食料对南亚果实蝇解毒酶活力的影响

昆虫解毒酶是一类异质酶系, 对分解大量的内源或外源有毒物质、维持正常生理代谢起着重要作用。本文采用生物化学的方法测定了5种寄主果实对南亚果实蝇Bactrocera tau Walker 3个虫态体内总蛋白含量和5种解毒酶的活力。双因子方差分析显示, 南亚果实蝇种群取食黄瓜Cucumis sativus L.、南瓜Cucurbita moschala L.、丝瓜Luffa cylindrical L.、冬瓜Benincasa hispida (Thunb.) Coqn.和苦瓜Momordica charantia L.后, 体内蛋白含量和解毒酶活性均存在显著差异。以丝瓜为食料时, 南亚果实蝇体内蛋白含量较高； 而以黄瓜和冬瓜为食料时蛋白含量则相对较低。在以上5种寄主果实间, 南亚果实蝇的羧酸酯酶（CarE）活性在黄瓜和南瓜上较高, 细胞色素P450 O-脱甲基和谷胱甘肽S-转移酶（GST）活性在苦瓜上较高, 酸性磷酸酯酶（ACP）和碱性磷酸酯酶（ALP）活性却分别在黄瓜和南瓜上较低。在幼虫、蛹和成虫3个虫态间, 解毒酶活性亦存在显著差异, 成虫具有较高的CarE活性；幼虫具有较高的细胞色素P450 O-脱甲基, GST和ALP活性，但具有较低的ACP活性；除ACP外，蛹期解毒酶活性均较低。据以上结果可以推测，南亚果实蝇解毒酶活力受寄主果实种类以及该种群本身发育阶段的影响。

Diet influences the detoxification enzyme activity of Bactrocera tau (Walker) (Diptera: Tephritidae)

Detoxification enzymes in insects are generally demonstrated as the enzymatic defense against foreign compounds and play significant roles in maintaining their normal physiological functions. In this study,protein contents and carboxylesterase (CarE),acid phosphatase (ACP),alkaline phosphatase (ALP),cytochrome P450-dependent O-demethylase and glutathione S-transferase (GST) activities of Bactrocera tau Walker were determined by biochemical methods. The results showed that protein contents and these detoxification enzyme activities of the fruit fly varied significantly when fed on different diets including cucumber, pumpkin,towel gourd,white gourd and balsam pear. For protein contents, they were highest on balsam pear while lowest on cucumber and white gourd. For these detoxification enzymes,the CarE activity was highest on cucumber and pumpkin,cytochrome P450-dependent O-demethylase and GST activities were highest on balsam pear, but ACP and ALP activities were lowest on cucumber and pumpkin, respectively. In addition, these detoxification enzyme activities were also significantly different in the larval, pupal and adult stages. Adults had the highest CarE activity, and larvae had the highest ALP,cytochrome P450-dependent O-demethylase and GST activities, but the lowest ACP activity. Generally, these detoxification enzyme activities in the pupal stage were lower than those in the larval and adult stages except for ACP. Based on the above results, it was inferred that these detoxification enzyme activities were closely related to host plant species and developmental stages of this fruit fly.