近日,，中科院動物研究所王琛柱研究組發(fā)現(xiàn)了一種有趣的氣味結合蛋白——OBP10,。一般認為，這類蛋白在嗅覺感器中發(fā)揮作用,，用來運輸氣味分子到嗅覺受體上,。但是，研究人員通過Western Blot和免疫組化的方法發(fā)現(xiàn),，這種蛋白不僅表達于棉鈴蟲和煙青蟲的嗅覺器官（觸角）中,，而且在雄蛾的精液中也有表達,。進一步研究證明，雄蛾可以通過交配將蛋白傳遞給雌蛾,，并最終出現(xiàn)于雌蛾產(chǎn)的受精卵表面,。相關論文發(fā)表在PLoS ONE上。
棉鈴蟲和煙青蟲是我國重要的農(nóng)業(yè)害蟲,。棉鈴蟲是典型的多食性昆蟲,，取食至少40科200余種植物，包括棉花,、小麥,、玉米、番茄,、花生,、煙草等農(nóng)作物；而煙青蟲是寡食性昆蟲,，僅取食同屬于茄科的煙草,、辣椒及酸漿屬的數(shù)種植物。兩種蛾子均具有在寄主植物上單粒分散產(chǎn)卵的習性,。
在這一過程中,，OBP10是否也在傳遞一種信息氣味物質(zhì)呢？研究人員用GC/MS法分析了兩種昆蟲雄性生殖器官的二氯甲烷提取物,，發(fā)現(xiàn)了多種不同鏈長的醛和其它化合物,。為了尋找OBP10的天然配體，他們利用凝膠層析,、SDS-PAGE,、Western blot、GC/MS等一系列方法,，鑒定出OBP10的天然蛋白,，并發(fā)現(xiàn)其最有可能結合的天然化合物為1-dodecene。之后用熒光結合實驗證實,，OBP10重組蛋白與1-dodecene具有較強的結合能力,。計算機模擬發(fā)現(xiàn)，OBP10與致倦庫蚊OBP1的氨基酸序列差異很大,，但三維結構卻很相似,，而后者的天然配體是一種促進蚊蟲產(chǎn)卵的信息素。
綜合已有的結果,，研究人員推測,，OBP10結合的1-dodecene極有可能是一種產(chǎn)卵趨避劑：在自然環(huán)境下，棉鈴蟲和煙青蟲幼蟲有同種相食的習性,，雄蛾通過交配作用將攜帶有1-dodecene的OBP10傳遞給雌蛾,，交配后的雌蛾所產(chǎn)的卵表面攜帶了1-dodecene,，雌蛾通過觸角中的OBP10來感受這種化合物，會自動避開已有卵粒的植物,，使得卵粒分散開來,，從而經(jīng)濟有效地避免自相殘殺。這是昆蟲氣味結合蛋白具有傳遞和感受氣味物質(zhì)雙重功能的一個新例證,。（生物谷Bioon.com）
doi:10.1371/journal.pone.0030040
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Expression in Antennae and Reproductive Organs Suggests a Dual Role of an Odorant-Binding Protein in Two Sibling Helicoverpa Species
Ya-Lan Sun1, Ling-Qiao Huang1, Paolo Pelosi1,2*, Chen-Zhu Wang
Odorant-binding proteins (OBPs) mediate both perception and release of semiochemicals in insects. These proteins are the ideal targets for understanding the olfactory code of insects as well as for interfering with their communication system in order to control pest species. The two sibling Lepidopteran species Helicoverpa armigera and H. assulta are two major agricultural pests. As part of our aim to characterize the OBP repertoire of these two species, here we focus our attention on a member of this family, OBP10, particularly interesting for its expression pattern. The protein is specifically expressed in the antennae of both sexes, being absent from other sensory organs. However, it is highly abundant in seminal fluid, is transferred to females during mating and is eventually found on the surface of fertilised eggs. Among the several different volatile compounds present in reproductive organs, OBP10 binds 1-dodecene, a compound reported as an insect repellent. These results have been verified in both H. armigera and H. assulta with no apparent differences between the two species. The recombinant OBP10 binds, besides 1-dodecene, some linear alcohols and several aromatic compounds. The structural similarity of OBP10 with OBP1 of the mosquito Culex quinquefasciatus, a protein reported to bind an oviposition pheromone, and its affinity with 1-dodecene suggest that OBP10 could be a carrier for oviposition deterrents, favouring spreading of the eggs in these species where cannibalism is active among larvae.
