pests. Our previous studies have shown that galectin-1 could interact with chitosan and chtin in vitro, indicating that chitosan and chitin could be a nature ligand of galectin-1. Moreover, the larvae development of diamondback moth (P. xylostella) was significantly disturbed when fed with galectin-1 extract and/or recombinant galectin-1 proteins purified from galectin-1 over-expressed E. coli. We have also established a galectin-transfected stable clone of Arabidopsis (GAL1-Arabidopsis). The GAL1-Arabidopsis clone showed insecticidal activity toward P. xylostella. These projects aim to further investigate the insecticidal activity of GAL1-Arabidopsis and dissect the insecticidal mechanism of GAL1-Arabidopsis. The galectin sequence will be further constructed into the vector of pCAMBIA1390-SUC2pro to establish a stable clone of Arabidopsis that over-expressed galectin in sieve tube member. The GAL1-Arabidopsis-fed larva will be further dissected for peritrophic membrane examination and immuno-stained with GAL1 monoclonal antibody. The long-term goal of this proposal also aim to over-expression of galectin in transgenic crops as a bio-insecticides. There are at least three prominent features of the chitin-targeted bio-insecticide. Firstly, galectin-based bio-insecticide is not toxic to humans, since galectin is derived from mammal tissues. Secondly, it is a proteinaceous bio-insecticide that is biogradable in nature. Third, it is a broad-spectrum bio-insecticide since its action is targeted at chitin, a component of all insects.幾丁質生物農藥圍食膜BioinsecticideChitinPeritrophic membrane