Tsuchihara Kazuko, Hisatomi Osamu, Tokunaga Fumio, Asaoka Kiyoshi
Iwaki Meisei University; Iwaki, Japan.
Commun Integr Biol. 2009 Jul;2(4):356-8. doi: 10.4161/cib.2.4.8613.
Oviposition is evoked by plant compounds, which are recognized by chemoreceptive organs of insects. The swallowtail butterfly, Atrophaneura alcinous, oviposits its eggs on the host plant, Aristolochia debilis, in the presence of only two stimulating compounds: an alkaloid, aristolochic acid, and a monosaccharide, sequoyitol. In our previous study, a unique protein of 23 kDa [Oviposition stimulant(s) binding protein (OSBP)] was found in the forelegs of female, but not male A. alcinous. The electrophysiological response of A. alcinous to an extract of A. debilis was depressed by the presence of OSBP antiserum, suggesting that OSBP presumably binds to oviposition stimulant(s). We show here, using a highly sensitive fluorescence micro-binding assay that native OSBP binds to a main oviposition stimulant, aristolochic acid, from its host plant, A. debilis. Three-dimensional molecular modeling studies also gave a reasonable structure for the OSBP/aristolochic acid complex. This is the first report of a native chemoreceptive protein binding to an oviposition stimulant ligand in insects.
产卵行为由植物化合物引发，昆虫的化学感受器官能够识别这些化合物。燕尾蝶（Atrophaneura alcinous）仅在两种刺激化合物存在的情况下将卵产在寄主植物马兜铃（Aristolochia debilis）上：一种生物碱，马兜铃酸，以及一种单糖，红杉醇。在我们之前的研究中，在雌性而非雄性的A. alcinous前腿中发现了一种独特的23 kDa蛋白质[产卵刺激物结合蛋白（OSBP）]。A. alcinous对A. debilis提取物的电生理反应因OSBP抗血清的存在而受到抑制，这表明OSBP可能与产卵刺激物结合。我们在此使用高灵敏度荧光微结合测定法表明，天然OSBP与其寄主植物A. debilis中的主要产卵刺激物马兜铃酸结合。三维分子建模研究也给出了OSBP/马兜铃酸复合物的合理结构。这是关于昆虫中天然化学感受蛋白与产卵刺激物配体结合的首次报道。
