曲酸对飞蝗酚氧化酶以及其他生化酶活性的影响

The effects of kojic acid on the activities of phenoloxidase and other biochemical enzymes of Locust migratoria L.

酚氧化酶(Phenoloxidase)可以催化黑色素中间体多巴胺的形成,是昆虫黑化作用中的关键酶,在昆虫细胞免疫和体液免疫过程中发挥着重要的作用。"近年来,酚氧化酶成为新型杀虫剂靶标的研究对象之一,而酚氧化酶的抑制剂曲酸(Kojic acid)对昆虫解毒酶和保护酶的影响的研究却很少。为了探索酚氧化酶与昆虫其他解毒酶或保护酶类的关系,本文利用含不同剂量曲酸的麦麸饲喂飞蝗,检测飞蝗存活率以及虫体酚氧化酶(PO)、乙酰胆碱酯酶(AChE)、解毒酶(ESTs和GSTs)和保护酶(POD、SOD和CAT)的活性。结果发现,曲酸对飞蝗无明显毒力;在曲酸处理1 d和3 d后,曲酸处理组飞蝗PO二酚酶活性显著低于对照,5 d和7 d后飞蝗PO活性与对照相比差异不大;处理3 d后,飞蝗AChE活性显著低于对照,而5 d后AChE相比于对照显著升高;偏高浓度的曲酸在1 d和3 d后对飞蝗ESTS和GSTs有显著的抑制,5 d和7 d后飞蝗ESTs和GSTs活性上升;曲酸在1 d和3 d后引起了飞蝗保护酶的升高,5 d后飞蝗保护酶有一定的下降。以上结果表明,曲酸对飞蝗PO有明显抑制作用,同时也干扰了昆虫其它生化酶的活性。由此推测,曲酸可以作为杀虫剂或者杀虫真菌的增效剂。

Phenoloxidase（ PO） catalyses the oxidation of phenols to quinones,which then will polymerize nonenzymatically to melanin. Therefore PO plays a pivotal role in melanisation reactions in the innate immune system of insects. In recent years,PO has been studied as a new target of insecticides. But few researches have looked at the effects of kojic acid which is an inhibitor of PO on detoxification enzymes and antioxidant enzymes in insects. To investigate the relationship between PO and other biological enzymes of insects,the activities of PO,acetylcholinesterase（ ACh E）,general esterases（ ESTs）,glutathione-Stransferases（ GSTs）,peroxidase（ POD）,superoxide dismutase（ SOD） and catalase（ CAT） were assayed after Locusta migratoria L. were treated with kojic acid. PO,ACh E,ESTs and GSTs activities decreased in the kojic acid-treated L. migratoria in comparison with control after 1,3 d. POD,SOD and CAT activities increased after 3 d and decreased after 5 d in comparison with control. The results indicated that kojic acid showed inhibitory effects on PO and other biochemical enzymes of L. migratoria and kojic acid may be asynergist for chemical and biological insecticides.