淡色库蚊DDVP抗性与酯酶活性的相关性

目的检测抗DDVP品系各世代的抗性指数及蚊体内酯酶(esterase)的活性,探讨蚊虫抗性与酯酶的关系。方法生物测定法,微滴定板法。结果淡色库蚊经过43代选育,抗性指数达12.17倍,蚊体内非特异性酯酶(nonpecificesterase,NSE)的活力随世代增加抗性增高而增强。OD≥0.9的个体频率逐渐增高,与生物测试法基本一致。乙酰胆碱酯酶(AChE)的平均抑制率随世代的增加、抗性增高而变低,而抑制率<30％的个体频率随世代增加而增加,呈相关关系。结论DDVP抗性与酯酶NSE和AChE的活性呈一定的相关关系。     

不同品系淡色库蚊各发育阶段的非特异性酯酶和乙酰胆碱酯酶活力变化

研究并探讨非特异性酯酶（NSE）和乙酰胆碱酯酶（AChE）活力在不同品系淡色库蚊（Cules pipiens pallens）各发育阶段的变化，为应用生物化学方法检测蚊虫抗药性及科学合理地进行蚊虫化学防治提供依据。用微量滴定板法测定单个蚊虫NSE和AChE活力，结果显示，敏感品系、DDVP抗性品系和残杀威抗性品系淡色库蚊NSE活力水平在不同发育阶段有变化，I－Ⅲ龄幼虫较低，Ⅳ龄幼虫、蛹和3日龄雌成蚊较高，在各发育阶段均是DDVP抗性品系NSE活力最高，残杀威抗性品系次之，敏感品系最低，其中Ⅳ龄幼虫、蛹和3日龄雌成蚊阶段三个品系间NSE活力差别更明显；三个品系淡色库蚊AChE活力在I－Ⅳ龄幼虫和蛹期较低，3日龄雌成蚊较高，三个品系间AChE活力稍有差异，从高到低依次为残杀威抗性品系、DDVP抗性品系和敏感品系。测定蚊虫NSE活力判断抗药性可选择Ⅳ龄幼虫、蛹和3日龄未吸血雌成蚊；测定蚊虫AChE不敏感性判断抗药性可选择3日龄未吸血雌成蚊；蚊虫化学防治中应选择低龄幼虫阶段施药。     

酯酶滤纸法检测淡色库蚊抗药性的研究

为探讨简捷灵敏的蚊虫抗药性早期测报技术,以α-乙酸萘酯为底物,坚硬固蓝B盐为显色剂,用滤纸法测定实验室和现场淡色库蚊（Cx.pipien pallens)酯酶活力,结果显示三个抗性品系淡色库蚊以抗DDVP品系抗性个体频率最高,其次为抗残杀威品系,抗氯氰菊酯品系较低,与敏感品系相近;三个现场淡色库蚊均对DDVP和残杀威产生不同程度抗性,其抗性个体频率均较高,表明酯酶滤纸法可用于检测蚊虫对有机磷和氨基甲酸酯类杀虫剂的抗性水平,该方法操作简便快速,观察结果直观灵敏,具有实用价值。     

非特异性酯酶在淡色库蚊对不同杀虫剂抗性中的作用研究

目的　探讨非特异性酯酶（Non-specific esterase,NSE）在淡色库蚊对不同杀虫剂抗性中的作用。方法　以β-乙酸萘酯为底物,坚固蓝B盐为显色剂,测定室内5个品系淡色库蚊的NSE活力。结果　5个品系淡色库蚊中以抗DDVP品系NSE活力水平最高,其次为抗DDVP降解品系和抗残杀威品系。抗氯氰菊酯品系较低,与敏感品系相近。结论　NSE在淡色库蚊对有机磷类杀虫剂的抗性中起重要作用,也是对氨基甲酸酯类杀虫剂产生抗性的机制之一,与对拟除虫菊酯类杀虫剂的抗性关系不大。     

非特异性酯酶在淡色库蚊对不同杀虫剂抗性中的作用研究

目的：探讨非特异性酯酶（Non-specific esterase,NSE)在谈色库蚊对不同杀虫剂抗性中的作用。方法：以β－乙酸萘酯为底物,坚固蓝B盐为显色剂,测定室内5个品系淡色库蚊的NSE活力。结果：5个品系淡色库蚊中以抗DDVP品系NSE活力水平最高,其次为抗DDVP降解品系和抗残杀威品系,抗氯氰菊酯品系较低,与敏感品系相近。结论：NSE在淡色库蚊对有机磷类杀虫剂的抗性中起重要作用,也是对氨基甲酸酯类杀虫剂产生的机制之一,与对拟除虫菊类杀虫剂的抗性关系不大。     

微板法测定抗药性酯酶检测淡色库蚊抗药性的研究

目的 研究简捷灵敏的蚊虫抗药性早期测报技术。方法 以β-乙酸萘酯为底物，坚固蓝B盐为显色剂，用酯酶微板法测定实验室和现场单个淡色库蚊体内非特异性酯酶活力。结果 实验室5个品系淡色库蚊以抗DDVP品系非特异性酯酶活力水平最高，其次为抗残杀威品系和抗DDVP降解品系，抗氯氰菊酯品系较低，与敏感品系相近；3个现场淡色库蚊种群对DDVP抗性为4．15～9．36倍，对残杀威抗性为1．02～3．8l倍，其非特异性酯酶活力水平均较高。结论 酯酶微板法测定非特异性酯酶能够检测蚊虫对有机磷和氨基甲酸酯类杀虫剂的抗性水平，能够早期预测抗性发展趋势，便于制订抗药性克服对策。     

微板法测定淡色库蚊体内非特异性酯酶检测其对杀虫剂抗性的研究

目的　探讨简捷灵敏的蚊虫抗药性早期测报技术。方法　以 β -乙酸萘酯为底物 ,坚固蓝B盐为显色剂 ,用微板法测定实验室和现场单个淡色库蚊体内非特异性酯酶活力。结果　实验室五个品系淡色库蚊以抗DDVP品系非特异性酯酶活力水平最高 ,其次为抗残杀威品系和抗DDVP降解品系 ,抗氯氰菊酯品系较低 ,与敏感品系相近 ;三个现场淡色库蚊种群对DDVP抗性为 4 15～ 9 36倍 ,对残杀威抗性为 1 0 2～ 3 81倍 ,其非特异性酯酶活力水平均较高。结论　微板法测定非特异性酯酶能够检测蚊虫对有机磷和氨基甲酸酯类杀虫剂的抗性水平。方法简便快速 ,结果客观准确 ,可重复性强 ;可测出抗性频率 ,早期发现抗性的存在 ;可测知抗性机制 ,便于制订抗药性克服对策     

微板法测定抗药性醋酶检测淡色库蚊抗药性的研究

目的 研究简捷灵敏的蚊虫抗药性早期测报技术。方法 以β-乙酸萘酯为底物,坚固蓝B盐为显色剂,用酯酶微板法测定实验室和现场单个淡色库蚊体内非特异性酯酶活力。结果 实验室5个品系淡色库蚊以抗DDVP品系非特异性酯酶活力水平最高,其次为抗残杀威品系和抗DDVP降解品系,抗氯氰菊酯品系较低,与敏感品系相近;3个现场淡色库蚊种群对DDVP抗性为4.15～9.36倍,对残杀威抗性为1.02～3.81倍,其非特异性酯酶活力水平均较高。结论 酯酶微板法测定非特异性酯酶能够检测蚊虫对有机磷和氨基甲酸酯类杀虫剂的抗性水平,能够早期预测抗性发展趋势,便于制订抗药性克服对策。     

微板法测定抗药性酯酶检测淡色库蚊抗药性的研究

目的研究简捷灵敏的蚊虫抗药性早期测报技术. 方法以β-乙酸萘酯为底物,坚固蓝B盐为显色剂,用酯酶微板法测定实验室和现场单个淡色库蚊体内非特异性酯酶活力. 结果实验室5个品系淡色库蚊以抗DDVP品系非特异性酯酶活力水平最高,其次为抗残杀威品系和抗DDVP降解品系,抗氯氰菊酯品系较低,与敏感品系相近;3个现场淡色库蚊种群对DDVP抗性为4.15～9.36倍,对残杀威抗性为1.02～3.81倍,其非特异性酯酶活力水平均较高. 结论酯酶微板法测定非特异性酯酶能够检测蚊虫对有机磷和氨基甲酸酯类杀虫剂的抗性水平,能够早期预测抗性发展趋势,便于制订抗药性克服对策.     

不同品系及不同性别淡色库蚊非特异性酯酶活性比较

目的探讨不同品系及不同性别淡色库蚊非特异性酯酶（NSE）活性的差异,为应用生物化学方法检测蚊虫抗药性提供依据。方法以β-乙酸萘酯为底物,坚固蓝B盐为显色剂,测定单个蚊虫NSE活性。结果抗敌敌畏（Rd）和抗残杀威（Rp）品系淡色库蚊NSE活性水平明显高于敏感（S）品系,抗氯氰菊酯（Rc）品系淡色库蚊NSE活性水平与S品系相近。S、Rd、Rp、Rc4种品系淡色库蚊3日龄雌雄成虫NSE活性均为雌性大于雄性。结论测定NSE活性可判断蚊虫抗药性状况,不同性别蚊虫应分别制定判断标准。     

Insecticide resistance status of Aedes aegypti in 10 localities in Colombia

Insecticide resistance is one of the major threats to the effectiveness of vector control programs. In order to establish a baseline susceptibility profile of Aedes aegypti in the southwest of Colombia, 10 localities in four Departments (States) were evaluated. Standardized WHO bioassay, CDC bottle bioassay and microplate biochemical assays of non-specific β-esterase (NSE), mixed function oxidases (MFO) and acetylcholinesterase were used. Cross resistance was evaluated with field collected mosquitoes that underwent selection pressure in the laboratory from DDT, propoxur and lambdacyhalothrin during three alternate generations. Mosquitoes with mortality rates below 80% in bioassays were considered resistant. Insecticide resistance varied geographically. Insecticide resistance was observed in 100% of localities in which mosquitoes were exposed to DDT, bendiocarb and temephos using both assays. WHO bioassays showed susceptibility to pyrethroids in all the localities evaluated, however CDC bottle bioassays showed decreases in susceptibility especially with lambdacyhalothrin. All localities showed susceptibility to the organophosphate malathion. Mosquitoes from eight regions with evidence of resistance to any of the insecticide evaluated were also evaluated biochemically. Mosquitoes from five of these regions had increased levels of NSE and two regions had increased levels of MFO. Increase levels of NSE explain partially the low susceptibility to temephos found in all the localities. However, the biochemical mechanisms evaluated do not explain all the resistance observed. Cross resistance was observed between the DDT-selected strain and lambdacyhalothrin, and between the lambdacyhalothrin-selected strain and propoxur and vice versa. The selected strains do not show changes in the biochemical assays evaluated, therefore the observed cross-resistance suggests different biochemical mechanisms. This study shows that Ae. aegypti from Colombia can develop resistance to most of the insecticide classes in the market. Periodic surveillance of insecticide resistance is necessary in order to maintain effective interventions. This study helped to establish the National Network for the surveillance of the insecticide resistance in Colombia.     

Insecticide cross-resistance spectra and underlying resistance mechanisms of Sri Lankan anopheline vectors of malaria

Present status of insecticide resistance was investigated in two major vectors of malaria; An. culicifacies and An. subpictus, collected from a high malaria transmission area in Sri Lanka during 1996/1998. Adult and larval bioassays were carried out to obtain log-probit mortality lines for malathion, propoxur, permethrin and chlorpyrifos. Respective LD50 values were 4.45%, 0.002%, 0.16% and 0.001% for An. culicifacies and 0.66%, 0.004%, 0.004% and 0.04% for An. subpictus. Adults were also tested for WHO standard discriminating dosages of malathion, propoxur, permethrin, DDT, cypermethrin, deltamethlin and lambda cyhalothrin. Both populations were highly resistant to DDT. An. culicifacies was more resistant to malathion and An. subpictus was more resistant to chlorpyrifos. About 25% of both populations were resistant to permethrin. An. culicifacies was susceptible to propoxur, deltamethrin and lambda cyhalothrin and An. subpictus to cypermethrin and lambda cyhalothrin. Adult mosquitos were individually tested for their insecticide detoxifying enzyme activities and altered target-site, acetylcholinesterase. High general esterase activity indicated the presence of amplified esterase genes in both populations. Native gel electrophoresis resolved one elevated esterase isoenzyme, with high affinity to organophosphates, from each species. Malathion carboxylesterase mechanism was present in both populations. Higher glutathione-S-transferase activity was marked in An. subpictus. Synergistic studies showed the possible involvement of monooxygenases in resistance in both species. Acetylcholinesterase activity of approximately 80% of both populations was not inhibited by a standard dosage of propoxur. Low resistance to carbamates shows that the impact of agricultural pesticides is not significant in the development of resistance especially in An. culicifaies. Pyrethroids, other than permethrin, can be successfully used in vector control programs. Carbamates will be an alternative.     

淡色库蚊对3种化学杀虫剂交互抗性的实验研究

目的 目的 了解淡色库蚊对常用化学杀虫剂的交互抗性, 为合理使用化学杀虫剂提供依据。方法 方法 采用WHO生物 测定方法, 检测淡色库蚊敏感品系和抗敌敌畏、 抗残杀威、 抗氯氰菊酯3种抗性品系IV龄幼虫分别对敌敌畏、 残杀威和氯 氰菊酯3种化学杀虫剂的抗性。 结果 结果 淡色库蚊抗敌敌畏品系对敌敌畏、 残杀威和氯氰菊酯3种化学杀虫剂的抗性系 数分别为14.47、 8.96和207.27, 抗残杀威品系对上述3种杀虫剂的抗性系数分别为3.27、 6.93和8.65, 抗氯氰菊酯品系对 3种杀虫剂的抗性系数分别为2.93、 1.61和501.11。 结论 结论 长期使用一种化学杀虫剂易产生抗性, 并对其他化学杀虫剂 产生不同程度的交互抗性。使用杀虫剂时应注意选择药物品种和剂量, 以避免和延缓蚊虫抗药性的产生。     

Temephos resistance in two forms of Aedes aegypti and its significance for the resistance mechanism

Aedes aegypti, at the larval stage, has been subjected to the temephos selection in laboratory. The level of temephos resistance was detected in a microplate by biochemical assay using WHO bioassay technique. The major enzyme-based resistance mechanisms involved in temephos resistance include elevated nonspecific esterase, oxidase and insensitive acetylcholinesterase. After 19 generations of temephos selection, the selected group showed resistance ratios of 4.64 and 16.92, when compared with a non-selected group and the WHO susceptible strain, respectively. The two seperated forms, type form and the pale form of Ae. aegypti showed low levels of resistance to temephos after 19 generations of selection, with resistance ratios of 4.82 and 4.07 for the type form and the pale form, respectively; when compared with the non-selected strain, 17.58 and 14.84, when compared with the WHO susceptible strain. This showed that the type form could develop higher level resistance than the pale form. The esterase inhibitor (S,S,S-tributyl phosphorotrithioate, DEF) or synergist implicated detoxifying esterase in all the temephos selected groups and the presence of elevated esterase were confirmed by biochemical assay. There were significant differences in elevated esterase activity between the temephos selected groups and the non-selected group. However no significant difference between the type form and the pale form was found. Besides the elevated esterase, there was no change in monooxygenase activity and no evidence of insensitive acetylcholinesterease for all temephos selected groups. These results suggest that temephos resistance could be developed in Ae. aegypti under selection pressure and that the main mechanism is based only on esterase detoxification.     

南昌国境口岸中华按蚊氟氯氰菊酯抗药性及其机制研究

目的了解南昌昌北国际机场中华按蚊的氟氯氰菊酯抗药性,初步探索其产生机制。方法应用WHO成蚊生测法检测当地中华按蚊抗药性水平,将生测过程中即将死亡蚊虫归为敏感蚊,存活蚊虫归为抗性蚊,检测并比较两组蚊虫P450单加氧酶、谷胱甘肽巯基转移酶(GST)活性;同时记录每只敏感蚊生测死亡时间,对生测死亡时间与P450单加氧酶、GST活性进行相关分析。结果当地中华按蚊生测死亡率为59.5%;抗性蚊、敏感蚊、实验室敏感蚊的P450单加氧酶活性差异具有统计学意义(F=151.89,P0.01),其中抗性蚊敏感蚊实验室敏感蚊;但三者GST活性差异无统计学意义(F=0.72,P0.05);蚊虫生测死亡时间与P450单加氧酶活性呈正相关性,相关系数为0.88,回归方程为y=79.479+1.512x;生测死亡时间与GST活性不具有相关性。结论南昌昌北国际机场中华按蚊对氟氯氰菊酯已产生抗药性,P450单加氧酶活性增强可能是其抗药性产生的机制之一。     

Determination of insecticide susceptibility in Culex quinquefasciatus Say adults by rapid enzyme microassays.

Rapid enzyme microassays for the detection of resistance due to organophosphate and carbamate in individual field-collected strains of Culex quinquefasciatus adults were conducted. These tests allowed accurate differentiation by eye, on the basis of color changes of susceptible and resistant individuals. Two separate tests were conducted for the biochemical assays. In the insensitive acetylcholinesterase (AChE) test, acetylthiocholine iodide (ACTH) and 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) were used as substrate and coupling agent respectively. The resulting yellow chromophore indicated AChE activity. Test results showed that the color intensity decreased as increasing concentrations of propoxur were added, thereby confirming the susceptibility of the enzyme to inhibitor. Assay of non-specific esterase however, indicated elevated levels which were correlated with degree of malathion resistance. Electrophoretic data revealed the presence of 2 esterase bands in all strains. It was concluded that such a pattern was not contributory to malathion resistance in adults.     

Rate of resistance development in wild Culex quinquefasciatus (Say) selected by malathion and permethrin

Wild caught female Culex quinquefasciatus (Say) from Kuala Lumpur were blood fed and reared in the insectarium. The late third stage of the F1 larvae which survived the high selection pressure of malathion and permethrin were reared and colonies were established from adults that emerged. Larvae from these colonies were then subjected in the subsequent 9 generations to higher selection pressure. The rate of resistance development were measured by LC50 value of larval bioassay, LT50 value of adult bioassay and the frequency of the elevated esterase levels. In another set of experiments using the same batch of Culex mosquitos, the larvae were not exposed to any insecticides and the decrease in resistance rate was monitored in each subsequent 9 generations by using similar methods. The heterozygous standard laboratory strain was selected for susceptibility using the single raft sib-selection method. The result showed that the field collected F1 generation was 96.0 and 6.3 fold more resistant to malathion and permethrin, respectively. After selection for about 9 generations the resistance ratio to malathion and permethrin was 6.2 and 767.3 fold more compared to the LC50 values of F1 generations, respectively. Esterase in F1 larvae was 6.0 fold more than the standard laboratory strain.     

山东济宁市淡色库蚊抗药性的测定及杀虫剂配方的筛选

目的为了延缓和克服蚊虫抗性的发生和发展,更好地选用卫生杀虫剂控制蚊虫,测定了常用杀虫剂复配对采自济宁市部分地区现场淡色库蚊幼虫的敏感性及增效作用。方法采用WHO生物测试法,计算LC50、回归方程、增效系数。结果DDVP+三氯杀虫酯、残杀威+三氯杀虫酯复配共毒系数分别为123.24～212.40和171.80～335.80,显示出较好的增效作用。DDVP+残杀威复配效果较差。结论当淡色库蚊产生抗药性后,采用有机磷或氨基甲酸酯类杀虫剂与有机氯类杀虫剂混用的方法,能取得较好效果。