| Culex pipiens pallens is one of important media to transmit Filariasis due to Wuchereria bancrofti and epidemic encephalitis B and so on which is widely found in northern China. Chemical pesticides are widely used as the main tool for mosquito control, which play an important role in the fight against mosquito-borne transmitted diseases while there is lots of difficulty appearing in disease prevention because of the excessive use which can bring mosquito drug resistance on different level. The amount of insects with Chemical resistance increases very sharply year by year since 1914, when Melander reported that the U.S. pear Diaspididae had resistance to lime sulphur. The Mosquito resistance to insecticides was observed for the first time in 1947. The larvae of Aedes taen-iorhynchus and Ae-des sollicitans could become resistant to DTT.Pyrethroid insecticides have been widely used in health pest control for the advantage of high efficiency, broad-spectrum, low toxicity and so on. But with extensive use of such reagents, pests get the resistance which is bad for the effect of the pesticides.Culex pipiens pallens was selected as the objective of this study. Via the earlier period preparation and observation, the methods of farming and resistance training were studied and drop method was taken to do resistance training and biological testing. The Culex pipiens pallens was the one long-term feed in Shandong Province Center for Disease Control and Prevention. Resistance was started from generation F0 which owned low level resistance to Beta-cypermethrin with the beta-cypermethrin as the resistance training pesticides. The processes and results of resistance training were observed and noted, the activities of several proteins such as GST, AChE, CAT in Culex pipiens pallens on different levels of resistance and then the difference of expressed proteins between Culex pipiens pallens with and without resistance to Beta-cypermethrin was also studied, followed by the final step, on which the development of resistance of Culex pipiens pallens was observed in the absence of beta-cypermethrin.Firstly, the resistance of Culex pipiens pallens was increasing from 3.8809 times in F0 to 269.5476 in F22, which was nearly 70 times of the test beginning of 22-generation resistance training. It was very difficult to control Culex pipiens pallens because of the high level of resistance in F22.Secondly, the protein activities of GSH-PX, AChE, NSE in Culex pipiens pallens on different levels of resistance had greatly changed in the training process. GST was the important enzyme for detoxification, which was the main reason for the linkage between activity improvement and resistance enhancement. The activity of AChE was decreasing with the improvement of the resistance. This enzyme was one important target enzyme that was insensitive to the target, which was good to reduce the damage of insecticide. CAT is one of the important enzymes on detoxication of insecticide in mosquito which is widely spreading in every tissue. In this study, the activity of CAT was increasing with the generation and the improvement of resistance.In addition, the expressed protein levels in susceptible strain and in resistant strain were different significantly in the test of protein analysis with the water-soluble proteins of Four instar larvae in F0 and F22.And finally, the attenuation of resistance reached to 98.46%,witch was close to the resistance level of susceptible strain via the 6-generation continuous feedings of F22 which demonstrated that the resistance of the strains cultivated in lab would decline rapidly without resistance pressure of pesticides. So in the process of Culex pipiens pallens control, it was a good way to use different pesticides together or alternatively which could prevent the resistance and improve the effect of Culex pipiens pallens control. |
