壳寡糖希夫碱配合物对感染TMV的烟叶中叶绿素和相关防御酶活性的调控效应

研究了壳寡糖希夫碱配合物药剂对烟草TMV抑制作用。结果表明:在珊西烟上施用壳寡糖希夫碱配合物药剂后叶片感染TMV的枯斑数减少;（2）施用3,5-二氯水杨醛壳寡糖希夫碱合铜于普通烟后,其受TMV侵染后烟叶中的叶绿素含量下降幅度降低,烟叶中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性均提高。      

纳米银对烟草花叶病毒(TMV)的抗性及作用机理

为了开发安全、高效、低毒的新型生物源抗烟草花叶病毒(TMV)药剂,用壳寡糖和壳寡糖席夫碱分别合成了壳寡糖纳米银(cos-Ag)和壳寡糖席夫碱纳米银(简称席夫碱纳米银,S-cos-Ag),并在珊西烟草和普通烟草品种秦烟96上进行了枯斑试验和与抗病性相关指标的测定。结果表明:1S-cos-Ag稀释30倍处理对TMV具有较好的预防和治疗效果,能够显著地减少感染TMV叶片的枯斑数目,预防效果达78.33%;2S-cos-Ag稀释30倍处理能够不同程度地提高烟草叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和苯丙氨酸解氨酶(PAL)活性,同时叶绿素和可溶性蛋白含量也有明显增加,而丙二醛(MDA)含量有所下降。说明S-cos-Ag稀释30倍处理能够较好地诱导烟草对TMV产生抗性,提高烟草免疫力,从而减轻TMV对烟草的侵害。     

烟草病程相关蛋白NtPR10基因克隆与表达分析

为鉴定烟草病程相关蛋白PR10的生物学功能,从普通烟草G28中克隆得到了Nt PR10基因,基因全长483 bp,编码160个氨基酸。基因结构分析表明,该基因编码的蛋白包含病程相关蛋白家族Bet_v_I保守域,具有与核酸酶活性相关的"P-Loop"结构。利用TMHMM、Signal P、Prosite Scan等软件分析发现,Nt PR10不含跨膜区,无信号肽,有胞内定位特征。采用实时荧光定量PCR分别分析了TMV诱导下该基因在抗、感品种枯斑三生和G28中的表达模式。结果表明,在TMV诱导下,Nt PR10基因在感病品种G28中显著上调表达;而在抗病品种枯斑三生中,TMV侵染后6 h,Nt PR10基因显著上调表达,第12小时至第8天显著下调表达,而后至第16天逐渐升高至侵染前水平。综合以上结果,Nt PR10应答了TMV侵染过程,并且在抗、感品种中整体呈现出相反的表达趋势,暗示了Nt PR10在TMV侵染过程中具有重要功能,为深入分析Nt PR10的抗病生物学功能奠定了基础。     

壳寡糖及其衍生物抗烟草花叶病毒机理的初步研究

为了开发一种低毒高效的新型抗烟草花叶病毒抑制剂,利用合成的新型寡糖希夫碱衍生物进行了抗烟草花叶病毒的药效研究。结果表明:(1)在珊西烟上,采用枯斑寄主半叶法进行抗烟草花叶病毒的药剂筛选,壳寡糖及其衍生物都能有效减少叶片感染烟草花叶病毒的枯斑数,以枯斑抑制率为66.39%的水杨醛席夫碱的预防效果最好;(2)在普通烟K326上,壳寡糖及其衍生物可降低侵染病毒烟草中的叶绿素下降幅度,还可以提高叶片中的防御酶超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和苯丙氨酸解氨酶(PAL)的活性,脯氨酸的含量也得到了积累。     

壳寡糖膦酸酯对烟草花叶病毒抗性及其机理的初步研究

为开发新的生物源抗烟草花叶病毒(TMV)剂,对合成的5种壳寡糖膦酸酯进行了抗性盆栽试验研究,通过心叶烟的鉴定发现,5种药剂对TMV都具有显著的抗病效果,其中浓度为200 μg·mL-1的COS-P-3处理效果最佳,达到了90.79％的枯斑抑制率,分别比市售药剂二(辛基胺乙基)甘氨酸盐和宁南霉素提高51.8％和24.0％,显著提高了预防效果.用筛选出的抗病毒剂处理豫烟5号,烟草叶片的叶绿素含量比接种对照明显提高,而同时超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性均有不同程度的提高.结果表明,新型壳寡糖膦酸酯COS-P-3通过诱导烟草防卫反应、提高防御酶活性,保护叶片中叶绿体合成,从而减轻病毒的侵害.     

高温介导N基因对TMV免疫丧失的代谢轮廓分析

高温(28℃)可引起含N基因的免疫寄主对TMV抗性丧失,导致TMV系统侵染。本研究以枯斑三生(Nicotianatabacum var.Samsun NN)烟草为研究材料,采用代谢组学方法,系统研究25℃和31℃条件下,TMV未侵染和TMV侵染12 h、24 h和48 h枯斑三生烟草的代谢差异。应用气相色谱与质谱联用(GC-MS)技术,结合主成分分析(PCA)和正交偏最小二乘-判别分析法(OPLS-DA)对不同温度下代谢产物的差异性进行分析。结果表明:GC-MS技术共检测到49种代谢物包括氨基酸类、糖类、有机酸类、脂肪酸类、醇类以及多胺类等。在25℃常温条件下,TMV侵染枯斑三生烟引起苹果酸、水杨酸、γ-氨基丁酸、脯氨酸和乙醇胺等代谢物含量上调,而在31℃高温处理N基因失活后,TMV侵染导致组织蔗糖和肌醇含量下调、葡萄糖和果糖含量上调以及伴随氨基酸类含量普遍上调。     

井冈霉素A处理珊西烟后对TMV枯斑数目和抗性相关酶的影响

1 μg/mL井冈霉素A处理珊西烟1 d、6 d、9 d后接种烟草花叶病毒TMV,在同株上的药剂处理叶片(叶位6)和药剂未处理叶片(叶位7、8、9)上的枯斑数目均比清水对照处理相同叶位叶片上的枯斑数目显著减少,之间的差异分别达到0.01和0.05的显著水平(t测验)。对1 μg/mL井冈霉素A处理后的珊西烟不同叶位叶片进行几丁质酶和β-1,3-葡聚糖酶的活性测定,结果表明这两种酶的活性在药剂涂抹后1 d、6 d和9 d的处理叶片与未处理叶片均比清水对照植株相同叶位叶片有明显的增加,并与井冈霉素A处理后相同叶位的TMV枯斑数目减少的结果似呈负相关关系。本研究结果初步表明井冈霉素A具有一定诱导植株产生系统抗病毒的作用,为今后扩大该抗生素的应用范围和深入探索其作用机理提供了依据和新的线索。      

枯草芽孢杆菌Tpb55抗烟草普通花叶病毒（TMV）活性研究

利用三生-NN烟测定Tpb55菌悬液对烟草普通花叶病毒(TMV)钝化、预防和治疗作用,结果表明,Tpb55菌悬液对TMV具有较好的钝化、预防和治疗效果,枯斑抑制率分别为96.15%、79.72%和65.71%.选用易感TMV烟草品种K326为试验材料,测定Tpb55对TMV控病作用,结果表明,先接种Tpb55菌液再接种TMV的烟株,发病程度明显低于接种TMV再接种Tpb55菌液的烟株;不论在烟株接种TMV前或后,用Tpb55菌液处理烟株的叶片与只接种病毒烟株相比,叶片内过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)活性均显著提高,以接毒前Tpb55菌液处理的烟株活性水平最高.从本试验结果来看,Tpb55具较强的抗TMV活性,可通过直接接触钝化作用及诱导烟草抗病性米抑制TMV侵染.     

复合亚氯酸钠灭活烟草花叶病毒的机理分析

为揭示复合亚氯酸钠（500 mg/L）杀灭烟草花叶病毒（Tobacco mosaic virus,TMV）的机理,采用荧光定量RT-PCR检测药剂处理后的病毒CP基因和Rep基因表达量,并利用间接酶联免疫吸附法测定了TMV CP的破坏程度;同时接种心叶烟,通过枯斑数统计分析了TMV的侵染活性;利用大片段步移RT-PCR检测TMV相关基因片段的损伤,并使用透射电镜观察药剂处理后病毒粒子被破坏的情况。结果显示：(1)药剂处理30 min可以完全抑制TMV CP基因的表达,处理60 min可完全抑制TMV Rep基因的表达。此时,TMV CP被完全破坏,病毒也完全丧失了对枯斑寄主心叶烟的侵染能力。(2)药剂处理30 min时,TMV的183kDa-1、183kDa-2、183kDa-3、183kDa-4、54kDa、CP&MP基因编码区等6个区域中的183kDa-2、183kDa-4和CP&MP区域首先被损伤,但接种叶叶脉和接种叶叶柄上的这3个区域可以正常扩增。处理45 min时,接种叶叶脉、接种叶叶柄和接种叶上部叶片的183kDa-1、183kDa-3和54kDa区域可以正...     

壳寡糖席夫碱纳米银溶液对烟草花叶病防治及烟叶色素的影响

为开发防治烟草花叶病的新型药剂,采用大田试验研究了壳寡糖纳米银溶液、壳寡糖席夫碱纳米银溶液及宁南霉素对烟草花叶病的田间防治效果。结果表明,壳寡糖和壳寡糖席夫碱的纳米银溶液对烟草花叶病的防治效果均优于宁南霉素,以预防和治疗效果分别达到53.32%、24.95%的壳寡糖席夫碱纳米银溶液为最好,能够减轻病株叶绿素和类胡萝卜素含量的下降幅度,增强烟株的光合作用强度,使烟株的抗病性得到提高。壳寡糖及其衍生物的纳米银溶液对烟草花叶病具有较好的防治效果,为今后开发绿色、高效的抗TMV药剂提供了新思路。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.