分散固相萃取-反相高效液相色谱法测定蔬菜尧水果中10种氨基甲酸酯类农药残留

建立分散固相萃取-反相高效液相色谱同时测定蔬菜和水果中10种氨基甲酸酯类农药（涕灭威,涕灭威砜,涕灭威亚砜,克百威,3-羟基克百威,灭多威,甲萘威,异丙威,速灭威,仲丁威）残留的分析方法。样品经乙腈提取, PSA分散固相萃取净化,液相色谱柱后衍生分离,荧光检测（姿ex＝330 nm,姿em＝465 nm）测定,外标法定量。10种农药在0.005～0.50 mg/L范围内线性关系良好;检出限在0.004～0.008 mg/L;平均加标回收率在75.6%～112.3%,相对标准偏差（RSD）在0.8%～10.2%。该方法具有快速、灵敏、准确、重现性好以及操作简单等特点,适合日常大批量蔬菜和水果样品中10种氨基甲酸酯类农药残留的测定。     

气相色谱-质谱法测定发酵乳中氨基甲酸乙酯含量

采用气相色谱-质谱法定量,建立测定发酵乳中氨基甲酸乙酯含量的分析方法。通过优化前处理条件,同时考察方法的线性关系、精密度、加标回收率、检出限及定量限等指标,内标法定量。结果表明：该方法在0～200?ng/mL范围内线性良好（r＞0.999）,氨基甲酸乙酯检出限为2.0?μg/kg,定量限为5.0?μg/kg,加标回收率为89.9%～105.2%,相对标准偏差小于10%。该方法灵敏、准确、重复性好,能满足发酵乳中氨基甲酸乙酯含量的测定要求。     

A biochemical mechanism of resistance to pirimicarb in two glasshouse clones of Aphis gossypii

The susceptibility of three clones of Aphis gossypii Glover to 15 insecticides was established by bioassay. A high level of resistance towards pirimicarb was confirmed for a clone from Holland (Dutch R) and a clone from Japan (Jap R), while the susceptible clone (S) was killed by very low doses of the insecticide. However, only limited cross-resistance was shown towards other carbamates and organophosphates, and no marked resistance to the pyrethroids tested. The acetylcholinesterase (AChE) of both resistant clones hydrolysed acetyl-choline faster than that of susceptible aphids, with greatest enzyme activity shown by the Dutch R clone. Inter-clone differences in these rates were consistent with differences in catalytic centre activities. Inhibition (I₅₀) of AChE by pirimicarb was approximately 900-fold higher for the resistant clones than for the S clone. First-order kinetics revealed that resistance to pirimicarb in Dutch R and Jap R involved a modified AChE which had a reduced (approximately 350-fold) affinity (K_d) for pirimicarb. The marked change in AChE affinity for pirimicarb was not repeated with the other carbamates tested, ethiofencarb and aldicarb. It was considered that the resistant aphids would not require mechanisms in addition to insensitive AChE in order to show the high level of resistance to pirimicarb shown in the bioassay.     

氨基甲酸苯丙酮肟酯类化合物的合成及生物活性

为寻找高活性的新农药化合物,以3-取代氨基-1-芳基丙酮-1-肟与氨基甲酸酯反应,设计并合成了19个氨基甲酸苯丙酮肟酯衍生物,其结构均经核磁共振氢谱和元素分析确证。初步的生物活性测定结果表明,化合物具有一定的生物活性,其中 c11 在浓度为500 mg/L时,对蚜虫Aphis craccivora的致死率达到90%以上; c16和c17 在1 000 mg/L时,对朱砂叶螨Tetranychus cinabarinus 的致死率达到100%。     

高效液相色谱柱后衍生化法检测蔬菜中氨基甲酸酯类杀虫剂农药残留

本文建立蔬菜中多种氨基甲酸酯类杀虫剂残留分析方法。样品以丙酮、二氯甲烷混合溶剂提取，以活性炭/Celite545柱净化，以高效液相色谱柱后衍生系统、荧光检测器检测。方法最低检出浓度1-2μg/kg,添加回收率70%-111.1%，相对标准偏差2.02%-12.09%。     

The influence of post-exposure temperature on the toxicity of insecticides to Ostrinia nubilalis (Lepidoptera: Crambidae)

The influence of post-treatment temperature on the toxicities of two pyrethroids (lambda-cyhalothrin and bifenthrin), a carbamate (methomyl) and a spinosyn (spinosad) to Ostrinia nubilalis (Hubner) larvae was evaluated in laboratory assays. From 24 to 35 degrees C, the toxicities of the pyrethroids decreased 9.5- and 13.6-fold while spinosad toxicity decreased 3.8-fold. The toxicity of methomyl did not change significantly. The results demonstrate that the most effective insecticide against a pest may vary with environmental conditions. In situations where comparable products from multiple insecticide classes are available, temperature should be included as a factor in the decision-making process.     

A novel immobilized cholinesterase for on-site screening of organophosphate and carbamate compounds

Acetylcholinesterase was physically adsorbed on polyvinylpyrrolidone K30 to prepare a novel immobilized cholinesterase, which was described for the first time. The immobilized enzyme was tested for its reactivity, enzyme activity stability, the solubility, the influence of pH and buffer, and characteristic reactivity with inhibitors, e.g., organophosphate and carbamate compounds. The result revealed that the immobilized cholinesterase held its original activity in solution, stable enough, easy to dissolve for convenient operation, and this immobilized cholinesterase could be well used for rapid, on-site screening of organophosphate and carbamate compounds, together with a portable pesticide analyzer.     

The Use of a Daphnia magna Bioassay for Rapid Screening of Acute Intoxications with Insecticides in Dogs and Cats

Sudden death due to acute insecticide intoxications occurs frequently in dogs and cats. The absence of characteristic lesions at autopsy often renders post-mortem diagnosis dependent on the analysis of samples taken from the carcase at autopsy. In the present study, a bioassay utilizing Daphnia magna was proposed and tested as a rapid screening method for acute intoxications in dogs and cats. The bioassay was shown to be highly sensitive for detecting carbamate and organophosphate insecticides in the stomach contents. Generally, the mean survival time of the waterfleas in the control group was 5.17 h (SD = 1.24) and in the intoxicated group 1.32 h (SD = 1.49), during a 6 h observation period. If a cut-off is set at 4 h, this Daphnia bioassay gave 5.5% false negative results and 18.2% false positive results, using the results of toxicological analyses as a gold standard.     

氟虫腈偶联磷酸酯及氨基甲酸酯类化合物的合成及生物活性

依据活性亚结构拼接原理,合成了6个新型含有磷酸酯和氨基甲酸酯结构片段的氟虫腈衍生物,其结构经核磁共振氢谱和碳谱、电喷雾质谱(ESI-MS)以及元素分析确证。初步生物活性及毒性测定结果表明:目标化合物对斜纹夜蛾 Spodoptera litura 和亚洲玉米螟 Ostrinia furnacalis 幼虫均具有良好的杀虫活性,其中化合物 1和2 对亚洲玉米螟幼虫的杀虫活性优于氟虫腈,LC50值分别为0.85和2.01 μ g/mL;目标化合物对意大利蜜蜂 Apis mellifera L.的毒性均显著低于氟虫腈。     

我国草地贪夜蛾种群杀虫剂靶标基因突变分析

【背景】草地贪夜蛾（Spodoptera frugiperda）原产于美洲热带和亚热带地区,是重大迁飞性农业害虫。2016年以来迅速扩散至全球100多个国家,目前已入侵我国27省（自治区、直辖市）,对粮食安全构成极大威胁。化学防治是草地贪夜蛾的重要应急防控措施,经过几年的药剂防治,草地贪夜蛾的抗药性可能会发生变化,进而影响防治策略的有效性。其发生范围持续北扩,而目前2020—2021年国内不同种群及长城防线种群抗药性现状以及年度间变化性研究较少。【目的】明确我国不同区域种群（包括长城防线）的抗药性现状与差异,为草地贪夜蛾防控的科学用药提供指导。【方法】采集13省（自治区、直辖市）的草地贪夜蛾田间种群样本,通过对单头样本杀虫剂靶标基因的PCR扩增产物直接测序,分析2020—2021年采自13省（自治区、直辖市）47市（区）草地贪夜蛾种群的362头个体氨基甲酸酯类、拟除虫菊酯类和双酰胺类杀虫剂靶标基因的突变情况。【结果】草地贪夜蛾部分个体在氨基甲酸酯类药剂靶标乙酰胆碱酯酶（acetylcholine esterase）基因ace-1上存在突变,种群有6种ace-1基因型。ace-1基因检测...