纳米生物传感器在氯霉素检测中的应用

利用pH 敏感的荧光指示剂F1300 可以量化ATP 合酶活性的特点,构建生物传感器,开发灵敏、特异、快速的氯霉素残留检测方法。将pH 变化敏感荧光物质F1300 标记到色素体(chromatophore)的内表面,然后,将β亚基抗体- 生物素- 链亲和素- 生物素- 氯霉素抗体系统连接到色素体上F0F1-ATPase 的β亚基上,该检测体系能与氯霉素相连接。采用微弱发光检测仪检测荧光值,根据荧光值确定氯霉素浓度。样品中氯霉素浓度越高表现出的总荧光值越低,反之亦然。该方法的检测限为1 × 10 － 11mg/mL,且检测操作仅需35min,能快速、高灵敏地检测氯霉素,具有很好的应用前景。     

利用分子马达技术检测霍乱弧菌

利用载色体chromatophore上的F0F1-ATPase分子马达生物传感器,建立了应用在食品检测中的快速检测方法。首先在ATP合酶的ε亚基上连接ε亚基抗体-生物素-链霉亲和素-生物素-ompW探针,将待测霍乱弧菌和阴性对照分别与此生物传感器结合,比较其催化ATP合成30 min后的ATP产生量,进而对霍乱弧菌的DNA进行检测。ATP合成的量可以通过环境H+的量进行测定,H+的量通过F-DHPE所体现的荧光强度大小标定。结果表明,Chro ompW的浓度在0.078 mg/mL,单核增生李斯特菌DNA浓度在40 ng/mL为最适检测条件。通过与实际检测样品的传统检测方法及PCR检测方法对照,具有良好的检测符合性。     

利用F_0F_1-ATPase分子马达技术检测志贺氏菌

利用载色体chromatophore上的F0F1-ATPase分子马达生物传感器,建立应用在食品检测中快速检测方法。首先从嗜热菌中提取载色体,合成生物素化宋内氏志贺氏菌IpaH探针,在载色体ATP合酶的ε亚基上连接ε亚基抗体-生物素-链霉亲和素-生物素-IpaH探针,将待测宋内氏志贺氏菌标准菌株和阴性对照分别与此生物传感器结合,比较其催化ATP合成10 min后的ATP产生量,进而对宋内氏志贺氏菌DNA进行检测。ATP合成的量可以通过luciferase-luciferin检测试剂所体现的荧光强度大小标定。结果表明,chroIpaH(连接在载色体chro上的IpaH探针)的浓度在0.031 mg/mL,宋内氏志贺氏菌DNA浓度在50 ng/mL为最适检测条件。通过与实际检测样品的传统检测方法及PCR检测方法对照,具有良好的检测符合性。     

F0F1-ATPase生物传感器检测肠出血性大肠埃希菌O157:H7

目的 研究F0F1-ATPase纳米生物传感器在肠出血性大肠埃希菌O157:H7检测中的应用, 开发高灵敏、特异性强的快速检测技术。方法 利用免疫技术构建信号识别元件, 根据F0F1-ATPase酶学机制建信号转化系统, 建立免疫生物传感器, 最后通过荧光扫描仪进行信号检测。本研究以食品中常见的大肠埃希菌(Escherichia coli)和沙门菌(Salmonella typhi)为干扰菌株进行了该方法的特异性研究。结果 检测时间为4.5 h, 102～104 cfu呈现良好的梯度性和线性, R2=0.9818。空白对照组和102 cfu/孔均与104 cfu/孔组存在极显著性差异, P值分均为P = 0.00＜0.01。结论 F0F1-ATPase纳米生物传感器对O157:H7检测快速、灵敏、特异性好, 有良好的应用前景。     

分子马达传感器对沙门氏菌快速检测方法的初步研究

利用F0F1-ATP合酶的旋转特性及对H+敏感的荧光物质F-DHPE作为指示剂来检测样本中有无目标物。通过生物素-亲和素系统将特异性invA核酸探针连接在F0F1-ATPase的ε亚基上构建生物传感器;将待测样品和阴性对照分别与生物传感器结合后,比较其催化ATP合成30min后的ATP产生量,依此对样品中的沙门氏菌DNA进行检测。结果表明,该方法对沙门氏菌DNA的检测时间为1h,检出限为10ng/mL。从食品样本分离得到的30株细菌,利用分子马达生物传感器的检测结果与PCR检测的结果一致。     

鲜猪肉中沙门和金葡菌荧光定量PCR检测

通过结合两种技术-免疫磁分离技术与双重荧光定量PCR技术,建立同时、快速对鲜猪肉进行沙门氏菌和金黄色葡萄球菌的检测方法。利用偶联有特异性抗体免疫磁球,在37℃的条件下能够有效地从250 m L循环体系中边富集边捕获目标菌。利用特异性的引物与探针,对两种食源性致病菌进行双重荧光定量PCR同时检测。本研究方法针对沙门氏菌和金黄色葡萄球菌的检测限分别达到3.6 CFU/g和9.2 CFU/g。方法总体灵敏度、特异性和准确度达到98.8%、100%以及98.9%。本研究建立的免疫磁分离-双重荧光定量PCR方法比国标方法更快速和高效,适用于鲜猪肉中沙门氏菌和金黄色葡萄球菌的快速检测。     

利用F0F1-ATPase分子马达生物传感器检测食品中的副溶血性弧菌

利用载色体上的F0F1-ATPase分子马达生物传感器对副溶血性弧菌检测快速检测。在ATP合酶的ε亚基上连接ε亚基抗体-生物素-链霉亲和素-生物素-toxR探针,将待测副溶血性弧菌标准菌株和阴性对照分别与生物传感器结合后,比较其催化ATP合成30min后的ATP产生量,可以对副溶血性弧菌的DNA进行检测。ATP合成的多寡可以通过环境中H+的量进行测量,而H+的多寡通过F-DHPE所体现的荧光强度大小来获得。结果表明,chro toxR的质量浓度在0.156mg/mL,副溶血性弧菌DNA质量浓度在40ng/mL时为最适检出条件。通过与实际检测样品的传统检测方法及聚合酶链式反应检测方法对照,具有良好的符合性。     

食源性混合病原菌生物被膜行为对金黄色葡萄球菌毒素因子转录水平的影响

以食源性病原菌(金黄色葡萄球菌、大肠杆菌和肠炎沙门氏菌)形成的混合菌生物被膜为研究对象,对其定性和定量检测,通过实时荧光定量PCR方法分别检测单一菌和混合菌生物被膜中金黄色葡萄球菌28种目的毒素基因转录水平的变化。结果表明,结晶紫染色法、银染法和扫描电镜法均表明混合菌在培养24 h时达到最大黏附度;混合菌生物被膜中3种细菌的活菌数均低于单菌生物被膜中的活菌数;28种毒素基因在金黄色葡萄球菌中均被检出,且混合菌相对于单一菌生物被膜,上调量显著的有肠毒素基因sep、ser,显著下降的有溶血素基因hla和脱皮毒素基因etd,肠毒素基因seb表达量相等。     

抗菌肽F1对金黄色葡萄球菌的胞内作用机制

研究副干酪乳杆菌FX-6产抗菌肽F1对金黄色葡萄球菌胞内抑菌作用机制。通过凝胶阻滞电泳、荧光光谱考察抗菌肽F1对金黄色葡萄球菌DNA的结合作用及方式,考马斯亮蓝法检测、聚丙烯酰胺凝胶电泳考察抗菌肽F1对金黄色葡萄球菌蛋白合成的影响,邻硝基苯-β-D-吡喃半乳糖苷法、荧光指示剂法分别测定抗菌肽F1对金黄色葡萄球菌胞内β-半乳糖苷酶、非特异酯酶表达活性的影响,流式细胞仪分析F1对金黄色葡萄球菌细胞周期的影响。结果显示,抗菌肽F1能以嵌插方式与金黄色葡萄球菌细胞内的DNA结合,阻碍其遗传信息正常表达,使其蛋白的合成减少,并使胞内β-半乳糖苷酶、非特异性酯酶的表达活性减弱,胞内酶系统紊乱,影响其正常代谢,生长周期无法顺利进行,从而起到抑菌的效果。     

食源性金黄色葡萄球菌的危害及其快速检测方法研究进展

金黄色葡萄球菌是一种常见的食源性致病菌,可通过污染乳制品、肉制品等蛋白质或淀粉含量丰富的食品引起食物中毒,还易引发人体局部化脓性感染、肺炎、心包炎等疾病,严重时甚至会出现败血症。采用准确、高效的金黄色葡萄球菌检测方法,是预防食源性金黄色葡萄球菌及食品安全质量控制的关键。金黄色葡萄球菌检测方法主要有免疫血清学检测技术、聚合酶链式反应检测技术和生物传感器检测技术等。本文总结了各类检测方法的核心技术特征和应用实例,为食源性金黄色葡萄球菌的快速检测方法的研发和使用提供思路。     

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.     

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