检索结果-南通市图书馆

A general method for assaying homo-and hetero-transglycanase activities that act on plant cell-wall polysaccharides

Journal of Integrative Plant Biology 2015年第4期57卷 411-428页

作者： Lenka Franková stephen c.fry The Edinburgh cell Wall Group Institute of Molecular Plant SciencesThe University of EdinburghDaniel Rutherford BuildingThe King's Buildings

Transglycanases（endotransglycosylases） cleave a polysaccharide（donor-substrate） in mid-chain, and then transfer a portion onto another poly-or oligosaccharide（acceptor-substrate）. Such enzymes contribute to plant cellwall assembly and/or re-structuring. We sought a general method for revealing novel homo- and hetero-transglycanases, applicable to diverse polysaccharides and oligosaccharides, separating transglycanase-generated3 Hpolysaccharides from unreacted3H-oligosaccharides—the former immobilized（on filter-paper, silica-gel or glassfiber）,the latter eluted. On filter-paper, certain polysaccharides [e.g.（1!3, 1!4）-b-D-glucans] remained satisfactorily adsorbed when water-washed; others（e.g. pectins） were partially lost. Many oligosaccharides（e.g. arabinan-, galactan-, xyloglucan-based） were successfully eluted in appropriate solvents, but others（e.g. [3H]xylohexaitol, [3H]mannohexaitol[3H]cellohexaitol） remained immobile. On silica-gel, all3 Holigosaccharides left an immobile ‘ghost’ spot（contaminating any3H-polysaccharides）, which was diminished but not prevented by additives e.g. sucrose or Triton X-100. The best stratum was glassfiber（GF）, onto which the reactionmixture was dried then washed in 75% ethanol. Washing led to minimal loss or lateral migration of3H-polysaccharides if conducted by slow percolation of acidified ethanol. The effectiveness of GF-blotting was well demonstrated for chara vulgaris transb-mannanase. In conclusion, our novel GF-blotting technique ef ficiently frees transglycanase-generated3H-polysaccharides from unreacted3H-oligosaccharides,enabling high-throughput screening of multiple postulated transglycanase activities utilising chemically diverse donorand acceptor-substrates.

关键词： Glass-fiber blotting plant cell wall polysaccharides（donor） radiolabeled oligosaccharides （acceptor） transglycanase

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The biosynthesis and wall-binding of hemicelluloses in cellulose-deficient maize cells:An example of metabolic plasticity

引用

Journal of Integrative Plant Biology 2015年第4期57卷 373-387页

作者： María de castro Janice G.Miller José Luis Acebes Antonio Encina Penélope García-Angulo stephen c.fry The Edinburgh cell Wall Group Institute of Molecular Plant SciencesSchool of Biological SciencesDaniel Rutherford BuildingThe King's Buildings Laboratory of Plant Physiology Faculty of Biological and Environmental SciencesUniversity of Léon

cell-suspension cultures（Zea mays L.,Black Mexican sweet corn） habituated to 2,6-dichlorobenzonitrile（DcB） survive with reduced cellulose owing to hemicellulose network modification. We aimed to de fine the hemicellulose metabolism modifications in DcB-habituated maize cells showing a mild reduction in cellulose at different stages in the culture cycle. Using pulse-chase radiolabeling, we fed habituated and non-habituated cultures with [3H]arabinose,and traced the distribution of 3H-pentose residues between xylans, xyloglucans and other polymers in several cellular compartments for 5 h. Habituated cells were slower taking up exogenous [3H]arabinose. Tritium was incorporated into polysaccharide-bound arabinose and xylose residues, but habituated cells diverted a higher proportion of their new [3H]xylose residues into（hetero） xylans at the expense of xyloglucan synthesis. During logarithmic growth, habituated cells showed slower vesicular traf ficking of polymers,especially xylans. Moreover, habituated cells showed a decrease in the strong wall-binding of all pentose-containing polysaccharides studied; correspondingly, especially in log phase cultures, habituation increased the proportion of 3H-hemicelluloses（[3H]xylans and [3H]xyloglucan） sloughed into the medium. These findings could be related to the cel walls’ cellulose-deficiency, and consequent reduction in binding sites for hemicelluloses; the data could also re fl ect the habituated cells’ reduced capacity to integrate arabinox ylans by extra-protoplasmic phenolic cross-linking, as well as xyloglucans, during wall assembly.

关键词： Arabinoxylan cell wall cross-linking 2,6-dichlorobenzonitrile Hemicellulose biosynthesis xyloglucan

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Phenolic metabolism and molecular mass distribution of polysaccharides in cellulose-deficient maize cells

引用

Journal of Integrative Plant Biology 2017年第7期59卷 475-495页

作者： María de castro Romina Martínez-Rubio José L.Acebes Antonio Encina stephen c.fry Penélope García-Angulo área de Fisiología Vegetal.Dpto.Ingenieríay ciencias Agrarias.Facultad de Biologíay ciencias Ambientales.Universidad de León The Edinburgh cell Wall Group Institute of Molecular Plant Sciences School of Biological Sciences Daniel Rutherford BuildingThe King's Buildings

As a consequence of the habituation to low levels of dichlobenil （DcB）, cultured maize cells presented an altered hemicellulose cell fate with a lower proportion of strongly wall-bound hemicelluloses and an increase in soluble extracellular polymers released into the culture medium. The aim of this study was to investigate the relative molecular mass distributions of polysaccharides as well as phenolic metabolism in cells habituated to low levels of DcB （1.5 μM）. Generally, cell wall bound hemicelluloses and sloughed polymers from habituated cells were more homogeneously sized and had a lower weight-average relative molecular mass. In addition, polysaccharides underwent massive cross-linking after being secreted into the cell wall, but this cross-linking was less pronounced in habituated cells than in non-habituated ones. However, when relativized, ferulic acid and p-coumaric acid contents were higher in this habituated cell line. Feasibly, cells habituated to low levels of DcB synthesized molecules with a lower weight-average relative molecular mass, although cross-linked, as a part of their strategy to compensate for the lack of cellulose.

关键词： Phenolic metabolism and molecular mass distribution of polysaccharides in cellulose-deficient maize cells were for

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hetero-trans-β-Glucanase Produces cellulose-Xyloglucan covalent Bonds in the cell Walls of Structural Plant Tissues and Is Stimulated by Expansin

引用

Molecular Plant 2020年第7期13卷 1047-1062页

作者： Klaus Herburger Lenka Frankova Martina Picmanova Jia Wooi Loh Marcos Valenzuela-Ortega Frank Meulewaeter Andrew D.Hudson christopher E.French stephen c.fry The Edinburgh cell Wall Group Institute of Molecular Plant SciencesSchool of Biological SciencesThe University of EdinburghEdinburgh EH93BFUnited Kingdom Institute of Quantitative Biology Biochemistry and BiotechnologySchool of Biological SciencesThe University of EdinburghEdinburgh EH93BFUnited Kingdom BASF BBCC Innovation Center Gent-Trait Research9052 Gent(Zwijnaarde)Belgium Zhejiang University-University of Edinburgh Joint Research centre for Engineering Biology Zhejiang UniversityHainingZhejiang 314400China Present address:Section for Plant Glycobiology Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg 1871Denmark

current cell-wall models assume no covalent bonding between cellulose and hemicelluloses such as xyloglu-can or mixed-linkageβ-D-glucan(MLG).However,Equisetum hetero-trans-β-glucanase(HTG)grafts cellu-lose onto xyloglucan oligosaccharides(XGOs)-and,we now show,xyloglucan polysaccharide-in vitro,thus exhibiting cXE(cellulose:xyloglucan endotransglucosylase)activity.In addition,HTG also catalyzes MLG-to-XGO bonding(MXE activity).In this study,we explored the cXE action of HTG in native plant cell walls and tested whether expansin exposes cellulose to HTG by disrupting hydrogen bonds.To quantify and visu-alize cXE and MXE action,we assayed the sequential release of HTG products from cell walls pre-labeled with substrate mimics.We demonstrated covalent cellulose--xyloglucan bonding in plant cell walls and showed that cXE and MXE action was up to 15%and 60%of total transglucanase action,respectively,and peaked in aging,strengthening tissues:cXE in xylem and cells bordering intercellular canals and MXE in scleren-chyma.Recombinant bacterial expansin(EXLX1)strongly augmented cXE activity in vitro.cXE and MXE ac-tion in living Equisetum structural tissues potentially strengthens stems,while expansin might augment the HTG-catalyzed cXE reaction,thereby allowing efficient cXE action in muro.Our methods will enable surveys for comparable reactions throughout the plant kingdom.Furthermore,engineering similar hetero-polymer formation into angiosperm crop plants may improve certain agronomic traits such as lodging tolerance.

关键词： cell wall cellulose hemicelluloses hetero-trans-p-glucanase hetero-transglycosylation xyloglucan

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Feruloylated Arabinoxylans Are Oxidatively cross- Linked by Extracellular Maize Peroxidase but Not by Horseradish Peroxidase

引用

Molecular Plant 2009年第5期2卷 883-892页

作者： Sally J. Burr stephen c. fry The Edinburgh cell Wall Group Institute of Molecular Plant Sciences School of Biological Sciences The University of Edinburgh Daniel Rutherford Building The King's Buildings Edinburgh EH9 3JH UK Present address: Ecologie Microbienne/UMR cNRS 5557 USc INRA 1193 Universite Claude Bernard--Lyon 1 Batiment Gregor Mendel 16 rue Dubois F-69622 Villeurbanne Cedex France

covalent cross-linking of soluble extracellular arabinoxylans in living maize cultures, which models the cross- linking of wall-bound arabinoxylans, is due to oxidation of feruloyl esters to oligoferuloyl esters and ethers. The oxidizing system responsible could be H2O2/peroxidase, O2/laccase, or reactive oxygen species acting non-enzymically, To distinguish these possibilities, we studied arabinoxylan cross-linking in vivo and in vitro. In living cultures, exogenous, soluble, extracellular, feruloylated [pentosyl-3H]arabinoxylans underwent cross-linking, beginning abruptly 8 d after sub-culture. crosslinking was suppressed by iodide, an H2O2 scavenger, indicating dependence on endogenous H2O2. However, exogenous H2O2 did not cause precocious cross-linking, despite the constant presence of endogenous peroxidases, suggesting that younger cultures contained natural cross-linking inhibitors. Dialysed culture-filtrates cross-linked [^3H]arabinoxylans in vitro only if H2O2 was also added, indicating a peroxidase requirement. This cross-linking was highly ionic-strength-dependent. The peroxidases responsible were heat-labile, although relatively heat-stable peroxidases （assayed on o-dianisidine） were also present. Surprisingly, added horseradish peroxidase, even after heat-denaturation, blocked the arabinoxylancross-linking action of maize peroxidases, suggesting that the horseradish protein was a competing substrate for [^3H]arabinoxylan coupling. In conclusion, we show for the first time that cross-linking of extracellular arabinoxylan in living maize cultures is an action of apoplastic peroxidases, some of whose unusual properties we report.

关键词： cell wall cross-links phenolics ferulate peroxidase soluble extracellular polysaccharides Zea mays L.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

changes in cinnamic Acid Derivatives Associated with the Habituation of Maize cells to Dichlobenil

引用

Molecular Plant 2011年第5期4卷 869-878页

作者： Hugo Melida Jesus Alvarez Jose Luis Acebes Antonio Encina stephen c. fry Area de Fisiologia Vegetal Facultad de CC Biologicas y Ambientales Universidad de Leon E-24071 Leon Spain Edinburgh cell Wall Group Institute of Molecular Plant Sciences School of Biological Sciences University of Edinburgh Daniel Rutherford Building The King＇s Buildings Edinburgh EH9 3JH UK

The habituation of cell cultures to cellulose biosynthesis inhibitors such as dichlobenil （DcB） represents a valu- able tool to improve our knowledge of the mechanisms involved in plant cell wall structural plasticity. Maize cell lines habituated to lethal concentrations of DcB were able to grow through the acquisition of a modified cell wall in which cellulose was partially replaced by a more extensive network of arabinoxylans. The aim of this work was to investigate the phenolic metabolism of non-habituated and DcB-habituated maize cell cultures. Maize cell cultures were fed [14c]cinnamate and the fate of the radioactivity in different intra-protoplasmic and wall-localized fractions throughout the culture cycle was analyzed by autoradiography and scintillation counting. Non-habituated and habituated cultures did not markedly differ in their ability to uptake exogenous [14c]cinnamic acid. However, interesting differences were found in the radiolabeling of low- and high-Mr metabolites. Habituated cultures displayed a higher number and amount of radiola-beled low-Mr compounds, which could act as reserves later used for polysaccharide feruloylation. DcB-habituated cultures were highly enriched in esterified [14c]dehydrodiferulates and larger coupling products. In conclusion, an extensive and early cross-linking of hydroxycinnamates was observed in DcB-habituated cultures, probably strengthening their cellulose-deficient walls.

关键词： cell wall Zea mays maize dichlobenil DcB dehydrodiferulate ferulate cinnamic acid.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

challenges of modeling solar disturbances' arrival times at the Earth

引用

Science china(Technological Sciences) 2008年第10期51卷 1580-1588页

作者： c. D. fry chin-chun WU Murray DRYER center for Space Plasma and Aeronomic Research The University of Alabama in Huntsville Huntsville AL 35899 USA Exploration Physics International Inc. Huntsville AL 35806 USA center for Space Plasma and Aeronomic Research The University of Alabama in Huntsville Huntsville AL 35899 USA Space Weather Laboratory NASA/Goddard Space Flight Center Greenbelt MD 20771 USA center for Space Plasma and Aeronomic Research The University of Alabama in Huntsville Huntsville AL 35899 USA Exploration Physics International Inc. Huntsville AL 35806 USA Space Weather Prediction Center National Oceanic and Atmospheric Administration (NOAA) Boulder Colorado USA

In recent years remarkable advances have been made in the development of phys-ics based models of various parts of the solar-terrestrial system (see JASTP special issues, October, November 2004; February 2007). In this paper, we focus our dis-cussions in a specific region of the Sun to the Earth’s environment (i.e. 1 AU). It is well-known that geomagnetic storms are caused by solar eruptions. The conse-quences of these storms include particle acceleration, solar wind impact on the Earth’s magnetosphere and ionosphere, UV-EUV radiation effects on the lower at-mosphere, etc. One of the main challenges is to predict the arrival time at 1 AU of the solar disturbance. The prospects look good for an accurate, real-time forecast scheme built on the acquisition of solar, heliosphere and the near-Earth data and large-scale models. However, the accuracy of these models still needs improve-ment. We will discuss the present status of the models and challenges to improve the simulation models.

关键词： space weather――magnetohydrodynamic (MHD) Modeling MHD Sun-Earth connection MHD Sun-corona

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

THE SYNTHESES OF 1,1,1-TRIFLUORO-2-SUBSTITUTED-PHENYL-2-PROPYL-3-^(14)c P- TOLUENESULFONATES

引用

Nuclear Science and Techniques 1990年第4期1卷 239-242页

作者：郭子丽 Arthur fry Shanghai Institute of Nuclear Research Acadcmia Siniea Shanghai 201800 China Department of chemistry and Biochemistry University of Arkansas. Fayetteville AR 72701 U.S.A

1,1,1,-Trifluoro-2- substituted- phenyl- 2- propanols- 3- 14c were prepared from addition of methyl- 14c magnesium iodide to appropriate trifluoroacetophenone. These alcohols were converted into tosylatcs by reaction with n-butyllithium and then with p-toluenesulfonyl chloride. The yield, boiling point or melting point and pertinent spectral data of these compounds are reported.

关键词： 1 1- Trifluoro- 2- substituted- phenyl- 2- propanols- 3- 14c 1 1- Trifluoro- 2- substituted- phenyl- 2- propyl - 3- 14c p- toluenesulfonates Trifluoroacetophenones c- Labelled compound

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

潜隐性疾病风险与生命早期砷暴露的关联机制：当前的研究趋势与科学缺口

引用

环境与职业医学 2016年第4期33卷 414-419页

作者： Kathryn A.Bailey Allan H.Smith Erik J.Tokar Joseph H.Graziano Kyoung-Woong Kim Panida Navasumrit Mathuros Ruchirawat Apinya Thiantanawat William A.Suk Rebecca c.fry 黄馨缘(译) Department of Environmental Sciences and Engineering UNC Gillinss School of Global Public Health Chapel Hill Noah Carolina USA Arsenic Health Effects Research Program School of Public Health University of California Berkeley Berkeley California USA NationalToxicology Program National Institute of Environmental Health Sciences( NIEHS ) National Institutes of Health ( NIH ) Department of Healthand Human Services ( DHHS ) Research Triangle Park North Carolina USA Department of Environmental Health Sciences ColumbiaUuiversity Mailman School of Public Health New York New York USA School of Environmental Science and Engineering Gwangiulnstitute of Science and Technology (GIST) Gwangju Republic of Korea Laboratory of Environmental Toxicology Chulabhorn ResearchInstitute Bangkok Thailand Superfund Research Program NIEHS NIH DHHS Research Triangle Park North Carolina USA 不详

[背景]全球约有数百万人的饮用水中无机砷水平对人体有害,尤其是农村地区和发展中国家。重要生长发育时期的无机砷暴露与多种不良健康效应相关,包括成年时期出现的不良健康效应。探索生命早期的无机砷暴露与后期潜隐性疾病(尤其是癌症)... 详细信息

[背景]全球约有数百万人的饮用水中无机砷水平对人体有害,尤其是农村地区和发展中国家。重要生长发育时期的无机砷暴露与多种不良健康效应相关,包括成年时期出现的不良健康效应。探索生命早期的无机砷暴露与后期潜隐性疾病(尤其是癌症)之间的分子作用机制得到研究者的广泛关注。[目标]本研究汇总了现有研究发现的生命早期无机砷暴露与成年期癌症风险增加背后的分子机制。[讨论]表观遗传重编码影响了基因表达功能改变、肿瘤干细胞形成和免疫调控是生命早期无机砷暴露引起潜在致癌效应的可能机制。[结论]越来越多的证据揭示了生命早期的无机砷暴露与之后癌症的形成有关。未来的研究应通过动物实验验证致病机制的假说,同时进行人群研究将生命早期的无机砷暴露、分子改变和潜在的疾病结局整合起来。

关键词：潜隐性无机砷砷暴露疾病风险关联机制基因表达肿瘤干细胞致癌效应新生儿脐带血表观遗传

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

对最近一个太阳活动周内两个最大的行星际扰动事件的模拟

对最近一个太阳活动周内两个最大的行星际扰动事件的模拟

引用

作者： S.-I.Akasofu 孙炜 c.fry W.Fillius M.Dryer 美国阿拉斯加大学地球物理研究所和空间物理、大气科学系中国科学院地球物理研究所美国加利福尼亚大学圣地亚哥分校美国国家大气、海洋局空间环境实验室

1982年6月—8月和1978年4月—6月的两次强太阳爆发包括6个大耀斑活动,本文用HA方法对行星际扰动的传播进行模拟,并综合各种观测结果进行了讨论.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：