大肠埃希菌感染后家蝇幼虫血清中3种酶活性的变化

目的探讨大肠埃希菌感染对家蝇3龄幼虫血清中3种酶活性的影响。方法（1）用比色法分别测定感染后不同时间家蝇3龄幼虫血清中酸性磷酸酶（ACP）及过氧化氢酶（CAT）活性的变化。（2）用聚丙烯酰胺凝胶电泳法测定感染后不同时间家蝇3龄幼虫血清中二酚氧化酶（DPO）活性的变化。结果（1）大肠埃希菌感染后各时间组血清中ACP及CAT活性显著高于对照组（P〈0．01）。其中ACP及CAT活性分别在感染8和16h达高峰，其值分别为（107．9±3．5）u／100ml和（174．6±4．7）u／ml，然后逐渐下降。（2）家蝇幼虫体内存在DPO，且感染后4hDPO活性上升，16h达高峰，其值为98805．39，之后下降。结论大肠埃希菌感染后家蝇3龄幼虫血清中ACP、CAT及DPO活性均增强，提示这3种酶在防御微生物感染过程中发挥了重要作用。

Activity change of three enzynmes in serum of the Musca domestica larva infected by Escherichia coli

Objective To explore the influence of Escherichia coli infection on the activity of three enzymes in serum of the Musca dornestica larva. Methods （1） The colorimetry was used to determine the activity of acidic phosphatase（ACP） and catalase（CAT） in the 3rd stage larva of M. domestica after infected by E. coli for different times, respectively. （2） PAGE was used to assay the activity of diphenol oxidase（DPO） in the 3rd stage larva after infection for different times. Results （1） The activities of both ACP and CAT in larvae serum were all much higher than that of the control after infection for 4, 8, 16 and 24 h（P〈 0.01）, and the peak of two enzymes activity were at 8 h and 16 h after infection, which were （107.9±3.5）U/100 ml and （174.6 ± 4.7）U/ml respectively, and then it gradually decreased. （2） DPO existed in the M. domestica larva, and its activity began to increase after infection for 4 h. The peak of enzyme activity appeared after infection for 16 h with the value of 98 805.39, and then it gradually decreased. Conclusion The activities of the ACP, CAT and DPO in serum of the 3rd stage larva of M. domestica enhanced after infected by E. coli, which suggested that three enzymes played an important defense role in the process of microorganism infection.