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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology letters 19 (1997), S. 417-420 
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract CMP-Sialic acid synthetase from Neisseria meningitidis 406Y was expressed in Escherichia coli K113 pLysS and produced at 360 U/L. The purified CMP-sialic acid synthetase used both N-acetyl-neuraminic acid (K m = 0.34 mM) and N-glycolyl-neuraminic acid (K m = 2.6 mM) as substrates. The recombinant synthetase could be used in a coupled reaction with an a-2,3-sialyltransferase to sialylate a lactose derivative in a one-reactor synthesis.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Glycoconjugate journal 16 (1999), S. 507-515 
    ISSN: 1573-4986
    Keywords: GM3 antigen ; sialyllactoside ; biantennary ; glycoconjugate ; antibody ; CTP, Cytidine 5′-triphosphate ; KLH, Keyhole Limpet Hemocyanin ; M2C2H, 4-(4-N-maleimidomethyl) cyclohexane-1-carboxyl hydrazide ; MPL, Monophosphoryl lipid A ; Sulfo-GMBS, N-(γ-maleimidobutyryloxy) sulfosuccinimide ester ; BSA, Bovine serum albumin ; HSA, Human serum albumin ; GBSPIa (GBSPIII), Type Ia (III) group B Streptococcus polysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A biantennary GM3-saccharide (sialyllactoside) derivative (4) was constructed using allylmalonic acid as a bivalent linker, both carboxylic acids of which were condensed with 3-aminopropyl lactoside (2) prior to enzymatic sialylation with a fusion enzyme. While ozonolysis of its allyl group generated a saccharide having a terminal aldehyde (6), we were unable to couple 6 directly to protein by reductive amination. However, extension of the spacer by means of introducing a maleimide group to 6 through its aldehyde group to give 7 enabled the latter to be successfully coupled to thiolated proteins. The average ratios of saccharide to protein were observed to be 35 in KLH conjugate (13) and 9–12 in HSA conjugates (14 and 15). The antisera obtained by immunizing mice with the biantennary sialyllactoside-KLH conjugate (13) together with MPL adjuvant were analyzed by ELISA. Using several structurally related saccharide-HSA conjugates as screening antigens, it was concluded that anti-sialyllactoside antibodies, both IgG and IgM, were effectively raised. This was further supported by competitive inhibition experiments using lactoside (1), sialyllactoside (8) and biantennary sialyllactoside (4) as inhibitors.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature structural & molecular biology 11 (2004), S. 163-170 
    ISSN: 1545-9985
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Sialic acid terminates oligosaccharide chains on mammalian and microbial cell surfaces, playing critical roles in recognition and adherence. The enzymes that transfer the sialic acid moiety from cytidine-5′-monophospho-N-acetyl-neuraminic acid (CMP-NeuAc) to the terminal positions of these ...
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Company
    Nature biotechnology 16 (1998), S. 769-772 
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] Large-scale enzymatic synthesis of oligosaccharides, which contain terminal N-acetyl-neuraminic acid residues requires large amounts of the sialyltransferase and the corresponding sugar-nucleotide synthetase, which is required for the synthesis of the sugar-nucleotide donor, CMP-Neu5Ac. Using genes ...
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature medicine 7 (2001), S. 752-753 
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] To the editor Campylobacter jejuni is the most frequent cause of bacterial diarrhea, which leads to the Guillain–Barré syndrome (GBS) or the Miller Fisher syndrome (MFS) in 1 in every 1000 infections. Neuropathy is probably triggered by molecular mimicry between C. jejuni lipooligo- ...
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 37 (2000), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Ganglioside mimicry by Campylobacter jejuni lipo-oligosaccharide (LOS) is thought to be a critical factor in the triggering of the Guillain–Barré and Miller–Fisher syndrome neuropathies after C. jejuni infection. The combination of a completed genome sequence and a ganglioside GM1-like LOS structure makes C. jejuni NCTC 11168 a useful model strain for the identification and characterization of the genes involved in the biosynthesis of ganglioside-mimicking LOS. Genome analysis identified a putative LOS biosynthetic cluster and, from this, we describe a putative gene (ORF Cj1139c), which we have termed wlaN, with a significant level of similarity to a number of bacterial glycosyltransferases. Mutation of this gene in C. jejuni NCTC 11168 resulted in a LOS molecule of increased electrophoretic mobility, which also failed to bind cholera toxin. Comparison of LOS structural data from wild type and the mutant strain indicated lack of a terminal β-1,3-linked galactose residue in the latter. The wlaN gene product was demonstrated unambiguously as a β-1,3 galactosyltransferase responsible for converting GM2-like LOS structures to GM1-like by in vitro expression. We also show that the presence of an intragenic homopolymeric tract renders the expression of a functional wlaN gene product phase variable, resulting in distinct C. jejuni NCTC 11168 cell populations with alternate GM1 or GM2 ganglioside-mimicking LOS structures. The distribution of wlaN among a number of C. jejuni strains with known LOS structure was determined and, for C. jejuni NCTC 12500, similar wlaN gene phase variation was shown to occur, so that this strain has the potential to synthesize a GM1-like LOS structure as well as the ganglioside GM2-like LOS structure proposed in the literature.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd.
    Molecular microbiology 55 (2005), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We recently demonstrated that Campylobacter jejuni produces a capsular polysaccharide (CPS) that is the major antigenic component of the classical Penner serotyping system distinguishing Campylobacter into 〉60 groups. Although the wide variety of C. jejuni serotypes are suggestive of structural differences in CPS, the genetic mechanisms of such differences are unknown. In this study we sequenced biosynthetic cps regions, ranging in size from 15 to 34 kb, from selected C. jejuni strains of HS:1, HS:19, HS:23, HS:36, HS:23/36 and HS:41 serotypes. Comparison of the determined cps sequences of the HS:1, HS:19 and HS:41 strains with the sequenced strain, NCTC11168 (HS:2), provides evidence for multiple mechanisms of structural variation including exchange of capsular genes and entire clusters by horizontal transfer, gene duplication, deletion, fusion and contingency gene variation. In contrast, the HS:23, HS:36 and HS:23/36 cps sequences were highly conserved. We report the first detailed structural analysis of 81-176 (HS:23/36) and G1 (HS:1) and refine the previous structural interpretations of the HS:19, HS:23, HS:36 and HS:41 serostrains. For the first time, we demonstrate the commonality and function of a second heptose biosynthetic pathway for Campylobacter CPS independent of the pathway for lipooligosaccharide (LOS) biosynthesis and identify a novel heptosyltransferase utilized by this alternate pathway. Furthermore, we show the retention of two functional heptose isomerases in Campylobacter and the sharing of a phosphatase for both LOS and CPS heptose biosynthesis.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 39 (2001), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We have identified a gene for the addition of N-acetylneuraminic acid (Neu5Ac) in an α-2,3-linkage to a lactosyl acceptor moiety of the lipopolysaccharide (LPS) of the human pathogen Haemophilus influenzae. The gene is one that was identified previously as a phase-variable gene known as lic3A. Extracts of H. influenzae, as well as recombinant Escherichia coli strains producing Lic3A, demonstrate sialyltransferase activity in assays using synthetic fluorescent acceptors with a terminal galactosyl, lactosyl or N-acetyl-lactosaminyl moiety. In the RM118 strain of H. influenzae, Lic3A activity is modulated by the action of another phase-variable glycosyltransferase, LgtC, which competes for the same lactosyl acceptor moiety. Structural analysis of LPS from a RM118:lgtC mutant and the non-typeable strain 486 using mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy confirmed that the major sialylated species has a sialyl-α-(2–3)-lactosyl extension off the distal heptose. This sialylated glycoform was absent in strains containing a lic3A gene disruption. Low amounts of sialylated higher molecular mass glycoforms were present in RM118:lgtC lic3A, indicating the presence of a second sialyltransferase. Lic3A mutants of H. influenzae strains show reduced resistance to the killing effects of normal human serum. Lic3A, encoding an α-2,3-sialyltransferase activity, is the first reported phase-variable sialyltransferase gene.
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