ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2012-01-18
    Description: N-linked glycans play key roles in protein folding, stability, and function. Biosynthetic modification of N-linked glycans, within the endoplasmic reticulum, features sequential trimming and readornment steps. One unusual enzyme, endo-α-mannosidase, cleaves mannoside linkages internally within an N-linked glycan chain, short circuiting the classical N-glycan biosynthetic pathway. Here, using two bacterial orthologs, we present the first structural and mechanistic dissection of endo-α-mannosidase. Structures solved at resolutions 1.7–2.1 Å reveal a (β/α)8 barrel fold in which the catalytic center is present in a long substrate-binding groove, consistent with cleavage within the N-glycan chain. Enzymatic cleavage of authentic Glc1/3Man9GlcNAc2 yields Glc1/3-Man. Using the bespoke substrate α-Glc-1,3-α-Man fluoride, the enzyme was shown to act with retention of anomeric configuration. Complexes with the established endo-α-mannosidase inhibitor α-Glc-1,3-deoxymannonojirimycin and a newly developed inhibitor, α-Glc-1,3-isofagomine, and with the reducing-end product α-1,2-mannobiose structurally define the -2 to +2 subsites of the enzyme. These structural and mechanistic data provide a foundation upon which to develop new enzyme inhibitors targeting the hijacking of N-glycan synthesis in viral disease and cancer.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2014-01-28
    Description: A well-balanced human diet includes a significant intake of non-starch polysaccharides, collectively termed 'dietary fibre', from the cell walls of diverse fruits and vegetables. Owing to the paucity of alimentary enzymes encoded by the human genome, our ability to derive energy from dietary fibre depends on the saccharification and fermentation of complex carbohydrates by the massive microbial community residing in our distal gut. The xyloglucans (XyGs) are a ubiquitous family of highly branched plant cell wall polysaccharides whose mechanism(s) of degradation in the human gut and consequent importance in nutrition have been unclear. Here we demonstrate that a single, complex gene locus in Bacteroides ovatus confers XyG catabolism in this common colonic symbiont. Through targeted gene disruption, biochemical analysis of all predicted glycoside hydrolases and carbohydrate-binding proteins, and three-dimensional structural determination of the vanguard endo-xyloglucanase, we reveal the molecular mechanisms through which XyGs are hydrolysed to component monosaccharides for further metabolism. We also observe that orthologous XyG utilization loci (XyGULs) serve as genetic markers of XyG catabolism in Bacteroidetes, that XyGULs are restricted to a limited number of phylogenetically diverse strains, and that XyGULs are ubiquitous in surveyed human metagenomes. Our findings reveal that the metabolism of even highly abundant components of dietary fibre may be mediated by niche species, which has immediate fundamental and practical implications for gut symbiont population ecology in the context of human diet, nutrition and health.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282169/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282169/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Larsbrink, Johan -- Rogers, Theresa E -- Hemsworth, Glyn R -- McKee, Lauren S -- Tauzin, Alexandra S -- Spadiut, Oliver -- Klinter, Stefan -- Pudlo, Nicholas A -- Urs, Karthik -- Koropatkin, Nicole M -- Creagh, A Louise -- Haynes, Charles A -- Kelly, Amelia G -- Cederholm, Stefan Nilsson -- Davies, Gideon J -- Martens, Eric C -- Brumer, Harry -- BB/I014802/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- DK084214/DK/NIDDK NIH HHS/ -- GM099513/GM/NIGMS NIH HHS/ -- K01 DK084214/DK/NIDDK NIH HHS/ -- R01 GM099513/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 Feb 27;506(7489):498-502. doi: 10.1038/nature12907. Epub 2014 Jan 19.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden [2]. ; 1] Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA [2]. ; 1] Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK [2]. ; 1] Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden [2] Wallenberg Wood Science Center, Royal Institute of Technology (KTH), Teknikringen 56-58, 100 44 Stockholm, Sweden. ; Michael Smith Laboratories and Department of Chemistry, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada. ; Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden. ; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA. ; Michael Smith Laboratories and Department of Chemical and Biological Engineering, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada. ; Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK. ; 1] Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden [2] Michael Smith Laboratories and Department of Chemistry, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24463512" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacteroides/enzymology/*genetics/growth & development/*metabolism ; Carbohydrate Metabolism/genetics ; Carbohydrate Sequence ; Cell Wall/chemistry ; Crystallography, X-Ray ; Diet ; Dietary Fiber ; Evolution, Molecular ; Gastrointestinal Tract/*microbiology ; Genetic Loci/*genetics ; Glucans/chemistry/*metabolism ; Glycoside Hydrolases/chemistry/genetics/metabolism ; Humans ; Metagenome ; Models, Molecular ; Molecular Sequence Data ; Phylogeny ; Protein Structure, Tertiary ; Symbiosis ; Xylans/chemistry/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2015-03-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuskin, Fiona -- Lowe, Elisabeth C -- Temple, Max J -- Zhu, Yanping -- Cameron, Elizabeth A -- Pudlo, Nicholas A -- Porter, Nathan T -- Urs, Karthik -- Thompson, Andrew J -- Cartmell, Alan -- Rogowski, Artur -- Hamilton, Brian S -- Chen, Rui -- Tolbert, Thomas J -- Piens, Kathleen -- Bracke, Debby -- Vervecken, Wouter -- Hakki, Zalihe -- Speciale, Gaetano -- Munoz-Munoz, Jose L -- Day, Andrew -- Pena, Maria J -- McLean, Richard -- Suits, Michael D -- Boraston, Alisdair B -- Atherly, Todd -- Ziemer, Cherie J -- Williams, Spencer J -- Davies, Gideon J -- Abbott, D Wade -- Martens, Eric C -- Gilbert, Harry J -- England -- Nature. 2015 Apr 16;520(7547):388. doi: 10.1038/nature14334. Epub 2015 Mar 4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25739504" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2015-01-09
    Description: Yeasts, which have been a component of the human diet for at least 7,000 years, possess an elaborate cell wall alpha-mannan. The influence of yeast mannan on the ecology of the human microbiota is unknown. Here we show that yeast alpha-mannan is a viable food source for the Gram-negative bacterium Bacteroides thetaiotaomicron, a dominant member of the microbiota. Detailed biochemical analysis and targeted gene disruption studies support a model whereby limited cleavage of alpha-mannan on the surface generates large oligosaccharides that are subsequently depolymerized to mannose by the action of periplasmic enzymes. Co-culturing studies showed that metabolism of yeast mannan by B. thetaiotaomicron presents a 'selfish' model for the catabolism of this difficult to breakdown polysaccharide. Genomic comparison with B. thetaiotaomicron in conjunction with cell culture studies show that a cohort of highly successful members of the microbiota has evolved to consume sterically-restricted yeast glycans, an adaptation that may reflect the incorporation of eukaryotic microorganisms into the human diet.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuskin, Fiona -- Lowe, Elisabeth C -- Temple, Max J -- Zhu, Yanping -- Cameron, Elizabeth A -- Pudlo, Nicholas A -- Porter, Nathan T -- Urs, Karthik -- Thompson, Andrew J -- Cartmell, Alan -- Rogowski, Artur -- Hamilton, Brian S -- Chen, Rui -- Tolbert, Thomas J -- Piens, Kathleen -- Bracke, Debby -- Vervecken, Wouter -- Hakki, Zalihe -- Speciale, Gaetano -- Munoz-Munoz, Jose L -- Day, Andrew -- Pena, Maria J -- McLean, Richard -- Suits, Michael D -- Boraston, Alisdair B -- Atherly, Todd -- Ziemer, Cherie J -- Williams, Spencer J -- Davies, Gideon J -- Abbott, D Wade -- Martens, Eric C -- Gilbert, Harry J -- 097907/Wellcome Trust/United Kingdom -- BB/G016127/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- GM090080/GM/NIGMS NIH HHS/ -- MOP-68913/Canadian Institutes of Health Research/Canada -- WT097907AIA/Wellcome Trust/United Kingdom -- England -- Nature. 2015 Jan 8;517(7533):165-9. doi: 10.1038/nature13995.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK [2] Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, USA. ; Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK. ; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109 USA. ; Department of Chemistry, University of York, York YO10 5DD, UK. ; School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia. ; Interdisciplinary Biochemistry Graduate Program, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, USA. ; Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, USA. ; Department of Pharmaceutical Chemistry, University of Kansas School of Pharmacy, 2095 Constant Avenue, Lawrence, Kansas 66047, USA. ; Oxyrane, 9052 Ghent, Belgium. ; Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, USA. ; Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada. ; Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada. ; USDA, Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, Iowa 50011, USA. ; 1] Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, USA [2] Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta T1J 4B1, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25567280" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacteroidetes/cytology/enzymology/genetics/*metabolism ; Biological Evolution ; Carbohydrate Conformation ; Diet ; Enzymes/genetics/metabolism ; Female ; Gastrointestinal Tract/*microbiology ; Genetic Loci/genetics ; Germ-Free Life ; Glycoproteins/chemistry/metabolism ; Humans ; Male ; Mannans/chemistry/*metabolism ; Mannose/metabolism ; Mice ; *Models, Biological ; Models, Molecular ; Oligosaccharides/chemistry/metabolism ; Periplasm/enzymology ; Yeasts/*chemistry
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5090-5094 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Insulated gate Ga0.47In0.53As/Al0.48In0.52As heterojunction field-effect transistors have been prepared using SiOx and SrF2 insulation and dilute acid and O2 plasma surface cleaning. The leakage current-gate voltage characteristics at different temperatures are analyzed by thermionic and field emission theories to extract the effective barrier heights. The transistor pinch-off characteristics and effective barrier height results are compared with elemental depth profiles obtained from Auger electron spectroscopy. It is concluded that O2 plasma cleaning followed by SiOx gate insulation, is the most suitable technique for fabricating devices and leads to an effective barrier height of 0.3±0.1 V. With refinement this fabrication route should lead to satisfactory room-temperature operation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The adsorption of triethylgallium on the GaAs (100) (4×1) surface has been studied using the techniques of low energy electron diffraction, x-ray photoelectron and Auger spectroscopies, high resolution electron energy loss spectroscopy and temperature-programmed desorption. Condensed multilayers of the organometallic compound formed following adsorption at 150 K desorb from the surface at ∼170 K to leave a chemisorbed molecular monolayer of triethylgallium. Upon further heating this layer partially desorbs and partially decomposes to form diethylgallium in two competing processes. The diethylgallium so formed can also desorb or otherwise decompose ultimately to adsorbed Ga atoms in a reaction which results in the formation of hydrogen, ethene, and ethane. The temperature-programmed desorption characteristics of these latter species are found to be similar to those observed for a dissociated layer of ethyl bromide. A reaction scheme is proposed to account for the observations and kinetic parameters are obtained from computer modeling of the temperature-programmed desorption results. The reaction scheme is also used to evaluate the temperature-dependent growth rate expected in metal organic molecular beam epitaxial growth of GaAs. Comparison with experimental results is made and the work is discussed in the light of the previous model which has been proposed for the epitaxial growth of GaAs by metal organic molecular-beam epitaxy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Herbage and faeces samples were retained from an intake and in vivodigestibility trial using material harvested at three different stages from five indigenous hill plant communities (those dominated by Agrostis-Festuca., Nardus stricta., Molinia caerulea., Eriophorum vaginatum and Tri-chophorum caespitosum) and from sown swards of ryegrass or white clover. Samples of the herbages and of their separate components, together with extrusa samples of the same herbages recovered from pen-fed sheep and cattle oesophageal fistulates, were digested in vitrousing rumen liquor. Measurements were made also of faecal nitrogen concentration (FN) and of indigestible acid-detergent fibre (IADF) using the samples from the original trial.The range of in vitrodisappearance values of the herbages (IVOMD; 0809-0278) was slightly wider than those of in vivodigestibility (OMD; 0-796-0-37I). Differences between OMD and IVOMD were greatest at low quality and relationships were best described by two separate linear regressions of OMD on IVOMD for (a) ryegrass, white clover, Agrostis-Festucaand Nardus(RSD; 0 0185) and, (b) Molinia, Tricho-phorumand Eriophorum(RSD; 00246). In vitrodisappearance values of extrusa were higher than those of herbages offered by 00503 and 00156 units for sheep and cattle respectively, partly because of greater levels of ensalivation, especially in the sheep. The relationships of OMD to IADF and to FN were poor, though inclusion of faeces output and fitting parallel lines for communities in the regression of OMD on FN reduced the RSD to 0020. We conclude that in vitrodigestion of samples of extrusa, using appropriate standards, is the best method of diet digestibility prediction for sheep and cattle grazing these communities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1804-1807 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of threshold current between 130 and 310 K of 1.65 μm In0.53Ga0.47As–InP bulk lasers grown by chemical beam epitaxy has been measured. Comparison with a calculation of the spontaneous recombination current at threshold allows one to determine the proportion of current loss over this temperature range. It is found that the loss can be described using an Auger recombination component of the form Rauger=C'n3 exp(−Ea/kBT) where n is the carrier population density in the undoped active region. The activation energy Ea is found to be 39±5 meV which is in excellent agreement with the theoretical value for the conduction to heavy hole band/split-off to heavy hole band Auger process. The values obtained for the Auger coefficient C over the temperature range are in close agreement with published values obtained by time resolved photoluminescence. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 1546-1548 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Anomalous doping behavior of the most commonly used n-type dopants, Si and Sn, has been observed in InP grown by chemical beam epitaxy from trimethylindium and cracked phosphine. In the case of Si, although incorporation is initially facile, the doping level decreases in successive runs. It is proposed that this decrease is due to the formation of SiC in the dopant cell. The behavior of Sn is more complex. In the range of Sn cell temperatures from 600 to 750 °C, incorporation is proportional to the elemental Sn vapor pressure. However, at low cell temperatures, 175–350 °C, anomalously large incorporations of Sn are observed. We attribute this behavior to the formation of a volatile metalorganic precursor within the Sn cell, its transport to the substrate, and subsequent decomposition and incorporation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 97-98 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Selective area growth of InP/InGaAs multiple quantum well laser structures has been demonstrated in openings defined in Si3 N4 layers on InP substrates. Growth was achieved, by metalorganic molecular beam epitaxy, in openings as small as 3 μm wide, but no growth occurred on the dielectric coating. Cathodoluminescence from individual laser stripes was observed at 300 K with a wavelength determined to be 1.57 μm and at 100 K with a wavelength of 1.46 μm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...