杀菌剂生物测定技术的发展

概述了杀菌剂生物测定的发展历史,探讨了离体、活体和组织筛选的常规生物测定技术,以及高通量筛选方法,同时从多个角度阐述了杀菌剂生物测定技术的发展趋势。     

杀菌剂生物测定技术

杀菌剂生物测定指的是利用病原菌或感菌生物体对杀菌剂的反应来确定杀菌剂效力的一种农药生物测定。该项测定始于１８０７年,当时Ｐｒｅｖｏｓｔ用孢子萌发法对小麦黑穗病菌孢子进行研究。以后经过多次改进,美国植物病理学会于１９４３年将孢子萌发法推荐为标准测定方法...     

杀菌剂毒力及其生物测定

杀菌剂毒力是化合物具有开发和应用价值的固有生物学性状,不仅是农药登记部门予以注册登记的前置条件,而且也是反映杀菌剂生物活性及其安全性和有效性的关键技术参数。本文明确了杀菌剂毒力术语的定义,强调了杀菌剂可能的未知作用方式及通过与病原菌、寄主和环境因子相互作用的病害及流行防控效力在杀菌剂毒力评价中的重要性。深入分析了化合物与受体蛋白相互作用的结构特异性和精确性及干扰靶标蛋白功能的毒理学机制,揭示了杀菌剂毒力的选择性原理。综述了杀菌剂毒力生物测定及其结果分析方法,分析了可能影响毒力测定结果评价的常见因素。本文所述内容可为从事农药创制、加工、应用、毒理与抗性及分子互作科研工作者提供参考。     

基于农药穿透生物学的杀菌剂生物测定

杀菌剂的生物测定是进行新品种筛选及抗性监测的重要手段。杀菌剂的生物活性是药剂、病原、环境间相互作用的结果。药剂在植物体的吸附、穿透和代谢是影响其生物活性的重要因子。基于农药穿透生物学的基本原理,通过对杀菌剂的作用特点、病原菌入侵行为、杀菌剂作用方式、传导方式以及杀菌剂的应用环境的分析,指出杀菌剂的生测离不开靶标寄主的参与,生物测定方法应尽可能真实地反映药剂在应用实践中的行为学特点,才有可能准确地表征化合物的生物活性或抗药性变化程度。     

4种常用有机溶剂对杀菌剂生物测定的影响

采用生长速率法测定了4种常用有机溶剂(丙酮、乙醇、二甲基亚砜、N,N-二甲基甲酰胺)对6种病原真菌菌丝生长的影响程度,同时研究了烯酰吗啉和霜脲氰在3种不同溶剂中对番茄晚疫病菌(Phytophthorainfestans)的毒力。结果表明,当溶剂浓度为0.5～1μL/mL时,丙酮对所测病原菌的菌丝生长没有影响,乙醇、二甲基亚砜及二甲基甲酰胺对大多数病原菌的生长都没影响。烯酰吗啉在3种溶剂中的毒力,其丙酮中对致病疫霉的毒力最小,而霜脲氰在3种溶剂中的毒力相当。     

杀菌剂生物测定动态评价时间-剂量-抑菌率模型

根据互补重对数数学模型的原理,建立了动态评价杀菌剂抑菌效应的时间-剂量-抑菌率模型,给出了模型参数估计和统计检验方法,并重点讨论了剂量的时间效应和不同时间段的剂量效应。最后提供了该模型的计算机算法实现和应用例子。     

除草剂生物测定方法

除草剂生物测定在除草剂的研制、应用过程中占有重要地位。除草剂的筛选、除草活性、杀草谱确定、除草剂对作物的安全性及其是否存在残留药害等诊断，都离不开生物测定。也正因为如此，生物测定得到了广泛的应用，特别是在新化合物的高通量筛选中是不可缺少的手段。除草剂的生物测定广义的包括了实验室、温室和大田三个试验层次，而狭义的仅主要指前两者，后者则为田间药效评价。为了能使生物测定方法在除草剂研究和应用过程中得到更好的利用和发挥更大的作用，本文仅就狭义的生物测定进行讨论。     

10种杀菌剂对板栗疫病菌的抑制作用

为了筛选防治板栗疫病的高效、低毒、低残留杀菌剂,采用菌丝生长速率法测定了10种杀菌剂对栗疫病菌菌丝生长的抑制效果。结果表明,苯醚甲环唑+丙环唑、苯醚甲环唑、咯菌腈、咪鲜胺和多氧霉素对栗疫病菌具有很强的抑制作用,EC₅₀在0.014 8～8.752μg/mL之间,为生产上有效地防治板栗疫病提供了依据。     

杀虫剂生物测定方法浅谈

建立一种新的实验方法用于发现新农药,而新农药存在于农药生测的每个异常现象之中。这在过去农药发现中已得到了证实。许多杀菌剂是通过活体实验法建立之后发现的;寄希望于除草的腐霉利发展成杀菌剂,除虫脲也是做为除草剂开发时偶然发现它抑制昆虫蜕皮,从而发展成杀虫...     

农药生物测定数据处理系统ABDS的设计

农药生物测定数据处理系统ＡＢＤＳ的设计茹李军（中国农业科学院植物保护研究所１０００９４）数据的处理分析是农药生物测定的一个重要的步骤，手工计算方法因为费时、易错和必须查表等缺点，已很少使用。现在常用的ＣＡＳＩＯ计算器和ＰＣ－１５００袖珍计算机虽然有体...     

橡胶树白粉病杀菌剂生物测定接种方法研究

对橡胶树白粉病菌的3种接种方法－抖粉法、涂抹法和喷雾法进行比较,并测定了喷雾法不同接种量对橡胶白粉病病情指数和10 mg/L三唑酮相对防效的影响。结果表明,喷雾法较抖粉法和涂抹法重复性更好,结果更稳定;在进行杀菌剂对橡胶树白粉病菌的室内盆栽毒力测定时,应采用喷雾法,接种量以5×10 4~10×104个/mL为宜。     

Synthesis and fungicidal activity of ethaboxam against Oomycetes

This study describes the chemical synthesis and intrinsic fungicidal activity of ethaboxam [(RS)-N-(alpha-cyano-2-thenyl)-4-ethyl-2-(ethylamino)-1,3-thiazole-5-carboxamide], a new Oomycetes fungicide. In in vitro tests, ethaboxam showed inhibitory activity against isolates of Phytophthora and some Pythium spp, with MIC values ranging from 0.1 to 0.5 mg litre(-1) for nine isolates of Phytophthora infestans (Montagne) de Bary and from 1.0 to 5.0 mg litre(-1) for eight isolates of Phytophthora capsici Leonian. In tests to determine time and concentration for complete inactivation of each pathogen (five isolates of P infestans and five isolates of P capsici), ethaboxam inactivated all isolates of P infestans within 48h at 10 mg litre(-1) and those of P capsici within 96 h at 10 mg litre(-1). Ethaboxam effectively suppressed development of tomato late blight caused by P infestans and pepper Phytophthora blight caused by P capsici in the studies conducted to determine its preventive, curative, persistent and systemic activity. These results show that ethaboxam has desirable fungicidal characteristics as an Oomycetes fungicide.     

Synthesis and fungicidal activity of a series of novel aryloxylepidines

A series of novel (hetero) aryloxylepidine derivatives was devised as hybrid structures of the phenoxyquinoline and phenethoxyquin(az)oline fungicides. Synthesis of these targets required the development of several new routes to derivatised 4-hydroxymethylquinolines, and subsequent coupling with phenols or haloarenes. The aryloxylepidines generally showed moderate broad-spectrum fungicidal activity across several diseases of cereals. Substitution of the quinoline ring with chlorine at the 7- and/or 5-positions gave molecules with high levels of protectant activity against Erysiphe graminis f sp tritici (powdery mildew of wheat), but this did not improve the level of fungicidal activity against other diseases. In vitro activity against mitochondrial electron transport complex I (MET) derived from Ustilago maydis showed that 8-fluorolepidine analogues were moderately active at this target site, while the more fungicidally active 7- and 5,7-substituted compounds were inactive. This indicates that MET is not the primary target of these highly active powdery mildewicides.     

Estimating benzimidazole residues in thatch and turfgrass by bioassay

Bioassays using pellets of agar, thatch-agar and turfgrass-agar were developed using benzimidazole-sensitive Penicillium expansum Link, to detect the fungicide methyl benzimidazol-2-ylcarbamate (MBC) which is the major fungitoxic degradation product of benomyl [methyl 1-(butylcarbamoyl)benzimidazol-2-ylcarbamate] in thatch and turfgrass clippings. These bioassays were used to estimate the amount of fungicide that was biologically available and hence, by subtraction from that applied, the amount that remained bound and biologically unavailable. The limit of quantitation was 0·5 mg kg⁻¹. From 19·9% to 93·2% of the applied fungicide was bound by thatch and 46·2% to 56·9% was bound to turfgrass clippings depending on the concentrations used. In-vitro degradation studies showed that MBC had a half life of approximately 2·5 weeks at 23°C in non-sterilized thatch.     

Metabolism of fungicidal cyanooximes, cymoxanil and analogues in various strains of Botrytis cinerea

BACKGROUND: The metabolism of cymoxanil [1‐(2‐cyano‐2‐methoxyiminoacetyl)‐3‐ethylurea] and fungicidal cyanooxime analogues was monitored on three phenotypes of Botrytis cinerea Pers. ex Fr. differing in their sensitivity towards cymoxanil. For this purpose, labelled [2‐¹⁴C]cymoxanil was added either to the culture medium of these strains or to its cell‐free extract. RESULTS: In the culture medium of the most sensitive strain, four main metabolites were detected. Three were isolated and identified. Cymoxanil was quickly metabolised by at least three concurrent enzymatic pathways: (i) cyclisation leading, after hydrolysis, to ethylparabanic acid, (ii) reduction giving demethoxylated cymoxanil, (iii) hydrolysis followed by reduction and then acetylation leading to N‐acetylcyanoglycine. In the cell‐free extract of the same strain, only the first and the second of these enzymatic reactions occurred. By comparing the metabolic profile of the most sensitive strain with that of the less sensitive ones, it was shown that the decrease in sensitivity to cymoxanil correlates with a reduced acetylcyanoglycine formation. Among all metabolites, only N‐acetylcyanoglycine is active against the most sensitive strain. Moreover, in a culture of this strain, two other fungicidal cyanooximes were also metabolised into this metabolite. CONCLUSION: The formation of N‐acetylcyanoglycine may play an important role in the fungitoxicity of cymoxanil and cyanooxime derivatives. Copyright © 2008 Society of Chemical Industry     

N-(3,5-二甲氧基-4-烷氧基苯乙基)扁桃酰胺类杀菌剂的设计合成及杀菌活性

以第一个扁桃酰胺类杀菌剂双炔酰菌胺为模板,在炔丙氧基的邻位引入第二个甲氧基,设计合成了15个未见文献报道的 N-(3,5-二甲氧基-4-烷氧基苯乙基)扁桃酰胺类化合物(8a～8o),其结构通过核磁共振氢谱和高分辨质谱确认。初步的离体和活体杀菌试验结果表明,化合物 8e、8h和8o 对辣椒疫霉 Phytophthora capsici 具有较好的杀菌活性,其中 8h和8o 在62.5 mg/L下对辣椒疫霉活体抑制率达100%。     

Synthesis and fungicidal activity against Pyricularia oryzae of 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone derivatives

A series of novel 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone (benzo[b]thiazin-4-one) derivatives was obtained by cyclisation via thiosemicarbazides which were prepared by reaction of hydrazines and the corresponding isothiocyanates. Their fungicidal activity was evaluated against the rice blast fungus Pyricularia oryzae. Of this series, 2,5,8-trimethyl-6-(1-propyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl) chromone, 6-(1-butyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone, 6-(1-hexyl-3-methyl-5-thioxo-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone and 6-(1-allyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone were highly active (pEC₅₀>6·0). Structure–activity relationship studies using the capacity factor k′ as a hydrophobicity index suggested that the log k′ optimum for 2,5,8-trimethyl-chromone and -1-thiochromone derivatives was around 1·0, equivalent to a log P_ow value of c. 4·4. © 1998 SCI     

Synthesis and structure-activity study of fungicidal anilinopyrimidines leading to mepanipyrim (KIF-3535) as an anti-Botrytis agent

A series of 2-anilinopyrimidines was prepared and their fungicidal activities against Botrytis cinerea Pers were examined. The activity fell sharply with any substitution on the anilinobenzene ring. Substituents at the 5-position of the pyrimidine ring greatly reduced the activity. Substituents such as chloro, methoxy, methylamino, methyl or 1-propynyl were well tolerated at the 4- and 6-positions of the pyrimidine ring. Among these substituents, the combination of methyl and 1-propynyl groups was the most favourable. 2-Anilino-4-methyl-6-(1-propynyl)pyrimidine (KIF-3535), which showed excellent activity and no significant phytotoxicity, was finally selected for development and has been given the common name mepanipyrim.