广西稻瘟病菌生理小种研究

 1976~1982年从广西78个县、市征集并分析出827个单孢有效菌株,在中国鉴别品种上可区分为7群55个小种。广西稻瘟病菌(pyricularia oryzae)的主要小种16个(A₁,B₁,B₉,B₁₁,B₁₃,B₁₅,C₁,C₉,C₁₁,C₁₃,C₁₅,D₁,E₁,E₃,F₁,G₁,)总频率达83.31%.     

滴灌减氮对四川盆地玉米吐丝后叶片衰老和物质积累的影响

为研究滴灌减氮对玉米吐丝后叶片衰老特性、碳氮代谢及物质积累的影响,设置正常施氮(240 kg·hm^-2,N₂₄₀)和减氮25%(180 kg·hm^-2,N₁₈₀)2个氮肥量和4个滴灌水平(0 m³·hm^-2,B₀;375 m³·hm^-2,B₁;750 m³·hm^-2,B₂;1 125 m³·hm^-2,B₃),并以不施氮且不滴灌为对照组(CK),分析比较了不同氮肥水平下滴灌对玉米吐丝后穗位叶叶绿素含量、保护酶(超氧化物歧化酶,SOD;过氧化物酶,POD;过氧化氢酶,CAT)和碳氮代谢酶(蔗糖合成酶,SS;谷氨酰胺合成酶,GS)活性及物质积累的影响。结果表明：玉米吐丝后穗位叶叶绿素含量、保护酶和碳氮代谢酶活性以及吐丝后物质积累量均随施氮量和滴灌...     

含酰肼结构阿维菌素衍生物的合成及生物活性

为减少能源消耗和环境污染，提高阿维菌素B₂的实际应用价值，将阿维菌素B_2a的23-OH氧化成羰基后分别与吡啶甲酰肼、苯磺酰肼、溴代苯甲酰肼以及肼基甲酸甲酯等反应，设计合成了6个新的酰肼类阿维菌素B_2a衍生物，采用高分辨质谱 (HRMS)、核磁共振氢谱 (1H NMR) 等对新化合物的结构进行表征，并初步测试了其对小菜蛾、蚜虫及朱砂叶螨的杀虫、杀螨活性。杀虫活性测试结果表明，间溴苯甲酰肼和异烟酸酰肼阿维菌素B_2a衍生物在质量浓度为1 μg/mL时对小菜蛾的致死率分别为75%和50%，活性明显高于苯磺酰肼以及甲氧基甲酰肼阿维菌素B_2a衍生物。     

生物农药麦丰宁B3对小麦纹枯病菌的抑制作用

 用平板双培养法在PDA、NA及K'B 3种培养基上测定B₃菌株(Bacillus sp.)对小麦纹枯病菌(Rhizoctonia cerealis)均有显著抑制作用。用喷菌法、四周划线法和四角点菌法测定的抑菌效果为73.6%~99.5%。B₃的无细胞培养滤液也能显著抑制病菌菌丝生长、菌核形成和菌核萌发。PDA中含12.5%B₃滤液时对菌丝生长的抑制效果达80%以上。滤液含量为10%时,病菌不能形成菌核。B₃无细胞培养滤液可使含病菌菌丝溶液电导率上升,还原糖、氨基酸和蛋白质等物质含量提高,加热处理后B₃滤液的作用减弱。显微观察表明,B₃处理的病菌菌丝生长畸形,分枝增多,原生质稀薄。     

珍龙13和窄叶青8号抗稻瘟病遗传分析

 用稻瘟病(Pyricularia oryzae)的菌株75-49和0206-1(分别代表ZB和ZC群小种)接种抗病品种窄叶青8号、珍龙13与感病品种朝六早、朝阳一号的杂交组合,根据F₁、F₂、F₃和B₁F₁分析结果,窄叶青8号对菌株75-49和0206-1的抗性由两对抗性基因控制,而珍龙13对菌株0206-1的抗性由单显性抗性基因控制。     

大蒜白斑病菌SS-毒素的结构鉴定

 大蒜白斑病是由Stemphylium solani 引起的一种重要的大蒜病害,病菌可产生致病毒素SS-毒素。本文采用薄层层析和高效液相色谱法对该毒素进行分离纯化,结合化学鉴定、紫外可见吸收光谱、红外光谱、质谱、元素分析以及核磁共振等方法鉴定毒素结构。通过化学反应可初步判断该毒素是一种酚类物质;毒素在215、264和458 nm处有紫外可见吸收峰;在红外光谱中可看出,毒素结构中有酚-OH(3 400 cm^-1)、-CH₃(2 946 cm^-1、1 449 cm^-1、1 395 cm^-1)、芳香环(3 092 cm^-1、1 595 cm^-1)、-CO(1 670 cm^-1)和酮-C=O(1 640 cm^-1)存在的伸缩振动;根据电喷雾质谱和元素分析结果得到SS-毒素的分子式为C₁₆H₁₆O₈;进一步结合毒素的核磁共振氢谱和碳谱将SS-毒素鉴定为7-甲氧基-2-甲基-1,2,3,4-四氢-1,2,3,4,5-五羟基蒽醌。本文是首次对S. solani致病毒素的化学结构进行鉴定。     

利用标记基因测定假单胞菌与棉苗的亲和性

 植物与微生物之间的亲和性是研究植物与微生物相互关系的重要内容。本文采用标记基因法,将外源抗性基因引入分离自棉花植株中的一个假单胞菌(Pseudomonas spp.)菌株B₄中,获得Kmr和Rifr的双重抗性株。利用抗性基因标记法,研究了B₄与棉花幼苗的亲和性,取得比较满意的结果。     

马铃薯环腐病棒杆菌单克隆抗体的制备

 用马铃薯环腐病棒杆菌的细胞壁蛋白粗提物作为抗原,应用杂交瘤技术,成功地建立了六株分泌抗马铃薯环腐病棒杆菌单克隆抗体的杂交瘤细胞株CH₁、CH₂、CH₃、CH₄、CH₅和cH₆。对这些杂交瘤细胞株所分泌的相应六种单抗McAb₁、McAb₂、McAb₃、McAb₄、McAb₅和McAb₆进行专化性测定的结果表明,McAb₄对环腐病菌具有亚种特异性,其它5种单抗除与环腐病菌呈阳性反应外,还与其它亚种的棒杆菌有不同程度的交叉反应。细胞株CH₄经体外培养传代30余代和液氮冻存5个月,其分泌抗体的滴度无明显改变。McAb₄属于IgG2a亚类,其诱发的小鼠腹水抗体效价达1:2×10⁵,CH₄的染色体数为95-102条。应用ELISA夹心法,McAb₄所能检测环腐病菌的最低浓度为10³个细菌/毫升。检测感染环染环腐病的马铃薯汁液,稀释1000倍仍呈阳性反应。     

西草净分子印迹电化学传感器的制备及应用

为了解决大型检测仪器在检测过程中的局限性，利用分子印迹技术，以西草净为模板分子、甲基丙烯酸为功能单体，采用原位引发聚合法，在玻碳电极表面进行热聚合成膜，制备出西草净分子印迹电化学传感器，并将其用于样品中西草净含量的检测。采用循环伏安法 (CV) 对印迹电极的电化学性能进行了测试，并使用超高效液相色谱-串联质谱法 (UPLC-MS/MS) 对测试结果进行验证。结果表明:在滴涂量为10 μL、60 ℃下热聚合制备出的西草净电化学传感器 (SMT-MIP/GCE) 具有良好的选择性、重复性和稳定性，其线性范围为0.5~1 μmol/L(1) 和2~30 μmol/L(2)，对应的线性关系分别为I₁ = ?3.33 c+39.03，I₂= ?0.75 c+35.52，相关系数分别为r₁ = 0.985，r₂ = 0.997，检出限 (LOD) 分别为LOD₁ = 0.13 μmol/L和LOD₂ = 0.89 μmol/L。将所建立的西草净分子印迹电化学检测方法用于烟叶添加样品提取液中西草净的检测，该印迹电极能够在8 min内完成对烟叶添加样品提取液中西草净的吸附，回收率为76%~88%，相对标准偏差为2.7%~7.6%，该方法能够初步满足烟草中西草净快速检测的需求。     

小麦抗根腐病突变体的抗病性研究

 将通过细胞工程技术获得的小麦抗根腐病突变体后代M₁、M₂和M₃进行抗病性鉴定。结果表明,其突变体后代M₁、M₂和M₃都能保持抗病性,同时,突变体的过氧化物酶的活性较标准型对照品种明显增强,在同工酶谱中出现2条新的酶带。     

有机氯类禁限用农药抗体的制备和应用研究进展

农药在防治病虫害、提高农产品产量和质量方面效果显著,但一些农药因高毒、致癌、致畸、致突变、代谢缓慢,对人类和环境产生不利影响而被我国禁止或限制使用。有机氯类禁限用农药作为其中产量最多、用量最大的一类,存在较高的健康或环境风险而备受关注。建立高效便捷的有机氯类禁限用农药残留的检测方法,对确保食品安全、助力绿色生态农业发展、打破食品进出口技术贸易壁垒具有重要意义。免疫分析法以其快速、简便、灵敏等优势被广泛应用于食品中农药残留的检测。本文综述了有机氯类禁限用农药免疫检测方法的研究进展,介绍了半抗原的合成和抗体的制备,总结了抗体在免疫检测中的应用,主要包括酶联免疫分析法、免疫层析试纸条法、化学发光法、荧光免疫分析法和免疫传感器,可对未来有机氯类禁限用农药免疫分析法的进一步研究开发提供参考。     

Molecular Diversity of Agriculturally Important Aspergillus Species

Although Aspergillus species are not usually considered as serious plant pathogens, Aspergilli are frequently encountered in plant products. The most important consequence of their presence is mycotoxin contamination. The main mycotoxins produced by Aspergilli are the aflatoxins, ochratoxin A and patulin, which are produced by a variety of Aspergillus species in different plant commodities. Phylogenetic analysis of sequences of the ribosomal RNA gene cluster is useful for clarifying taxonomic relationships among toxigenic Aspergilli causing pre- and postharvest contamination of agricultural products. Molecular data has enabled us to clarify the taxonomy of black Aspergilli, A. flavus and its relatives, and sections Circumdati and Clavati, which include ochratoxin and patulin-producing species. Phylogenetically unrelated species were found to produce the same mycotoxins, indicating that mycotoxin-producing abilities of the isolates have been lost (or gained) several times during the evolution of the genus. The data also indicate that biosynthetic gene-based probes are necessary for molecular detection of these mycotoxin-producing organisms. The organisation of the biosynthetic genes of patulin and ochratoxins is unknown, although experiments are in progress in several laboratories to clarify the genetic background of biosynthesis of these mycotoxins. Identification of biosynthetic genes responsible for mycotoxin production is essential for clarifying the evolution of mycotoxin biosynthesis in Aspergilli, and to develop specific gene probes for the detection of mycotoxin-producing Aspergilli in agricultural products.     

Recent developments in pathogen detection arrays: implications for fungal plant pathogens and use in practice

ABSTRACT The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection, and accurate quantification of plant pathogens. In addition, since plants or parts thereof can be infected by multiple pathogens, multiplex assays that can detect and quantify different pathogens simultaneously are highly desirable. Technologies that can meet these requirements, especially those involving polymerase chain reaction, are being developed and implemented in horticultural and agricultural practice. Currently, DNA array technology is the most suitable technique for multiplex detection of plant pathogens. Recently, a quantitative aspect was added to this technology, making DNA arrays highly attractive for various research and practical applications. Here, we review the most important recent advances in molecular plant pathogen diagnostics, with special attention to fungal molecular diagnostics. In addition to their applicability in practice, the different criteria that have to be fulfilled for developing robust detection procedures that can routinely be used by diagnostic laboratories are discussed.     

农药隐性成分现状、危害、检测技术及管理措施

农药隐性成分主要是指农药制剂中人为添加标称有效成分以外的农药。本文综述了农药隐性成分的现状、危害、检测技术和管理措施,为降低我国农产品的重大安全隐患和农药的质量管理和控制提供技术参考。     

作物病虫害绿色防控效果评价方法现状及发展趋势

科学合理的评价方法是快速高效检测农作物常见病虫害绿色防控技术应用效果的关键，对于提高农产品质量，保障食品安全有着重要意义。根据现有研究成果，本文从评价区域范围、评价指标和评价模型等方面阐述了我国当前农作物病虫害绿色防控技术应用效果评价方法现状，分析了现有农作物病虫害绿色防治技术应用效果评价方法中存在的不足，并就未来的发展趋势进行了展望。     

纳米标记免疫层析法在农药残留检测中的应用研究进展

农药残留超标已成为影响农产品质量安全的重要问题,迫切需要探寻开发灵敏、准确、可靠、便捷且适用性强的农药残留快速检测方法。免疫层析法是将抗原抗体特异性免疫反应和色谱层析分离技术相结合的一种快速检测方法,其中,基于胶体金标记的免疫层析技术以其便捷、成本低、可视化等优点而受到普遍欢迎。近年来随着量子点、时间分辨荧光微球、上转换发光纳米粒子等新型纳米标记材料的出现,免疫层析技术得到了广泛发展。文章从标记类型（非共价作用标记及共价作用标记）及标记材料（胶体金、纳米碳、量子点、上转换发光纳米粒子、磁性纳米颗粒、时间分辨荧光微球及荧光乳胶颗粒）等方面,综述了不同纳米材料标记的免疫层析技术及其在农药残留检测领域的研究及应用进展,可为深入开展农药残留免疫层析技术研究提供参考。     

生物检材中有机磷农药代谢物检测技术研究进展

有机磷农药代谢物检测分析在有机磷农药中毒、投毒案件定性、临床诊断和生物监测等方面发挥着重要作用。发展精确检测痕量甚至超痕量有机磷农药代谢物的技术,建立检测生物样本复杂基质中有机磷农药代谢物的方法,成为法庭科学领域亟待解决的问题之一。目前国内外常见的实验室检测方法有气相色谱、气相色谱-质谱联用、液相色谱-串联质谱等,本文重点综述了这些检测方法在有机磷农药代谢物检测方面的研究进展,以及血液、尿液等生物检材所需的液-液萃取、固相萃取、QuEChERS等前处理技术和毛发生物检材所需的固-液萃取等前处理技术。此外,本文还介绍了荧光探针法、免疫分析法、生物传感器法等快速检测技术的原理及应用进展,并对现有检测技术存在的问题进行了总结。     

Detection and Differentiation of Trichothecene and Enniatin-Producing Fusarium Species on Small-Grain Cereals

A large number of Fusarium species are associated with Fusarium head blight of wheat and other small-grain cereals as well as seedling blight and brown foot rot. Different Fusarium species tend to predominate under different environmental conditions and in different regions. In addition to causing disease, these fungi are of particular significance because they produce a number of mycotoxins including the trichothecenes and enniatins that contaminate infected grain. The nature and amount of the mycotoxins that accumulate will alter according to the species or even the particular isolates involved in the infection. It is highly desirable to be able to analyse such complex infections to determine which species and, preferably, which chemotypes are present, in order to understand the factors that affect the pathogenicity of each species and to evaluate the potential risk for contamination of grain with mycotoxins. This paper reports the development of molecular methods, based upon the polymerase chain reaction (PCR), for the detection of mycotoxigenic fungi. Several of the Fusarium species involved are closely related, making the development of specific assays problematic. We describe the development of primers specific to individual species and discuss how this work provides insight into fungal populations and relates to taxonomic studies. In some instances, it is desirable to detect the presence of potential mycotoxin producers rather than individual fungal species. Generic assays have been produced for several genes involved in trichothecene biosynthesis and for enniatin synthetase in order to permit the detection of species able to produce the associated mycotoxins. Additional work is under way to refine assays to enable detection related to the class of trichothecene and chemotype of isolate because of the potential risk posed to human and animal consumers by different trichothecenes.     

Mycotoxins in Alternaria alternata - infected olive fruits and their possible transfer into oil1

Alternaria species, mostly A. alternata, have occasionally been found in some years on olive samples collected in Puglia (southern Italy). A survey was consequently made on the occurrence of the major Alternaria mycotoxins, i.e. alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT), altertoxin-I (ATX-I), and tenuazonic acid (TA) in olives and products of their processing (oil and husks). The toxigenicity of Alternaria strains isolated from olives, and the possible transfer of mycotoxins into the oil, were also investigated. Four out of 13 olive samples were contaminated by 2–4 Alternaria mycotoxins. The highest contamination was found in a badly damaged sample containing 2.9, 2.3, 1.4 and 0.3 mg kg^?1 of AME, AOH, ALT and ATX-I, respectively. No mycotoxins were detected in olive oil destined for human consumption (6 samples) or olive husks (3 samples) collected from oil-mills after the first pressing of olives. An oil sample produced in our laboratory by processing the most contaminated olive sample, contained AOH (0.79 mg kg^?1) and AME (0.29 mg kg^?1). The estimated amount of mycotoxin transferred into the oil was 4%, for AME, 1.8% for AOH, and zero for ALT and TA (considering oil yield as 15%). The A. alternata strains isolated from olive produced much more mycotoxins when cultured on rice (up to 3 orders of magnitude for TA) than on olive.     

United States Department of Agriculture-Agricultural Research Service research on pre-harvest prevention of mycotoxins and mycotoxigenic fungi in US crops

Mycotoxins (ie toxins produced by molds) are fungal metabolites that can contaminate foods and feeds and cause toxic effects in higher organisms that consume the contaminated commodities. Therefore, mycotoxin contamination of foods and feeds results is a serious food safety issue and affects the competitiveness of US agriculture in both domestic and export markets. This article highlights research accomplished by Agricultural Research Service (ARS) laboratories on control of pre-harvest toxin contamination by using biocontrol, host-plant resistance enhancement and integrated management systems. Emphasis is placed on the most economically relevant mycotoxins, namely aflatoxins produced by Aspergillus flavus, Link, trichothecenes produced by various Fusarium spp and fumonisins produced by F verticillioides. Significant inroads have been made in establishing various control strategies such as development of atoxigenic biocontrol fungi that can outcompete their closely related, toxigenic cousins in field environments, thus reducing levels of mycotoxins in the crops. Potential biochemical and genetic resistance markers have been identified in crops, particularly in corn, which are being utilized as selectable markers in breeding for resistance to aflatoxin contamination. Prototypes of genetically engineered crops have been developed which: (1) contain genes for resistance to the phytotoxic effects of certain trichothecenes, thereby helping reduce fungal virulence, or (2) contain genes encoding fungal growth inhibitors for reducing fungal infection. Gene clusters housing the genes governing formation of trichothecenes, fumonisins and aflatoxins have been elucidated and are being targeted in strategies to interrupt the biosynthesis of these mycotoxins. Ultimately, a combination of strategies using biocompetitive fungi and enhancement of host-plant resistance may be needed to adequately prevent mycotoxin contamination in the field. To achieve this, plants may be developed that resist fungal infection and/or reduce the toxic effects of the mycotoxins themselves, or interrupt mycotoxin biosynthesis. This research effort could potentially save affected agricultural industries hundreds of millions of dollars during years of serious mycotoxin outbreaks.