抗吡丙醚淡色库蚊种群相对适合度研究

【目的】比较淡色库蚊抗吡丙醚种群和敏感种群的生物学特性。【方法】采用生物测定法,实验室内观察2个蚊虫种群的孵化率、化蛹率、羽化率、种群相对适合度以及累积发育速率的差异。【结果】抗吡丙醚淡色库蚊种群与敏感种群相比,卵孵化率差异无统计学意义,化蛹率、孵化率以及世代存活率间测差异有统计学意义,其中抗吡丙醚种群化蛹率平均为46.01%,敏感种群化蛹率平均为98.34%。抗吡丙醚淡色库蚊种群的卵孵化时间、蛹羽化时间均迟于敏感种群,其中卵孵化时间推迟12 h,开始化蛹时间推迟24 h,化蛹的持续时间延长108 h。两种群相对适合度为0.61。【结论】淡色库蚊抗吡丙醚种群呈现繁殖不利现象,可以通过停药或轮换使用药剂延缓抗性发展。     

2种品系淡色库蚊对常用杀虫剂的敏感性比较

目的比较2种实验室品系淡色库蚊幼虫对3种常用杀虫剂的敏感性,进而筛选更为敏感的实验室品系。方法采用WHO提供的幼虫浸渍法,测定2种实验室品系淡色库蚊幼虫对不同杀虫剂的LC50,并计算抗性指数.结果 西安品系淡色库蚊高效氯氰菊酯的LC50低于北京敏感品系,其抗性指数为0．9倍;双硫磷和溴氰菊酯的LC50均高于北京敏感品系．其抗性指数分别为1．5和2．5倍。结论与北京敏感品系淡色库蚊相比,西安品系淡色库蚊仍具有一定抗药性？     

淡色库蚊二氯苯醚菊酯抗性株的选育

目的：研究蚊虫对拟除虫菊酯抗性的发生发展规律，深入探讨抗性机理。方法：在实验室条件下，对淡色库蚊敏感品系用二氯苯醚菊酯丙酮液筛选，连续筛选20代。结果：成功地选育出淡色库蚊实验室抗性品系，现抗性倍数保持在70倍左右。结论：该抗性品系的种群生存力明显降低，表现为用药后卵孵化率、化蛹率、羽化率和成成蚊率比正常的敏感品系要低。     

微板法检测蚊虫体内乙酰胆碱酯酶活性研究

目的：检测不同敏感品系（Ｓ）蚊虫和室内选育的抗性品系淡色库蚊体内乙酰胆碱酯酶活性。方法：微滴定板法。结果：４种Ｓ品系蚊虫中,以中华按蚊体内ＡｃｈＥ水平最高;３种抗性品系蚊虫中,抗残杀威品系的ＡｃｈＥ活性〉抗氯氰区酯品系〉抗ＤＤＶＰ品系,且后者一Ｓ品系差异无显著性。蚊虫体内ＡｃｈＥ活性随发育而逐步增高,以不同浓度残杀威作抑制剂,测定室内不同品系淡色库蚊个体的ＡｃｈＥ活性,表明蚊虫ＡｃｈＥ活性的抑制率     

淡色库蚊敏感和抗氯氰菊酯品系铁调节蛋白基因表达量的分析

目的利用相对定量分析铁调节蛋白基因在淡色库蚊敏感和抗氯氰菊酯品系体内的表达量。方法设计引物、提取RNA、普通PCR、纯化测序、序列比对、荧光定量PCR,采用F检验和t检验对敏感和抗性品系淡色库蚊体内铁调节蛋白基因表达量进行统计学分析。结果将扩增的淡色库蚊铁调节蛋白基因片段进行序列比对,与致倦库蚊相似性较高。荧光定量PCR数据分析,淡色库蚊敏感品系(IRP_敏)和抗性品系(IRP_抗)铁调节蛋白Ct平均值分别为15.17和18.37,内参基因(β_敏和β_抗)Ct平均值分别为20.49和19.06,t检验显示两样本铁调节蛋白基因表达差异具有统计学意义(t=9.52,P0.001),铁调节蛋白基因在淡色库蚊抗性品系中的表达量降低。结论淡色库蚊铁调节蛋白可能参与了抗性机制。     

杭州地区淡色库蚊抗药性调查

目的了解杭州地区淡色库蚊的抗药性情况，为杭州市灭蚊工作提供指导。方法采用浸渍法检测杭州地区淡色库蚊现场品系和敏感品系4龄幼虫对敌敌畏、三氯杀虫酯、残杀威、溴氰菊酯、高效氯氰菊酯、丙烯菊酯等4类6种杀虫剂的抗性。结果杭州地区淡色库蚊现场品系与敏感品系相比较，溴氰菊酯抗性倍数最高，为5．30倍；其次是残杀威，2．91倍；三氯杀虫酯，1．92倍；其余LD50近于敏感品系；高效氯氰菊酯与敏感品系比较抗性降低，抗性倍数为0．43倍。结论本次监测的杀虫剂杭州市区蚊虫对高效氯氰菊酯抗性低于敏感品系，其余均为低抗性或接近敏感品系。     

淡色库蚊抗性种群和敏感品系中铁蛋白基因表达量的分析

目的对淡色库蚊抗性种群和敏感品系中的铁蛋白基因表达量进行分析。方法设计引物,扩增目的基因全长、纯化测序、序列分析,荧光定量PCR检测铁蛋白基因的表达水平;采用假设检验中的t检验方法,对2种不同处理的淡色库蚊样本体内铁蛋白基因表达量进行统计分析。结果成功扩增淡色库蚊铁蛋白基因片段,经荧光定量PCR测定,淡色库蚊敏感品系铁蛋白荧光定量(F敏)和抗性种群铁蛋白荧光定量(F抗)平均值分别为11.41和15.73,内参基因荧光定量(β敏和β抗)平均值分别为10.03和18.27,铁蛋白基因在淡色库蚊抗性种群中的表达量是敏感品系的15.08倍,t检验结果显示,两样本体内铁蛋白基因表达差异有统计学意义(t=26.100,P0.001)。结论淡色库蚊铁蛋白基因可作为蚊虫抗性检测及治理的靶标基因。     

2012年北京市西城(南)区淡色库蚊抗药性监测

目的了解北京市西城(南)区淡色库蚊的抗药性情况,为蚊虫防制工作提供指导。方法采用幼虫浸渍法检测淡色库蚊野外品系和敏感品系四龄幼虫对高效氯氰菊酯、溴氰菊酯、仲丁威、双硫磷、敌敌畏等5种杀虫剂的抗性。结果与敏感品系相比较,从西城(南区)采集到的淡色库蚊野外品系对高效氯氰菊酯、敌敌畏、仲丁威等3种药物相对敏感,对于双硫磷、溴氰菊酯较不敏感。结论西城(南)区淡色库蚊对双硫磷、溴氰菊酯已产生抗性,应谨慎使用。     

抗氯氰菊酯淡色库蚊P450特异性探针的制备及应用

目的 制备淡色库蚊氯氰菊酯抗性株细胞色素P450特异性DNA探针，并用于抗性品系与敏感品系的检测。方法 简并引物PCR法制备特异性DNA探针，生物素杂交检测氯氰菊酯抗性淡色库蚊。结果 摸索得到合适的区分抗性与敏感品系的探针浓度，在该探针浓度下抗性与敏感品系杂交点的阳性率有差异。结论 该方法为抗拟除虫菊酯类杀虫剂媒介昆虫基因检测的实用性研究及抗性分子生物学机制的研究打下了基础。     

东阿县淡色库蚊对常用杀虫剂抗性的测定

目的了解山东东阿县淡色库蚊对常用杀虫剂抗性的发展趋势,为科学合理地使用化学杀虫剂提供科学依据。方法采用WHO推荐的生物测定方法,测定了淡色库蚊敏感品系和现场种群对4种常用杀虫剂的抗性倍数。结果山东东阿县淡色库蚊对双硫磷抗性倍数为4.61,溴氰菊酯为3.29,均为低抗;氯菊酯、高效氯氰菊酯分别为0.16和1.23,均为敏感。结论东阿县淡色库蚊对常用化学杀虫剂的抗性发展趋缓,但仍需采取适当的应对措施延缓抗性。     

白纹伊蚊抗溴氰菊酯品系与敏感品系的生物学特性及室内种群动力学研究

目的比较白纹伊蚊溴氰菊酯抗性品系和敏感品系的生物学特性及种群变化。方法实验室内观察2个蚊虫品系的繁殖、发育、吸血等生物学特性,构建实验种群生命表。结果白纹伊蚊抗溴氰菊酯品系的孵化率、蛹化率以及羽化率分别比敏感品系低16．67％、8．92％和0．44％,除羽化率外,上述指标两者之间差异均有统计学意义（P〈0．05）。抗性品系的吸血率及单雌产雌数均比敏感品系低。前者的净增值率和内禀增殖率分别为151．86和0．16,后者的净增殖率和内禀增值率分别为177．18和0．20。结论白纹伊蚊抗性品系已表现出环境适应能力下降和繁殖不利性的影响。     

Biological fitness of a Culex quinquefasciatus population and its resistance to Bacillus sphaericus

Biological fitness components of a field-collected colony of Culex quinquefasciatus Say that was highly resistant to Bacillus sphaericus strain 2362 (resistance ratio greater than 163,000) after 46 generations of selection were compared to those of a susceptible colony (CqSF) that had originated from the same parental cohort but that had not been exposed to B. sphaericus. The effect of B. sphaericus on the fitness of Cx. quinquefasciatus was determined in terms of fecundity, fertility, and development time. The resistant colony (CqRL) showed significantly lower fecundity and fertility, and slower development than the susceptible colony. Development time from egg to egg showed a 20% increase in CqRL compared to CqSF. The generation time increased from 21.6 days to 26 days for highly resistant generations of CqRL.     

三种淡色库蚊抗菊酯品系的生存力比较

目的 在实验条件下通过对3种拟除虫菊酯抗性品系的蚊虫选育,了解抗性发生、发展规律,为蚊、蝇的防制提供理论依据。方法 采用浸液法,分别用三氟氯氰菊酯、溴氰菊酯、胺菊酯对淡色库蚊进行抗性品系的选育,了解抗性发生、发展规律;分析抗性品系的种群生存力等主要生物学特征,比较3个品系的相对适合度。结果 胺菊酯不易产生抗性,在连续选育8代后抗性仅达4．66倍;三氟氯氰菊酯、溴氰菊酯易产生抗性。对三氟氮氰菊酯抗性经6代的选育后达到41．8倍,对溴氰菊酯抗性经5代的选育后达到50．68倍。结论 抗性品系存在相对适合度缺陷。三氟氮氰菊酪、溴氰菊酯、胺菊酯抗性品系相对适合度分别为0．41、0．47和0．29。     

Penetration and comparative metabolism of leptophos in susceptible and resistant houseflies.

The metabolism and rate of penetration of leptophos (O-methyl O-4-bromo-2,5-dichlorophenyl phenylphosphonothioate) was determined in a susceptible strain and a strain of housefies which was 50-fold resistant to leptophos. Penetration of leptophos into resistant flies was substantially slower than into susceptible flies but large differences in metabolism, both quantitatively and qualitatively, were not observed. No difference was observed in the sensitivity of flyhead and thorax acetylcholinesterase to leptophos-oxon in vitro, and tolerance to leptophos by the resistant strain is explained in terms of decreased rates or penetration and minor differences in metabolism.     

冰冻储存对淡色库蚊非特异性酯酶活性的影响

目的探讨冰冻储存对淡色库蚊非特异性酯酶（non-specific esterase,NSE）活性的影响,为蚊虫抗药性生物化学检测方法的推广应用提供依据。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DDVP抗性品系淡色库蚊NSE活性水平明显高于敏感品系;经完全随机设计的方差分析比较,-20℃冰冻0、7、14、21、28d的淡色库蚊NSE活性A值之间的差别,敏感品系4龄幼虫的F值为0．7642,该品系3日龄雌成虫的F值为0．7452,DDVP抗性品系4龄幼虫的F值为0．1092,该品系3日龄雌成虫的F值为0．1521,P值均〉0．05,差异无统计学意义。结论-20℃冰冻28d对淡色库蚊4龄幼虫和3日龄雌成虫体内NSE活性无影响,可在现场采集蚊虫带回实验室集中测定。     

Immunity after treatment of human schistosomiasis mansoni. II. Identification of resistant individuals, and analysis of their immune responses

Intensities of re-infection were monitored at three-monthly intervals after treatment of Schistosoma mansoni infections in a group of 119 Kenyan schoolchildren, whose levels of water contact were also observed. 22 children showed high reinfection intensities (greater than 100 eggs per gram of faeces) by 12 months after treatment, and were considered to be susceptible. Out of 70 children who showed low reinfection intensities during the same period (less than 30 eggs per gram), 35 showed high levels both of total water contact and of contact with sites containing infected snails. In these children, the relative lack of reinfection could not be attributed to a lack of exposure, and they were classified as resistant to reinfection. Comparison of the two groups, resistant and susceptible, revealed no difference in pretreatment intensities of infection. However, there was a marked difference in age, the mean age of the resistant group being two years greater than that of the susceptible group, within a restricted starting age range. These findings indicated that resistance was an acquired and age-dependent phenomenon, not obviously related to previous egg-induced pathology. Studies of immune responses revealed no clearcut correlate of resistance, but there were interesting differences between the two groups. Whereas anti-egg antigen responses declined after treatment to a greater extent in the resistant than in the susceptible group, antibodies mediating eosinophil-dependent killing of schistosomula rose markedly in both groups, strongly suggesting that the resistant children were being exposed to cercariae. Anti-adult worm antibodies rose sharply in both groups immediately after treatment, and thereafter declined to pretreatment levels. Although some individual children showed high levels of IgE anti-schistosomulum antibodies, there were no significant differences between the two groups. Since all children showed detectable levels of antibodies mediating eosinophil-dependent killing of schistosomula, the possibility was considered that such antibodies might be a necessary, but not a limiting, factor in immunity. Instead, the functional state of the effector cells mediating antibody-dependent killing might be limiting. Eosinophil levels, measured as an indirect estimate of eosinophil functional activity, did not differ between the two groups. There were, however, marked differences between different individuals in their capacity to produce eosinophil-stimulating monocyte mediators, and although this cannot yet be related to resistance, this aspect is worth further study.(ABSTRACT TRUNCATED AT 400 WORDS)     

Penetration and comparative metabolism of leptophos in susceptible and resistant houseflies

The metabolism and rate of penetration of leptophos (O-methylO-4-bromo-2,5-dichlorophenyl phenylphosphonothioate) was determined in a susceptible strain and a strain of houseflies which was 50-fold resistant to leptophos. Penetration of leptophos into resistant flies was substantially slower than into susceptible flies but large differences in metabolism, both quantitatively and qualitatively, were not observed. No difference was observed in the sensitivity of flyhead and thorax acetylcholinesterase to leptophos-oxonin vitro, and tolerance to leptophos by the resistant strain is explained in terms of decreased rates of penetration and minor differences in metabolism.     

A model to understand the confounding effects of natural sediments in toxicity tests with Chironomus riparius

Recently, we built a model to link feeding input with growth, emergence, and reproduction of the midge Chironomus riparius exposed to an artificial sandy sediment. This model is based on assumptions about both feeding behavior and use of energy. Here, we show how it can be used for toxicity tests with natural sediments to understand and model the influence of sediment characteristics. We measured growth, emergence, and reproduction of chironomids exposed in beakers to four unpolluted natural sediments and three feeding conditions (no feeding, 0.2 mg Tetramin/larva/d, and 1.4 mg Tetramin/larva/d) and compared the results with data obtained on our artificial sandy sediment. Sediment characteristics had lower influence on growth than feeding level, but their influence could not be neglected. First, we could distinguish between sandy sediments and other sediments. This difference resulted in a significant delay of about 18 h in the growth curves. Second, in case of food limitation, chironomids could use the organic materials in the sediment, provided that the C:N ratio of the sediment was less than 14. Our model proved to be able to incorporate those two phenomena. As for reproduction, we observed a better reproduction (measured in number of eggs per mass) for natural sediments than for artificial sediments. We showed that this difference could be due to the lipid content of the natural sediments.     

Resistance to cadmium and parasite infection are inversely related in two strains of a freshwater gastropod

Phenotypes that are either resistant or susceptible to infection by the trematode parasite Schistosoma mansoni exist in the tropical freshwater snail Biomphalaria glabrata. We tested the hypothesis that a cost of parasite resistance in B. glabrata is greater sensitivity to cadmium toxicity, using parasite-resistant and parasite-susceptible strains exposed to cadmium in the laboratory. Survival analysis showed that time to death for cadmium was significantly shorter in eggs, juveniles, and adults of the parasite-resistant BS90 strain in comparison with the parasite-susceptible NMRI strain. Cadmium exposure increased time to hatch in both strains, but the effect was greater in BS90. Percentage hatch decreased with increased cadmium; BS90 was again more sensitive than NMRI. Comparison of the median effective concentration (EC50) for hatching and median lethal concentrations (LC50s) for survival of juveniles and adults showed that the order for cadmium resistance was adults > juveniles > eggs in NMRI and adults > eggs > juveniles in BS90. Cadmium resistance of F1 and F2 progeny of BS90/NMRI crosses was intermediate to that of parental strains. Numerical estimates indicated that a single genetic factor was responsible for the difference in cadmium resistance in the two strains. These findings were consistent with the hypothesis that greater sensitivity to cadmium is a cost of resisting parasitic infection.     

淡色库蚊溴氰菊酯抗性与敏感品系单蚊杂交群体的构建

目的建立淡色库蚊溴氰菊酯抗性与敏感品系单蚊杂交群体,并对比观察杂交系与自交系的生物学特性,为鉴定抗性基因遗传多态性和遗传作图奠定基础。方法正交组以抗性品系为母本交配敏感品系雄蚊,即R-S组;反交组以抗性品系雄蚊交配敏感品系雌蚊,即S-R组;对照为抗性品系和敏感品系自交,即R-R组和S-S组。观察比较4组产卵率、孵化率及各发育阶段成活率。WHO蚊幼虫浸渍法检测各组幼虫对溴氰菊酯的抗性水平。结果产卵率:S-S组为94.44%,R-R组为100%,R-S组和S-R组分别为61.11%和72.22%;孵化率:S-S组和R-R组分别为94.12%和100%,R-S组和S-R组分别为36.36%和69.23%;各组幼虫成活率,成蛹率及羽化率均达到90%以上,无显著性差异;抗性水平:R-R组、R-S组和S-R组F2代的抗溴氰菊酯水平分别是敏感品系的53倍、29倍和10倍。结论杂交群体F2代的抗性水平位于两亲本之间,符合遗传学规律。