共查询到17条相似文献，搜索用时 140 毫秒
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除草剂安全剂作用机理研究进展 总被引：4，自引：0，他引：4
除草剂安全剂是一类可在不影响除草剂对靶标杂草活性的前提下,有选择性地保护作物免受除草剂伤害的特殊用途化合物,有关安全剂作用机理的研究对新安全剂的开发具有重要意义。目前关于除草剂安全剂的作用机理主要有4种观点:1）影响除草剂在作物体内的吸收和转运;2）与除草剂竞争靶标位点;3）影响靶标酶的活性;4）增强作物对除草剂的代谢。文章对近年来安全剂作用机理及安全剂对杂草的影响等研究进展进行了综述,并分析了当前存在的问题及未来的研究方向,旨在为深入研究安全剂的作用机理及新安全剂开发提供参考。 相似文献
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原卟啉原ＩＸ氧化酶是血红素和叶绿素生物合成中的关键酶，是过氧化型除草剂的分子靶标，当植物用二苯醚类，酞酰亚胺以及一些吡啶衍生物等除草剂处理后，造成原卟啉原ＩＸ积累，膜脂质破坏，最终细胞死亡，同ＡＬＳ抑制剂一样，作用靶标为原卟啉原化酶的除草剂，具有用药量低，活性高，杀草谱广，对哺乳动物低毒，对环境影响较小等良好特性，本文介绍了作用靶标为原卟啉原氧化酶的代表性品种。 相似文献
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除草剂安全剂的生理生化作用机制研究进展 总被引：9，自引：0，他引：9
除草剂安全剂是一种化学物质,它可以通过生理或生化的途径降低除草剂对作物的毒性,而不降低除草剂的功效.安全剂影响作物的吸收和传导,诱导作物体内P450酶活性、谷胱甘肽调控及其靶标酶ALS的活性.其生理和生化机制研究,不仅有助于安全剂的开发和优化,同时也是了解和运用除草剂活性和抗性机制的途径.该文综述了近年来国内外安全剂生理生化作用机制的研究进展,并探讨其研究方向. 相似文献
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寻找新的除草剂靶标酶一直是生物学家和农药化学家不断探索的课题,每当发现一个新的作用靶标,就会有一批新的除草剂问世,并带来一场化学除草的革命。如乙酰乳酸合成酶（ＡＬＳ）的发现,将除草剂推入到一个超高效的时代,并开发出磺酰脲类、咪唑啉酮类、磺酰胺类、三唑... 相似文献
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乙酰乳酸合成酶及其抑制剂研究新进展 总被引：1，自引：0，他引：1
乙酰乳酸合成酶(AHAS)是支链氨基酸生物合成途径中的一个关键酶,是绿色除草剂的重要作用靶标。由于此生物合成过程只存在于植物和微生物体内,因此该类抑制剂对哺乳动物具有生物安全性。近年来,随着AHAS三维结构的阐明,人们不仅深入了解了已有抑制剂的作用机制,并且依此设计开发了一些新型的抑制剂,拓展了其在抑菌活性方面的生物学功能。文章对近年来AHAS及其抑制剂的最新研究进展进行了综述,重点就AHAS的酶学特征、结构特征及结合方式,以AHAS为靶标的新颖除草活性化合物的设计开发以及AHAS抑制剂的抗菌生物活性研究进展等问题详细进行了总结,以期为设计开发靶向AHAS的新型除草剂或抗菌药物提供参考。 相似文献
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除草剂靶标酮醇酸还原异构酶(KARI)研究进展 总被引：2，自引：2，他引：2
酮醇酸还原异构酶(KARI)是植物和微生物体内支链氨基酸生物合成的关键酶之一,可以作为设计除草剂的靶标,通过抑制酶的活性中断支链氨基酸的合成使植物死亡,达到除草目的。文章综述了KARI的催化性质、晶体结构以及作为除草剂靶标的研究现状。 相似文献
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The proposed target enzyme for benzoylcyclohexanedione herbicides, 4-hydroxyphenylpyruvate dioxygenase (HPPD) was purified from etiolated maize seedlings with a purification factor of 105. Enzyme activity was measured by detection of carbon dioxide formed from radiolabelled substrate. The enzyme has a pH optimum of 7·3 and an apparent molecular mass of 43 kDa, similar to that of the mammalian liver enzyme. Activity needs the presence of a reducing system glutathione/dichlorophenol indophenol or ascorbate and catalase. Surprisingly, a commercial catalase preparation of low specific activity—generally used for the enzyme assay—showed HPPD activity which was separable from the catalase activity on a gel filtration column. According to kinetic studies with purified maize HPPD, experimental herbicides from the family mentioned were strong competitive inhibitors of the plant enzyme in nanomolar range withKi values of 5 and 15 nM for 2-(2-nitro-4-chlorobenzoyl)-5-(2-methoxyethyl) cyclohexane- 1,3-dione and 2-(2-chloro-4-methanesulfonylbenzoyl)- cyclohexane-1,3-dione (SC-0051; sulcotrione), respectively. 相似文献
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在干旱胁迫下,用不同浓度的壳聚糖溶液处理花生幼苗,连续处理5d后,测定过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)等花生保护酶活性的变化,结果显示:用壳聚糖处理的花生幼苗保护酶活性明显比不用壳聚糖处理的花生幼苗的酶活性高。随着干旱程度的加强,保护酶活性总体呈现下降的趋势。浓度为0.15g/L的壳聚糖溶液处理花生幼苗CAT、POD活性最高,而浓度0.20g/L壳聚糖溶液处理花生幼苗SOD活性最高。由此说明外源壳聚糖使得花生幼苗的保护酶活性得到了提高,使得花生具有了更强的抗逆性。 相似文献
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BACKGROUND: Tolerance to the oomycete‐specific carboxylic acid amide (CAA) fungicides is a poorly understood mechanism in Pythium species. The root‐rot and damping‐off causative agent Pythium aphanidermatum and the CAA fungicide mandipropamid (MPD) were used to investigate the molecular basis of CAA tolerance. RESULTS: Five genes putatively involved in carbohydrate synthesis were identified and characterised: one chitin synthase gene, PaChs, and four cellulose synthase genes PaCesA1 to PaCesA4, of which PaCesA3 encodes the MPD target enzyme. These genes were differentially expressed throughout the life cycle of P. aphanidermatum. Mycelium treated with MPD concentrations slightly affecting mycelial growth did not cause a change in PaCesA3 expression nor a strong upregulation of PaCesA homologues. The high tolerance level of P. aphanidermatum and the lack of PaCesA upregulation imply that MPD tolerance is the result of a specific amino acid configuration in the cellulose synthase 3 (CesA3) target enzyme. Indeed, P. aphanidermatum displays the amino acid L1109 which is also associated with MPD resistance in artificial mutants of Phytophthora species. CONCLUSION: It is concluded that MPD tolerance in P. aphanidermatum is not caused by compensatory mechanisms but most likely by an inherent target‐site configuration in PaCesA3 that hinders MPD binding to the enzyme pocket. Copyright © 2012 Society of Chemical Industry 相似文献
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Arginine kinase (ATP:l-arginine ω-N-phosphotransferase, EC2.7.3.3.; AK) is an enzyme with crucial functions in the energy metabolism of insects and other invertebrates as well as some protozoa and has been proposed as a parasiticidal and pesticidal drug target. In this study we report the identification, cDNA cloning, genomic gene structure and functional expression of an AK gene from the parasitic sheep blowfly Lucilia (L.) cuprina. The blowfly AK-encoding gene is devoid of introns and present in a single copy in the L. cuprina genome. AK is present in L. cuprina flies as a highly expressed soluble enzyme and is more abundant in the thorax, where it represents up to 2% of the total soluble protein, compared to head or abdomen. Guanidino substrate specificity studies show that L. cuprina AK is stereospecific for the l-form over the d-form of its specific substrate arginine. Furthermore, the presence of a free or esterified carboxylic group as well as an unsubstituted α-amine group are essential for acceptance of the l-arginine substrate while modifications in the aliphatic side chain are better tolerated. The apparent Michaelis-Menten constants KM and the molecular size of the recombinant enzyme are virtually identical to that of the native enzyme suggesting that the gene cloned in this study encodes the highly expressed AK enzyme of the sheep blowfly. 相似文献
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Fabbri BJ Duff SM Remsen EE Chen YC Anderson JC CaJacob CA 《Pest management science》2005,61(7):682-690
The carboxyterminal processing protease of D1 protein (CtpA) is predicted to be an excellent target for a general broad-spectrum herbicide. The gene for spinach CtpA has been expressed in Escherichia coli. The expressed protein that was found mainly in inclusion bodies has been purified and refolded on a nickel-chelate column. Active recombinant CtpA was recovered. Two assays for CtpA activity were developed, a medium-throughput HPLC assay using a fluorescent substrate and a high-throughput assay based on fluorescence polarization capable of application in a high-throughput 96-well plate format. This high-throughput assay was developed to screen chemistry for CtpA inhibitors. Native spinach CtpA was partially purified and the native and recombinant enzymes were compared kinetically for their K(m) and V(max) values using different peptide substrates. Native CtpA partially purified from spinach was shown to have similar kinetic properties to recombinant CtpA. Antibodies developed against the recombinant protein were used to estimate the in planta abundance of the native enzyme in spinach. Since only a small proportion of the recombinant protein is refolded during isolation and it appears that only a small proportion of this enzyme is active, size-exclusion chromatography and light scattering experiments were performed on rCtpA in order to gain insight into its structure and the reasons why most of the protein is not active. The use of rCtpA to screen for herbicidal compounds and the more general question of how good a herbicide target the enzyme is are discussed. 相似文献
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This review summarises recent investigations into the molecular mechanisms responsible for the decline in sensitivity to azole (imidazole and triazole) fungicides in European populations of the Septoria leaf blotch pathogen, Mycosphaerella graminicola. The complex recent evolution of the azole target sterol 14α‐demethylase (MgCYP51) enzyme in response to selection by the sequential introduction of progressively more effective azoles is described, and the contribution of individual MgCYP51 amino acid alterations and their combinations to azole resistance phenotypes and intrinsic enzyme activity is discussed. In addition, the recent identification of mechanisms independent of changes in MgCYP51 structure correlated with novel azole cross‐resistant phenotypes suggests that the further evolution of M. graminicola under continued selection by azole fungicides could involve multiple mechanisms. The prospects for azole fungicides in controlling European M. graminicola populations in the future are discussed in the context of these new findings. Copyright © 2012 Society of Chemical Industry 相似文献
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采用套筛富集人工接种于土壤中的大豆疫霉卵孢子。结果表明,当接种量为104、103、102、101、100时,富集百分率分别为45.9%、39.6%、11.8%、1.7%、5.6%。采用玻片压碎法提取微量卵孢子中DNA后,采用PCR技术快速进行检测的结果表明,提取10,5,1个卵孢子中DNA进行PCR扩增成功率分别为83.3%、33.3%、0。提取10个卵孢子中DNA进行PCR扩增时,2个处理出现非特异性PCR产物。内切酶MspI能将特异性PCR产物消化为204bp和124bp两个片段;内切酶RsaI能将特异性PCR产物消化为242bp和86bp两个片段。 相似文献