油松毛虫雌蛾对油松松针两种手性化合物的触角电位反应

Electroantennogram responses of female Dendrolimus tabulaeformis Tsai et Liu to two volatile enantiomers of Pinus tabulaeformis Carr

采用触角电位技术测定了油松毛虫雌蛾触角对油松挥发物的两对手性单萜的剂量反应,并在饱和剂量下测定了α-蒎烯、β-蒎烯手性化合物及其消旋体的触角电位值。剂量反应测试表明,油松毛虫雌蛾对(-)-α-蒎烯的饱和剂量为1600μL,对(+)-α-蒎烯、(+)-β-蒎烯、(-)-β-蒎烯的饱和剂量为800μL。α-蒎烯右旋异构体的反应值高于(-)-α-蒎烯的反应值,说明(+)-α-蒎烯能够更有效的与感受器中的分子受体结合;β-蒎烯则相反,(-)-β-蒎烯的EAG反应值高于(+)-β-蒎烯,说明β-蒎烯的右旋异构体不能有效的与多数感受器中的分子受体结合。在饱和剂量下的测定结果表明油松毛虫雌蛾对α-蒎烯和β-蒎烯消旋体的反应均与对其手性异构体反应相当,说明油松毛虫雌蛾用同一个感受细胞来接受α-蒎烯的两个对映异构体,同样β-蒎烯的两个对映异构体也是被同一个受体细胞来接受。结果提示,手性化合物的比例可能在油松毛虫寄主识别中有重要作用。

Electroantennograms were recorded from female Dendrolimus tabulaeformis Tsai et Liu to serial stimulus doses （50 μL, 100 μL, 400 μL, 800 μL, 1 600 μL, and 3 200 μL） of four monoterpene hydrocarbons （（＋）-α-pinene, （-）-α-pinene, （-）-β-pinene, and （＋）-β-pinene）, and the saturating dose was tested. Dose-response curves constructed from the EAGs revealed that the saturating dose of （-）-α-pinene was 1 600 μL and that of the other three chemicals was 800 μL. The relative volume of the electroantennogram response was higher for （＋）-α-pinene compared to （-）-α-pinene, suggesting that greater affinity to receptor molecules for （＋）-α-pinene than （-）-α-pinene; on the contrary, response of the moth to the （-）form of the β-pinene was higher than that to the （＋） form, suggesting that （＋）-β-pinene does not bind as efficiently as （-）-β-pinene with the receptor molecules in many of the sensilla. Electroantennogram recording using mixtures of the enantiomers at saturating dose levels showed that the response to the mixture of α-pinene was almost equal to those of the two forms of α-pinene, suggesting that the two forms of α-pinene were detected by the same receptor neurons; and the same for the β-pinene. Discrimination between enantiomers by plant olfactory receptor neurons in the moth suggested that the enantiomeric ratios of volatile compounds might be important in host location of D. tabulaeformis.