基于DNA条形码技术对常见石首鱼科鱼胶的物种鉴定

摘　要：目的　运用DNA条形码技术对常见石首鱼鱼胶进行物种鉴定。方法　通过对26份鱼胶样品基因组DNA提取，PCR扩增COI基因、测序，用BOLD物种鉴定系统，与数据库中已有鱼类序列进行比对分析，鉴定出各鱼胶的物种；根据Kimura双参数模型计算样品序列遗传距离，并将所得序列构建NJ和MP系统发育树，进行聚类分析。结果　26份鱼胶样品通过鉴定引物“Fish-F”、“Fish-R”均可实现扩增，条带清晰单一，扩增和测序成功率均为100%；BOLD鉴定结果显示，26份鱼胶样品中23份能够确定物种来源（相似性达98%以上），包括石首鱼科12属15种鱼类，且多数为外来物种，另外3份鱼胶可推测其近缘物种。此外，系统发育树聚类分析结果与物种鉴定结果一致。结论　目前石首鱼类鱼胶来源物种较多，且多为外来基原鱼种。DNA条形码技术与BOLD鉴定系统相结合，可对大部分鱼胶进行准确的物种鉴定。     

燕窝显微特征及基于DNA条形码的基源鉴别

目的 建立基于Cytb等5种基因序列的DNA条形码燕窝基源鉴别方法。方法 以泰国、越南、马来西亚、印度尼西亚等地的20个正品燕窝和1个伪品燕窝为研究对象,利用显微对21个样品进行观察,提取基因组DNA,再分别利用5对引物扩增Cytb、ND2、12S、COI和Fib基因序列并双向测序。PCR产物测序分析后,输入Genbank中进行BLAST搜索,分析样品遗传距离,利用最大似然法(ML)进行系统发育分析。结果 正品燕窝和伪品燕窝在外部形态上具有较明显区别。BLAST分析表明,所获得的4个基因序列均与雨燕科的爪哇金丝燕(Aerodramus fuciphagus)具有最高的序列一致性。系统发育分析表明不同种类的燕窝处于不同分支中,所测定的4个基因序列均与爪哇金丝燕处于同一分支中,显示出最近的亲缘关系。结论 该方法可用于燕窝样品基源的快速分子鉴定。本研究为燕窝的真伪鉴别及溯源提供理论依据。     

肉鸡中魏斯菌属细菌的分离与鉴定

应用16S DNA基因测序法对肉鸡中分离出的可疑魏斯菌属细菌菌株进行鉴定。从沈阳某养鸡场抽取病死鸡在无菌条件下采集样品10份,微需氧条件下进行细菌分离纯化,比对魏斯菌属的基本形态和革兰氏染色特点,得到与魏斯菌属类似菌株14株。采用16S rDNA基因测序方法对分离出的细菌进行基因序列分析。在NCBI网站用BLAST软件在GenBank上进行同源性比较,比对结果表明编号为X1001、X1002、X1006、X1008、X1009的株菌同源性达90%。生化实验结果表明,X1006号菌株为魏斯菌属中的融合魏斯菌属菌株。     

DNA条形码技术在鲑科鱼类真伪鉴别中的应用

本研究建立了基于DNA条形码技术的鲑科鱼类特异性检测方法,并用此方法对17种市售鲑科鱼进行物种检测。先从样品中扩增得到DNA细胞色素C氧化酶I(COI)和16S核糖体RNA(16S rRNA)的基因片段,然后进行一代测序,对测序结果进行比对,验证样品的真实属性。结果表明,以COI为靶标、16S r RNA为辅助靶标,可实现对由单一物种组成的鲑鱼制品的物种鉴定。本研究结果证实DNA条形码技术可用于鲑科鱼类的物种鉴别,为鲑科鱼的市场监管提供技术支撑。     

55株芽孢杆菌16S rRNA基因序列测定与系统发育学分析

采用16S rRNA基因序列分析法对中国工业微生物菌种保藏管理中心(CCIC)保藏的55株枯草芽孢杆菌(Bacillus subtilis)进行复核鉴定。菌株经纯化培养,以改良CTAB法提取总DNA,采用细菌16S rRNA通用引物、TD-PCR方法(touchdown-PCR)进行16S rRNA基因序列扩增,PCR产物纯化后直接进行序列测定,序列经人工校对后用Clustal X进行比对分析,最后用MEGA3.1软件构建系统发育树。系统发育分析结果表明:55株枯草芽孢杆菌中有52株菌种与原鉴定结果一致,有3株菌种与原鉴定结果存在差异,其中2株鉴定结果为巨大芽孢杆菌(B.megaterium),另1株鉴定结果为地衣芽孢杆菌(B.licheniformis)。     

基于线粒体COI和COII基因的米象与玉米象的分子鉴定

为建立基于线粒体COI和COII基因序列的米象和玉米象的分子鉴定方法。采自全国6个地理种群的米象和2个地理种群的玉米象,PCR扩增试虫线粒体COI和COII基因,将获得的基因序列在GenBank中进行BLAST比对,分析基因序列相似性,分别计算基于COI和COII基因序列的遗传距离,并构建系统发育树。结果表明在本研究所分析的2种象虫样本中,米象COI基因的种内相似度在98.17% 以上,米象和玉米象COI基因的种间相似度为85.84%~86.92%;米象COII基因的种内相似度在98.37% 以上,玉米象COII基因的种内相似度在97.77% 以上,2种象虫COII基因的种间相似度为86.27%~88.31%。米象的种内遗传距离为0.002~0.020(COI)和0.011~0.015(COII),玉米象的种内遗传距离为0.001~0.023(COII)。两种象虫的种间遗传距离为0.145~0.185(COI)和0.128~0.154(COII),基于COI和COII基因的种间遗传距离显著高于种内遗传距离。系统发育树结果显示,在2个基因的系统发育树上,米象、玉米象的基因序列分别位于不同的进化支,同种象虫的基因序列位于相同的进化枝。根据本研究所用的线粒体COI和COII基因序列的差异性可以进行米象和玉米象的分子鉴定。     

腐败杨梅中两株细菌的分离与鉴定

以腐烂杨梅为研究对象,采用平板划线分离与斜面纯化技术,筛选出两株编号为YMS-7和YMN-5的细菌,分别提取两株菌的DNA后,扩增16S r DNA序列并克隆测序,获得的基因序列在Ez Bio Cloud数据库中进行同源性比对,构建16S r DNA系统发育树,结合生理生化分析,将YMS-7和YMN-5分别鉴定为类芽孢杆菌Paenibacillus agaridevorans与嗜气芽孢杆菌Bacillus aerophilus。     

非脱羧勒克菌YT—1107生理生化特性研究及16SrRNA序列分析

目的 菌株YT-1107是一株从污染食物中分离得到的非脱羧勒克菌,对其进行生理生化特性研究及16S rRNA序列分析确定其归属.方法 根据流行病学调查及临床表现,选择疑似病原菌,用ATB微生物自动鉴定系统对采集的样品进行病原菌分离与鉴定.对菌株的16S rRNA基因测序结果进行同源性分析,采用MEGA4.0软件的Neighbor-Joining方法构建系统发育树.结果 对该菌株生理生化特征的研究及16S rRNA序列分析表明,该菌株是革兰阴性菌,属于Enterobacter asburiae.结论 通过16S rRNA基因序列的同源性比对,系统进化树的构建,初步认定菌株YT-1107与Enterobacter asburiae LF7a为同一物种.     

鱼胶基原鱼种鉴定技术研究进展

鱼胶作为我国传统滋补药材,近年来其消费市场日益繁荣,鱼胶基原鱼种来源范围不断扩大,尤其是进口基原鱼种占比不断提升,部分市售鱼胶真伪难辨,鱼胶基原鱼种鉴定需求不断增加。本文概述了鱼胶基原鱼种形态学鉴定法、光学分析法和分子生物学鉴定法的发展历程、应用情况,对比了分子生物学方法中不同基因片段、不同引物等的适用性,分析了上述方法的优缺点。传统形态学鉴定具有快速、不需要鉴定人员具备较高实验操作能力的优势,但依赖专家个人经验和观察手段,且对鱼胶残片等形态特征缺失的样品鉴定能力有限;光学分析法无法精确到种属;而以DNA条形码技术为主的分子生物学方法是对某一特定区域的DNA序列排列顺序进行对比分析,鉴定结果准确,但较为耗时。由于鱼胶是动物组织干制品,在物种鉴定方面具有形态信息较少、样品处理时间较长等特点;本文有针对性地综合国内外相关研究,填补了特殊动物组织物种鉴定研究方法综述的空白,为以后进口贸易或市场监管中如何优化鉴定技术提供理论依据。     

降解乳蛋白菌株的分离筛选与鉴定

从腐败食物中分离筛选到一株可降解牛乳蛋白的菌株,并通过菌落形态观察与测定、生理生化指标测定、核酸特征分析以及16S rRNA基因序列测定等方面对该菌株进行鉴定,经BLAST比对构建了该菌株的系统发育树。经上述几方面的鉴定后,判定该菌株属于枯草芽孢杆菌。     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press