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Objective To compare the differentially expressed proteins between cypermethrin-resistant and -sensitive Culex pipiens pallens, so as to unravel the mechanism underlying the resistance to cypermethrin in Cx. p. pallens. Methods A quantitative proteomic analysis was performed among cypermethrin-sensitive and -resistant isolates of Cx. p. pallens using isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results A total of 164 differentially expressed proteins were identified between cypermethrin-sensitive and -resistant isolates of Cx. p. pallens, including 54 up-regulated proteins and 110 down-regulated proteins. A large number of cuticular proteins, larval cuticular proteins, pupal cuticular proteins and cuticular structural constituent proteins, which are associated with cytoskeletal structure and components, were differentially expressed between cypermethrin-sensitive and -resistant isolates of Cx. p. pallens. Thirteen proteins, which were involved in energy production and conversion, translation, ribosomal structure and biogenesis, lipid transport and metabolism, post-translational modification, protein turnover, chaperones, cytoskeleton and intracellular transportation, were validated to be differentially expressed between cypermethrin-sensitive and -resistant isolates of Cx. p. pallens, which may serve as potential markers of cypermethrin resistance. Conclusion Multiple insecticide resistance mechanisms contribute to the resistance to cypermethrin in Cx. p. pallens, including cuticular resistance and metabolic resistance, and the cuticular protein genes and cytochrome P450 enzymes may play an important role in the resistance of Cx. p. pallens to cypermethrin.
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Objective To explore the sensitivity of Culex pipiens pallens to common chemical insecticides in the southwestern region of Shandong Province, so as to provide a theoretical basis for the development of reasonable and effective mosquito control measures. Methods The resistance of Cx. pipiens pallens larvae to 5 chemical insecticides, such as cypermethrin, deltamethrin, DDVP, propoxur, and acetofenate were tested by using the WHO biological test method in 2018, and the co-toxicity coefficients after compounding the above-mentioned insecticides were tested by using a drug compounding method. Results The resistance indexes of Cx. pipiens pallens to cypermethrin, deltamethrin, DDVP, propoxur, and acetofenate in 3 cities were 144.43–557.54, 118.17–445.33, 6.44–19.00, 2.37–8.10, and 0.88–2.98, respectively, and expect the difference between the DDVP resistances of Cx. pipiens pallens in Jining City and Heze City was not statistically significant (P > 0.05), all the other differences were statistically significant (all P < 0.05). The synergistic coefficients of cypermethrin + DDVP, cypermethrin + propoxur, DDVP + acetofenate, and propoxur + acetofenate were 199.58 – 456.95, 190.56 – 292.37, 123.32 – 319.24, and 192.31 – 367.32, respectively. The lower synergism was observed by using the mixture of DDVP + propoxur (synergistic coefficient: 99.87–108.36) . Conclusions After decades of chemical control, Cx. pipiens pallens in the southwestern region of Shandong Province has produced different degrees of resistance to common chemical insecticides. Therefore, comprehensive control measures should be taken to control mosquito breeding and prevent the development of insecticide resistance.
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Objective To examine the effect of low temperature on trehalose and trehalase levels in Culex pipiens pallens. Methods The fourth instar larvae and female adult mosquitoes of Cx. pipiens pallens were exposed at 4 ℃ for 0, 1, 3, 6, 12, 18, 24 h and 0, 1, 3, 6, 12, 18, 24, 36, 48, 72 h, respectively. Then, the trehalose and trehalase contents were detected by enzyme-linked immunosorbent assay (ELISA) in mosquitoes. Results The contents of trehalose and trehalase significantly increased in the larval and female adult mosquitoes post-exposure to low temperature. The changing trend of trehalose levels was consistent in the larval and female adult mosquitoes, and the highest levels were (2.458 8 ± 0.379 2) mg/g and (2.825 7 ± 0.211 1) mg/g 3 h post-exposure to low temperature, respectively. The trehalose and trehalase levels fluctuated greatly within the first 6 h post-exposure to low temperature. Following adaptation for a period of time, the trehalose and trehalase levels remained at a relatively high level. Conclusion Low temperature may induce the production of trehalose and trehalase in Cx. pipiens pallens, and the trehalose and trehalase may play an important role in the improvement of the cold resistance.
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Objective To compare the difference of protein expression between the post-overwintering stage and the diapauses preparation stage in Culex pipiens pallens, so as to reveal the mechanisms underlying the overwintering diapause of Cx. pipienspallens. Methods A quantitative proteomic analysis was performed in Cx. pipiens pallens before and after overwintering diapause by using isobaric tags for relative and absolute quantification (iTRAQ) labeling. Results A total of 244 differentially expressed proteins were identified in Cx. pipiens pallens before and after overwintering diapause, including 126 up-regulated proteins and 118 down-regulated proteins. iTRAQ-based quantitative proteomic analysis revealed that these differentially expressed proteins were linked to function and energy production and conversion, lipid metabolism, remodeling of cytoskeleton, carbohydrate metabolism, protein transport, molecular chaperones, stress tolerance and metabolic enzymes. Conclusions This is the first study to identify the overwintering diapause-related proteins in Cx. pipiens pallens using proteomics tools, which reveals KEGG pathways and GO terms associated with the overwintering diapauses of Cx. pipiens pallens. Our findings provide additional understandings pertaining to the mechanisms underlying the overwintering diapauses of Cx. pipiens pallens.
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Objective To compare the difference of protein expression between the post-overwintering stage and the diapauses preparation stage in Culex pipiens pallens, so as to reveal the mechanisms underlying the overwintering diapause of Cx. pipienspallens. Methods A quantitative proteomic analysis was performed in Cx. pipiens pallens before and after overwintering diapause by using isobaric tags for relative and absolute quantification (iTRAQ) labeling. Results A total of 244 differentially expressed proteins were identified in Cx. pipiens pallens before and after overwintering diapause, including 126 up-regulated proteins and 118 down-regulated proteins. iTRAQ-based quantitative proteomic analysis revealed that these differentially expressed proteins were linked to function and energy production and conversion, lipid metabolism, remodeling of cytoskeleton, carbohydrate metabolism, protein transport, molecular chaperones, stress tolerance and metabolic enzymes. Conclusions This is the first study to identify the overwintering diapause-related proteins in Cx. pipiens pallens using proteomics tools, which reveals KEGG pathways and GO terms associated with the overwintering diapauses of Cx. pipiens pallens. Our findings provide additional understandings pertaining to the mechanisms underlying the overwintering diapauses of Cx. pipiens pallens.
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Objective To examine the effect of low temperature on trehalose and trehalase levels in Culex pipiens pallens. Methods The fourth instar larvae and female adult mosquitoes of Cx. pipiens pallens were exposed at 4 ℃ for 0, 1, 3, 6, 12, 18, 24 h and 0, 1, 3, 6, 12, 18, 24, 36, 48, 72 h, respectively. Then, the trehalose and trehalase contents were detected by enzyme-linked immunosorbent assay (ELISA) in mosquitoes. Results The contents of trehalose and trehalase significantly increased in the larval and female adult mosquitoes post-exposure to low temperature. The changing trend of trehalose levels was consistent in the larval and female adult mosquitoes, and the highest levels were (2.458 8 ± 0.379 2) mg/g and (2.825 7 ± 0.211 1) mg/g 3 h post-exposure to low temperature, respectively. The trehalose and trehalase levels fluctuated greatly within the first 6 h post-exposure to low temperature. Following adaptation for a period of time, the trehalose and trehalase levels remained at a relatively high level. Conclusion Low temperature may induce the production of trehalose and trehalase in Cx. pipiens pallens, and the trehalose and trehalase may play an important role in the improvement of the cold resistance.
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Objective To investigate the seasonal fluctuations of mosquitoes in Taibai Lake area of Jining City,and evaluate the application effects of two mosquito trapping tools(Gongfu Xiaoshuai mosquito lamp and WJ-C mosquito sampler),so as to provide references for the effective surveillance,prevention and control of local mosquito vectors.Methods The overnight cap-ture of mosquitoes with a man-bait net trap,Gongfu Xiaoshuai mosquito lamp,and WJ-C mosquito sampler was performed to col-lect mosquitoes.The species of adult mosquitoes and seasonal fluctuations were investigated and analyzed.Results A total of 10 914 mosquitoes belonging to 13 species,5 genera were collected with the overnight capture of mosquitoes with the man-bait net trap,and Culex tritaeniorhynchus,Cx.pipiens palllen and Mansonia uniformis were the dominant species,accounting for 77.41％of the total.The proportion of Coquillettidia ochracea increased significantly.All the adult mosquitoes appeared in June,and reached the density peak in July and August.Both of the two surveillance tools showed relatively sensitive capture perfor-mance against mosquitoes.The trapping results of WJ-C mosquito sampler were basically the same as the man-bait trapping meth-od,however,the amount of Mansonia uniformis and Coquillettidia ochracea collected by Gongfu Xiaoshuai mosquito lamp was significantly lower than that of the man-bait trapping method.Conclusions The mosquito species are varied in Taibai Lake area of Jining City.Therefore,monitoring should be strengthened.In addition,the two mosquito trapping tools are sensitive,but they have both advantages and disadvantages,thus we should better pay attention to the consistency of monitoring methods in use.
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Objective To explore the characteristics of gene sequence of mtDNA-COⅠof Culex pipiens pallens from differ-ent geographical regions in Shandong Province and different resistant strains from the lab and five common mosquito species, and analyze the genetic diversity of these mosquitoes.Methods Adult mosquitoes were collected from Jinan,Jining,Qingdao cities and other places in Shandong Province.The sensitive,dichlorvos-resistant,pyrethroid-resistant and propoxur-resistant strains were reared in the lab.Five species of mosquito(Cx.pipiens pallens,Cx.tritaeniorhynchus,Anopheles sinensis,Aedes al-bopictus,and Armigeres subalbatus)were collected from Jining City and identified in the lab.mtDNA-COⅠwas specifically am-plified by PCR and sequenced.The gene sequences were compared and analyzed by the biological information systems,and the phylogenetic tree was constructed.Results The amplified mtDNA-COⅠfragments of Cx.pipiens pallens from eight different cit-ies and four different resistant strains were 528 bp in length,with 67.4% A+T contents and two mutation sites.The nucleotide se-quence homology among the different geographic strains was 99.95% and the gene sequences of the four resistant strains were the same,showing a high homogeny.The amplified mtDNA-COⅠfragments of the five species of mosquitoes were 528 bp with 408 conserved sites,120 variable sites,42 parsimony informative sites and 78 singleton sites. The A+T contents were between 65.7% and 68.0%.The nucleotide sequence homology among the different mosquito species was between 86.17% and 92.05%,and the molecular identification was consistent with the traditional morphological identification. The molecular phylogenetic study showed that the different species were clustered at their own branch at the species and genus levels,while genera Armiger-es was distantly related to the others.Conclusion mtDNA-COⅠcould not serve as the molecular marker to analyze the popula-tion genetic variation and phylogenesis of Cx.pipiens pallens from different geographical regions and different resistant strains, but it has species and genus specificities,which could be used for the identification of the mosquito species and genus.
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OBJECTIVE@#To conduct an analysis of the epidemiological changes in malaria that have occurred in Shanxian county from 2002 to 2016.@*METHODS@#A retrospective study was conducted and data were collected from web-based reporting system to explore the epidemiological characteristics in Shanxian county from 2002 to 2016. All individual case information was obtained from village malaria servicers organized by the local Shandong Institute of Parasitic Diseases.@*RESULTS@#A total of 133 cases were identified as malaria in Shanxian county during this period, including 124 indigenous cases (93.2%) and 9 imported cases (6.8%). The 124 indigenous malaria cases were infected with Plasmodium vivax (P. vivax), whereas 7 of the 9 confirmed imported cases were infected with Plasmodium falciparum (P. falciparum), 1 was infected with Plasmodium ovale (P. ovale) and 1 patient was infected with P. falciparum mixed with P. vivax. The total number of malaria cases included 86 males (64.7%) and 47 females (35.3%). Age of the patients ranged from 1 to 83 years, although most (64.7%) infections occurred in the 21-to 60-year-old age group. Remarkably, 117 of the total malaria cases (98.0%) were reported from 2006 to 2011. The epidemic season was from June to October, with the peak occurring yearly from July to September. The most common occupation of the infected patients was farmer. In total, 58.1% of the cases occurred in 3 townships, namely, Fugang, Huanggang and Caozhuang.@*CONCLUSIONS@#In Shanxian county, the local malaria incidence experienced an emerge-peak-control-eliminate status. However, due to the numbers of migrant labourers returning from Africa, imported cases were continuous and presented an increasing annual trend, which became a non-negligible and a significant impediment for malaria elimination. Therefore, the need to eliminate instances of malaria reintroduction to receptive malaria-free areas should drive strategies to align with the epidemiological changes.
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Objective To conduct an analysis of the epidemiological changes in malaria that have occurred in Shanxian county from 2002 to 2016. Methods A retrospective study was conducted and data were collected from web-based reporting system to explore the epidemiological characteristics in Shanxian county from 2002 to 2016. All individual case information was obtained from village malaria servicers organized by the local Shandong Institute of Parasitic Diseases. Results A total of 133 cases were identified as malaria in Shanxian county during this period, including 124 indigenous cases (93.2%) and 9 imported cases (6.8%). The 124 indigenous malaria cases were infected with Plasmodium vivax (P. vivax), whereas 7 of the 9 confirmed imported cases were infected with Plasmodium falciparum (P. falciparum), 1 was infected with Plasmodium ovale (P. ovale) and 1 patient was infected with P. falciparum mixed with P. vivax. The total number of malaria cases included 86 males (64.7%) and 47 females (35.3%). Age of the patients ranged from 1 to 83 years, although most (64.7%) infections occurred in the 21-to 60-year-old age group. Remarkably, 117 of the total malaria cases (98.0%) were reported from 2006 to 2011. The epidemic season was from June to October, with the peak occurring yearly from July to September. The most common occupation of the infected patients was farmer. In total, 58.1% of the cases occurred in 3 townships, namely, Fugang, Huanggang and Caozhuang. Conclusions In Shanxian county, the local malaria incidence experienced an emerge-peak-control-eliminate status. However, due to the numbers of migrant labourers returning from Africa, imported cases were continuous and presented an increasing annual trend, which became a non-negligible and a significant impediment for malaria elimination. Therefore, the need to eliminate instances of malaria reintroduction to receptive malaria-free areas should drive strategies to align with the epidemiological changes.