番茄碱对棉铃虫的毒性作用机理初探

采取荧光光谱法分析了番茄碱及虫体内钙调蛋白的图谱,从钙调蛋白的角度探讨了番茄碱的作用机理.结果显示:(1)番茄碱对棉铃虫具有毒性,随浓度的增加及饲喂时间的延长,对棉铃虫的杀伤力增强;(2)番茄碱对虫体内钙调蛋白的影响较大,随番茄碱浓度的增加,钙调蛋白的含量逐渐降低;(3)钙离子的加入增强了钙调蛋白的刚性,荧光图谱出现了红移(由350 nm移至416.58 nm);(4)番茄碱的加入破坏了钙调蛋白-钙离子复合物的刚性,荧光图谱出现了蓝移(416.58 nm移至377.65 nm).以上可以说明,番茄碱可能作为钙调蛋白的拮抗剂,拮抗钙调蛋白被钙离子激活的位点,影响其与靶酶的结合而发挥作用.此项的研究为探讨番茄碱的杀虫机理提供了科学依据.

Preliminary Study of Action Mechanism of Tomatine Toxicity to Helicoverpa armigera

The spectra of tomatine and calmodulin(CaM) were investigated by fluorescent spectrometry and the action mechanism of tomatine toxicity were analyzed from the angle of calmodulin.The results showed that(1) tomatine was toxic to Helicoverpa armigera and its lethality to the insect increased as its concentration increased and its feeding time prolonged;(2) Tomatine exerted great influence on endosomatic calmodulin of the insect,increased tomatine concentration resulting in gradually declined endosomatic calmodulin content;(3) Calcium ion addition increased calmodulin rigidity so that red shift occurred in the fluorescent spectra (from 35 nm to 416.58 nm);(4) After its addition,tomatine damaged CaM-Ca~(2 ) rigidity so that blue shift occurred in the fluorescent spectra(from 416.58 nm to 377.65 nm).Those above tell that tomatine is probably used as an antagon to calmodulin and the Ca~(2 )-activitated site of calmodulin take effect by affecting the combination of calmodulin with target enzymes.This study provided scientific basis to studying the insect-disinfecting mechanism of tomatine.