cis-Jasmone treatment induces resistance in wheat plants against the grain aphid,Sitobion avenae (Fabricius) (Homoptera: Aphididae)

cis-Jasmone is a plant volatile known to have roles as an insect semiochemical and in inducing plant defence. It was evaluated in laboratory and field trials for control of cereal aphids. In an olfactometer bioassay cis-jasmone was repellent to alatae of the grain aphid, Sitobion avenae (Fabricius) (Homoptera: Aphididae). Moreover, wheat, Triticum aestivum (L), seedlings sprayed with formulated cis-jasmone 24 h previously were less susceptible to attack by S. avenae than control plants. In field simulator studies, significantly fewer alate S. avenae settled on cis-jasmone-treated plants over a 24-h period. In addition, the intrinsic rate of population increase, r(m), of S. avenae apterae was reduced on cis-jasmone treated seedlings. In a series of small-plot experiments conducted over four years, cis-jasmone applications reduced cereal aphid populations infesting wheat in the field.     

Role of the ejaculatory bulb in biosynthesis of the male pheromone cis‐vaccenyl acetate in Drosophila melanogaster

In Drosophila melanogaster, the male ejaculatory bulb is the site of synthesis of a male‐specific pheromone, cis‐vaccenyl acetate, which functions as both an attractant and an anti‐aphrodisiac. This long monounsaturated acetate is structurally similar to a number of shorter gland‐synthesized moth pheromones. The cell monolayer that forms the Drosophila male ejaculatory bulb wall is responsible for the production and secretion of cis‐vaccenyl acetate into the seminal fluid. When dissected bulbs were incubated with sodium [14‐C]‐acetate (or deuterated acetate), a labeled acetate ester was synthesized. The labeled acetate ester co‐migrated with cis‐vaccenyl acetate in thin layer chromatography. Incubation of the abdomens of males from which the ejaculatory bulbs had been removed, or the abdomens of females, with radiolabeled acetate did not yield any acetate ester, but did yield other lipid products, including hydrocarbons. When the isolated labeled acetate ester was hydrolyzed, no radioactive vaccenol was formed. This strongly suggests that the acetyl group is incorporated via a transacetylation reaction, but that the vaccenyl moiety is not synthetized in the blub. The transacetylation enzyme activity was localized in the microsomal subfraction of the bulb homogenate, and its affinity for vaccenol was not very different from that reported for monounsaturated alcohol substrates in moths.     

脯氨酸顺式肽键的神经网络筛选

运用神经网络的方法,试图揭示脯氨酸局部序列、肽链氨基酸组分对于顺式脯氨酸形成与否的影响,构造基于局部序列和基于氨基酸组分的最优结构的神经网络,同时对顺式脯氨酸进行筛选。结果表明,脯氨酸采取顺式还是反式构象与其局部的序列以及整条肽链的氨基酸组分均有较强的关联。     

顺-1,3-二氯丙烯与反-1,3-二氯丙烯室内抑菌活性对比

采用改进的菌丝生长速率法,对比测定了顺、反式1,3-D对8种常见植物病原真菌的室内抑菌活性。室内生物测定结果表明:2种熏蒸剂对不同植物病原真菌的室内抑菌活性均存在差异,且EC50值均为trans-1,3-D>1,3-D>cis-1,3-D。在防治植物病原真菌上,cis-1,3-D优于trans-1,3-D,但有待于进行田间试验进一步验证。     

蒎烷的制备及其下游产品开发应用综述

介绍了由蒎烯催化加氢合成顺式蒎烷的工艺，以及蒎烷在合成芳樟醇、香叶醇和二氢月桂烯及其下游萜类产品的应用。     

芹菜APX基因家族鉴定及其表达分析

抗坏血酸过氧化物酶（Ascorbate peroxidase, APX）是植物活性氧代谢中重要的抗氧化酶之一,在植物抵抗氧化胁迫方面发挥重要作用。利用生物信息学方法对芹菜基因组中的APX基因家族成员进行鉴定和分析,并通过实时荧光定量PCR（quantitative real\|time PCR, qRT-PCR）验证分析AgAPXs在高温胁迫下的表达情况,为开展芹菜APX基因参与高温胁迫调控机制提供依据。结果表明：芹菜基因组中共有9个APX基因,随机分布在5个染色体上,并出现了基因片段复制现象;大多数基因被定位在细胞质中。系统发育分析表明,AgAPX基因家族可分为3个亚族,同一亚族中的成员具有相似的基因结构和基序。启动子顺式元件分析表明,大多数AgAPX基因含有多种与生长发育、植物激素和逆境胁迫相关的顺式元件。高温胁迫下,芹菜APX活性提高。qRT-PCR分析表明,AgAPXs在不同时间的高温处理下表达具有显著差异,并与转录组表达丰度相一致,AgAPX2、AgAPX3、AgAPX4、AgAPX5、AgAPX7的表达量和APX活性具有显著相关性,推测AgAPXs可能参与了芹菜抵御高温的调控过程。本研究初步鉴定并提供了芹菜APX基因家族成员信息,为今后进一步探索芹菜APX基因功能提供了重要的研究基础。     

高效液相色谱法测定混剂中氯氰菊酯和辛硫磷

采用高效液相色谱法测定了混合制剂中氯氰菊酯和辛硫磷含量。结果表明 :氯氰菊酯顺式异构体 (有效体 )和反式异构体及辛硫磷色谱峰分离完全 ,其中氯氰菊酯顺式异构体和辛硫磷回收率分别为 99.1 9%～ 1 0 0 .71 %和 98.69%～1 0 1 .4 5% ;6次重复测定的标准偏差分别为 0 .0 1 4 %和 0 .34 5% ;变异系数分别为 1 .4 %和 1 .9%。     

A new aqueous suspension concentrate formulation of cis‐permethrin and its insecticidal activity

Isomers of pyrethroids usually have different insecticidal activities. Permethrin, a non‐cyano pyrethroid, is not an exception and cis‐permethrin is much more active than the trans‐isomer against Triatoma infestans, vector of Chagas' Disease in Argentina. The large‐scale separation of cis‐ and trans‐permethrin was performed by successive recrystallizations from ethanol‐water mixtures. An aqueous suspension concentrate (flowable) formulation of pure crystalline cis‐permethrin was prepared and assayed for its insecticidal activity on wood and ceramic surfaces against nymph V of T infestans. This formulation was at least three times more effective than deltamethrin, with LC₅₀ values on ceramic of 0.11 µg cm⁻² and 0.33 µg cm⁻² respectively. On wood surfaces, the LC₅₀ value was 0.57 µg cm⁻² compared with 3.20 µg cm⁻² for deltamethrin. Against other insect species such as Periplaneta americana, Aedes aegypti and Culex quinquefasciatus, the suspension concentrate formulation of cis‐permethrin was, however, less effective than similar formulations of deltamethrin or β‐cypermethrin. © 2000 Society of Chemical Industry