Electrophoretic heterogeneity of polypeptide chains of specific antibodies

Heavy and light polypeptide chains isolated from different specific antibodies to haptens and from (gamma)G-immunoglobulin of normal rabbits have been resolved into distinct, multiple components by disc electrophoresis in polyacrylamide gels in the presence of urea. In spite of the resolution of these chains into multiple bands, different specific antibodies and normal rabbit (gamma)G-immunoglobulin were indistinguishable from each other by this method.     

Antibody active sites and immunoglobulin molecules

In order to obtain detailed information about the relationship between structure and function in antibody molecules, a method called affinity labeling has been devised to attach chemical labels specifically to amino acid residues in the active sites of antibody molecules. With antibodies to three different haptens, highly specific labeling of the active sites has been achieved. Tyrosine residues on both heavy and light polypeptide chains have been labeled in a molar ratio close to 2:1, and labels on the two chains are equally specific to the active sites. Peptide fragmentation studies of the labeled chains of one antibody system have shown that: (i) within 25 amino acid residues of the labeled tyrosine on either chain, substantial chemical heterogeneity exists among different antibody molecules of the same specificity; and (ii) the labeled peptide fragments from both chains are very similar in physicochemical characteristics, including average size, heterogeneity, and unusual hydrophobicity. These experimental results have led us to the view that a particular region of the heavy chain and a particular region of the light chain are utilized to construct the active sites of the three different antibodies, differences in specificity arising from chemical perturbations in these two regions. Correlated structural studies of affinity-labeled antibodies and of the homogeneous light chains (Bence Jones proteins) and heavy chains produced in multiple myeloma may permit the identification of these special active-site regions. The view that active sites of different specificity are chemical perturbations of a particular region of the antibody molecule has a possible close analogue in enzyme systems, particularly among the esterases. The marked chemical similarities we have observed between the active site regions of heavy and light chains indicate to us that chemical homologies, but not identities, exist between the chains. This is reinforced by recently obtained amino acid sequence data which reveal homologies between the two chains near their carboxyl-terminals. These results indicate that the structural genes which code for the synthesis of heavy and light chains are related, presumably having arisen from some common ancestral gene during evolution. This conclusion strongly suggests that both heavy and light chains determine antibody specificity, and has important implications for the still-unknow mechanisms of antibody biosynthesis.     

Focused evolution of HIV-1 neutralizing antibodies revealed by structures and deep sequencing

Antibody VRC01 is a human immunoglobulin that neutralizes about 90% of HIV-1 isolates. To understand how such broadly neutralizing antibodies develop, we used x-ray crystallography and 454 pyrosequencing to characterize additional VRC01-like antibodies from HIV-1-infected individuals. Crystal structures revealed a convergent mode of binding for diverse antibodies to the same CD4-binding-site epitope. A functional genomics analysis of expressed heavy and light chains revealed common pathways of antibody-heavy chain maturation, confined to the IGHV1-2*02 lineage, involving dozens of somatic changes, and capable of pairing with different light chains. Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies thus involves the evolution of antibodies to a highly affinity-matured state required to recognize an invariant viral structure, with lineages defined from thousands of sequences providing a genetic roadmap of their development.     

北沙柳及几种柳树过氧化物酶同功酶遗传变异的研究

采用聚丙烯酰胺垂直电泳技术地北沙柳及其它柳树进行过氧化物酶同功酶遗传变异的研究。结果表明,试材共有酶带２５条,基本酶带９条,变异带１６条,其中有１条酶带为试材所共有。在沙柳无性系中是多的有１３条带,最少的４条带,从酶谱图中可知,按染色程度可划分为３个区,从负极到正极依次为Ａ,Ｂ,Ｃ三区,可假定分属为３个基因位点控制,每个位点从分子水平讲,含有多个座位亦即多个等位基因,从而表现了过氧化物酶同功酶的可     

水稻不同部位酯酶同工酶酶带和酶谱分析

采用聚丙烯酰胺凝胶电泳，对供试水稻不同品种９个部位６２３１个样本进行酯酶同工酶分析．重复性较好的酶带共有１７条．不同部位酶带的条数各不相同．酶带和酶谱类型与品种形态特征有密切关系．同一个部位的酶带因品种而异，分为所有品种都出现的基本酶带及不是所有品种都会出现的鉴别酶带两种类型．以鉴别酶带条数为ｎ，用Ｍ＝２ｎ可以估计该部位酶谱类型的数量Ｍ．各条酶带表达了不同等级的差异水平．各部位酶谱类型可以作为水稻品种鉴别和分类的一种生化指标．     

甜荞·苦荞和大野荞的高分子量种子蛋白亚基研究

[目的]探讨甜荞、苦荞和大野荞的高分子量种子蛋白亚基。[方法]利用SDS-PAGE电泳法对18个不同地方居群的大野荞、3个甜荞和3个苦荞收集系的高分子量种子蛋白亚基进行研究。[结果]从这3个物种的24个收集系中,在高分子量区域（20-70 kDa）共发现12个不同的种子蛋白亚基谱带,种间差异大,种内差异小。3个物种在种子蛋白亚基分布上存在一定的相似性,约30%的谱带相同。其中,甜荞发现有9个谱带,含1个独特谱带（SSP33.71）;苦荞有8个谱带,含不同于甜荞的2个独特谱带（SSP39.15和SSP29.35）;大野荞有7个谱带,不仅含有苦荞的独特谱带,而且其谱带分布与苦荞极为相似。[结论]该研究为荞麦品质遗传育种、种间系统关系、高品质种子蛋白亚基基因工程等研究提供指导。     

Macroglobulin structure: variable sequence of light and heavy chains

The variable regions of the light and heavy chains on the same macroglobulin (immunoglobulin M) molecule are no more related in amino acid sequence than are the variable regions of the light and heavy chains of different immunoglobulin molecules. Subgroups of micro chains are similar in their variable sequence to subgroups of gamma chains.     

Unusual topogenic sequence directs prion protein biogenesis

Biosynthetic studies of the prion protein (PrP) have shown that two forms of different topology can be generated from the same pool of nascent chains in cell-free translation systems supplemented with microsomal membranes. A transmembrane form is the predominant product generated in wheat germ (WG) extracts, whereas a completely translocated (secretory) form is the major product synthesized in rabbit reticulocyte lysates (RRL). An unusual topogenic sequence within PrP is now shown to direct this system-dependent difference. The actions of this topogenic sequence were independent of on-going translation and could be conferred to heterologous proteins by the engineering of a discrete set of codons. System-dependent topology conferred by addition of RRL to WG translation products suggests that this sequence interacts with one or more cytosolic factors.     

花生种子不同部位脂肪氧化酶同工酶的鉴定研究

[目的]为了筛选脂肪氧化酶缺失的花生品种。[方法]根据花生种子脂肪氧化酶同工酶等电点差异,利用等电聚焦电泳技术,对6份花生种子不同部位的脂肪氧化酶进行鉴定分析。[结果]完整的花生种子脂肪氧化酶同工酶有3条带,子叶脂肪氧化酶同工酶有2条带,种胚的脂肪氧化酶同工酶有7条带;花生种胚脂肪氧化酶同工酶的IEF-PAGE图谱有差异,除品种P86呈现6条带以外,其他品种均呈现7条酶带,P86缺失1条带;相同品种花生种子不同部位的脂肪氧化酶的电泳图谱不同。[结论]脂肪氧化酶主要集中在花生的种胚部分。     

棉花黄萎病菌田间动态的分子监测

 分别于1994年3月和1995年3月从同一棉田,采集分离了48个大丽轮枝菌菌株.应用RAPD技术,从240个随机引物中筛选了17个扩增效果好的引物,对供试菌株进行了DNA指纹分析.结果表明:17个引物对48个菌株扩增出120条DNA分子片段,其中43条分子片段为多态带,占35.83%.将扩增结果输入计算机,用PHYLIP分析软件(3.5版本),UPGAME程序进行类聚分析,结果表明95年的5个菌株与其它菌株存在明显的遗传差异.     

四川四倍体小麦地方品种酯酶同工酶

对30份产于四川的四倍体小麦地方品种(T.TurgidumL.)的酯酶同工酶分析表明,四倍体小麦的幼苗、剑叶和幼穗间酯酶同工酶存在较大差异。其中,幼苗有14条带,12种类型;剑叶15条带,13种类型;幼穗13条带,11种类型。3次测定合并分析,则产生21种类型。若仅以1次测定看,多样性指数以剑叶最高,为0 1119,说明剑叶酯酶同工酶能更好地反映其遗传多样性。同时酯酶同工酶的差异证明,来源相同又同名但原始编号不同的两份"棒棒南麦"和两份"早佐"具有不同的基因型,应视为不同的品种。     

鹅观草属三个物种及其居群间的酯酶同工酶分析

利用聚丙烯酰胺垂直平板电泳技术对小麦族鹅观草属 3个物种 :毛叶鹅观草Roegneriaamurensis (Drob .)Nevski、纤毛鹅观草R .ciliaris (Trin .)Nevski和竖立鹅观草R .japonensis (Honda)Keng的 2 2份材料的幼苗进行了酯酶同工酶比较分析。结果表明 :① 3个物种的酯酶同工酶酶谱相似 ,说明 3个物种有相同或相近的遗传基础 ,亲缘关系较近 ,但 3个物种种间无完全相同的酶谱 ,或多或少表现差异 ;②种间差异大于种内差异 ;③同种不同居群间酶谱也存在差异。     

滇中茶树种质资源亲缘关系的ISSR分析

采用ISSR技术对滇中不同地区17份有代表性的茶样的亲缘关系进行研究。随机选择28条ISSR引物进行筛选,获得15条能产生清晰条带的引物。将这些引物分别进行ISSR-PCR扩增,共获得稳定且清晰的谱带112条,多态性谱带103条,多态性比率为91.96%,平均每条引物扩增出7.4条谱带。17份滇中茶样的遗传相似系数变化范围为0.58-0.80,聚为两类,第Ⅰ类包含12份种质,第Ⅱ类包含5份种质。     

Two novel classes of small ribonucleoproteins detected by antibodies associated with lupus erythematosus

The RNP and Sm antigens recognized by lupus erythematosus antibodies are located on discrete particles containing single small nuclear RNA's complexed with proteins. The antigens Ro and La are also on ribonucleoproteins. The small RNA's in ribonucleoproteins with Ro are discrete, like those associated with RNP and Sm; in contrast, ribonucleoproteins with La contain a striking highly banded spectrum of small RNA's from uninfected cells as well as virus-associated RNA from adenovirus-infected cells.     

濒危植物缙云卫矛细胞色素氧化酶的同工酶变异

采用丙烯酰胺琼脂电泳技术,对重庆北碚缙云山麓特产缙云矛３个居群的３６个个体功能叶片细胞色素氧化酶的同工酶谱带进行了测定,并进行编码,然后采用Ｓｏｋａｌ－Ｓｎｅａｔｈ结合系数的组平均法（ＵＰＧＭＡ）和Ｓｏｋａｌ－Ｍｉｃｈｅｎｅｒ结合系数的加权平均法（ＷＰＧＭＡ）对各酶谱带进行聚类分析;同时结合遗传杂合度（Ｈｅ）、遗传相似性系数（Ｉ）、遗传距离（Ｄ）进行遗传分析。结果表明,来自同一居群的个体,不但同工     

利用醋酸纤维素薄膜电泳显示金针菇酯酶同工酶

[目的]利用醋酸纤维素薄膜电泳分析金针菇酯酶同工酶。[方法]以6种金针菇为材料,采用醋酸纤维素薄膜电泳对其酯酶同工酶进行分析,并与利用PAGE法得到的针菇酯酶同工酶图谱进行对比。[结果]6种金针菇共电泳得到20条酯酶同工酶带,其中相对迁移率不同的共有8条,大小分别为0.580、0.613、0.645、0.709、0.806、0.839、0.871、0.934;6种金针菇中,①号和②号有3条相同的带,④号和⑤号条带完全相同,③号与④号、⑤号有2条相同的带,⑥号与其他5种菌株间相同的条带较少。[结论]该试验结果与PAGE法显示的金针菇酯酶同工酶图谱基本一致,为实现利用醋酸纤维素薄膜电泳技术快速检测各类食用菌酯酶同工酶提供了可能。     

SSR标记在疣粒野生稻和普通栽培稻中的多态性研究

利用SSR标记分析了疣粒野生稻同栽培稻IR24间的遗传多样性,并对引物扩增条带类型进行了比较分析.结果表明,在所用的159对引物中共有153对引物检测到多态性位点,占总引物数的96.8%.在2个材料中共有848个位点扩增出条带,其中扩增条带片段大小相同的有67条,占总带数的7.9%.引物扩增多态性条带可以分为扩增条带片段大小不同、扩增条带数目不同和扩增条带强弱不同3种类型.说明在栽培稻中开发的SSR标记在疣粒野生稻中发生了很大的变异,不适宜进行遗传多样性分析,但仍可以应用于疣粒野生稻进行分子标记辅助选择.     

Molecular diffuse interstellar band carriers in the red rectangle

High-resolution optical spectroscopic observations of unidentified emission bands from the unusual biconical nebula known as the Red Rectangle are reported. The peak wavelengths and the widths of prominent bands near 5799, 5853, and 6616 angstroms decrease with increasing offset from the central A0-type star HD 44179 and, in the limit of large distance from the star, are shown to converge toward the known values for some of the narrower diffuse interstellar absorption bands at 5797, 5850, and 6614 angstroms. The same carriers give rise to both Red Rectangle emission and corresponding diffuse interstellar absorption bands, and these particular bands arise from electronic transitions in gas-phase molecules.     

洞庭湖区不同体色鲇不同组织同工酶的比较研究

采用聚丙烯酰胺垂直凝胶电泳技术(PAGE),对洞庭湖区两种体色(灰色、黄色)鲇的肝脏和肌肉组织中的苹果酸脱氢酶(MDH)、酯酶(EST)和乳酸脱氢酶(LDH)等3种同工酶进行研究。结果表明,在MDH同工酶中,两种鲇肝脏各有5条酶带,肌肉均有4条酶带表达;两种体色鲇鱼的同种组织中EST同工酶的酶谱不相同,黄色鲇鱼的EST同工酶检测出8条酶带,而灰色鲇鱼只有4条酶带;EST同工酶在不同组织中也表现出明显的组织特异性。在LDH同工酶中,黄色鲇肝脏有2条酶带,肌肉有1条酶带;而灰色鲇肝脏和肌肉中各有1条酶带。     

柑桔的柑桔炭疽菌酯酶同工酶的测定

<正> 近十多年来探索菌体蛋白的凝胶电泳方法作为微生物分类辅助手段的研究愈来愈多,已证明对鉴定腐霉、锈菌、长啄菌、链孢霉、镰刀菌及疫霉有帮助。此外,利用同工酶对各物种、种群的特异性表达作生物分类的研究,也是对传统分类学的重要补充。因此,同工酶的测定作为真菌分类的手段也受到重视。吕金殿等(1980)对我国主要产棉区的42个分离系进行了酯酶同工酶的测定,结果表明测定棉桔萎病菌酯酶同工酶可以作为用鉴别寄主鉴定