醋酸棉酚抑制人骨肉瘤MG-63细胞增殖

目的:研究醋酸棉酚(gossypol acetic acid,GAA)对人骨肉瘤MG-63细胞增殖的影响及其可能作用机制.方法:采用MTT法检测GAA对MG-63细胞的增殖抑制作用,Hoechst 33258荧光染色观察细胞核的形态变化,流式细胞仪分析细胞凋亡相关蛋白Bcl-2与Bax的表达情况.结果:GAA对MG-63细胞具有显著的增殖抑制作用,并呈剂量、时间依赖性;Hoechst 33258荧光染色可观察到明显核固缩、染色质凝集等细胞凋亡现象;流式细胞仪检测发现细胞凋亡相关基因Bcl-2表达下调,而Bax表达则相对上调.结论:GAA能够抑制人骨肉瘤MG-63细胞的增殖,促进其凋亡,其作用机制可能是通过调节凋亡相关蛋白Bcl-2、Bax实现.     

牛蒡子苷元对人前列腺癌PC3细胞侵袭、迁移的影响

目的研究牛蒡子苷元对PC3细胞侵袭、迁移的影响。方法体外培养PC3细胞,采用MTT法检测牛蒡子苷元(ARG)对PC3细胞增殖抑制率,Transwell法检测细胞侵袭,划痕实验检测细胞迁移,以RT-PCR法检测侵袭、迁移标志物基质金属蛋白酶9(MMP-9),MMP-2,CXC趋化因子受体4(CXCR4)的基因表达,并以Western blot法检测其蛋白表达。结果 ARG可显著抑制PC3细胞增殖,且具有时间依赖性;与空白对照组比较,ARG 10μmol/L组和2.5μmol/L组均能有效抑制PC3细胞侵袭,其侵袭抑制率分别为73.5%和51.3%;10μmol/L组和2.5μmol/L组划痕修复率明显低于空白对照组,其差异有统计学意义(P0.01,P0.05);ARG可降低MMP-9,MMP-2,CXCR4的基因与蛋白表达,且具有浓度依赖性。结论 ARG在体外可抑制PC3细胞的侵袭、迁移,下调细胞中MMP-9、MMP-2和CXCR4的基因与蛋白表达。     

响应面优化超声波提取冬凌草甲素工艺及其抗肿瘤活性研究

目的:应用单因素实验和响应面法优化超声波提取冬凌草甲素工艺并探索冬凌草甲素的体外抗肿瘤活性.方法:通过单因素实验确定料液比、超声时间和超声功率的参数范围,经响应面法优化提取工艺;体外培养肿瘤细胞HepG2,经过对HepG2细胞存活率和凋亡蛋白Caspase-3和Caspase-9表达的研究,探讨冬凌草甲素的抗肿瘤活性....     

冬凌草甲素诱导小鼠肝癌细胞醌还原酶活性及其机理研究

为筛选鉴定出溪黄草中抗癌活性组分,本研究以溪黄草为材料得到乙酸乙酯提取物,通过硅胶柱层析、半制备色谱分离纯化,利用小鼠肝癌细胞Hepa1c1c7体外模型测定分离产物对细胞存活率和醌还原酶(quinone reductase,QR/NAD(P)H:reductase 1,NQO1)诱导活性。通过核磁共振、质谱分析鉴定组分结构;采用细胞外信号调节蛋白激酶(extracellular signal-regulated kinase,ERK)、磷脂酰肌醇-3-激酶(phosphatidylinositol 3-kinase,PI3K)、丝裂原活化蛋白激酶(mitogen activated protein kinases,MAPK)p38、蛋白激酶C(protein kinase C,PKC)和c-Jun N-末端激酶(c-Jun N-terminal kinase,JNK)5种蛋白激酶的特异性抑制剂,确定冬凌草甲素诱导QR活性的信号转导通路,采用实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)和Western blot法分别检测NQO1的m RNA和蛋白表达情况。结果:1)从溪黄草中筛选鉴定出一较强诱导QR活性组分为冬凌草甲素;2)冬凌草甲素质量浓度为0.94μg/m L时,即可诱导QR活性倍增;3)PI3K抑制剂处理显著抑制冬凌草甲素诱导的QR活性,而ERK抑制剂处理显著促进冬凌草甲素诱导的QR活性,但PKC、p38和JNK抑制剂处理对冬凌草甲素诱导的QR活性无明显影响;4)冬凌草甲素显著提高细胞内NQO1的m RNA和蛋白表达水平。结论:溪黄草中的冬凌草甲素具有抗癌活性,其抗癌活性通过提高Hepa1c1c7细胞中NQO1基因的转录及翻译水平以增加QR活性实现,并且其抗癌功能主要通过激活PI3K通路、抑制ERK通路进行信号传导。研究结果为深入开展溪黄草和冬凌草甲素的癌症化学预防研究奠定前期理论基础。     

醋酸棉酚抑制人骨肉瘤MG-63细胞增殖

目的研究醋酸棉酚(gossypol acetic acid,GAA)对人骨肉瘤MG-63细胞增殖的影响及其可能作用机制。方法采用MTT法检测GAA对MG-63细胞的增殖抑制作用,Hoechst 33258荧光染色观察细胞核的形态变化,流式细胞仪分析细胞凋亡相关蛋白Bcl-2与Bax的表达情况。结果 GAA对MG-63细胞具有显著的增殖抑制作用,并呈剂量、时间依赖性;Hoechst 33258荧光染色可观察到明显核固缩、染色质凝集等细胞凋亡现象;流式细胞仪检测发现细胞凋亡相关基因Bcl-2表达下调,而Bax表达则相对上调。结论 GAA能够抑制人骨肉瘤MG-63细胞的增殖,促进其凋亡,其作用机制可能是通过调节凋亡相关蛋白Bcl-2、Bax实现。     

二膦酸盐对人骨肉瘤细胞株MG-63细胞中OPG/RANKL表达的影响

目的 研究二膦酸盐作用于人骨肉瘤细胞株MG-63细胞后,对细胞中成骨细胞护骨素(OPG)及细胞核因子κB受体活化因子配体（RANKL）表达的影响.方法 人骨肉瘤细胞株MG-63细胞培养、传代后分为:二膦酸盐10 μmol/L组、二膦酸盐50 μmol/L组和阴性对照组3组,保温72 h后,应用RT-PCR和Western blot检测干预后OPG和RANKL mRNA和蛋白水平的表达.结果 二膦酸盐作用于人骨肉瘤细胞株MG-63细胞后,细胞中OPG mRNA和蛋白水平表达升高,RANKLmRNA及蛋白水平则降低(均P＜0.05).结论 二膦酸盐可能通过调节人骨肉瘤细胞株MG-63细胞OPG/RANKL轴的表达,抑制骨肉瘤的溶骨性破坏,对治疗人骨肉瘤有潜在价值.     

二膦酸盐对人骨肉瘤细胞株MG-63细胞中OPG/RANKL表达的影响

目的研究二膦酸盐作用于人骨肉瘤细胞株MG-63细胞后,对细胞中成骨细胞护骨素(OPG)及细胞核因子κB受体活化因子配体(RANKL)表达的影响。方法人骨肉瘤细胞株MG-63细胞培养、传代后分为:二膦酸盐10μmol/L组、二膦酸盐50μmol/L组和阴性对照组3组,保温72 h后,应用RT-PCR和Western blot检测干预后OPG和RANKL mRNA和蛋白水平的表达。结果二膦酸盐作用于人骨肉瘤细胞株MG-63细胞后,细胞中OPG mRNA和蛋白水平表达升高,RANKL mRNA及蛋白水平则降低(均P<0.05)。结论二膦酸盐可能通过调节人骨肉瘤细胞株MG-63细胞OPG/RANKL轴的表达,抑制骨肉瘤的溶骨性破坏,对治疗人骨肉瘤有潜在价值。     

沙棘多糖对肝癌细胞Hep-G2生长、凋亡、迁移和侵袭的影响

目的:研究纯化沙棘多糖(SBP-3)通过p38通路对肝癌细胞Hep-G2增殖、凋亡、迁移、侵袭的影响。方法:将不同浓度SBP-3作用于Hep-G2细胞,采用CCK-8法检测细胞增殖情况,流式细胞术检测细胞凋亡、划痕试验,细胞迁移侵袭试验(Transwell)检测细胞迁移及侵袭情况, 蛋白免疫印迹法(Western blot)检测 p-p38、MMP-2 和 MMP-9 蛋白表达水平。结果:经SBP-3作用48 h,125,250,500,1 000 μg/mL剂量组细胞抑制率均显著升高(P<0.05);125,250,500 μg/mL各剂量组均能诱导Hep-G2细胞产生凋亡作用(P<0.01),且细胞凋亡率随SBP-3浓度的增加而逐渐升高;SBP-3能降低Hep-G2细胞侵袭和迁移能力(P<0.01),抑制p-p38、MMP-2 和 MMP-9 蛋白表达(P<0.01)。结论:沙棘纯化多糖SBP-3能够抑制肝癌细胞Hep-G2的增殖、迁移和侵袭,促进凋亡,这些作用可能是通过调节 p38 信号通路抑制MMP-2和MMP-9蛋白表达来实现。     

6-姜烯酚诱导SW480凋亡及对APC基因表达的影响

本文通过体外细胞实验观察研究6-姜烯酚诱导结直肠癌细胞凋亡及与APC(肿瘤抑制基因)表达的关系,以探讨6-姜烯酚抑制结直肠肿瘤的可能机制。首先通过体外细胞实验应用不同浓度6-姜烯酚(0、5、10、15和20μM)分别对SW480进行干预诱导24 h,再利用高倍荧光显微镜观察细胞数目、形态变化,CCK8法测定细胞抑制率,Annexin V-FITC/PI流式细胞术检测细胞凋亡率及细胞凋亡周期,最后用Western-blot检测分析APC蛋白表达变化。结果显示,与对照组相比,6-姜烯酚可致使SW480细胞增殖周期阻断在G2/M期,并呈浓度依赖性地促进SW480凋亡,进而抑制细胞增殖,而且增强了APC表达(p0.05)。因此,可以得出6-姜烯酚可诱导SW480凋亡从而抑制细胞增殖,并且可能与激活APC相关,随着这一研究的不断深入,6-姜烯酚作为临床潜在的抗肿瘤辅助药物,其抑制肿瘤细胞增殖将得到更深层次分子机制的支持。     

胭脂萝卜天竺葵素抑制人胃癌细胞迁移与侵袭

主要探讨胭脂萝卜天竺葵素对人胃癌细胞(MKN45)迁移侵袭能力的影响及机制。采用不同浓度的天竺葵素处理MKN45细胞,用MTT法、流式细胞术、细胞划痕实验和Transwell~(TM)小室实验分别检测细胞增殖、周期、迁移和侵袭能力变化,并用蛋白印迹法检测细胞黏附蛋白E-cadherin和N-cadherin的表达。结果表明,6μg/m L天竺葵素能显著抑制细胞的增殖,迁移和侵袭,并使细胞阻滞在S期。天竺葵素抑制细胞迁移和侵袭的机制可能是促进E-cadherin蛋白的表达和抑制N-cadherin蛋白的表达。     

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.     

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.     

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.     

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.     

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.