近日，中科院动物研究所王琛柱研究组发现了一种有趣的气味结合蛋白——OBP10。一般认为，这类蛋白在嗅觉感器中发挥作用，用来运输气味分子到嗅觉受体上。但是，研究人员通过Western Blot和免疫组化的方法发现，这种蛋白不仅表达于棉铃虫和烟青虫的嗅觉器官（触角）中，而且在雄蛾的精液中也有表达。进一步研究证明，雄蛾可以通过交配将蛋白传递给雌蛾，并最终出现于雌蛾产的受精卵表面。相关论文发表在PLoS ONE上。
棉铃虫和烟青虫是我国重要的农业害虫。棉铃虫是典型的多食性昆虫，取食至少40科200余种植物，包括棉花、小麦、玉米、番茄、花生、烟草等农作物；而烟青虫是寡食性昆虫，仅取食同属于茄科的烟草、辣椒及酸浆属的数种植物。两种蛾子均具有在寄主植物上单粒分散产卵的习性。
在这一过程中，OBP10是否也在传递一种信息气味物质呢？研究人员用GC/MS法分析了两种昆虫雄性生殖器官的二氯甲烷提取物，发现了多种不同链长的醛和其它化合物。为了寻找OBP10的天然配体，他们利用凝胶层析、SDS-PAGE、Western blot、GC/MS等一系列方法，鉴定出OBP10的天然蛋白，并发现其最有可能结合的天然化合物为1-dodecene。之后用荧光结合实验证实，OBP10重组蛋白与1-dodecene具有较强的结合能力。计算机模拟发现，OBP10与致倦库蚊OBP1的氨基酸序列差异很大，但三维结构却很相似，而后者的天然配体是一种促进蚊虫产卵的信息素。
综合已有的结果，研究人员推测，OBP10结合的1-dodecene极有可能是一种产卵趋避剂：在自然环境下，棉铃虫和烟青虫幼虫有同种相食的习性，雄蛾通过交配作用将携带有1-dodecene的OBP10传递给雌蛾，交配后的雌蛾所产的卵表面携带了1-dodecene，雌蛾通过触角中的OBP10来感受这种化合物，会自动避开已有卵粒的植物，使得卵粒分散开来，从而经济有效地避免自相残杀。这是昆虫气味结合蛋白具有传递和感受气味物质双重功能的一个新例证。（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.
