农药低剂量导致其抗性发展

从生态调控和社会经济的角度出发,较低剂量农药的应用成为一种发展趋势。而这也致使农药新型抗性的发展。数十年之前,害虫对某种农药的抗药性大多数是由主效基因突变产生是单基因抗药性,属于主效基因编码的靶标位点抗性,而该位点处的受体酶将发生变异,不再与药剂进行特异性结合。早期主要使用较高的推荐剂量的农药防治抗性     

氰戊菊酯系列复合制剂“25%菊氧乳油”配方设计和研究

氰戊菊酯具有杀虫力强、击倒迅速、杀虫谱广、用量少、毒性低等优点。但杀螨效果差,害虫易于产生抗药性。氧化乐果具有内吸作用,杀螨效果优越。为了延缓菊酯类农药对害虫抗药性的发展,扩大单剂的杀虫谱和探索复合制剂     

害虫抗性管理100年

在1914年,A．L．Melander首次报道了害虫的抗药性——介壳虫对一个无机杀虫剂产生抗性。自第一次发现农业重要害虫对农药发展了抗性到现在已经100年了。在抗性发生后,由于DDT抗性的广泛发展,在20世纪50年代前,大部分的种植者就熟知害虫的抗药性。这以后,种植者就预期到由于抗性问题一个杀虫剂最终会失去效力。而对于每一类杀虫剂,如有机磷类、氨基甲酸酯类、甲脒类、拟除虫菊酯类、多杀菌素类和新烟碱类,在上市后2～20年内就出现抗性。     

棉蚜抗药性及其抗性治理对策的研究

棉蚜(Apkis gossypii Glover)是一种世界性的农业害虫．对有机氯、有机磷、氨基甲酸酯、拟除虫菊酯类等多种杀虫剂均产生了抗药性。主要对棉蚜抗药性的形成与发展、影响因素、抗性机制等方面进行了综述，并探讨了抗性治理对策。对于延缓棉蚜抗药性和治理该虫有一定的参考价值。     

农药治虫存在的问题和对策

农药治虫是农作物保产的必要措施。根据近来研究的结果,有的农药除了治虫保产之外,还能促进作物生长,提高产品质量,增加产量。但是由于长期使用,或由于滥用农药,害虫产生了抗药性,降低了治虫效果,形成治虫不保产,因此,农作物遭受虫害损失,需要研究对策,预防抗性的产生,克服抗性,充分发挥农药的保产增产效益。     

测定增效醚对酯酶封闭作用的新方法

害虫种群遗传变化导致的抗性可能会致使以前有用的农药不再有理想的防治效果。杀虫剂抗性水平和抗性发展速率与杀虫剂的化学特性、害虫的遗传和生物学因素有关。这些因素包括：杀虫剂的用量和使用频率;杀虫剂作用机理;单基因抗性还是多基因抗性;昆虫种群的内在遗传变异水平、生活史和生态学。例如,害虫世代周期短和能产生大量后代有利于抗药性的迅速发展和蔓延。     

甲氨基阿维菌素苯甲酸盐的抗性机理研究进展

甲氨基阿维菌素苯甲酸盐是一种高效、低毒、低残留的十六元大环内酯类杀虫剂。由于其独特的作用方式,且对鳞翅目害虫幼虫表现出很好的毒性,目前甲维盐已成为我国广泛使用的用来防治蔬菜害虫的新型农药。然而,甲维盐的大量使用使得人们对其抗药性问题甚感忧虑,且已有田间害虫产生抗药性的相关报道。从代谢抗性、靶标抗性以及ABC转运蛋白3个方面,就昆虫对甲维盐的抗药性机理进行综述。     

甜菜夜蛾对昆虫生长调节剂的抗药性研究进展

甜菜夜蛾是一种重要的农业害虫,已对有机磷类、拟除虫菊酯类、氨基甲酸酯类杀虫剂产生了较高水平的抗药性,目前生产中主要以昆虫生长调节剂、生物农药及新型农药为主进行防治,本文就甜菜夜蛾对昆虫生长调节剂的抗药性现状、交互抗性及抗性机理进行了综述,并提出了抗性治理对策。     

专利文摘

中国专利CN1178636A报道一种无公害化学生物农药及其制备方法,该农药采用含有生物碱的植物提取液和溶剂油的加成物作为杀虫的主要成分,能够对危害蔬菜、果树及农作物的多种害虫起到防治作用,并与化学农药相比无污染、无残留,药效长、成本低、害虫不易产生抗药性,该农药是一种高效、低毒、成本低的新型农药。     

北卡罗莱纳州东部美洲棉铃虫抗Bt显性基因的概率评估

近年来，转基因棉花特别是含有Bt内毒素的转基因棉花大面积种植，在那些棉铃虫类(棉铃虫、烟蚜和美洲棉铃虫的幼虫)为主要农业害虫的地区，Bt棉花提供了一种对这些害虫行之有效的防治方法。然而，许多研究者也担心因为害虫对转基因Bt棉花的抗性的增加而使这种方法成为短期的行为。为了有效地控制Bt抗药性在棉花害虫棉铃虫类上的增长，这就要求种植的棉花必须表达高剂量毒素杀死敏感和部分抗性的害虫。近年来实验室与田间研究     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.