拟除虫菊酯类农药残留降解菌的筛选及其生理特性研究

从活性污泥的富集培养物中分离得到可降解几种拟除虫菊酯农药的菌株qw5,初步鉴定qw5为地衣芽孢杆菌 (Bacilliuslicheniformis)。菌株qw5在通气、pH7～ 8、温度 3 0℃左右的环境条件下生长较好。培养 5天 ,菌株qw5对氰戊菊酯、氯氰菊酯、溴氰菊酯的降解率分别为 5 3 .8%、41 .2 %和 61 .7%。经质谱分析 ,菌株qw5降解氰戊菊酯产生中间代谢产物 3 -苯氧基苯甲醛。qw5对小白鼠无致病力 ,对几种常用的抗生素敏感。盆钵和小区试验表明 ,菌株qw5对青菜中残留的拟除虫菊酯有明显去除效果。     

Short-term effects of a nun moth suppression programme (Lymantria monacha), (Lepidoptera: Lymantriidae) on epigeic non-target arthropods

The short-term responses of non-target soil arthropods to insecticides (Nomolt: Teflubenzuron, Karate: lambda-Cyhalothrin) applied against the nun moth (Lymantria monacha L.) were investigated in 2003. This phytophagous pest infested 30–40-year-old monocultures of Scots pine (Pinus sylvestris L.) located at an active military training area in northeast Saxony (Germany). According to the non-target epigeic arthropods, extinction of a higher systematic taxon (family, order) was not observed. Activity densities of soil macroarthropods were lower on plots treated with Karate, while those of necrophagous ground beetles increased considerably. Nomolt revealed no distinct impact on soil invertebrate density. Statistical analysis did not prove any consistent insecticidal effects on non-target arthropods. Adjacent open-heathland arthropods were not affected by a possible drift of the agents.     

Mutation of threonine 422 to glutamic acid mimics the phosphorylation state and alters the action of deltamethrin on Cav2.2

Effects of deltamethrin on voltage-sensitive calcium channels (VSCC) from rat brain (Ca_v2.2) expressed in Xenopus oocytes were assessed electrophysiologically. Deltamethrin reduced peak current of wild-type Ca_v2.2 in a stereospecific and concentration-dependent manner with an EC₅₀ of 1 × 10⁻⁹ M. Phosphorylation of threonine 422 enhances voltage-sensitive calcium current, increases the probability that Ca_v2.2 will open under depolarizing conditions and antagonizes the inhibition of the channel by the betagamma subunit of heterotrimeric G-protein (Gβγ). Site-directed mutagenesis of threonine 422 to glutamic acid (T422E) results in a channel that acts as if it were permanently phosphorylated. Deltamethrin (10⁻⁷ M) significantly enhanced peak current via the T422E channel (1.5-fold) compared to the nontreated control and the increase was significantly greater than for either the wild-type (T422) or T422A (permanently unphosphorylated mutant) channels. The effect of deltamethrin on T422E Ca_v2.2 was stereospecific and concentration-dependent with an EC₅₀ of 9.8 × 10⁻¹¹ M. Thus, Ca_v2.2 is modified by deltamethrin but the resulting perturbation is dependent upon the phosphorylation state of threonine 422.     

Pyrethroid insecticide resistance and treated bednets efficacy in malaria control

Most of the studies on insecticide impregnated bednets efficacy in malaria control have been undertaken in areas where mosquitoes are pyrethroid susceptible. The efficacy of pyrethroid-treated bednets was not compromised even when mosquitoes were kdr resistant. Here, we evaluate a case in which mosquitoes have kdr-like pyrethroid resistance coupled with metabolic mechanisms. Metabolic and kdr-resistance mechanisms in Anopheles stephensi were characterised in our previous study and this easily colonised species was used as a model to examine the efficacy of pyrethroid-treated bednets in the laboratory. Bioassays performed on adults of susceptible (Beech) and resistant (DUB-S) strains using WHO 0.75% permethrin-impregnated papers showed a resistance ratio of 9.75. The recovery rate of the mosquitoes of the DUB-S strain was significantly higher than that of the susceptible strain Beech. The overall permethrin metabolism rates by DUB-S, measured by HPLC method, were 1.5-fold more than by Beech strain. Bioassays performed on DUB-S mosquitoes using different pyrethroid-treated bednets showed that only deltamethrin at 25 mg/m² and α-cypermethrin at 40 mg/m² produced adequate mortality rates. Four other pyrethroids, including permethrin, were ineffective. The deterrency test performed on susceptible and resistant An. stephensi showed that there are significant differences between the entry rates of susceptible and resistant mosquitoes into the exposure tube containing permethrin-treated bednet. These data show that when mosquitoes have both kdr-type and metabolic resistance mechanisms, the efficacy of pyrethroid-treated bednets is questionable.     

有机磷和拟除虫菊酯类农药在小麦及其制品中降解与代谢研究进展

有机磷农药（organophosphorus pesticides）是一类含有磷原子的有机酯类化合物,由磷酸盐和特定的有机组成部分构成;拟除虫菊酯类农药（pyrethroids pesticides）是仿效天然除虫菊化学结构的合成农药,其分子由菊酸和醇两部分构成。有机磷和拟除虫菊酯类农药是我国目前使用量最大的两种农药,由于具有高效、快速、广谱等特点而被广泛应用于农作物病虫害防治中。但是农药的大量使用导致其通过食物链的富集作用,使农产品中的农药残留超标,严重影响小麦产量与品质,给人类食品安全带来危害。我国目前对农药的评估主要是针对其母体化合物的研究,对农药降解产物、代谢机理的评估研究相对匮乏。本文综述了这两类农药的毒性以及在小麦生长、贮藏和加工过程中的残留特性、降解产物与代谢过程,可为农药在小麦中的科学合理使用、提高小麦及其制品中的质量安全提供理论依据。     

拟除虫菊酯对映体毒性选择性研究进展

拟除虫菊酯类农药因高效、对哺乳动物低毒、易降解而被广泛使用。其分子结构中存在手性中心,含有多个对映异构体(简称对映体),不同对映体的杀虫活性及生物毒性存在差异。目前对手性污染物的认识相对零散、不系统,对对映体选择性毒理研究还很少。本文综述了拟除虫菊酯对靶标生物、非靶标生物急性毒性及慢性毒性的对映体选择性,重点综述了拟除虫菊酯对映体的慢性毒性,包括神经毒性、内分泌毒性、免疫毒性、发育及行为毒性、遗传毒性及细胞毒性,并对拟除虫菊酯毒性选择性的发展进行了展望。     

江西马尾松毛虫的抗药性及克服抗性发展对策

根据对江西部分林区马尾松毛虫毒力测定结果分析，江西林区马尾松毛虫对功夫菊酯和多来保敏感，对氯、氰菊酯和氰戊菊酯的耐药力有所提高，高安、贵溪等林区马尾松毛虫对溴氰菊酯产生了抗药性。在此基础上提出了克服马尾松毛虫抗性发展的对策。     

Insecticide resistance in Brazilian populations of the cotton leaf worm, Alabama argillacea

The cotton leaf worm, Alabama argillacea, is a key cotton pest in Brazil and is managed with repeated insecticide applications. Reports of insecticide control failures have recently increased, particularly with pyrethroids. The present work assessed the resistance status of A. argillacea to a number of different insecticides currently used in cotton crops. Bioassays were conducted to estimate the response of 2nd-instar A. argillacea populations to deltamethrin, chlorpyrifos, endosulfan, abamectin and spinosad. A leaf dip bioassay with diluted insecticide formulations was performed in the laboratory with five to nine populations depending on the insecticide. LC₅₀ values were estimated by probit analysis after correction for control mortality data and used to calculate the resistance ratios (RR). All assessed populations exhibited varied and significant levels of resistance to all insecticides tested, but only moderate levels of resistance to deltamethrin were observed (RR = 52.3). The LC₅₀ values for deltamethrin were higher than 30 mg/l for most populations, and above the field rate (12.5 mg/l). This suggests that the frequency of resistant individuals in these populations was likely above the critical frequency. There was low to moderate resistance to abamectin, chlorpyrifos, endosulfan and spinosad formulations (the highest RRs observed were 4.2, 8.4, 11.1 and 23.5, respectively). Despite the moderate levels of resistance to pyrethroids in A. argillacea, overall results indicate the presence of low to moderate resistance of A. argillacea to insecticides currently used against cotton pests in Brazil.     

拟除虫菊酯合成中的不对称环丙烷化研究进展

拟除虫菊酯是一类重要的环境友好杀虫剂,手性金属配合物催化的不对称环丙烷化反应是合成拟除虫菊酯的重要途径。总结了近10年来不对称环丙烷化反应在拟除虫菊酯合成中的研究进展,并对其发展趋势进行了展望。     

高效氯氰菊酯、氰戊菊酯、三唑酮在黄瓜上的残留动态研究

在大棚栽培条件下,研究了喷施高效氯氰菊酯、氰戊菊酯和三唑酮农药在黄瓜中残留动态和最终残留。结果表明,在推荐用量下高效氯氰菊酯、氰戊菊酯、三唑酮的半衰期分别为1.29、3.15和4.63d。高效氯氰菊酯在黄瓜中的残留量少、降解速度快,二次喷药后3d其残留量远低于我国无公害黄瓜的最高限量标准。在推荐用量下,氰戊菊酯在第3天、三唑酮在第7天的残留量均达到无公害黄瓜标准。