Comparative proteome analysis of glutenin synthesis and accumulation in developing grains between superior and poor quality bread wheat cultivars

BACKGROUND: Wheat glutenins are the major determinants of wheat quality. In this study, grains at the development stage from three wheat cultivars (Jimai 20, Jin 411 and Zhoumai 16) with different bread‐making quality were harvested based on thermal times from 150 °C_d to 750 °C_d, and were used to investigate glutenin accumulation patterns and their relationships with wheat quality. RESULTS: High and low molecular weight glutenin subunits (HMW‐GSs and LMW‐GSs) were synthesised concurrently. No obvious correlations between HMW/LMW glutenin ratios and dough property were observed. Accumulation levels of HMW‐GSs and LMW‐GSs as well as 1Bx13 + 1By16 and 1Dx4 + 1Dy12 subunits were higher in superior gluten quality cultivar Jimain 20 than in poor quality cultivar Jing 411 and Zhoumai 16. According to the results of two‐dimensional gel electrophoresis, six types of accumulation patterns in LMW‐GSs were identified and classified. The possible relationships between individual LMW‐GSs and gluten quality were established. CONCLUSION: The high accumulation level of HMW‐GSs and LMW‐GSs as well as 1Bx13 + 1By16 and 1Dx4 + 1Dy12 subunits contributed to the superior gluten quality of Jimai 20. Two highly expressed and 16 specifically expressed LMW glutenin subunits in Jimain 20 had positive effects on dough quality, while 17 specifically expressed subunits in Zhoumai 16 and Jing 411 appeared to have negative effects on gluten quality. Copyright © 2011 Society of Chemical Industry     

Effects of amounts of HMW glutenin subunits determined by capillary electrophoresis on technological properties in wheat doubled haploids

BACKGROUND: Knowledge of the types and amounts of individual HMW glutenin subunits (HMW-GS) is important for predicting technological quality. In this study, 228 wheat doubled haploids were compared in respect of HMW-GS composition, seed protein content, flour yield, rheological properties of dough, and loaf properties. The quantitative and qualitative composition of particular HMW-GS was determined by CE. The relative amounts of x-type and y-type subunits encoded by individual Glu-1 loci were considered. RESULTS: The results show that the amounts of some pairs x + y of HMW-GS are correlated with technological properties. The importance of quantities of particular pairs of HMW-GS for technological values depends on allele compositions in all the Glu-1 loci. Positive correlation was found between the amount of subunits Ax1, Ax2*, Bx7 + By8 or Dx5 + Dy10 and loaf volume (r = 0.215–0.618, P < 0.05). The influence of an increasing amount of Ax1 was positively correlated with dough softening (r = 0.451, P < 0.01) and negatively with dough development time (r = − 0.209, P < 0.05) and stability (r = − 0.351, P < 0.01), whereas for subunit Ax2* these associations were opposite. CONCLUSION: The results confirm the occurrence of epistatic interactions between alleles of Glu-1 loci. The effects of amounts of HMW subunits on bread-making quality should be considered only within glutenin subunit compositions. Copyright © 2008 Society of Chemical Industry     

Quantification of monomeric and polymeric wheat proteins and the relationship of protein fractions to wheat quality

Wheat protein composition is important for understanding the biochemical basis of wheat quality. The objective of this study was to design a simple protein fractionation protocol with low cross‐contamination and to show that these protein fractions were associated with wheat quality. The protocol consists of three sequential extractions from 100 mg of flour with 7.5% propan‐1‐ol and 0.3 M sodium iodide (monomeric‐rich protein), 50% propan‐1‐ol (soluble glutenin‐rich protein) and 40% propan‐1‐ol and 0.2% dithiothreitol (insoluble glutenin‐rich protein). Nitrogen content of protein solubility groups was determined from dry residues using an automated combustion nitrogen analyser. About 90% of the total protein in the flour was solubilised. Cross‐contamination of protein fractions was evaluated by SDS‐PAGE, SE‐HPLC and RP‐HPLC. Variation in nitrogen content of the protein solubility fractions was lowest for monomeric‐rich protein (<2%) and insoluble glutenin‐rich protein (<4%). Three wheats with similar high‐molecular‐weight (HMW) glutenin subunit composition, Alpha 16, Glenlea and Roblin, varied significantly (P ≤ 0.05) in the proportion of monomeric‐rich and insoluble glutenin‐rich protein in the flour. Dough rheological properties were directly related to the proportion of insoluble glutenin‐rich protein and inversely related to the proportion of monomeric‐rich protein. The protocol was validated using an expanded set of 11 wheats which also showed that inter‐cultivar differences in the proportion of monomeric‐rich, insoluble glutenin‐rich protein and glutenin‐to‐gliadin ratio in the flour governed dough rheological properties such as mixograph, farinograph and microextension tests. The protocol has merit for quality screening in wheat‐breeding programmes when the sample size is too small or when time constraints limit the ability to perform traditional rheological tests. For the Department of Agriculture and Agri‐Food, Government of Canada, Copyright © Minister of Public Works and Government Services Canada 2003. Published for SCI by John Wiley & Sons, Ltd.     

六种植物籽果仁油的提取及油质评价

采用CO2超临界萃取分别对柚子籽、桔子籽、樟树籽、哈密瓜籽、西红柿籽和茶叶树籽等6种果仁提取它们的油脂，并用气相色谱法分析它们各自脂肪酸组成。萃取结果表明，上述各油料均有较高的出油率，出油率在22％以上。脂肪酸含量分析结果表明，它们的亚油酸含量较高（大于25％），其中哈密瓜籽仁的砸油酸含量高达64．19％。根据测定结果对它们的开发前景作了讨论。     

枣挥发油的提取及其化学成分的气相色谱─—质谱分析

以红枣为原料，经浸提处理得到以透光率为90％，可溶性固形物含量为14％的大枣清汁，在0．09MPa真空度条件下浓缩至可溶性固形物含量为65％，馏分用乙醚萃取后，利用色谱─质谱联用系统测定。结果表明，馏分中含有71种化合物，在已知的39种中，有7种酯类物质，17种有机酸，6种烷类物质，2种醛类物质，4种醇类物质，2种烯类物质和一种酚类物质。在酯类物质当中，相对含量最高的是戊酸甲酯     

山东省不同年代主要栽培小麦品种(系)高分子量谷蛋白亚基分布

用SDS－PAGE法鉴别了山东省从50年代至今推广的106个小麦品种（系）的HMW－GS组成。结果表明：山东省小麦品种（系）高分子量谷蛋白亚基（HMW－GS）组成以1Anu11或1A1，1Bx＋1By9或1Bx7＋1By8，1Dx2＋1Dy12为主，不同年代间亚基的分布具有一定特点，研究过程中还发现了一些较为罕见的亚基和亚基组合。针对以上结果，对山东省今后小麦品质的改良提出了几点看法。     

枣挥发油的提取及其化学成分的气相色谱——质谱分析

以红枣为原料，经浸提处理得到以透光率９０％，可溶性固形物含量为１４％的大枣清汁，在０．０９ＭＰａ真空度条件下浓缩至可溶性固形物含量为６５％，馏分用乙醚萃取后，利用色谱一质谱联用系统测定，结果表明，馏分中有７１种化合物，在已知的３９种中，有７种酯类物质，１７种有机酸，６种烷类物质，２种醛类物质，４种醇类物质，２种烯物质和种酚类物质。在酯类物质当中，相对含量最高的戊酸甲酯。     

小麦重组自交系中HMW-GS表达量与品质性状关系的研究

利用99G45/京771重组自交系F8的72个株系,对高分子量麦谷蛋白亚基表达量与全麦粉蛋白质含量、湿面筋含量、Zeleny沉降值和SDS沉降值间的关系进行了研究.结果表明,7亚基的表达量最高,1亚基的表达量最低;就单个亚基与品质性状的关系而言,仅有10亚基的表达量与蛋白质含量的相关性达5%的显著水平,2亚基的表达量与湿面筋含量呈负相关,其余单个亚基对品质性状均无显著影响;就x型与y型亚基的比例来看,2/12和5/10对湿面筋含量都有显著的负效应;对某一位点等位基因控制的亚基表达总量来看,2 12对SDS沉降值有显著负效应.     

面筋蛋白及其对面包品质的影响

总结了近几十年来有关面筋蛋白、特别是高分子麦谷蛋白亚基组（HMW－GS）的调查和研究情况，从中试图找出面筋蛋白各组分的组成、含量与面团、面包品质之间的关系，旨在更好地调控面包制作，改善面包品质。     

GS1牛肉全程质量追溯系统框架研究

GS1 是EAN/UCC 的新名字,由编码体系、可自动识别的数据载体和电子数据交换标准组成的全球统一标准。本文基于GS1 标准,针对“源头”追溯、标准化、动态数据共享等难题,搭建了牛肉全过程质量追溯系统的通用框架。框架中个体标识采用RFID 耳标与EAN/UCC 条码,RFID 耳标编码采用EPCglobal 标签数据标准;各流通环节的信息服务器采用三层架构：访问层、业务层、资源层,异构分布架设,以HTTP/SOAP 协议提供用户访问接口;采用信息发现服务结合对象名服务,定位动态分布的信息服务器,实现动态数据共享。     

采用GS1系统建立非转基因大米制品溯源体系

2011年欧盟出台2011/884/EU决议,针对中国出口的大米及米制品中转基因成分扩大范围进行检测,加强了对中国出口米制品的转基因管理。自该决议出台以来,中国米制品生产企业产品出口欧盟屡屡受阻。本研究以上海市C食品有限公司生产的非转基因年糕及白粿干为例,从水稻种植、收割、大米碾磨、年糕和白粿干加工、包装、仓储6 个关键环节进行信息的收集,并按照GS1系统的格式分别对转基因年糕及白粿干的6 个关键环节收集到的信息进行设计和编码,并按照产品的生产加工流程将6 组设计的编码组合在一起,形成一套完整的GS1-128码。通过对GS1-128码进行扫描和解读,可以对该公司生产的非转基因年糕和白粿干产品进行溯源,为出口米制品的出口贸易提供溯源保障。     

释酸剂在弱酸性染料染真丝中的应用

探讨了释酸剂对弱酸性染料染真丝的影响。结果表明，释酸剂GS能逐渐降低染液的PH值，提高真丝织物的染色牢度、染色鲜艳度、匀染性，并改善织物于感。     

N-糖基化修饰对极端嗜热酸性α-淀粉酶ApkA酶学性质的影响

为探索N-糖基化修饰对极端嗜热酸性α-淀粉酶Apk A酶学性质的影响,同时为构建酵母工程菌奠定基础,将Apk A缺失信号肽突变体Apk Ads及含有2个潜在N-糖基化修饰位点的突变体Apk Ads D182N/G373S在毕赤酵母(Pichia pastoris)GS115中进行表达。Apk Ads和Apk Ads D182N/G373S在Pichia pastoris GS115中大量表达并分泌到胞外,Apk Ads的表观分子质量约为45 k D,Apk Ads D182N/G373S的表观分子质量约为55 k D。酶学性质分析表明,与Apk Ads相比,Apk Ads D182N/G373S的酶学性质发生了一定的变化。其最适反应p H值由6.5降低至5.5~6.0,酸性条件下稳定性增强;最适反应温度由90℃提高至100℃;于90℃的半衰期由5 h增加至5.5 h,于100℃保温10 min后的相对酶活力由32.03%增加至49.04%。结果表明N-糖基化修饰可适当提高Apk A的酸性条件下酶活力和稳定性、最适反应温度、热稳定性。突变体Apk Ads D182N/G373S的酶学性质使其适于淀粉液化工艺的应用。     

合成嗜热酸性淀粉酶的毕赤酵母表达

把密码子优化后的超耐热酸性α-淀粉酶的基因BD5088,引入载体pPIC9K中,将正确构建的重组质粒pPIC9K-BD5088转化毕赤酵母GS115细胞,得到酵母工程菌株。在酵母α-Factor及AOX1基因启动子和终止信号的调控下,重组超耐热酸性α-淀粉酶PrBD5088在甲醇酵母中大量表达并分泌到胞外。该酶受甲醇的严格调控和诱导,在诱导培养5 d后酶活力达到最大值,表达量可达到约200 mg/L。与原核表达产物ErBD5088相比,PrBD5088的酶学性质发生了一定的改变。其最适反应温度由80℃增加到90℃。最适反应pH值仍为pH5.6,但范围更宽,在pH值5.0～6.5之间,其相对酶活在90%以上,在pH4.0～8.0范围内酶活性保留50%以上。而ErBD5088则只在pH5.0～7.0范围内能维持活性的50%以上。且PrBD5088的温度稳定性远高于ErBD5088。PrBD5088在100℃条件下热处理1 h仍具有80%以上的酶活力,而ErBD5088相同条件下的半衰期只有20 min。此外,Ca2+和Zn2+对维持rBD5088活性和稳定性会产生轻微促进作用,该酶的这些优点使其非常适于在工业生产上应用。SDS-PAGE测得该酶的分子量为56 ku,高于原核表达的酶蛋白。重组α-淀粉酶PrBD5088不存在N-连接的糖基化,但是存在O-连接的糖基化现象。本实验结果表明O-连接糖基化可适当提高PrBD5088的热稳定性、最适温度和酸性pH条件下酶活性。