Cytokinin activity: localization in transfer RNA preparations

Transfer RNA from yeast, liver, and Escherichia coli has cytokinin activity in the tobacco callus bioassay, whereas ribosomal RNA from yeast is inactive. In contrast to fractions of yeast transfer RNA rich in serine acceptor and cytokinin activity, preparations (70 to 90 percent pure) of arginine transfer RNA(2), glycine transfer RNA, phenylalanine transfer RNA, and valine transfer RNA(1) and of highly purified alanine transfer RNA from yeast were inactive at concentrations of 20 to 2500 micrograms per liter. One molecule of 6-(gamma,gamma-dimethylallylamino) purine per 20 molecules of yeast tRNA would account for the observed cytokinin activity. The number of major molecular species contributing to cytokinin activity of transfer RNA, therefore, must be small.     

适于葡萄不同组织RNA提取方法的筛选

比较了CTAB法、改良CTAB法、Trizol法、SDS-苯酚法和改良SDS法5种RNA提取方法提取葡萄叶片、花序、茎尖、卷须和果实组织RNA的效果。并进一步从总RNA中分离出了高质量的低分子量RNA(LMWRNA),建立了葡萄LMWRNA提取的方法。改进后的改良SDS法能够克服果实中RNA提取难度大的问题,能够从果实中提取到质量和产量都很高的RNA。结果表明,改良SDS法适用于葡萄叶片、花序、茎尖、卷须组织中总RNA的提取,改进的改良SDS法是从果实中提得LMWRNA较佳选择。在总RNA提取的基础上建立的葡萄LMWRNA提取方法能够达到研究的要求。     

Messenger RNA in early sea-urchin embryos: size classes

Rapidly labeled RNA from four-cell embryos and blastulae of sea urchins was analyzed by sedimentation and for ability to form DNA-RNA hybrids. The RNA was derived from polyribosomes and from the "gel interphase," an extraction compartment resulting from treatment of whole embryos with phenol and known to be enriched with nuclei. The RNA from both sources displayed a high degree of structural complementarity to DNA. This DNA-like RNA of the polyribosomes sedimented in discrete classes, rather than in the sedimentation continuum demonstrable for the labeled RNA of the gel interphase. Thus messenger RNA appears to emerge in the cytoplasm in discrete size classes.     

鱼腥草叶片总RNA提取方法研究

[目的]筛选出适合鱼腥草（Houttuynia cordata）叶片RNA提取的方法。[方法]以鱼腥草叶片为材料,比较了经典RNA提取试剂盒、Trizol试剂盒A、Trizol试剂盒B以及富含多糖类材料RNA提取试剂盒提取鱼腥草RNA的效果。[结果]Trizol试剂盒A、Trizol试剂盒B和经典RNA提取试剂盒难以提取出高质量的RNA,而富含多糖类材料RNA提取试剂盒提出的RNA质量高,完整性好,可以满足进一步分子生物学研究的要求。[结论]普通RNA提取试剂盒难以提取出鱼腥草叶片的RNA。     

Trizol试剂法快速高效提取3种作物不同组织总RNA

[目的]建立适用于禾本科作物不同组织总RNA的快速、高效提取方法,为进行后续的分子生物学研究奠定基础.[方法]采用Trizol试剂法,通过改变抽提上清液吸取量、沉淀方法及沉淀漂洗次数,对甘蔗、玉米和水稻的叶片、茎尖和根尖的总RNA提取方法进行优化.[结果]与吸取0.4 mL上清液相比,吸取0.2 mL上清液的总RNA OD260/OD280、OD260/OD230值分别在1.95~2.00和2.11~2.44,所获得的总RNA纯度较高.沉淀漂洗两次的OD260/OD230值(2.11~2.47)明显高于沉淀漂洗1次的总RNA OD260/OD230值(1.01~1.61),总RNA纯度较高.经异丙醇沉淀所得的各材料的总RNA 28S、18S和5S谱带清晰,无拖尾现象,总RNA完整性较好;LiCl沉淀法的RNA条带较模糊粘连,5S条带明显弥散,总RNA产率相对较低.以Trizol-异丙醇法提取的甘蔗总RNA为模板进行GAPDH基因片段扩增,所获甘蔗的叶片、茎尖和根尖的GAPDH基因表达丰度很强,无特异扩增,目的片段长度为153bp.[结论]改良Trizol-异丙醇法提取甘蔗、玉米和水稻不同组织的总RNA带型清晰、完整性好、纯度和产率高,适用于快速、高效提取禾本科植物不同组织总RNA.     

Detergent-solubilized RNA polymerase from cells infected with foot-and-mouth disease virus

The foot-and-mouth disease virus RNA polymerase complex was dissociated from cellular membranes with deoxycholate in the presence of dextran sulfate. The soluble polymerase complex was active in the cell-free synthesis of virus-specific RNA; solubilization of the complex permitted direct analysis of the cell-free reaction mixtures without recourse to RNA extraction. A major RNA-containing component found early during cell-free incubation ranged from approximately 140 to 300S. The final major products of the cell-free system were 37S virus RNA, 20S ribonuclease-resistant RNA, and a 50S component containing RNA.     

木本植物组织总RNA提取的要点与原理

根据提取木本植物组织RNA时所获得的知识和经验，对木本植物组织总RNA提取时所遇到的提取产量低、RNA降解、多酚物质干扰、DNA干扰、多糖干扰、蛋白质干扰及杂质干扰等问题进行了探讨，并提出了具体的解决方法。同时，对各种常用的RNA提取方法进行了分类，并对它们的原理及优劣进行了论述与评价。     

Specific interactions in RNA enzyme-substrate complexes

Analysis of crosslinked complexes of M1 RNA, the catalytic RNA subunit of ribonuclease P from Escherichia coli, and transfer RNA precursor substrates has led to the identification of regions in the enzyme and in the substrate that are in close physical proximity to each other. The nucleotide in M1 RNA, residue C92, which participates in a crosslink with the substrate was deleted and the resulting mutant M1 RNA was shown to cleave substrates lacking the 3' terminal CCAUCA sequence at sites several nucleotides away from the normal site of cleavage. The presence or absence of the 3' terminal CCAUCA sequence in transfer RNA precursor substrates markedly affects the way in which these substrates interact with the catalytic RNA in the enzyme-substrate complex. The contacts between wild-type M1 RNA and its substrate are in a region that resembles part of the transfer RNA "E" (exit) site in 23S ribosomal RNA. These data demonstrate that in RNA's with very different cellular functions, there are domains with similar structural and functional properties and that there is a nucleotide in M1 RNA that affects the site of cleavage by the enzyme.     

山梨醇对李果肉组织总RNA提取的影响

探讨了不同浓度的山梨醇清洗溶液对李果肉组织中RNA提取效果的影响。经琼脂糖凝胶电泳、核酸蛋白分析仪和RT-PCR等方法对RNA质量和产率进行了分析,结果表明:李果肉组织研磨后用山梨醇清洗溶液处理有利于总RNA的提取,而不添加山梨醇的清洗溶液,提取液中检测不到RNA,当清洗溶液中山梨醇浓度为1.10mol/L时,李果肉组织总RNA的产率明显高于山梨醇浓度为0.35 mol/L和3.00 mol/L时的产率;以不同贮藏天数的李果实为试材提取总RNA,其结果是一致的;通过RT-PCR扩增蛋白延伸因子EF-2基因,结果证明本试验提取的总RNA可以用于基因转录表达特性分析。     

成熟油菜种子RNA提取方法的改良

[目的]从成熟油菜种子中抽提出高质量的RNA。[方法]该研究通过将天根植物总RNA提取试剂盒与康为世纪植物总RNA提取试剂盒相结合,使用β-巯基乙醇抑制酚类物质氧化,DNA酶去除DNA,并采用吸附柱有效去除多糖类物质等措施,对油菜种子RNA的提取方法进行有效改进。[结果]采用该方法能提取出质量高且完整性好的RNA,可一次满足后续分子生物学研究的要求。[结论]该研究提出了一种高效快捷的成熟油菜种子RNA提取方法。     

Secondary structure of ribosomal RNA

Infrared spectra were obtained for 16S and for 23S ribosomal RNA's in D(2)O solutions. The percentage of each base in the paired and unpaired regions of the RNA was determined from the spectra. The secondary structures of 16S and 23S ribosomal RNA's (from Escherichia coli) are significantly different from each other and are also different from those of yeast ribosomal RNA, formylmethionyl-transfer RNA, and the anticodon fragment of this transfer RNA.     

水稻RNA纯化方法的比较和改进

本实验利用TRIZOL试剂提取水稻苗期叶片总RNA,对三种常用的RNA纯化方法和改进的纯化方法进行了比较。通过凝胶电泳、紫外分光光度法和RT-PCR法检测提取的RNA样品的品质,结果表明,应用改进的RNA纯化方法可有效去除水稻RNA中的DNA污染,电泳条带清晰无降解;OD260/OD280为1.91~1.98,具有较高的纯度;改良方法纯化的RNA逆转录为cDNA,作为PCR扩增的模板,以不同的循环数进行扩增,在反应适宜循环数内检测不到DNA片段污染,说明用改进方法提取的RNA,其质量和纯度可以满足下一步分子生物学研究的需要。     

番木瓜果肉RNA提取方法的比较

为了从成熟末期的番木瓜果肉中提取纯净完整的RNA,本试验采用了TRIzol试剂盒、改良TRIzol、SDS法、CTAB法等4种方法从番木瓜果实中提取总RNA。从RNA的完整性、产率和纯度等方面对这几种方法进行比较和评价,结果表明,采用改良TRIzol所得RNA完整性较其他方法好,条带清晰无明显降解,28S和18S RNA的亮度比约为2∶1,D260/D280达1.9且得率较高,为380.5μg.g-1,经RT-PCR后得到一特异条带表明该RNA可用于后续分子生物学操作。     

适合RT-PCR的苹果芽RNA快速提取方法研究

[目的]从苹果单芽中高效、快速提取RNA,为后续分子生物学研究奠定基础。[方法]分别以苹果品种新红星、嘎拉和富士的单芽为材料,用改良SDS法提取RNA,并经过甲醛变性琼脂糖凝胶电泳和RT—PCR检测RNA质量。[结果]研究出一种高效、快速的苹果单芽RNA提取方法,该方法能在2．5h内得到完整的RNA,经RT—PCR检验,能获得理想的目的片段。[结论]该方法稳定可靠,适合苹果单芽RNA提取。     

BALB/C小鼠不同组织RNA提取方法的比较

为获得高质量BALB/C小鼠的核酸用于荧光定量RT-PCR分析,用某公司的RNA试剂盒、TRIzol试剂、氯化锂分别提取BALB/C小鼠心脏、肝脏和肾脏组织中的RNA。经紫外分光光度计检测发现,用TRIzol试剂在小鼠肾脏组织中获得的核酸片段具有更高的纯度及浓度,而1%琼脂糖凝胶电泳检测发现三种来源的RNA均具有较好的完整性。RT-PCR方法扩增小鼠主要组织相容性复合体蛋白H-2K编码基因,3个样品均可扩增出104 bp的特异性条带。试验验证了TRIzol试剂从不同组织中提取小鼠总RNA均可作为RT-PCR的模板,为后续试验工作奠定基础。     

木薯总RNA提取初步研究

为了筛选适合木薯不同部位总RNA提取的方法,采用常规CTAB法、TRIZOL和RNAplant试剂对木薯叶片和块根总RNA进行提取,并采用两步法进行RT—PCR检测。结果表明,采用常规CTAB法提取木薯总RNA耗时长、效率低,不利于提取大批量材料,但其RNA纯度较高,能产生理想的条带。TRIZOL有利于提取木薯叶片的总RNA而不能提取块根总RNA;RNAplant试剂可以提取木薯各部位的RNA,但纯度不高,且有DNA污染,需要用DNase I处理才能进行RT—PCR检测。TRIZOL和RNAplant试剂混合可以很好地提取木薯各部位总RNA,条带清晰,很少出现降解现象,但仍然无法消除DNA。因此,可根据木薯不同部位要求,选用合适的方法提取总RNA。     

Localization of amyloid beta protein messenger RNA in brains from patients with Alzheimer's disease

The distribution of cells containing messenger RNA that encodes amyloid beta protein was determined in hippocampi and in various cortical regions from cynomolgus monkeys, normal humans, and patients with Alzheimer's disease by in situ hybridization. Both 35S-labeled RNA antisense and sense probes to amyloid beta protein messenger RNA were used to ensure specific hybridization. Messenger RNA for amyloid beta protein was expressed in a subset of neurons in the prefrontal cortex from monkeys, normal humans, and patients with Alzheimer's disease. This messenger RNA was also present in the neurons of all the hippocampal fields from monkeys, normal humans and, although to a lesser extent in cornu ammonis 1, patients with Alzheimer's disease. The distribution of amyloid beta protein messenger RNA was similar to that of the neurofibrillary tangles of Alzheimer's disease in some regions, but the messenger RNA was also expressed in other neurons that are not usually involved in the pathology of Alzheimer's disease.