昆虫神经元与骨骼肌中非突触钠通道研究进展

昆虫离子通道具有多样性,其神经元与骨骼肌中非突触钠通道主要选择性允许钠离子跨膜通过,开放性受电压控制,被称为电压门控性钠通道,其主要功能是维持细胞膜兴奋性及其传导。细胞膜钠离子通道结构和功能正常是生理活动基础,钠通道基因突变或异常表达会导致其激活、失活功能异常,引起组织功能紊乱,甚至会诱发疾病。同时钠通道也是许多天然神经毒素和杀虫剂靶标。本文就昆虫非突触离子通道钠通道结构、基本功能和调节机制方面研究进展进行综述,为农药杀虫机制研究提供科学依据。     

钠离子通道与拟除虫菊酯击倒抗性的研究进展

拟除虫菊酯类杀虫剂具有高效低毒低残留性 ,现已占有全球超过 2 5 %的杀虫剂市场 ,广泛用于农业和卫生害虫的防制。然而 2 0多年来的持续应用 ,导致很多昆虫都对之产生了抗药性 ,从而减损了这种杀虫剂持续有效的应用〔1〕。神经生理学研究表明 ,ＤＤＴ和拟除虫菊酯的作用机制是干扰电位依赖的Ｎａ 通道闸门开闭的动力学 ,使得Ｎａ 通道延迟关闭 ,引起重复后放 (ｒｅｐｅｔｉｔｉｖｅａｆｔｅｒｄｉｓｃｈａｒｇｅ)和突触传递的阻断〔2 -3〕。昆虫神经系统对拟除虫菊酯类杀虫剂的敏感性下降主要与神经细胞膜上Ｎａ 通道的敏感性降低有关。…     

昆虫抗药性的形成及机理

１ 抗性的现状及危害 迄今为止，除舌蝇外，几乎所有媒介昆虫都有抗性报告，对已经使用的杀虫剂，均发生不同水平的抗性昆虫群体。目前抗性杀虫剂和抗性媒介种类在不断增多，抗性媒介覆盖地区在不断扩大，抗性增长的速度也在迅速提高。 拟除虫菊酯由于其独特性质，如药效高、低用量、广谱性、对人畜安全、对环境几无影响，在世界各地很快就普及开来，出现了“菊酯热”。因长期、连续、单一地大面积使用，几年以后，许多昆虫对它产生了抗性，且有些种群抗性发展速度之快，让人难以想象。例如到１９８５年，山东聊城棉蚜对溴氰菊酯的抗性已增…     

特异性等位基因PCR扩增技术检测家蝇击倒抗性相关钠通道的基因突变

城市家蝇（Musca domestica）的化学防制多以混配或复配拟除虫菊酯类杀虫剂为主，近10年来国内各城市均有家蝇对拟除虫菊酯产生抗药性的报道。昆虫对拟除虫菊酯类杀虫剂的抗性主要是击倒抗性（knockdown resistance，kdr），Farnham发现kdr在家蝇对拟除虫菊酯的抗性中具有重要作用。     

一种新菊酯的合成及药效

本文介绍二氯菊酸酰氯与胺醇缩合制得一种新型菊酯类杀虫剂，并报道其合成路线。所得样品通过元素分析，理论值与实测值相符。其药效，对淡色库蚊幼虫的ＬＣ５０为０．００２６４ｐｐｍ，对家蝇为０．００１６５～０．００１８２μｇ／虫；以５ｍｇ／ｍ３剂量喷雾，对淡色库蚊成虫的ＫＴ５０为４．７ｍｉｎ，对家蝇为３．７ｍｉｎ，两者２４ｈ死亡率均为１００％。按５４ｍｇ／ｍ２剂量强迫接触试验，对美洲大蠊的ＫＴ５０为６．２ｍｉｎ，对德国小蠊为６．０ｍｉｎ。     

山东省卫生杀虫剂应用现状

卫生害虫的防制方法有多种,如物理防制、化学防制、生物防制和综合防制,其中化学防制具有快速、高效、经济、简便的特点,成为目前使用最广泛、最有效的防制方法。化学防制的核心是用卫生杀虫剂以适宜的形式对卫生害虫进行作用,从而有效地控制害虫的繁衍及疾病的传播。山东省应用卫生杀虫剂防制媒介昆虫已有几十年的历史,随着科学技术的不断进步及化学合成农药的不断创新,卫生杀虫剂应用的种类由过去的有机氯、有机磷占主导地位,逐步转化为以拟除虫菊酯类杀虫剂为主流;杀虫剂剂型由过去的几种,发展为目前的几十种。现将近年来我省卫生杀虫剂…     

应用拟除虫菊酯选育三种蚊媒的研究

目的：了解应用拟除虫菊酯选育蚊媒时杀虫剂敏感度的变化。方法：采用杀虫剂单独选育及交叉选育三种蚊虫Ⅳ龄幼虫的方法来进行实验室选育。结果：致倦库蚊、白纹伊蚊幼虫经胺菊酯选育后，其后代敏感度有所降低，显示出低水平的抗药性，各代蚊幼虫选育后的蚊蛹羽化率均在90％以上；致倦库蚊幼虫经敌百虫、溴氰菊酯交叉选育后，选育后代对溴氰菊酯的敏感度变化不明显，仍处于敏感水平，各代蚊幼虫选育后蚊蛹羽化率在80％以上；中华按蚊幼虫用氯菊酯选育时不易建立选育系。结论：致倦库蚊、白纹伊蚊幼虫经胺菊酯选育后可产生低水平抗药性，致倦库蚊用两种不同作用机制的杀虫剂交叉选育时不易产生抗药性。     

拟除虫菊酯水剂杀虫剂的研制

选择合适的助溶活性剂和拟除虫菊酯配制而成的水剂杀虫剂，经实验室和现场试验，对蚊蝇、蟑螂都有显著杀灭作用，并且有高效、低毒、稳定性好和价格低廉等优点，对卫生害虫的击倒、杀灭作用优于同等含药量的醇制剂，目前已经应用于部队。     

Voltage-gated sodium channel gene mutations and pyrethroid resistance in Rhipicephalus microplus

Pyrethroid pesticides are extensively used to manage animal and human disease vectors including the southern cattle tick Rhipicephalus microplus (Canestrini). The indiscriminate and incorrect use of pyrethroids has led to the almost ubiquitous development of resistance to this pesticide class for this tick species. Voltage-gated sodium channels (Na-channels) are the primary target-site of pyrethroids and several studies on the involvement of mutations in the coding gene among pyrethroid-resistant R. microplus populations from different parts of the world have shown that there are various single nucleotide polymorphisms (SNPs) that are associated with resistance to pyrethroids. Identification of the exact location of the mutations in the protein coding regions of the targeted gene facilitates the design of various molecular tools for genotyping the resistant populations and thus promotes the rapid detection of resistance. This review aims to provide an update on the identification of pyrethroid resistance-associated Na-channel mutations from R. microplus.The database of diverse mutations from different regions of the world helped us to develop the molecular markers for resistance monitoring in a rapid and efficient manner. Their role and the development of different forms of molecular tools for genotyping ticks for mutations in the Na-channel gene are also discussed. In this review, the word mutation is used interchangeably with SNP.     

Fluctuating Asymmetry in Insecticide-Resistant and Insecticide-Susceptible Strains of the Maize Weevil, <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> (Coleoptera: Curculionidae)

Insecticide resistance is an evolutionary response of specific insect populations subjected to exposure and consequent selection by an insecticide. As such, this phenomenon is important as a biomonitoring strategy and also has economical importance in the case of insect-pests by compromising their control. Fluctuating asymmetry (FA) of bilateral traits is a measure of developmental instability also suggested as a monitoring tool for environmental pollution with potential consequences for fitness. Responses to selective agents might have pleiotropic effects influencing development and phenotype, which has yet to be examined for agricultural insecticides and insect-pests. Higher levels of FA are expected in the insecticide-resistant strains, which are usually at a selective disadvantage, relative to susceptible strains, in the absence of the insecticide. Two insecticide-resistant strains and an insecticide-susceptible strain of the maize pest insect Sitophilus zeamais (Coleoptera: Curculionidae) were subjected to FA measurements in 12 traits of wing veins and tibias of 100 individuals of both sexes of each strain. The insecticide-resistant strains showed lower FA than the susceptible strain, in contrast with the initial expectation. An extended period of insecticide selection probably led to the evolution of fitness-modifier genes improving the performance of the resistant genotypes, reducing their FA levels, and leading to their eventual fixation in the population. In addition, one insecticide-resistant strain and the insecticide-susceptible strain showed significant differences in FA between sexes, with more symmetrical males suggesting possible sexual selection by the females. The observed results have potential consequences for insecticide-resistance evolution and dispersal.     

应用钠离子通道基因突变技术检测家蝇抗药性的研究

目的了解济南市家蝇抗药性现状,预测抗性发展趋势。方法生物测定法与分子检测法相结合。结果生物测定结果表明,济南市家蝇对常用的拟除虫菊酯类杀虫剂的抗性已经达到中、高度水平;对济南市家蝇个体进行钠离子通道突变位点检测,发现抗性个体占种群的80.43%,然而纯合子仅为28.26%。结论将两种测定方法结果结合,清楚地表明虽然济南市家蝇对拟除虫菊酯类杀虫剂已经达到中、高度抗性,但种群内仍有大部分为杂合子,应及时采用合理措施,延缓家蝇抗药性的发展。     

增效胺应用于几种卫生害虫对某些杀虫剂的增效作用

本文就MGK 2C4应用于淡色库蚊、家蝇和德国小鳙对拟除虫菊酯类二氯苯醚菊酯、胺菊酯、右旋反式丙烯菊酯(EBT)、苄呋菊酯,氨基甲酸酯类残杀威以及有机磷类马拉硫磷等杀虫剂的增效作用进行了研究。结果表明,MGK 264和二氯笨醚菊酯(1:1)、苄呋菊酯(1:1)、马拉硫磷(10:1)混用时,对抗苄呋菊酯淡色库蚊幼虫的增效比分别为2.3、2.4和3.8:其与二氯苯醚菊酯(5:1)、胺菊酯(1:1)混用时,对抗苄呋菊酯淡色库蚊成虫的增效比为2.0和1.5;其与二氯苯醚菊酯(3:1)、胺菊酯(1:1)、残杀威(3:1)混用时,对德国小蠊的增效比分别为1.8.1.6和2.0;其与二氯苯醚菊酯等杀虫剂混用(1:1),对抗有机磷淡色库蚊幼虫无增效作用;其与EBT(3:1)混用,对家蝇的增效比为1.5。总的来看,MGK 264对残杀威杀灭德国小蠊效果尤佳。     

Evidence of multiple pyrethroid resistance mechanisms in the malaria vector Anopheles gambiae sensu stricto from Nigeria

Pyrethroid insecticide resistance in Anopheles gambiae sensu stricto is a major concern to malaria vector control programmes. Resistance is mainly due to target-site insensitivity arising from a single point mutation, often referred to as knockdown resistance (kdr). Metabolic-based resistance mechanisms have also been implicated in pyrethroid resistance in East Africa and are currently being investigated in West Africa. Here we report the co-occurrence of both resistance mechanisms in a population of An. gambiae s.s. from Nigeria. Bioassay, synergist and biochemical analysis carried out on resistant and susceptible strains of An. gambiae s.s. from the same geographical area revealed >50% of the West African kdr mutation in the resistant mosquitoes but <3% in the susceptible mosquitoes. Resistant mosquitoes synergized using pyperonyl butoxide before permethrin exposure showed a significant increase in mortality compared with the non-synergized. Biochemical assays showed an increased level of monooxygenase but not glutathione-S-transferase or esterase activities in the resistant mosquitoes. Microarray analysis using the An. gambiae detox-chip for expression of detoxifying genes showed five over-expressed genes in the resistant strain when compared with the susceptible one. Two of these, CPLC8 and CPLC#, are cuticular genes not implicated in pyrethroid metabolism in An. gambiae s.s, and could constitute a novel set of candidate genes that warrant further investigation.     

注射用哌拉西林钠他唑巴坦钠致局部组织坏死1例

目的探讨注射用哌拉西林钠他唑巴坦钠的药物不良反应。方法研究分析笔者所在医院在使用该药过程中发生的1例药物不良反应。结果注射用哌拉西林钠他唑巴坦钠静脉滴注致局部组织坏死。结论该药物不良反应可能是由于静脉滴注过程中药液渗漏所致。     

埃及伊蚊电压依赖性钠离子通道3′端cDNA的克隆及序列分析

目的扩增埃及伊蚊电压依赖性钠离子通道基因3′末端，并对其核苷酸序列进行分析。方法提取埃及伊蚊雌蚊总RNA，以Trsa为反转录引物反转录成单链cDNA，继而设计阳性与阴性对照，采用巢式聚合酶链反应（PCR）和快速扩增cDNA3′末端（3′RAcE）技术，对埃及伊蚊电压依赖性钠离子通道基因3′末端进行PCR扩增、克隆与测序。结果获得钠离子通道基因的3′端核苷酸序列共809bp，包括编码区和非编码区poly（A）尾，编码区共编码208个氨基酸。相似性分析结果显示编码区氨基酸序列与家蝇钠离子通道基因3′端氨基酸序列相似性为65％左右。结论成功获得埃及伊蚊钠离子通道基因3′端，为进一步研究该基因的分子生物学特性奠定了基础。     

头孢呋辛/他唑巴坦注射剂的毒理学研究

目的分析头孢呋辛/他唑巴坦注射剂对小鼠的急性毒理学和大鼠的长期毒理学实验,为指导临床抗菌药物的合理应用提供参考依据。方法对60只小鼠及120只大鼠进行急性毒性实验及长期毒性实验,急性毒性实验选取禁食24h的60只的小鼠,每20只分别尾静脉注射头孢呋辛、他唑巴坦和头孢呋辛/他唑巴坦(4∶1)3种抗菌药物,连续注射1周;长期毒性试验选取120只大鼠,每20只分别腹腔注射头孢呋辛、他唑巴坦和头孢呋辛/他唑巴坦(4∶1)高2.4g/(kg·d)、中1.2g/(kg·d)、低0.6g/(kg·d)3个剂量,连续注射4周,注射后立刻观察动物的毒性反应,记录中毒情况;观察大鼠的各种临床表现、血液指标和解剖后的脏腑变化。结果急性毒性实验结果显示,头孢呋辛、他唑巴坦和头孢呋辛/他唑巴坦(4∶1)3种抗菌药物注射后,均无明显毒性异常表现发生;长期毒性实验结果显示,头孢呋辛/他唑巴坦(4∶1)高中低剂量组大鼠给药期间并无明显的异常表现;给药4周后,除高剂量组的红细胞和白细胞总数偏高之外,其他各项指标和单剂量相比差异无统计学意义;病理组织学检查和单剂量相比,差异无统计学意义。结论头孢呋辛/他唑巴坦(4∶1)与两者单剂量应用其急性毒性和长期毒性差异不大,且两者作为复方制剂联合应用,可以降低细菌的耐药性,在临床上对细菌的感染治疗值得推广。     

注射用阿洛西林钠和注射用青霉素钠致剧烈咳嗽1例

目的：探讨使用注射用阿洛西林钠和注射用青霉素钠能够导致剧烈咳嗽。方法通过对我院临床用药过程中发现的一例由注射用阿洛西林钠和注射用青霉素钠引起地不良反应进行研究和分析。结果本例用药导致的剧烈咳嗽这一不良反应确实是由使用注射用阿洛西林钠和注射用青霉素钠所引起的。结论在今后的临床应用中医师应该注意此类不良反应发生地可能,在用药过程中密切观察患者用药期间有无不适症状,确保患者用药安全。