植物源昆虫拒食活性物质的研究和应用

植物在与昆虫协调进化过程中形成了许多具有防御功能的次生代谢物质。作者对近年来植物源昆虫拒食活性物质的研究和应用进行了综述,其结构类型主要涉及萜类、生物碱类、酚类等,讨论了制约植物源昆虫拒食剂发展的因素并展望了植物源昆虫拒食剂在未来害虫综合治理中的作用。     

三种植物源杀虫活性成分对东方粘虫中肠细胞的毒力测定

采用MTT([3-(4,5-二甲基噻唑-2)-2,5-二苯基]四氮唑溴盐)比色法、中性红摄取法和台盼蓝拒染法,分别测定植物源杀虫活性成分苦皮藤素Ⅴ、白鲜碱和梣皮酮对中肠细胞的毒力。结果表明:急性分离的东方粘虫中肠细胞能在Grace’s昆虫细胞培养基中维持生长;3种供试药剂对中肠细胞均有明显的细胞毒性。MTT比色法、中性红摄取法和台盼蓝拒染法测得苦皮藤素Ⅴ对中肠细胞的LC50依次为9.0,7.79和10.94μg/mL;白鲜碱为27.85,31.77和36.42μg/mL;梣皮酮为186.66,164.00和192.34μg/mL。     

卫矛科植物苦皮藤杀虫成分化学研究新进展

卫矛科植物苦皮藤(Celastrus angulatus Max.)是我国著名的杀虫植物。近些年来,我国对这一杀虫植物从化学和生物学的角度进行了多学科的交叉研究。本文结合笔者近年来的研究,从苦皮藤的杀虫化学成分的结构、构效关系、环境中的稳定性以及结构修饰等方面综述了对苦皮藤杀虫成分化学研究的新进展。     

紫穗槐叶杀虫成分的研究

用活性跟踪法从紫穗槐叶中分离出一有效混合物,经薄层制备,分离出４种化合物纯品。经鉴定分别为：６α１２α－脱氢－灰叶酚;６α,１２α－脱氢－鱼藤素－灰叶素－６－羟基－６α,１２α－脱氢－在叶酚。对大皱鳃金龟甲的试验表明,这些化合物中的任何一种,单独给药时,均不具有明显的杀虫效果,但以一定的比例混合后用药,则表现出理想的杀虫效果。可能是协同作用的结果。     

粗茎鳞毛蕨杀虫成分

粗茎鳞毛蕨杀虫成分王润华（江西农业大学植保系３３００４５）一、名称：粗茎鳞毛蕨（ＤｒｙｏｐｔｅｒｉｓｃｒａｓｓｉｒｈｉｚｏｍａＮａｋａｉ）为鳞毛蕨科鳞毛蕨属植物,父名东北贯众、大贯众、野鸡膀子。二、形态特征：根状茎直立,连同叶柄基部密生褐棕色、卵状披...     

陇东地区杀虫植物资源的研究初报

室内测定了采自甘肃陇东地区的136种植物样品的提取物对6种农业害虫的生物活性,筛选出了对试虫有50%以上生物活性的植物35种,其中豆科5种,菊科4种,茄科3种,其余各科不足3种,通过综合分析,认为骆驼蓬,苦豆子等10余种植物具有明显地开发应用价值。     

非洲山毛豆的主要杀虫活性成分研究

对非洲山毛豆（Ｔｅｐｈｒｏｓｉａ ｖｏｇｅｌｉｉ）的主要杀虫活性成分进行了研究。用快速柱层析、薄层层析和液相色谱等对氯仿提取物进行分离提纯,通过红外光谱法、质谱及气－质联用系统分析、核磁共振波谱等分析手段进行分子结构鉴定。结果表明,其主要杀虫活性成分为鱼藤酮、鱼藤醇酮、鱼藤酚酮等鱼藤酮类化合物。     

可可粉中几种外源植物源性成分的PCR检测

大豆粕、芝麻粕、花生壳和板栗壳是常见的几种可可粉外源掺假成分,根据它们所特有的基因片段设计引物,以高等植物18S rDNA基因为内参照基因,应用改良CTAB法抽提材料DNA,对分离的DNA进行PCR扩增并分析,建立了可可粉中这几种外源植物成分的快速检测方法。用建立的PCR方法对可可基因组进行扩增,均无特异条带;扩增出的PCR产物测序结果表明与目标片段一致;将各材料DNA倍比稀释,分别对各个稀释度的DNA进行PCR扩增。结果表明,该方法对大豆粕、芝麻粕、花生壳和板栗壳DNA检测的敏感度分别可达82．5pg／μl、32．5pg／μl、124pg／μl和157pg／μl。模拟样品试验发现,该方法的最低检测限（w／w）分别达0．5％、0．5％、5％和5％,可作为可可粉及其制品中这几种外源成分鉴别检测的有效方法。     

四种协同杀虫成分分离及作用规律研究

从紫穗槐叶和茎中分离出具有协同毒杀大皱腮金龟甲作用的四种化合物:6a,12a-α-脱氢灰叶酚(A);6a,12a-脱氢鱼藤素(B);(±)灰叶素(C);(-)-6-羟基-6a,12a-脱氢灰叶酚(D)。该4种组分按1.00:2.54:4.18:2.54的天然质量比例混配成0.2%的乳液,防治大皱腮金龟甲成虫,死亡率达90.0%。紫穗槐中该四种化合物的含量和毒效以展叶初期最高;平茬后次年为最高,以后略有所降低,但大至保持在第2年的水平;沙地环境下生长的紫穗槐中有效成分含量高于黄土、石质硬梁地和下湿滩地。     

福建杀虫植物资源初步调查

福建杀虫植物有53科107种。含种类较多的科有:菊科8种;豆科、大戟科各7种;卫矛科、蓼科、唇形科、茄科各4种。通过综合分析认为,福建杀虫植物中以苦楝、苦皮藤、鱼藤、苦参、羊踯躅、羊角拗、苦蓝盘、猪毛蒿、烟草、辣蓼、土荆芥、百部等具有较高的开发价值。本文对福建杀虫植物的研究方向和合理开发利用提出若干建议。     

Insect antifeedant elemanolide lactones from Vernonia amygdalina

Chemical investigation of insect antifeedants from the bitter tasting leaves of Vernonia amygdalina by the application of semi-preparative reversed     

A toxin protein from Xenorhabdus nematophila var. pekingensis and insecticidal activity against larvae of Helicoverpa armigera

Xenorhabdus nematophila var. pekingensis, which is highly virulent for many insects, is a symbiotic bacterium of Steinernema carpocapsae isolated from Beijing soil in China. Previous studies demonstrated that the bacterium had high antifeedant activity against larvae of Helicoverpa armigera, Plutella xylostella and Spodoptera exigua. Herein, we report the purification, molecular cloning and antifeedant activity of an intracellular toxic protein from the bacterium. The purified protein displayed a single band and a relative molecular weight of over 212 kDa determined by SDS-PAGE. We designated the protein as XnAFP2. Peptide segments were obtained by MALDI-TOF and covered 40% of the amino acid sequence of a toxin protein from X. nematophilus PMFI1296. The full cDNA sequence encoding for XnAFP2 (Genbank accession number FJ222606) was amplified from X. nematophlia var. pekingensis and consists of 7575 bp. The gene showed homology with up to 99% identity to the A2 gene from X. nematophila strain BP (GenBank accession number AY282763) and 92% identity to the insecticidal toxin xptA2 gene from X. nematophila PMFI 1296 (GenBank accession number AJ308438). The protein caused a rapid cessation in feeding and reduction in larval weight of H. armigera. When fed to third instar larvae of H. armigera in an artificial diet at 6.0 µg/g (w/w) toxin protein, growth reduction reached 97.9%. The insecticidal protein greatly decreased fourth instar larval weight, lengthened larval stage, and reduced pupation and emergence rates. The antifeedant rate in choice and no-choice leaf disk tests against fifth instar larvae was 78.4 and 87.6% in 24 h, respectively.     

昆虫拒食剂蓼二醛的合成及其对害虫的拒食活性

以 β-环柠檬醛为原料 ,经 6步合成了蓼二醛 ( ( -) -polygodial)的消旋体 ,总收率为 1 9 8% ;并合成了其甲胺衍生物。经生物活性测定 ,辣蓼的粗提物和合成的蓼二醛及其甲胺的衍生物对蚜虫和菜青虫有很好的拒食活性     

Biological activity of essential oils from seven Azorean plants against Pseudaletia unipuncta (Lepidoptera: Noctuidae)

Ten essential oils from seven Azorean plant species were evaluated for their insecticidal, ovicidal, feeding‐deterrence and growth inhibition activities against Pseudaletia unipuncta. The oils of Laurus azorica (leaves), and Juniperus brevifolia (leaves) showed strong moderate insecticidal effect on fourth‐instar larvae causing 93.3% and 46.7% mortality, respectively. Juniperus brevifolia (leaves), L. azorica (leaves), Persea indica (leaves), Hedychium gardnerianum (leaves) and Pittosporum undulatum (fruits and leaves) significantly affected the hatching of P. unipuncta eggs (<8% eclosions). Five oils showed significant feeding deterrent activities (L. azorica, 92.4%, J. brevifolia, 93.6%, P. undulatum leaves, 95.5% and fruits, 83.8% and H. gardnerianum, 88.2%). All of the essential oils tested, significantly inhibited the larval growth after 5 days of feeding on the treated diet. Essential oils from L. azorica and J. brevifolia were the most potent growth inhibitors among the oils tested, producing a decrease in the initial larva weight (?14.8 and ?14.5 mg, respectively). Our results indicate that L. azorica (leaves), J. brevifolia (leaves), P. indica (leaves), H. gardnerianum (leaves), and P. undulatum (leaves and fruits) can be exploited for the development of bioactive compounds as a new source of agrochemicals. Further emphasis on isolation and identification of active constituents can be useful to develop new environment‐friendly insect control agents.     

Potent Limonoid Insect Antifeedant from Melia azedarach

Systematic fractionation of a fruit extract from Argentine Melia azedarach L., which was monitored by an insect antifeedant bioassay, led to the isolation of meliartenin, a limonoid antifeedant, which existed as a mixture of two interchangeable isomers. At 4 μg/cm² and 1 μg/cm², the isomeric mixture was as active as azadirachtin in strongly inhibiting the larval feeding of Epilachna paenulata Germ. (Coleoptera: Coccinellidae) and the polyphagous pest, Spodoptera eridania (Lepidoptera: Noctuidae), respectively.     

Differential herbivory of the specialist beetle Stolas punicea on chemical phenotypes of its host Mikania micrantha

We assessed the preference of two populations of the specialist beetle Stolas punicea, on plants from three phytochemically differentiated geographical mosaics of the American weed Mikania micrantha. Our results show a significant geographic variation in host preference in S. punicea that could affect its success as a biocontrol agent.     

A spatial model of the development of pest resistance to a transgenic insecticidal crop: European corn borer on Bt maize

A mathematical model was constructed to describe the evolution of resistance to the Bacillus thuringiensis toxin (Bt) in an insect pest (European corn borer) population on a transgenic crop (Bt corn). The model comprises a set of partial differential equations of the reaction-diffusion type; local interactions of three competing pest genotypes formed by alleles of Bt resistance and susceptibility are described as in the Kostitzin model, and the spread of insects is modeled as diffusion. The model was used to evaluate the influence of pest characteristics on the efficacy of the high-dose/refuge strategy aiming to prevent or delay the spread of Bt resistance in pest populations. It was shown, by contrast, that a model based on Fisher-Haldane-Wright equations and formally incorporating a diffusion term cannot adequately describe the evolution of Bt resistance in a spatially inhomogeneous pest population. Further development of the proposed demo-genetic model is discussed.     

番茄抽提物对小菜蛾的忌避,拒食及抑制产卵作用

在自然变温条件下,研究了番茄抽提物对小菜蛾成虫的忌避、幼虫的拒食作用及成虫繁殖力的影响。试验表明：番茄抽提物对小菜蛾成虫具有很强的忌避作用;用番茄抽提物处理过的包菜叶饲喂小菜蛾幼虫,其拒食率达５３％;番茄提物对小菜蛾成虫产卵也有明显抑制作用,产卵量下降６０％;番茄与包菜间种能明显地抑制小菜蛾种群数量的增长。其种群可下降５０％以上。