旌德罗索线虫野外防治按蚊的效果

2004-2006年对室内培养旌德罗索线虫Romanomermis jingdeensis进行了室内和野外防治按蚊效果试验。结果表明,室内培养的旌德罗索线虫对室内培养和野生按蚊孑孓（主要是中华按蚊和嗜人按蚊的幼虫）均有很强的感染能力,野外释放的最高表观感染率可高达75%,实际的一、二龄孑孓的被感染率则高于90%,达到了理想的控蚊效果。基于试验结果提出旌德罗索线虫野外释放条件是：设立天敌保护性措施,每亩水体设立释放点20个,释放线虫约100g,释放期间不宜施用化肥、农药等线虫致死化学制剂。     

Evaluation of bromophos-ethyl for the control of Anopheles Sp. In Southern iran

Field experiments were carried out in Iran during 1966 to evaluate bromophos-ethyl against larvae of three Anopheles species. Preliminary studies with Culex pipiens fatigans in polluted water near Teheran had shown a residual effect of from 5 to 8 days. In a large-scale trial in southern Iran a mean residual effect of 5 days was obtained against larvae of Anopheles Stephensi mysorensis. Persistence of bromophosethyl could be related to the rate of water exchange.     

Studies on the acetylcholinesterase of Anopheles albimanus resistant and susceptible to organophosphate and carbamate insecticides

Acetylcholinesterase from fourth instar Anopheles albimanus larvae was studied in vitro. The acetylcholinesterase from both the resistant and susceptible strains behaved as a single enzyme “type,” with straight pseudo first-order insecticide inhibition lines which intersected the Y axis at 100%. The enzyme from resistant larvae was more slowly inhibited than the susceptible enzyme; bimolecular rate constants (k_i) differed by approximately 1.2- to 6-fold for a range of organophosphorous compounds and 17- to 1570-fold for the carbamates. There was a good correlation between the levels of resistance and the acetylcholinesterase inhibition rates.     

Mode of action of methoprene in affecting female reproduction in the African malaria mosquito,Anopheles gambiae

BACKGROUND: One of the most studied actions of juvenile hormone (JH) is its ability to modulate ecdysteroid signaling during insect development and metamorphosis. Previous studies in mosquitoes showed that 20‐hydroxyecdysone (20E) regulates vitellogenin synthesis. However, the action of JH and its mimics, e.g. methoprene, on female reproduction of mosquitoes remains unknown. RESULTS: Here, a major malaria vector, Anopheles gambiae Giles, was used as a model insect to study the action of methoprene on female reproduction. Ecdysteroid titers and expression profiles of ecdysone‐regulated genes were determined before and after a blood meal. An ecdysteroid peak was detected at 12 h post blood meal (PBM). The maximum expression of ecdysone‐regulated genes, such as ecdysone receptor (EcR), hormone receptor 3 (HR3) and vitellogenin (Vg) gene, coincided with the ecdysteroid peak. Interestingly, topical application of methoprene at 6 h PBM delayed ovarian development and egg maturation by suppressing the expression of ecdysone‐regulated genes in female mosquitoes. CONCLUSION: The data suggest that ecdysteroid titers are correlated with Vg synthesis, and methoprene affects vitellogenesis by modulating ecdysteroid action in A. gambiae. Copyright © 2010 Society of Chemical Industry     

Laboratory evaluation of fipronil,a phenylpyrazole insecticide,against adult Anopheles (Diptera: Culicidae) and investigation of its possible cross‐resistance with dieldrin in Anopheles stephensi

Adult mosquitoes from two strains of Anopheles gambiae and from three strains of Anopheles stephensi were exposed to 0.25% fipronil‐treated papers in WHO test kits or to 500 mg fipronil m⁻² impregnated mosquito netting in bioassay spheres. For comparison, tests were also carried out with the pyrethroid permethrin, using the same methods and doses, and on papers treated with 0.4 and 4% of the cyclodiene insecticide dieldrin. Compared with the same doses of permethrin, fipronil showed less and delayed activity. Two of the An stephensi strains were resistant to fipronil and dieldrin. To investigate whether this was due to a resistance mechanism in the An stephensi strains acting against both insecticides, the most fipronil‐ and dieldrin‐tolerant strain was further selected in two separate lines with one of the insecticides, followed by tests with the insecticide that the line had not been selected with. This indicated a concomitant rise of resistance to dieldrin in the fipronil‐selected line and vice versa. Repeated back‐crossing of the two lines with a susceptible strain and re‐selection with either dieldrin or fipronil gave evidence for the involvement of a single resistance mechanism to both insecticides. Permethrin resistance in both lines declined with selection for dieldrin or fipronil and confirms the absence of cross‐resistance between fipronil and pyrethroids. © 2001 Society of Chemical Industry     

人工培养液在植原体昆虫介体筛选中的适用性

研究了一种人工培养液对各种常见的昆虫(主要是叶蝉)的亲和性和适用性.结果表明,该人工培养液适于本试验中大多数昆虫的人工饲养.用此方法,悬钩子广头叶蝉Macropsis.ftscula Zetterstedt和桤树广头叶蝉Oncopsis alniSchrank分别被再次确认为悬钩子矮化植原体和桤树黄化植原体的传播介体;田旋花麦蜡蝉Hyalesthes obsoletus Signoret再次被确认为葡萄黄化(stolbur)植原体的传播介体.此前,上述三种叶蝉已被传统的人工接种方法鉴定为相应植原体的传播介体.危害桤树的河谷树叶蝉Allygus modestus Scott尽管虫体DNA检测结果经常为阳性,但迄今其人工培养液的检测结果都是阴性,因此,我们认为河谷树叶蝉不是桤树黄化植原体的传播介体.Eppendorf管人工培养液饲养法不仅适用于潜在的植原体介体昆虫的筛选鉴定,而且可用于介体昆虫的生物防治研究.此外,本研究首次发现自然感染了葡萄上的一种被德国人称为"Vergi-lungskrankheit"植原体(AY组)的草地脊冠叶蝉Aprodes makarovi Zachvatkin.     

New aphid vectors and efficiency of transmission of Potato virus A and strains of Potato virus Y in the UK

The aphid‐transmitted viruses Potato virus Y (PVY) and Potato virus A (PVA) commonly affect seed potatoes in the UK. The transmission efficiency for aphid species is used to calculate a potential transmission risk and is expressed as a relative efficiency factor (REF). These REFs have not previously been calculated for UK strains of viruses or aphid clones. Using a previously published method, REFs have been calculated for the aphid species and viruses commonly occurring in UK potatoes. The efficiency of transmission of Myzus persicae is nominally set to a REF of 1 and REFs for other species are calculated relative to this. These data represent the first set of REFs calculated for PVA transmission. Macrosiphum euphorbiae (REF 0.91) was almost as efficient as M. persicae at PVA transmission. The data were further analysed to compare transmission rates of PVY and PVA using a binomial (logit) generalized mixed model to take into account the potential influence of variation in virus titre between leaves. This approach found that there is little variation between the efficiency of transmission between clones of each aphid species or between strains within a virus species. This is a first report that Aphis fabae, Metopolophium dirhodum, Sitobion avenae, Acyrthosiphon pisum and Cavariella aegopodii have the ability to vector PVA. This study also represents a first report that C. aegopodii has the ability to vector PVY and confirms the potential of S. avenae, A. fabae, M. euphorbiae and Rhopalosiphum padi as important PVY vectors.     

利用桥梁载体策略构建水稻条斑病菌T3SS基因诱导表达检测体系

 水稻条斑病菌(Xanthomonas oryzae pv. oryzicola, Xoc)侵染水稻,引起细菌性条斑病(bacterial leaf streak, BLS)。Xoc主要依靠hrp基因簇(T3SS基因)编码的III型分泌系统(type III secretion system, T3SS)将效应蛋白注入水稻细胞中,激发寄主水稻的感(抗)病性。为了准确在Xoc中进行T3SS基因表达调控的分析,本研究设计出桥梁载体策略,将目标基因的启动子或者功能片段构建在高拷贝的桥梁载体,获得融合表达元件,通过亚克隆的方式将融合元件转入骨架载体上,获得用于转录表达和蛋白表达分析的载体。为了验证该策略的可行性,选取hrpG、hrpX和hrcC基因构建了相应的启动子探针载体和蛋白表达载体,将这些载体导入毒性调控子基因trh、lrpX和zur的突变体中,GUS活性测定、荧光定量PCR以及蛋白免疫杂交结果显示:在trh、lrpX和zur的突变体中,hrpG、hrpX和hrcC的转录表达水平、mRNA水平和蛋白表达水平呈现一致。这表明这套桥梁载体策略能够有效应用于T3SS基因转录表达和蛋白表达的分析。综上所述,运用桥梁载体能够克服低拷贝载体DNA遗传操作效率低的缺陷,这一策略也适用于毒性相关基因调控机理的研究,这将为Xoc-水稻互作研究提供高效的工作系统。     

基于磁光图像的飞机铆钉缺陷识别

针对飞机铆钉磁光图像的识别问题,提出了一种基于模糊支持向量机的裂纹有无和裂纹方向自动识别的新方法。该方法首先对铆钉磁光图像进行预处理得到铆钉二值化图像;然后采用阈值法求取铆钉中心;最后将由铆钉中心发出的星形射线矢量作为特征,采用模糊支持向量机方法对铆钉有无裂纹和裂纹方向进行分类。其中,支持向量机的核宽及惩罚常数采用网格法进行选取,并结合模糊隶属度函数解决多类分类问题中存在的错分和拒分现象。实验结果表明,使用训练获得的支持向量机分类器识别裂纹缺陷取得了很好的效果,能够满足自动检测的高实时性要求。     

植物病毒与媒介昆虫互作促进其传播的研究进展

近年来植物病毒病频发,严重制约着农作物的产量与品质。绝大多数植物病毒依赖媒介昆虫进行传播,而传播的关键是病毒如何突破昆虫的肠屏障、唾液腺屏障和卵屏障等多个生物屏障。植物病毒一方面利用其外壳蛋白或非结构蛋白突破媒介昆虫的中肠屏障和唾液腺屏障;另一方面则与昆虫体内卵黄原蛋白、共生菌以及精子表面蛋白发生特异性互作,促进病毒跨越卵障碍,最终实现病毒在昆虫体内复制。此外,植物病毒还能通过侵染寄主植物影响其防御性状,间接改变媒介昆虫生理及其行为反应,促进病毒在植物间的传播。该研究对植物病毒突破昆虫生物屏障的分子机制,以及植物病毒-植物-媒介昆虫互作对于病毒传播的影响进行了综述,并对阻断病毒传播的方法进行展望。     

利用桥梁载体策略构建水稻条斑病菌T3SS基因诱导表达检测体系

 水稻条斑病菌(Xanthomonas oryzae pv. oryzicola, Xoc)侵染水稻,引起细菌性条斑病(bacterial leaf streak, BLS)。Xoc主要依靠hrp基因簇(T3SS基因)编码的III型分泌系统(type III secretion system, T3SS)将效应蛋白注入水稻细胞中,激发寄主水稻的感(抗)病性。为了准确在Xoc中进行T3SS基因表达调控的分析,本研究设计出桥梁载体策略,将目标基因的启动子或者功能片段构建在高拷贝的桥梁载体,获得融合表达元件,通过亚克隆的方式将融合元件转入骨架载体上,获得用于转录表达和蛋白表达分析的载体。为了验证该策略的可行性,选取hrpG、hrpX和hrcC基因构建了相应的启动子探针载体和蛋白表达载体,将这些载体导入毒性调控子基因trh、lrpX和zur的突变体中,GUS活性测定、荧光定量PCR以及蛋白免疫杂交结果显示:在trh、lrpX和zur的突变体中,hrpG、hrpX和hrcC的转录表达水平、mRNA水平和蛋白表达水平呈现一致。这表明这套桥梁载体策略能够有效应用于T3SS基因转录表达和蛋白表达的分析。综上所述,运用桥梁载体能够克服低拷贝载体DNA遗传操作效率低的缺陷,这一策略也适用于毒性相关基因调控机理的研究,这将为Xoc-水稻互作研究提供高效的工作系统。     

Insecticide resistance in vector mosquitoes in China

Because of their special behaviour, physiology and close relationship with humans, mosquitoes act as one of the most important vectors of human diseases, such as filariasis, Japanese encephalitis, dengue and malaria. The major vector mosquitoes are members of the Culex, Aedes and Anopheles genera. Insecticides play important roles in agricultural production and public health, especially in a country with a huge human population, like China. Large quantities of four classes of insecticides, organochlorines, organophosphates, carbamates and pyrethroids, are applied annually to fields or indoors in China, directly or indirectly bringing heavy selection pressure on vector populations. The seven major species of vector mosquito in China are the Culex pipiens L. complex, C. tritaeniorhynchus Giles, Anopheles sinensis Wied., A. minimus Theobald, A. anthropophagus Xu & Feng, Aedes albopictus (Skuse) and Ae. aegypti L., and all have evolved resistance to all the above types of insecticide except the carbamates. The degree of resistance varies among mosquito species, insecticide classes and regions. This review summarizes the resistance status of these important vector mosquitoes, according to data reported since the 1990s, in order to improve resistance management and epidemic disease control, and to communicate this information from China to the wider community.