Objective To observe the larvicidal activities of transgenic cyanobacteria with CryIVD gene of Bacillus thuringiensis subsp. israelensis against different larval instars of Culex pipiens pallens. Methods Transgenic cyanobacteria with CryIVD gene of Bacillus thuringiensis subsp. israelensis were cultured in large numbers and were then dried and stored. The larvicidal activities of transgenic cyanobacteria stored for different periods were determined against different larval instars of Cx. pipiens pallens.Results The dried and stored transgenic cyanobacteria demonstrated a high toxicity to Cx. pipiens pallens larvae, and the longer the dried ones were stored, the lower their toxicity was. Compared with fresh ones, the stored transgenic cyanobacteria had slightly decreased larvicidal activity. They killed over 50% of larvae of different instars in 48 hours at concentration of 105 cells/ml. At a concentration of 106 cells/ml, transgenic cyanobacteria stored for one year, two years, and three years showed similar larvicidal activities, resulting in no significant differences in mortality rate of Cx. pipiens pallens larvae (F=9.32, P>0.01), but there was significant difference in the mortality rate when comparison was made between the transgenic cyanobacteria stored for one year and three years at a concentration of 105 cells/ml (F=101.21, P<0.01). Conclusion The cryIVD gene of Bacillus thuringiensis subsp. israelensis and larvicidal activity of stored transgenic cyanobacteria remain stable, and the stored transgenic cyanobacteria provide a convenient way for use in the field.

Prophenoloxidase-activating system is an important part in the immune system of Musca domestica and plays an essential role in the pathogen recognition and immune defense. Until now, however, the key genes in the prophenoloxidase-activating system and the system's action mechanism remain unclear. On this occasion, we performed transcriptomic analysis of M. domestica to obtain a number of expressed sequence tags of the key genes of prophenoloxidases, prophenoloxidase-activating enzymes, serine proteinase inhibitors (Serpin), and upstream pattern-recognition receptors in the prophenoloxidase-activating system. This article reviews the research advances in the key genes in the prophenoloxidase-activating system of M. domestica.

【Abstract】 Objective To explore the effect of frozen storage on non-specific esterase (NSE) activity of Culex pipiens pallens and provide a basis for the generalization and application of insecticide-resistance detection of mosquito by biochemical method. Methods The NSE activity of single mosquito was determined based on β-naphthalene acetic acid ester (β-naphthyl acetate, β-NA) as substrate and solid blue B salt (fast blue B salt) as developer. Results The NSE activity of DDVP-resistant strain was obviously higher than that of susceptible strain. For the A value of NSE activity from Cx.pipiens pallens after frozen for 0, 7, 14, 21 and 28 days at -20 ℃, the F value of 4 instar larvae of susceptible strain mosquito was 0.7642 by the complete randomized design variance comparison and the F value of 3-day-old adult female of susceptible strain mosquito was 0.7452. The F value of 4 instar larvae of DDVP resistant strain mosquito was 0.1092, and the F value of 3-day-old adult female of DDVP-resistant strain mosquito was 0.1521. All of the P value were greater than 0.05 and no significant difference was found. Conclusion There was no difference between on the NSE activity of 4 instar larvae and 3-day-old adult female of Cx.pipiens pallens after frozen for 28 days, and mosquitoes collected from the field could be taken to the lab for batch determination.

Objective To explore the correlation of the resistance of Propoxurresistant,DDVPresistant and Cypermethrinresistant Culex pipiens pallens strains with Acetylcholinesterase(AChE) activity. Methods WHO bioassay and microplate method were used for the tests. Results The resistance indices of the three resistant strains became increased with the extension of generations during the 43generations' insecticide resistance selection. The average AChE inhibition rate of Propoxurresistant strain decreased with the extension of generations and the individual frequency of those with inhibition rate no less than 30% was the highest in the three resistant strains,followed by DDVPresistant strain,showing a correlation. The results were consistent basically with those of bioassay. The AChE activity in Cypermethrinresistant strain was similar to that of the susceptible strain. Conclusion The AChE activity showed a correlation with the resistance of Cx.pipiens pallens to carbamates and organophosphorus insecticides,and little with that to pyrethroids.

Objective To study the resistance development and cross-resistance of Propoxur-resistant Culex pipiens pallens to several chemical insecticides for their rational use. Methods WHO standard bioassay was employed to calculate LC ₅₀ ,regression equation and resistance index. Results The resistance index of Culex pipiens pallens rose up to 11.26 folds after 43 generation's propoxur selection. The indexes of the resistant mosquito to propoxur,DDVP,cypermethrin,acetofenate and deltamethrin were 9.54 ,2.68,7.00 ,1.74 ,1.70 folds in the 21 generation and 11.34 ,2.85 ,8.07 ,2.00 ,1.80 folds in the 30 generation,respectively. In the 39 generation,those were 11.78 folds to propoxur,3.35 to DDVP and 9.71 to cypermethrin. Conclusion The resistance and cross-resistance were easily developed for a long term use of one kind of insecticide,which showed that the insecticides should be rationally used in mosquito control to delay the development of the resistance and cross-resistance.

Objective The toxicity and synergism of several commonly used insecticide mixtures,and DDVP mixed with synergists,to the larvae of DDVP-resistant Culex pipiens pallenswere detected to delay the development of mosquito resistance to insecticides. Methods WHO standard bioassay was employed to calculate LC ₅₀and synergistic coefficient. Results The synergistic effects of propoxur+acetophenate,DDVP+ acetophenate,cpermethrin+DDVP and cpermethrin+propoxur was 139.94-151.95,125.62-133.29 ,151.09-175.81 ,and 143.04-151.83,repectively,and those of DDVP+S ₁,DDVP+S ₂,DDVP+Amine Synergist were 4.73-7.31,2.97-5.46and 2.43- 4.11,respectively. Conclusion The insectide mixtures of pyrethroids or organochloride with organophosphate or carbamate may have better efficacy against DDVP-resistant mosquitoes,and the mixed use of the insecticide with synergists may also provide better efficacy.

Objective To delay the occurrence and evolution of resistance,to use insecticide scientifically,and to control Culex pipiens pallens,the susceptibility of this insect was determined to several common insecticide mixtures in same areas of Shandong province.Methods WHO standard bioassay method was applied to calculate LC ₅₀ and synergistic coefficient.Results The synergistic effects of propoxur+Cypermethrin,DDVP+Cypermethrin against mosquitoes were 125.78- 395.21,127.37- 364.50 respectively,while DDVP+propoxur was lower.Conclusion Pyrethroids used in mixture with Organophosphates or Carbamates could effectively control insecticide resistance mosquito.

Objective To discuss the insecticide resistance status of mosquitoes in different areas and different periods.Methods WHO bio-assay and distinguishing dosage method.Results The pyrethroid resistance of different areas and different periods was high at large,the propoxur resistance was high at large dosage area,and Acetophenate resistance emerged in some area.In some area,there was still high DDT resistance where it had been ceased use for several years,and the Acetophenate resistance level in some area was close to sensitive strain's.Conclusion The resistance of mosquitoes of different insecticide had obvious discrimination in different regions,and it was related to the use frequency.The use of single insecticide for a long time will raise the resistant level,and reasonable use of insecticides is needed.

Objective:To observe the larvicidal activity of the dried genetically engineered Cyanobacteria against the larvae of Culex pipiens pallens.Methods:Desiccation,storage and detection of larvicidal activity.Results:The dried genetically engineered Cyanobacteria still kept high toxicity.And the longer the dried ones were stored,the lower toxicity they had.But there were no significant differences within the three dried genetically engineered Cyanobacteria.Conclusion:The shuttle plasmid in Cyanobacteria kept stable and high expressing and the dried genetically engineered Cyanobacteria might be a prospective insecticide for field control.

Objective:To explore simple and sensitive technic for insecticide resistance detection and early prediction.Methods:Microplate test was used to detect non-specific esterase(NSE) of single Cx.pipeins pallens of laboratory and field population,using β-Naphthyl acetate as the substrate and fast blue B salt solution as the colour agent.Results:The NSE level was highest in anti-DDVP strain,followed by anti-propoxur strain and anti-DDVP degenerated strain,while the level was similar between anti-cypermethrin and susceptible strain.Three field collected Cx.pipiens pallens populations have 4.15-9.36 fold higher resistance against DDVP and 1.02 - 3.81 fold higher resistance against propoxur than susceptible mosquito,and their NSE level was also higher than susceptible strain.Conclusion:Microplate test for NSE can be used for the detection of resistance against Op and carbamate insecticides.The method is easy and rapid to perform with high precision and objective results.Resistance frequency and mechanism can be detected at the same time,so early prediction of resistance and working out resistance management measure is possible.

Objective:To establish the filter paper test for the determination on non-specific esterase and acetylchotin esterase as a resistant determination method.Method:Filter paper test.Result:Filter paper test was used in this study to test the non-specific esterase(NSE)and acetylchotin(AchE)activities of susceptible and resistant strain of Cx.pipiens pallens,so as to determine the resistant level of individual mosquito according to colour changes.The results indicated that susceptible mosquitoes showed no or slight colour reaction while resistant mosquitoes revealed deep colour,and the NSE and AchE activity was inhabited in susceptible individuals by insecticides,while it cannot be inhabited in resistant individuals.It was demonstrated that there existed the difference in the AchE activity between susceptible and resistant mosquitoes.Conclusion:This method can rapidly determine the NSE and AchE activity in mosquitoes,and easy to perform,so it can be used for qualitatively determining the resistant level of mosquitoes and be convenient to be popularized in the field.

Under the different controlled temperatures in the laboratory,the developmental period of different stage An.sinensis and the sporogony duration of Plasmodium vivax in An.sinensis were observed.It was shown that at 25～28℃,quick development and rapid multiplication of different stage An.sinensis,and short sporogony duration and high density sporozoite density in An.sinensis were observed.In combination with the air temperature in every places,the peak development and reproduction period of An.sinensis were calculated,which was in accordance with the epidemic of vivax malaria.

Microplate assay was employed for the determination of nonspecific esterase level in individual susceptible,anti-DDVP and anti-propoxur resistant Culex pipiens pallens.Among susceptible mosquitoes detected, 17.16% was of high esterase activity with OD value more than 0.9.Among anti-DDVP and antipropoxur resistant mosquitoes, the OD value more than 0.9 was found in 83.33% and 74.89% respectively.This indicated that there existed obvious difference in the level of nonspecific esterase between susceptible and resistant mosquitoes.

This paper reported the results of predatory copepod Mesocyclops leukarti collected in local area of Shandong province on the control of Ae. albopictus larvae under laboratory and field conditions. M. leukarti was highly predatory on Ae.albopictus' first instar larvae. One gravid copepod could swallow 56 larvae within 48hours. Cage simulation test indicated that M. leukarti eliminated larval mosquito population in 7 weeks and adult mosquito population in 9 weeks. Under filed conditions, M. leukarti alone successfully controlled the breeding of mosquito larvae in the whole mosquito active season, and the combination of M. leukarti with B.thuringiensis H-14 revealed more effective. As the Mesocyclops can be produced easily and economically at large scale and it is able to establish its colony in the mosquito breeding site and so make long-term sustained control possible, it is believed to be one of the most promising biocontrol agents for Aedes mosquitoes.