盐酸克伦特罗残留酶联免疫吸附(ELISA)检测方法的研究

建立了间接ELISA检测盐酸克伦特罗的方法,并对其参数进行了分析计算。在该检测方法中,抗盐酸克伦特罗(CL)抗体最适稀释度为1∶1000,羊抗兔酶联抗体(HRP-IgG)的最适稀释度为1∶1500。该检测方法的检测灵敏度可达0·1046μg/L,生物检测限为1·452μg/L,线性检测范围为7·26~90·75μg/L。     

基于赭曲霉毒素A模拟表位的无毒素ELISA方法

以抗赭曲霉毒素A的单克隆抗体亲和筛选随机7肽库,ELISA方法鉴定阳性克隆,DNA测序推导出赭曲霉毒素A的模拟表位肽,共获得了11个模拟表位肤,共有序列为IRPMV.将化学合成的模拟表位肽与载体BSA偶联后,以之建立无毒素的竞争酶联免疫检测方法,并与常规酶联免疫吸附检测方法及高效液相色谱比较.结果表明:以赭曲霉毒素A模拟表位建立的竞争ELISA方法的线性范围和检测下限都与常规竞争ELISA方法结果相近,样品测试结果与常规竞争ELISA方法及高效液相色谱一致,显示良好的应用前景.     

应用ELISA定量检测转基因玉米中Bt1蛋白的研究

应用纯化的Bt1杀虫晶体蛋白作为标准蛋白和免疫抗原,通过抗体-抗原-酶标抗体反应,建立了酶联免疫吸附测定法(ELISA),以定量检测转基因玉米中的Bt1表达蛋白。用建立的ELISA法对4种进口玉米产品进行了测定,实验结果得到了免疫印迹分析的验证,并与进口试剂盒方法的定量分析结果相一致,因而建立的ELISA法具有操作简便、快速特异、定量准确、经济实惠的优点,特别适合于大批量检测,有着良好的应用前景。     

葡萄球菌A型肠毒素检测竞争ELISA方法的建立

为建立快速、灵敏、特异的检测食品中金黄色葡萄球菌A型肠毒素的方法,应用构建的pGEX-6P-SEA、pET28α-SEA重组质粒表达带有不同融合肽的葡萄球菌A型肠毒素,分别通过谷胱甘肽亲和纯化、镍螯合纯化获得SEA的重组融合表达蛋白HIS-SEA、GST-SEA,以HIS-SEA为包被抗原,以GST-SEA、天然SEA肠毒素为竞争抗原,确立了SEA型肠毒素ELISA检测的工作条件:包被浓度为2.5μg/mL,阳性血清稀释度为1∶50,辣根过氧化物酶标记的羊抗鸡免疫球蛋白工作浓度为1∶2000。建立了以重组肠毒素GST-SEA作为竞争抗原检测葡萄球菌肠毒素SEA的间接竞争ELISA（ciELISA）方法,竞争肠毒素GST-SEA蛋白浓度x与P/N值y的关系式:x（GST-SEA）=1.99-y/0.34,R2（GST-SEA）=0.9964,线性检测范围均为1～62.5ng/mL,最低检测量为1ng/mL,此方法丰富了食品中A型肠毒素的检测手段。      

艾丝纶~(TM)蛋白纤维的制备及性能研究

阐述艾丝纶~(TM)蛋白纤维的制备工艺,指出其制备工艺的先进性。重点对艾丝纶~(TM)蛋白纤维的形态结构、物理机械性能、蛋白质含量以及所编织织物的抑菌性能进行测试研究,介绍各性能指标的测试方法并进行结果分析。并根据艾丝纶~(TM)蛋白纤维的性能特点,介绍其在针织及梭织领域的开发应用。     

基于噬菌体展示技术的赭曲霉毒素A高密度模拟表位的表达研究

通过噬菌体展示技术展示赭曲霉毒素A(ochratoxin A,OTA)模拟表位。将带有OTA模拟表位序列的寡核苷酸双链克隆至载体pC89-COTA。利用噬菌体展示技术,通过优化辅助噬菌体感染复数、IPTG加入的时间与剂量等培养条件获得表达有高密度OTA模拟表位的噬菌体。再通过酶联免疫吸附检测(ELISA)方法比较不同的条件下的表达效果,探索最优表达条件。结果表明:成功获得高密度表达OTA模拟表位的噬菌体,辅助噬菌体感染复数与IPTG加入量对模拟表位表达量影响不大,IPTG加入时间对模拟表位表达量有较大影响,优化后模拟表位表达量大大高于优化前。     

塔式(门座式)起重机提升系统的节能分析

为了解决塔式(门座式)起重机在施工过程中存在的提升系统节能问题,根据机械设计节能基本原理对塔式(门座式)起重机的提升系统进行相关能耗分析,发现这两类起重机提升系统都存在能量未合理利用的问题,并提出利用配重块、蓄能器及发电机组的方式实现提升系统能量综合回收与利用的节能方案,可以为后续类似工作状况设备的研发与节能化改造提供了新思路。     

脱氧雪腐镰刀菌烯醇(DON)直接竞争ELISA方法的建立

利用前期制备得到的DON酶标抗原(辣根过氧化物酶标记)以及抗DON抗体,建立检测食品中DON含量的直接竞争ELISA方法。该方法的检测范围1～100ng/mL,灵敏度达0.56ng/mL,半数抑制浓度IC50为10ng/mL;与DON类似物T-2毒素的交叉反应率为12%;玉米淀粉样品回收率在80.2%～91.1%之间,平均批间变异<15%,平均批内变异<3%。     

纯生啤酒存放过程中泡沫稳定性与酵母蛋白酶A以及蛋白含量与组成变化的研究

酵母蛋白酶A已经被证实对啤酒泡沫稳定性有负面作用。通过测定纯生啤酒存放过程中酵母蛋白酶A活性变化、泡持性衰减及蛋白含量的变化,进一步说明酵母蛋白酶A以及蛋白种类与含量对纯生啤酒泡沫稳定性的影响及其相互关系。对不同存放时期纯生啤酒样品中蛋白质进行电泳鉴定的结果显示,存放3月后的纯生啤酒中脂肪转运蛋白1(LTP1)完全消失,这一结果表明LTP1是影响啤酒泡沫稳定性的主要蛋白,该蛋白降解可能是酵母蛋白酶A作用的结果。     

鲤鱼主要组织中金属硫蛋白提取工艺的研究

预先将鲤鱼暴露于Cd2+ (10mg/L)质量浓度溶液中诱导镉-金属硫蛋白(Metallothionein,MT)的合成;以原子吸收法测得镉提取量和Ellman'试剂测得巯基含量为评价指标,综合传统经典方法对鲤鱼不同组织进行批量MT的诱导提取并与不同鱼种MT的氨基酸含量进行对比;比较不同组织中MT的含量,分别用酶联免疫吸附法与血红蛋白/镉饱和法测定MT含量,最后研究了鲤鱼MT的性质.结果表明:Cd2+ (10mg/L)能诱导鲤鱼产生大量MT,此方法能批量诱导鲤鱼合成MT氨基酸的种类和数量与鱼标准MT基本一致;半胱氨酸与疏基测定结果相同,也不合有芳香族氨基,MT的性质与哺乳动物MT的性质相似.ELISA法和血红蛋白/镉饱和法测定鲤鱼肝脏和肾脏中MT含量比较一致.     

The Saccharomyces cerevisiae poly (A) binding protein (Pab1): Master regulator of mRNA metabolism and cell physiology

Pab1, the major poly (A) binding protein of the yeast Saccharomyces cerevisiae, is involved in many intracellular functions associated with mRNA metabolism, such as mRNA nuclear export, deadenylation, translation initiation and termination. Pab1 consists of four RNA recognition motifs (RRM), a proline-rich domain (P) and a carboxy-terminal (C) domain. Due to its modular structure, Pab1 can simultaneously interact with poly (A) tails and different proteins that regulate mRNA turnover and translation. Furthermore, Pab1 also influences cell physiology under stressful conditions by affecting the formation of quinary assemblies and stress granules, as well as by stabilizing specific mRNAs to allow translation re-initiation after stress. The main goal of this review is to correlate the structural complexity of this protein with the multiplicity of its functions.     

聚氧化乙烯对大豆分离蛋白静电纺丝影响的研究

初步研究了聚氧化乙烯(PEO)对大豆分离蛋白(SPI)静电纺丝的影响,分析了SPI/PEO共混配比和相应过程参数(电压、溶液流速和接收距离)对共混溶液性质和静电纺丝可纺性的影响,通过扫描电镜对所得纤维形态进行了表征。结果表明,随着溶液中PEO含量的增加,体系的粘度增大,电导率下降,得到的电纺纤维形态均一,直径分布较窄,明显改善了SPI的可纺性;电压、溶液流速和接收距离均对电纺纤维的形成及形貌有一定的影响,三者过高或过低都会导致纤维形貌的变化,形成串珠或颗粒。10wt%SPI/PEO共混溶液的最佳电纺共混比为70/30,电压为15kV,接收距离为10cm,溶液流速为1.5mL/h。      

食品非转基因标识使用的法律规制

食品非转基因标识在中国被广泛使用,信息不对称增加了非转基因标识被滥用的风险,市场机制不足以对其进行调节,且中国对非转基因标识使用的法律规制存在立法规定不细致、司法"不认定"等问题。现有研究也主要针对非转基因广告而不是非转基因标识本身。对比来看,德国、日本、美国均有专门针对食品非转基因标识使用的法律规范,具体规定了可使用非转基因标识的食品范围及要求,通过对非转基因食品进行认证管理以确保使用标识的食品的非转基因身份真实,设置统一的标识形式以确保统一的市场并避免消费者被误导。中国应当借鉴这些共通的经验,食品标识相关的法律法规要专门对非转基因标识的使用设立规范,并细化对非转基因标识的形式要求;构建专门的非转基因食品认证制度,由食品药品监督管理局授权专门认证机构对其进行认证。     

Study of the effect of using different levels of tahinah (sesame butter) on the protein digestibility‐corrected amino acid score (PDCAAS) of chickpea dip

This study was conducted to investigate the effect of using different proportions of tahinah (0–25%) on the protein digestibility‐corrected amino acid score (PDCAAS) of chickpea dip and to evaluate this parameter when chickpea dip is consumed with wheat bread. Protein quality was evaluated using the methods of amino acid score and true protein digestibility in weanling Sprague–Dawley rats. The levels of tahinah that provided the best true protein digestibility and protein digestibility‐corrected amino acid score were 20 and 25%. Values of true protein digestibility were significantly higher (P ≤ 0.05) than for the other types of chickpea dip (0.87 and 0.88 respectively). The consumption of wheat bread with chickpea dip led to a marked improvement in the true protein digestibility of the protein mixture (0.90); however, the protein digestibility‐corrected amino acid score did not change in the same manner owing to the relatively low amino acid score. It can be concluded that the addition of tahinah to chickpea led to an increase in the protein digestibility‐corrected amino acid score of chickpea dip (based on laboratory rat requirements for essential amino acids) and that the consumption of chickpea dip with bread led to an improvement in the protein digestibility of chickpea dip but not in the protein digestibility‐corrected amino acid score. © 2002 Society of Chemical Industry     

Kinetic and Thermodynamic Parameters for Heat Denaturation of Cry1A(b) Protein from Transgenic Maize (Zea mays)

ABSTRACT:  The effect of heat treatment on the denaturation of Cry1A(b) protein expressed in transgenic maize was studied over a temperature range of 69 to 77 °C. Denaturation of Cry1A(b) protein was measured by the loss of reactivity with its specific antibodies using a sandwich ELISA. The process of denaturation was studied by analyzing the values of inmunoreactive protein after each heat treatment by kinetic analysis. Denaturation of Cry1A(b) protein was best described assuming a reaction order of 1.5. D -values calculated were 4338, 2350, 1272, 734, and 601 s at 69, 71, 73, 75, and 77 °C, respectively. Z -value was estimated to be 9.0 °C and the activation energy value was 266.15 kJ/mol. Thermodynamic parameters for the process of denaturation of Cry1A(b) protein were also calculated. The high values of the enthalpy of activation and the positive values of the entropy of activation obtained for Cry1A(b) protein are typical of a reaction in which the denaturation of the protein is the rate-determining process that predominates over an aggregation process during heating.     

Immunochemical detection of Cry1A(b) protein in model processed foods made with transgenic maize

Immunoassays are used to screen for the presence of genetically modified organisms in raw materials. However, processing may condition the usefulness of immunoassays to analyse genetically modified foods because it leads to protein denaturation that affects recognition by antibodies. We studied the effect of processing on the detection of Cry1A(b) protein in model foods prepared with transgenic maize using a sandwich ELISA. Nixtamalization at 100 °C for 5 min and at 85 °C for 60 min gave 40 and 70% loss of Cry1A(b) protein. In the preparation of porridge, the concentration of Cry1A(b) protein did not change until the mixture reached 75 °C, but it decreased by 90% after 3 min at that temperature. Concentration of Cry1A(b) protein decreased by 90% in tortillas griddled at 180 °C for 20 s, but no protein was detected in fried tortillas after 10 s at 190 °C. Cry1A(b) protein is rapidly denatured by heat treatment resulting in a marked decline in concentration and decreased detection in processed foods.     

烟草对烟蚜[Myzus persicae(Sulzer)]抗性机理的研究

研究结果表明，烟草生长前期（第一蚜高峰期），烟蚜数量与烟叶内烟碱含量呈负相关；与氨含量呈明显的正相关，相关系数（r＝0.7150）达到了显著水平；与氨基酸、糖等关系不明显。烟草生长后期（第二蚜高峰期），烟蚜数量与烟叶内的氨含量的相关性达到了极显著水平（r＝0．7568）；与烟碱含量呈显著负相关性（r＝－0.6217）；与烟叶内脯氨酸、缬氨酸、异亮氨酸等呈显著或极显著正相关（r＝0．7464，0.7343，0.6308）。     

动物蛋白酶解研究（Ⅰ）

本文主要目的是以美拉德（Maillard）反应产物（MRPs)的风味为判断依据，以水解度（DH）为动物蛋白酶解液－Maillard反应底物之一的特征性指标，根据MRPs的风味确定动物蛋白水解液的最佳DH或DH范围。