关键词: 家蝇幼虫, 大肠埃希菌, 血清, 酶活性

Abstract: Objective To explore the influence of Escherichia coli infection on the activity of three enzymes in serum of the Musca domestica 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.