大熊猫AP2S1基因cDNA 克隆及分析

该研究运用RT-PCR技术,首次从大熊猫Ailuropoda melanoleuca的肌肉组织总RNA中成功克隆了AP2S1基因的编码序列,并对其进行了全面分析.结果表明:大熊猫AP2S1基因编码序列克隆片段全长为512bp,开放阅读框(ORF)为429bp,编码142个氨基酸的蛋白质,该蛋白的相对分子质量为1.7×104,等电点pI为5.82,含有4种类型共5个功能位点,即1个蛋白激酶C磷酸化位点、2个酪蛋白激酶Ⅱ磷酸化位点、1个N-酰基化位点和1个网格蛋白调节素小肽链标签;且该蛋白在哺乳动物网状细胞中的半寿期(half-life)大于30h,不稳定指数(in-stability index)为26.99,属于稳定蛋白.进一步分析发现,大熊猫AP2S1基因与已报道的人、苏门答腊猩猩、牛、褐家鼠和小家鼠5个哺乳动物物种的编码序列及其编码的氨基酸序列具有很高的相似性,表明该基因及其编码蛋白在物种漫长的进化过程中极其保守.     

巴西橡胶树CCaMK基因家族成员的鉴定和表达分析

钙/钙调素依赖型蛋白激酶(CCa MK,calcium-and calmodulin-dependent protein kinase)是一种钙离子结合蛋白,在钙信号传导过程中起重要作用。本研究以已发表的CCa MK序列作为检索序列,对橡胶树和其他5种植物(木薯、水稻、杨树、蓖麻和拟南芥)的基因组和转录组数据进行全面搜索,鉴定得到6个CCa MK基因,其中包括一个橡胶树CCa MK基因,命名为Hb CCa MK1。序列分析发现:5种植物的CCa MK氨基酸序列同源性较高,为73%~94%。基因结构分析发现,Hb CCa MK1和所分析的其他植物CCa MK一样均,含有6个内含子、1个蛋白激酶结构域和3个EF-hand结构域;从结构和进化上看,Hb CCa MK1和蓖麻、木薯2种植物的CCa MK具有较近的亲缘关系;在表达方面,Hb CCa MK1在橡胶树根中表达丰度最高,其次为树叶和花;另外,Hb CCa MK1的表达还与叶片发育、真菌侵染和低温胁迫有关。     

巴西橡胶树叶片蛋白样品的制备及质谱初步分析

采用TCA-丙酮沉淀法并稍做改进提取巴西橡胶树叶片总蛋白,蛋白溶解后,用试剂盒对蛋白上清液进行纯化和浓度测定。十二烷基磺酸钠-聚丙烯酰胺凝胶电泳（SDS—PAGE）和双向凝胶电泳（2-DE）的结果均表明,所制得的蛋白样品质量较高,并且纯化过的蛋白样品2-DE（双向电泳）图谱效果更好（7cm,考染）。根据预实验结果,选用17cm IPG预制干胶条对纯化的蛋白样品进行2-DE实验,采用快速银染法进行染色,随机挖取银染胶上6个蛋白点进行MALDI-TOF MS分析和数据库检索,鉴定了3个蛋白,它们是：1-氨基环丙烷-1羧酸合酶2,核酮糖-1,5-二磷酸羧化酶／加氧酶大亚基和F1104．2。本实验为进一步对巴西橡胶树叶片中具有重要生物学功能蛋白的筛选和鉴定打下了方法学基础。     

适于双向电泳分析的番茄叶片总蛋白提取方法的优化

比较了三氯乙酸(TCA)、酚和十二烷基硫酸钠(SDS)3种提取方法在所获番茄叶片总蛋白产量及其在SDS聚丙烯酰胺凝胶电泳分辨率等方面的区别,并对3种蛋白溶解液以及超声处理在蛋白质溶解中的作用进行了分析探讨。结果表明,TCA提取法最佳,该方法提取番茄叶片总蛋白的得率最高、所获蛋白在SDS聚丙烯酰胺凝胶电泳中形成条带数目最多,最清晰;酚法次之;SDS法最差。由离液剂和去污剂组成的蛋白溶解液复溶蛋白沉淀所获蛋白产量显著高于Tris-NaCl溶解液。还原剂和两性电解质以及超声处理显著增进蛋白质的溶解,提高蛋白产量。采用TCA提取法获得蛋白沉淀,再以溶解液Ⅱ(7 mol/L尿素,2 mol/L硫尿,2%CHAPS,2%SB3-10,65 mmol/L DTT,0.2%两性电解质)溶解,结合超声助溶的方法体系可以获得高得率和高电泳分辨率的番茄叶片总蛋白样品,该方法适用于双向电泳分析等下游操作。     

猪CD8β分子重组蛋白的表达、纯化与免疫活性鉴定

对猪CD8β(pCD8β)基因重组蛋白的表达纯化条件以及免疫活性进行了研究.结果表明:pET-28a-pCD8β重组菌诱导表达产物的分子量约为24 ku,与预计的分子量大小相符.包涵体形式表达的重组蛋白的纯化产物经免疫印迹分析和ELISA检测证实有良好的特异性反应;SDS-PAGE后的目的胶带以直接研磨法和电洗脱纯化法加佐剂分别免疫BALB/c小鼠后,ELISA检测抗原免疫效价均大于1∶6 400,说明本试验对pET-28a-pCD8β纯化的重组蛋白具有良好的免疫原性和反应原性,可以制备CD8β的单克隆抗体.     

青杨双向电泳实验体系的建立

用改良丙酮沉淀法、三氯乙酸（TCA）-丙酮沉淀法和酚抽法抽提青杨Populuscathayana的蛋白质,分别获得了437,603和721个蛋白斑点,以酚抽法提取的分离纯化方法效果最佳,不仅能很好地提取蛋白,而且能有效去除样品中的盐分。通过比较,分析了双向电泳不同条件对电泳结果的影响,确立了300μg·IPG胶条^-1的最佳上样量、90000V·h的聚焦时间以及20min平衡时间的双向电泳条件。研究还比较了氯化钠胁迫前后双向电泳图谱差异,发现有46个蛋白点存在差异,其中10个下调,36个上调（4个新诱导表达）。     

Molecular Cloning, and Characterization of an Adenylyl Cyclase-Associated Protein from Gossypium arboreum L.

The aim of this study was to clone CAP （adenylyl cyclase-associated protein） gene from Gossypium arboreum L. and develop a platform for expressing and purifying CAP protein, which is a base for the construction and function researches of CAP. In this work, a CAP homolog from cotton （DPL971） ovule was identified and cloned. And the cDNA sequence consisted of an open reading frame of 1 416 nucleotides encoding a protein of 471 amino acid residues with a calculated molecular weight of 50.6 kDa. To gain insight on the CAP role in cotton fiber development, the cloned CAP cDNA was expressed. A significant higher yield pure protein was obtained with the chromatographic method. Further experiments showed that the purified protein can bind with the actin in vitro indicating that the recombinant cotton CAP is functional. The procedure described here produced high yield pure protein through one chromatographic step, suitable for further structure-function studies.     

沙冬青热胁迫相关蛋白基因AmHsa32超表达提高大肠杆菌的抗热性

热胁迫相关蛋白32（Heat stress associated protein 32,Hsa32）与植物的抗逆性密切相关。本文将从沙冬青低温干旱EST库中获得的热胁迫相关蛋白基因AmHsa32进行了非生物胁迫下的表达分析与转化大肠杆菌研究。生物信息学分析表明,AmHsa32的编码区全长858 bp,编码286个氨基酸,预测分子量约32 kD,与拟南芥HSA32亲缘关系较近。qRT PCR分析显示,AmHsa32在沙冬青幼苗中受热胁迫诱导后表达量迅速提高,1 h后达到对照的25倍;对其他非生物胁迫如低温、干旱及盐均有响应,表达量有不同程度的增加,说明AmHsa32对沙冬青非生物胁迫抗性的提高可能发挥着重要作用。将AmHsa32基因转化大肠杆菌,同野生菌相比,热胁迫（50 ℃）条件下,转基因大肠杆菌存活率明显提高。本研究结果表明,AmHsa32可用于通过转基因技术提高热敏感植物抗热性的研究。      

小麦高蛋白质含量基因GPC-B1的分子标记研究

应用SSR分子标记技术对4份来自美国的小麦研究材料的高蛋白含量基因GPC-B1进行分子标记分析。通过引物筛选和标记研究,其SSR分子标记为Xuhw89122。为鉴定其分子标记分析结果,对所有的小麦研究材料进行蛋白质含量的测定,来自美国的4份研究材料之一的PI638740的蛋白质含量高达20.41%,明显高于其他研究材料。田间观察结果显示,PI638740的成熟期比别的研究材料提前衰老一周左右。本研究将为转移控制小麦高蛋白质含量的基因到其他优良小麦品种(品系)中、推进小麦育种进程及改进小麦育种技术提供理论依据。     

简析氮素营养对超高产小麦的调控

小麦籽粒蛋白质含量与氮代谢密切相关。许多研究表明,小麦籽粒氮一方面来自开花后吸收的氮素,另一方面来自开花前营养体积累氮素的再运转。在营养体氮素的再运转中,蛋白质的降解起着重要作用,蛋白质的降解又与蛋白水解酶活性的上升相关,小麦籽粒中的氮素绝大部分来自开花前植株贮存氮素的再运转,只有少部分是开花后吸收的。因此,在小麦生产中除了强调提高植株后期吸收氮素的能力外,应十分重视叶片蛋白质的降解,即氮素的再运转分配,选择开花后氮素吸收同化和氮素再运转能力强的小麦品种,既有利于提高籽粒产量,又可提高籽粒蛋白质含量。此外,小麦籽粒也具有氮素同化能力,关于籽粒的氮素同化能力与籽粒蛋白质含量的关系,有待进一步研究。通过氮素对小麦光合能力、生理活性、群体质量、籽粒产量及粒质量的调控,以及对库源流关系的影响,达到小麦高产的目的。     

Splice junctions: association with variation in protein structure

A comparison between eukaryotic gene sequences and protein sequences of homologous enzymes from bacterial and mammalian organisms shows that intron-exon junctions frequently coincide with variable surface loops of the protein structures. The altered surface structures can account for functional differences among the members of a family. Sliding of the intron-exon junctions may constitute one mechanism for generating length polymorphisms and divergent sequences found in protein families. Since intron-exon junctions map to protein surfaces, the alterations mediated by sliding of these junctions can be effected without disrupting the stability of the protein core.     

Systematic evolution of ligands by exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase

High-affinity nucleic acid ligands for a protein were isolated by a procedure that depends on alternate cycles of ligand selection from pools of variant sequences and amplification of the bound species. Multiple rounds exponentially enrich the population for the highest affinity species that can be clonally isolated and characterized. In particular one eight-base region of an RNA that interacts with the T4 DNA polymerase was chosen and randomized. Two different sequences were selected by this procedure from the calculated pool of 65,536 species. One is the wild-type sequence found in the bacteriophage mRNA; one is varied from wild type at four positions. The binding constants of these two RNA's to T4 DNA polymerase are equivalent. These protocols with minimal modification can yield high-affinity ligands for any protein that binds nucleic acids as part of its function; high-affinity ligands could conceivably be developed for any target molecule.     

烟草环斑病毒的RT-PCR和IC-RT-PCR检测方法研究

根据TRSV CP基因的保守序列设计引物,RT-PCR和IC-RT-PCR能从TRSV的2个分离物中分别扩增到与预期大小相同的DNA条带,序列测定和分析表明所扩增序列为TRSV CP基因的部分序列,在系统关系树上与TRSV的其他分离物形成一簇,表明所建立的RT-PCR和IC-RT-PCR检测方法是可靠的。     

Circumsporozoite protein heterogeneity in the human malaria parasite Plasmodium vivax

Phenotypic heterogeneity in the repetitive portion of a human malaria circumsporozoite (CS) protein, a major target of candidate vaccines, has been found. Over 14% of clinical cases of uncomplicated Plasmodium vivax malaria at two sites in western Thailand produced sporozoites immunologically distinct from previously characterized examples of the species. Monoclonal antibodies to the CS protein of other P. vivax isolates and to other species of human and simian malarias did not bind to these nonreactive sporozoites, nor did antibodies from monkeys immunized with a candidate vaccine made from the repeat portion of a New World CS protein. The section of the CS protein gene between the conserved regions I and II of a nonreactive isolate contained a nonapeptide repeat, Ala-Asn-Gly-Ala-Gly-Asn-Gln-Pro-Gly, identical at only three amino acid positions with published nonapeptide sequences. This heterogeneity implies that a P. vivax vaccine based on the CS protein repeat of one isolate will not be universally protective.     

灌水处理对不同强筋小麦品种产量和蛋白质含量的影响

选用来自7个省的不同强筋小麦品种,进行不同春季灌水处理,分析其产量和子粒蛋白质含量的变化。结果表明：在春季干旱的情况下,随着春季灌水次数的增加产量提高,不同品种间的产量差异极显著,以烟农19的产量最高,其次是济麦20。不同品种的子粒蛋白质含量随着春季灌水次数的增加而降低（皖麦38除外）,不同品种间、不同灌水处理间蛋白质含量差异极显著,以临优145的蛋白质含量最高,其次是8901-11。     

大肠杆菌不耐热肠毒素B亚单位基因的原核表达

大肠杆菌(Escherichia coli)不耐热肠毒素B亚单位(LTB)不仅是重要的黏膜免疫原,而且作为佐剂在黏膜免疫中起着重要的作用.试验采用PCR方法扩增了肠毒素性大肠杆菌的LTB基因,并将其克隆到pGEX-KG原核表达栽体上,构建了重组质粒pKG-LTB,经酶切和测序鉴定后,转化到大肠杆菌BL21(DE3)进行IPTG诱导表达,经SDS-PAGE和Western-blot分析表明,克隆的LTB基因与谷胱甘肽转移酶(GST)基因获得了高效融合表达,表达的融合蛋白GST-LTB分子量约为35kDa,并具有免疫反应活性.这为进一步研究LTB蛋白黏膜免疫原性和黏膜佐剂的作用奠定了基础.     

The DNA-binding properties of the major regulatory protein alpha 4 of herpes simplex viruses

The transition from the expression of alpha, the first set of five herpes simplex virus genes expressed after infection, to beta and gamma genes, expressed later in infection, requires the participation of infected cell protein 4 (alpha 4), the major viral regulatory protein. The alpha 4 protein is present in complexes formed by proteins extracted from infected cells and viral DNA fragments derived from promoter domains. This report shows that the alpha 4 protein forms specific complexes with DNA fragments derived from 5' transcribed noncoding domains of late (gamma 2) genes whose expression requires viral DNA synthesis as well as functional alpha 4 protein. Some of the DNA fragments to which alpha 4 binds do not contain homologs of the previously reported DNA binding site consensus sequence, suggesting that alpha 4 may recognize and interact with more than one type of DNA binding site. The alpha 4 proteins can bind to DNA directly. A posttranslationally modified form of the alpha 4 protein designated alpha 4c differs from the alpha 4a and alpha 4b forms with respect to its affinity for DNA fragments differing in the nucleotide sequences of the binding sites.     

改良一步法提取植物RNA、DNA和蛋白质的研究

[目的]利用改良的一步法提取植物RNA、DNA和蛋白质。[方法]采用CTAB试剂对Biozol抽提法进行改良,用一步法分别对玉米（Zea maysL.）、大豆（Glycine maxL.）、苜蓿（Medicago sativaL.）和黄瓜（Cucumis sativusL.）4种作物根的RNA、DNA和蛋白质进行共提取,并对其HO-1和CDPK1基因及HO-1蛋白进行鉴定。[结果]经紫外分光光度计测定和琼脂糖凝胶电泳分析证明获得的RNA和DNA样品纯度较高;HO-1基因和CDPK1基因的RT-PCR结果呈阳性;所提取的蛋白质也可用于Western blot分析;整个提取过程只需3h。[结论]该方法实用性较强,具有广泛的应用价值。     

One polypeptide with two aminoacyl-tRNA synthetase activities

The genome sequences of certain archaea do not contain recognizable cysteinyl-transfer RNA (tRNA) synthetases, which are essential for messenger RNA-encoded protein synthesis. However, a single cysteinyl-tRNA synthetase activity was detected and purified from one such organism, Methanococcus jannaschii. The amino-terminal sequence of this protein corresponded to the predicted sequence of prolyl-tRNA synthetase. Biochemical and genetic analyses indicated that this archaeal form of prolyl-tRNA synthetase can synthesize both cysteinyl-tRNA(Cys) and prolyl-tRNA(Pro). The ability of one enzyme to provide two aminoacyl-tRNAs for protein synthesis raises questions about concepts of substrate specificity in protein synthesis and may provide insights into the evolutionary origins of this process.