小麦种子贮藏蛋白的遗传学研究进展

AdvanceofGencticStudiesonSeedStoragcProteininWheatWangGang;JiJing;HuHan(InstituteofGenetics,AcadcmiaSinica,Beijing100101)小麦是世界上最重要的粮食作物之一．对其品质的研究具有十分重要的意义．多年来,人们一直在寻求改良小麦品质的途径,以满足不同食品加工对小麦各种品质的需求．但只是近10年里,对决定小麦品质位点的遗传及生物化学的研究才取得了突破性的进展（主要集中于英国、美国及澳大利亚）．本文将着重介绍目前国际上对小麦种子贮藏蛋白的遗传学及生物化学研究现状,至于如何将这些研究成果结合到育种工作…     

小麦体细胞无性系醇溶蛋白电泳图谱初步分析

本试验对小麦品种的休细胞无性系及其对照品种的种子醇溶蛋白进行电泳图谱比较分析。结论是：(1)同一小麦品种存在着不同的醇溶蛋白生物型;(2）小麦醇溶蛋白与外部性状在总体变异程度上有一定的正相关;(3)利用小麦醇溶蛋白电泳图谱,可以鉴别混杂株系,确定体细胞无性系的来源,但需注意选择合适的对照图谱。     

小麦低分子量麦谷蛋白亚基研究进展

低分子量麦谷蛋白亚基(LMW-GS)是小麦胚乳中的一种聚合蛋白组分,LMW-GS彼此间或／和高分子量麦谷蛋白亚基(HMW-GS)间形成分子内二硫键,进而产生麦谷蛋白聚合体,决定小麦面团的加工品质。由于 LMW-GS与醇溶蛋白的提取特性和电泳迁移率相近,其研究进展缓慢。近年来随着电泳技术的提高,LMW-GS的研究也成为品质性状研究的新热点,越来越多的研究证实了LMW-GS对品质具有重要作用。然而,关于LMW-GS 的研究在我国尚处于起步阶段。本文从小麦LMW-GS的分类、染色体定位、结构及其与品质间关系等方面回顾其研究状况,并讨论研究中存在的问题。     

基因型与生态环境对小麦籽粒品质与蛋白质组分的影响

通过2年3点试验,研究了40个小麦(Triticum aestivum)品种(品系)籽粒品质性状和蛋白质组分含量的变异。结果表明,籽粒品质和蛋白质组分在基因型间存在较大的差异;根据小麦籽粒品质的综合性状,可将40个小麦品种(品系)分为6组不同的品质类型,在本试验点的生态环境条件下。基本以中筋及弱筋小麦为主;生态环境对小麦籽粒的容重、沉降值、湿面筋含量、蛋白质含量、赖氨酸含量与蛋白质组分含量均有极显著的影响,而面筋指数、淀粉含量和直链淀粉含量对环境反应不敏感,适宜的生态环境条件有利于形成合理的谷蛋白／醇溶蛋白比。面粉面筋质量好,基因型与生态环境的互作对小麦籽粒品质。谷蛋白与醇溶蛋白及两者的比值有显著影响,对球蛋白影响不大,而面粉蛋白质含量、面筋含量、沉降值及千粒重主要受基因的表达和环境的独立影响,蛋白质组分含量在基因型间和环境间的变化与小麦籽粒烘烤品质密切相关。     

利用RIL群体进行小麦品质性状及其与产量性状的相关分析

利用小麦重组自交系(RIL)群体,对小麦主要品质性状、及其与产量的关系进行了分析。结果表明,RIL群体品质、产量性状都表现了较大的变异幅度;蛋白质各性状内、淀粉各性状内相关性多数显著,但二者之间相关性多不显著,这说明在小麦品种改良中,优良的蛋白质性状和优良的淀粉性状可以兼得;稳定时间、沉降值等重要的加工品质性状和淀粉性状与产量相关不显著,说明加工品质可以与产量很好地协调起来;适当降低千粒重,增加穗数,有利于强筋的形成和粘度的提高;矮杆、半矮杆性状能够与良好的加工品质、高蛋白质含量、高GMP含量协调起来。     

小麦品种品质性状的基因型因子分析

用陕西省关中小麦品种区域试验所选用的20个小麦品种(品系)在12个试点1996／97、1997／98两年度的数据资料,通过基因型因子分析,探讨小麦品种籽粒品质性状间相互关系的内在规律。结果表明：可将12个品质指标用4个“公共因子”表示。因子1对蛋白质含量、沉淀值、形成时间、稳定时间、软化度与评价值等品质性状起支配作用,主要反映的是蛋白质的质与量;因子2对湿面筋含量、容重和出粉率起支配作用,反映了湿面筋含量与磨粉品质之间存在着较密切的、直接的联系;因子3对籽粒硬度与吸水率起支配作用,反映了小麦籽粒的质地结构特性;因子4中,只有千粒重有较大载荷。表明千粒重与其它品质性状的直接联系较小,受相对较为独立的遗传因素控制。     

陕西省小麦品种品质性状研究

通过采用国际标准分析方法对陕西省３５个主要推广小麦品种,品系籽粒、品质性状、蛋白质品质特性、磨粉品质、粉质参数、拉伸参数及烘烤特性的全面系统分析,并采用对品质亚性状得分后,再综合加权评分的办法,获陕西省小麦品种的品质分为三类（优质、中等、一般）５级。本研究对小麦新品种的审定、推广,小麦品质育种以及商品粮基地建设,发展陕西的粮食与食品加工工业,都具有极其重要的理论和经济意义。     

小麦品质性状的免疫化学测定及不同近缘种属贮藏蛋白的免疫同源性

利用普通小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）高分子量谷蛋白亚基（ＨＭＷＧＳ）多克隆抗体和单克隆抗体,对小麦品质性状及不同麦类作物近缘种属的籽粒贮藏蛋白进行了免疫化学测定,以建立小麦品种性状的快速测定方法并研究不同麦类作物胚乳贮藏蛋白的免疫同源性。结果表明：抗原抗体反应与品质性状的相关性因抗体种类及品质性状的不同而不同,多抗略优于单抗,不同单、多抗间相差较大;籽粒蛋白质含量及干、湿面筋含量与吸附值相关程度较高,与沉淀值则中等,而面包性状相关性较差。多克隆抗体吸附值与籽粒蛋白质含量、湿面筋含量、干面筋含量、面包体积及面包比容的最大相关系数分别为０．７６２０、０．８９４２、０．８８７３、０．６１０３、０．４５９８和０．４７４４,单克隆抗体吸附值与其最大相关系数分别为０．７８３７、０．７７４５、０．７８２２、０．６８４１、０．６８７３和０．５９８２。小麦近缘种属籽粒贮藏蛋白与普通小麦１Ｄｙ１０亚基具有一定程度的免疫同源性,其中以黑麦（ＳｅｃａｌｅｃｅｒｅａｌｅＬ．）、斯卑尔脱（Ｔ．ｓｐｅｌｔａＬ．）、节节麦（ＡｅｇｉｌｏｐｓｓｑｕａｒｒｏｓａＬ．）及圆锥小麦（Ｔ．ｔｕｒｇｉｄｕｍＬ．）与其同源程度较高。     

小麦种子贮藏蛋白质研究进展

小麦醇溶蛋白组成可以作为小麦品种鉴定的指纹图谱,其分离方法有酸性电泳、反相高压液相色谱（RP－HPLC）和毛细管电泳（CE）等手段,3种方法相互补充,而CE分辨率最高。对醇溶蛋白酸性电泳条件的改良和完善仍在进行中,利用最新的分离技术对小麦醇溶蛋白基因进行染色体定位和遗传行为分析是近年来醇溶蛋白研究的另一领域。小麦高分子量麦谷蛋白亚基（HMW－GS）与小麦面包烘烤质量密切相关,关于它的研究目前主要集中在3个方面;对各个迁3移率较近的亚基进行快速,准确分离方法的研究,HMW－GS与小麦面包烘烤质量关系的研究和通过基因工程来改良小麦的品质、提高面粉的加工特性等。低分子量麦保蛋白（LMW－Glutenin)影响小麦面粉的特性,截止目前已经获得了17个该基因的克隆,并对其基因结构进行了描述,有些低分子量麦谷蛋白亚基（LMW－GS）加入碱性面粉后改变了面筋的性质,报道了小麦醇溶蛋白,高分子量麦谷蛋白亚（HMW－GS）、低分子量麦谷蛋白亚基（LMW－GS）3个方面的最新研究进展。     

西藏和北京异地种植小麦的品质变化

1998～2001年在林芝、日喀则、拉萨、北京布点,开展了多品种异地种植的春播和秋播田间联合试验,统一检测了籽粒蛋白质含量、湿面筋含量、沉降值、降落值、籽粒硬度5项指标,以探讨异地种植的品质变化,为西藏发展优质专用小麦提供试验依据。结果表明,不同小麦品种之间以及相同品种不同地点之间,品质性状都有差异,但地点间差异更大,经相关分析,蛋白质含量分别与湿面筋含量、沉降值、降落值、籽粒硬度呈正相关,籽粒蛋白质含量可作为小麦品质性状中的一项核心指标,在相同地点种植,内地品种的品质性状参数比西藏品种高,西藏品种表现弱筋或中筋小麦特性;相同品种在北京种植,品质性状参数高于西藏3试点,内地品种在西藏种植,品质性状参数降低,在西藏3试点之间,相同品种的品质性状也有差异,生态高度(纬度×海拔)与品种的生育天数呈正相关,生育天数与蛋白质含量呈负相关,生态高度又与蛋白质含量呈负相关,在西藏小麦生产中,应以发展中筋小麦为主,还可引入一些优良的内地品种,并且按照品质区划种植。     

环境变异对青稞热稳定蛋白质含量及蛋白质Z的影响

热稳定蛋白是衡量麦芽品质的重要指标,为探明青稞籽粒和麦芽热稳定蛋白的含量、蛋白质Z的组成特征以及影响条件。本研究以3份青稞和1份对照大麦品种Gairdner为试验材料,对青稞籽粒及其麦芽的热稳定蛋白进行分析与鉴定,研究了不同生态环境下青稞热稳定蛋白质含量和蛋白质Z的组成特征,同时筛选出了优异啤用品质青稞品种(品系)。结果表明,青稞发芽温度为20℃,发芽时间为72 h,培养溶液PH为5时,发芽及焙焦条件下最有利于青稞热稳定蛋白总含量及蛋白质Z的累积。利用该发芽条件筛选种植于西宁、湟源和海晏的青稞资源,发现种植于西宁的青稞种子和发芽后热稳定蛋白质总含量最低,但是焙焦后热稳定蛋白质和蛋白质Z含量最高;同时从150份青稞资源中筛选出热稳定蛋白质含量及蛋白质Z条带清晰、含量高的优异资源15份。本研究结果为酿造青稞品种选育、啤用青稞和麦芽质量评价指标提供理论依据。     

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of ram seminal plasma proteins and their correlation with semen characteristics

The present study was conducted to investigate fertility-associated proteins in ram seminal plasma and the correlation between specific protein and semen characteristics in sheep. Thirty-eight German merino sheep clinically proven healthy were chosen and divided into three groups according to fertility. Ejaculates were collected by an artificial vagina and semen characteristics (volume, pH value, motility, viability and concentration) were recorded. Seminal plasma was harvested by centrifugation and then subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE) analysis in parallel with molecular weight standards. Fifteen protein bands with different molecular weights, ranging from 15.13 to 116.20 kDa, were identified on the gel. The results showed that the relative content of eight protein bands was significantly different between the high-fertility group (H-group) and the low-fertility group (L-group). Although the remaining seven protein bands showed no fertility-associated changes in their relative content, some of them were negatively or positively correlated with some semen quality parameters (motility, viability, concentration or pH value). Thus, this study indicates that ram seminal plasma contains specific proteins that are associated with fertility and semen characteristics. Also, these proteins could be utilised in developing a reliable and simple method to determine the ram fertility or semen quality.     

Flow cytometric quantification and characterization of intracellular protein aggregates in yeast

The sequestration of misfolded proteins into aggregates is an integral pathway of the protein quality control network that becomes particularly prominent during proteotoxic stress and in various pathologies. Methods for systematic analysis of cellular aggregate content are still largely limited to fluorescence microscopy and to separation by biochemical techniques. Here, we describe an alternative approach, using flow cytometric analysis, applied to protein aggregates released from their intracellular milieu by mild lysis of yeast cells. Protein aggregates were induced in yeast by heat shock or by chaperone deprivation and labeled using GFP- or mCherry-tagged quality control substrate proteins and chaperones. The fluorescence-labeled aggregate particles were distinguishable from cell debris by flow cytometry. The assay was used to quantify the number of fluorescent aggregates per μg of cell lysate protein and for monitoring changes in the cellular content and properties of aggregates, induced by stress. The results were normalized to the frequencies of fluorescent reporter expression in the cell population, allowing quantitative comparison. The assay also provided a quantitative measure of co-localization of aggregate components, such as chaperones and quality control substrates, within the same aggregate particle. This approach may be extended by fluorescence-activated sorting and isolation of various protein aggregates, including those harboring proteins associated with conformation disorders.     

蛋白质丰度调控及整体分布的规律性认识

蛋白质是生命的重要物质基础之一,也是生命活动的主要承担者.蛋白质丰度与其执行的生物学功能息息相关,受基因表达各个过程严格精密的调控.蛋白质丰度的直接影响因素包括相应mRNA初始量、蛋白质合成速率和降解速率.细胞对此3因素的调控将决定蛋白质最终的丰度.得益于定量蛋白质组学的飞速发展,规模化蛋白质丰度数据的产出,使得研究者可致力于发掘蛋白质丰度与其内在性质(如进化特征、结构特征、功能类型等)间规律性的相关性,这对于深入认识生命系统组成的基本原则具有重要意义.本文总结了蛋白质丰度调控及蛋白质丰度与其内在性质相关性的最新研究进展,及对这些规律性现象反映的生物学意义的解读.     

植物表达分泌蛋白的运输及定位

分泌途径主要由内膜系统构成,内质网和高尔基体对于分泌蛋白的运输及定位具有重要作用。分泌蛋白的运输包括顺行途径和逆行途径。蛋白质通过质流和受体介导的途径运输到小泡中。在植物中,分泌蛋白的运输主要通过小泡和相连的小管来完成。分子伴侣和质量控制不仅能优化新合成蛋白的折叠和组装,而且去除了有折叠缺陷的蛋白。分泌蛋白的定位需要特定的信号肽,而高尔基体固有蛋白以依赖跨膜长度的方式,沿着分泌途径的细胞器分布。本文对植物表达分泌蛋白的分泌途径及定位、相关的分子伴侣和质量控制进行了综述。     

Protein misfolding and aggregation research: Some thoughts on improving quality and utility

Once misfolded and aggregated proteins were as interesting as yesterday's trash, just a bothersome byproduct of productive activities. Today, they attract sustained interest from both basic researchers and practicing engineers. In the burgeoning biopharmaceutical industry, protein misfolding and aggregation pose significant challenges to the economic manufacture of safe and effective protein products. In the clinic, protein aggregates are believed to be pathological agents in a number of serious neurodegenerative disorders, such as Alzheimer's and Parkinson's. Over the past few years, the quantity of research into biotechnological aspects of protein misfolding and aggregation has skyrocketed. However, the quality of the published work is quite variable. In this brief opinion piece, we describe what we believe are some key features of high‐quality publications in protein aggregation. We focus on experimental studies that may also have a kinetic modeling component. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1109–1115, 2013     

乳蛋白的主要组分及其研究现状

乳蛋白是乳中最重要的成分,包括酪蛋白、乳清蛋白和乳脂肪球膜蛋白等。本文对乳中主要蛋白质的结构组成特点、分泌的规律和功能等进行了综述,并介绍了国内外乳蛋白研究的最新进展及其研究乳蛋白的意义。     

Gene ontology improves template selection in comparative protein docking

Structural characterization of protein-protein interactions is essential for our ability to study life processes at the molecular level. Computational modeling of protein complexes (protein docking) is important as the source of their structure and as a way to understand the principles of protein interaction. Rapidly evolving comparative docking approaches utilize target/template similarity metrics, which are often based on the protein structure. Although the structural similarity, generally, yields good performance, other characteristics of the interacting proteins (eg, function, biological process, and localization) may improve the prediction quality, especially in the case of weak target/template structural similarity. For the ranking of a pool of models for each target, we tested scoring functions that quantify similarity of Gene Ontology (GO) terms assigned to target and template proteins in three ontology domains—biological process, molecular function, and cellular component (GO-score). The scoring functions were tested in docking of bound, unbound, and modeled proteins. The results indicate that the combined structural and GO-terms functions improve the scoring, especially in the twilight zone of structural similarity, typical for protein models of limited accuracy.     

蛋白质的错误折叠与疾病

蛋白质是生物体内一切功能的执行者.人体内的任何功能,从催化化学反应到抵御外来侵略都是蛋白质作用的结果.蛋白质折叠是生命活动的最基本过程,近年发现蛋白质的错误折叠可以导致一些疾病.蛋白质的错误折叠与疾病的关系已成为分子生物学新的研究前沿.介绍了细胞内保证蛋白质正常功能的“质量控制”系统,重点讨论了翻译后的质量控制、与蛋白质错误折叠有关的一些疾病和治疗这一类疾病的原则方法.     

Yield, solubility and conformational quality of soluble proteins are not simultaneously favored in recombinant Escherichia coli

Many enzymes or fluorescent proteins produced in Escherichia coli are enzymatically active or fluorescent respectively when deposited as inclusion bodies. The occurrence of insoluble but functional protein species with native-like secondary structure indicates that solubility and conformational quality of recombinant proteins are not coincident parameters, and suggests that both properties can be engineered independently. We have here proven this principle by producing elevated yields of a highly fluorescent but insoluble green fluorescent protein (GFP) in a DnaK- background, and further enhancing its solubility through adjusting the growth temperature and GFP gene expression rate. The success of such a two-step approach confirms the independent control of solubility and conformational quality, advocates for new routes towards high quality protein production and intriguingly, proves that high protein yields dramatically compromise the conformational quality of soluble versions.