Effects of alpha- and theta-cypermethrin insecticide on transient outward potassium current in rat hippocampal CA3 neurons

The effects of two cypermethrin insecticides, alpha-cypermethrin and theta-cypermethrin on the transient outward potassium (I_A) channels in freshly dissociated hippocampal CA3 neurons of rat, were studied using whole-cell patch clamp technique. The results indicate that alpha-cypermethrin increased the amplitude of I_A and theta-cypermethrin decreased the amplitude of I_A, and both of them shifted steady activation curve of I_A towards negative potential. Theta-cypermethrin contributed in the inactivation of I_A. Alpha-cypermethrin prolonged the time constants for the recovery from inactivation kinetics of I_A. These results imply that transient outward potassium (I_A) channels are the target of cypermethrin, which may explain the mechanism of toxical effects of cypermethrin on mammalian animals.     

高尔夫球场化肥农药迁移规律研究

采用模拟试验和现场监测的方法,研究了百菌清、氯氰菊酯、肥料在高尔夫球场草坪中随水迁移规律及在土壤和植物中的残留变化。结果表明：在低、中、高3种浓度施用情况下,氯氰菊酯和百菌清在土壤和淋溶液中的迁移含量均在检出限以下,施药7d后3种浓度在草坪植物中的残留量分别为23．8、505．0和771．5μg／kg;施肥22d后磷素在水中的迁移总量仅为施肥量的0．45％;三氮随水迁移的总量为施氮量的75．2％,其中迁移液中最高浓度可达（GB3838-2002国家地表水水质标准》V水质标准的1500倍,表明三氮是高尔夫球场草坪地表水和地下水潜在的污染源之一。现场监测结果表明,球场上下游人工湖水氮素含量相差0．0222mg／L,对外界影响不大;施药3d后球场地表水、淋溶液和土壤中农药均未检出,在果领植物样中的残留量最高达1349μg／kg。     

λ-cyhalothrin and cypermethrin induced in vivo alterations in the activity of acetylcholinesterase in a freshwater fish, Channa punctatus (Bloch)

In the present study, the in vivo effects of λ-cyhalothrin and cypermethrin on the activity of acetylcholinesterase (AChE, EC 3.1.1.7) were evaluated for 96 h in brain, muscle and gills of Channa punctatus. Both compounds exhibited tissue specific as well as dose dependent decrease in the activity of AChE. The treated fish showed a significant decrease in the activity of AChE in brain and a lesser inhibition in muscle and gills in response to the increasing concentrations of λ-cyhalothrin as well as cypermethrin. Our results indicated that the brain was the main target organ for both insecticides, followed by muscle and gills, as determined by AChE inhibition study. However, these organs showed variations in the degree of AChE inhibition for separate treatments of both insecticides. The λ-cyhalothrin was a more potent AChE inhibitor as compared to cypermethrin. These findings indicated that apart from the established mechanism of delayed closure of sodium ion channels, these pyrethroids inhibit the activity of AChE in C. punctatus which could further aggravate their neurotoxic effects.     

金塔县胡杨林杨潜叶跳象的发生规律及药剂防治效果

近年来杨潜叶跳象对河西走廊地区胡杨(Populus eaphratica)林的危害日益加剧。在金塔县杨潜叶跳象的调查中发现,金塔县气温超过10℃时,杨潜叶跳象出蛰恢复活动,出蛰后立即上树为害胡杨,5月下旬开始化蛹,6月上旬为化蛹盛期。通过喷施5%高效氯氰菊酯乳油1 000倍液,2.5%溴氰菊酯乳油2 000倍液对杨潜叶跳象进行防治,结果表明,4月初在树下喷施1 000倍5%高效氯氰菊酯乳油的胡杨平均好叶率明显高于清水对照胡杨平均好叶率,林内及树下喷施1 000倍5%高效氯氰菊酯乳油,蛹的平均校正死亡率分别为99%、100%,成虫几乎无法完成羽化。     

集装箱底板用防虫剂的研究

研究了一种非辛硫磷类的新型复配防虫剂,该防虫剂主要用于集装箱底板用胶合板的防护处理。应用滤纸药膜法和大鼠急性毒性实验研究了该防虫剂的毒性,试验研究了防虫剂对胶黏剂和胶合性能的影响,检测分析了防虫剂有效成分氯氰菊酯在集装箱底板中的保持率,采用钻孔法和群集实验法检验了防虫处理后的底板对竹蠹虫和白蚁的杀灭作用。结果证明:该新型防虫剂与酚醛树脂胶黏剂具有较好的混溶性,对胶黏剂的稳定性和胶合强度均无不良影响,通过胶层处理的底板中防虫剂有效成分保有量较高,防虫剂对人体毒性低、对竹蠹虫和白蚁具有较强杀灭作用,而且该防虫剂价格较低,是辛硫磷类防虫剂的理想替代品。     

1%苦参碱可溶性液防治草原蝗虫田间药效试验

苦参碱是1种新型的生物防治制剂,具有对人畜安全、不污染环境、易于就地取材、节约开支、使用经济等优点。为了确定苦参碱是否对草原蝗虫具有良好的防治效果,2010～2011年连续2 a以常用药剂4.5%高效氯氰菊酯乳油为药剂对照,在天然草场上测试了1%苦参碱可溶性液使用量4.5 g/hm2、6.0 g/hm2和7.5 g/hm2对草原蝗虫的防治效果。结果表明：1%苦参碱可溶性液4.5～7.5 g/hm2处理对草原蝗虫表现出了较好的防治效果,2 a防治效果均在90%以上。本研究结果可为1%苦参碱药剂的产品登记以及为生产上选择适于防治草原蝗虫的药剂提供科学依据。     

Cypermethrin-induced alterations in vital physiological parameters and oxidative balance in Caenorhabditis elegans

Cypermethrin belongs to the class of synthetic pyrethroids, which are being widely used as an insecticides in agricultural practices. The toxicity of cypermethrin is well studied in Drosophila melanogaster, fish, rats, mice, and is reported to cause neurotoxicity and oxidative stress during its metabolism. In this study, we evaluated the biological consequences of 4 h exposure to cypermethrin at sublethal concentrations (1, 5 and 15 mM) in Caenorhabditis elegans on physiological parameters such as egg laying, brood size, feeding and lifespan and oxidative stress parameters such as ROS, hydrogen peroxide levels, protein carbonyl, enzymatic antioxidants and glutathione levels. There was a significant and dose-dependent decrease in brood size (18-53%), egg laying (54-67%), feeding (29-58%) and marked decrease in lifespan (20%) at 15 mM of cypermethrin. Increase in levels of oxidative markers such as ROS (21-56%), intracellular hydrogen peroxide (17-62%), protein carbonyl (8-29%) and alteration in the activity of enzymatic antioxidants as well as depletion of glutathione (13-38%) were also observed. Our study offers evidence to show that cypermethrin induces significant oxidative stress in C. elegans and alters several physiological parameters in these worms, which can lead to impaired functioning, and survival of these worms.     

Toxico-pathological effects of cypermethrin upon male reproductive system in rabbits

The objective of this work was to identify the reproductive toxico-pathological effects of cypermethrin (CY) in mature male rabbits. Apparently healthy adult age- and weight-matched rabbits (n = 40) were procured from the local market, kept under similar management conditions and divided into four equal groups. Different doses of CY (50, 100 and 150 mg kg⁻¹ body mass) mixed in mustard oil were injected intraperitonealy at weekly intervals in male rabbits (groups B-D) prior to mating. Group A served as control and each animal in this group received equivalent volume of mustard oil. Treatment was continued for 71 days. Decreased testicular and epididymal sperm counts were recorded mostly in dose and time dependent manner in CY-treated rabbits. The serum testosterone concentrations in CY-treated rabbits were significantly lower than those of control group. Degeneration, arrested spermatogenesis and connective tissue (CT) proliferation in testes, while sperm-less seminal plasma and tailless spermatozoa in epididymis of CY-treated rabbits were observed. It was inferred that CY-induced defects in sperms and pathological alterations in testes and epididymis.     

两种杀虫剂对甘蓝蚜的毒力测定及室内药效试验

 在室内用氯氰菊酯、敌敌畏分别对甘蓝蚜［Brevicoryne brassicae(Linnaeus)］进行了毒力测定及防治试验。结果表明:氯氰菊酯和敌敌畏乳油对甘蓝蚜的ＬC₅₀分别为4.113 7,116.486 1 μg/mL,10%氯氰菊酯和80%敌敌畏乳油分别稀释成1 500～3 000倍液和1 500倍液对甘蓝蚜的室内防治效果较好,其药后第1～5 d的防效分别为75.3%～87.4%和76.7%～86.6%.