Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (23)
Source
  • Articles: DFG German National Licenses  (23)
Material
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 96 (1992), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The CMP-N-acetylneuraminic acid (CMP-NeuNAc) synthetase gene of Neisseria meningitidis group B is located on a 2.3-kb EcoRI fragment within the cps gene cluster. Nucleotide sequence determination of the gene encoding the CMP-NeuNAc synthetase revealed a 515-bp open reading frame that can encode a 18.9-kDA protein. A computer data base scan revealed a 59.4% identity to the CMP-NeuNAc synthetase gene of E. coli K1. Enzymatic activity was confirmed in vitro and in vivo. Transformation of the CMP-NeuNAc defective E. coli K1 strain EV5 with the meningococcal CMP-NeuNAc synthetase could complement the defect in E. coli.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The capsule polysaccharide of Neisseria meningitidis serogroup B is composed of a homopolymer of α-2→8 linked N-acetyl-neuraminic acid (sialic acid). The enzymes required for sialic acid biosynthesis and polymerization are encoded in region A of the capsule gene complex. We here describe the enzymatic activity of the siaA gene product as determined by biochemical analysis. siaA was overexpressed in Escherichia coli and the SiaA protein was purified to homogeneity. Enzymatic assays revealed that SiaA did not accept N-acetyl-glucosamine as substrate, but only N-acetyl-glucosamine-6-phosphate (EC 5.1.3.9). SiaA catalyzes the isomerization of N-acetyl-glucosamine-6-phosphate to form N-acetyl-mannosamine-6-phosphate. This reaction represents the first step in capsule biosynthesis of N. meningitidis B.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In a previous study, we determined the epitope of the Pseudomonas aeruginosa Hsp60 heat shock protein which is recognized by the specific monoclonal antibody (MAb) 2528. Subsequent investigations revealed a weak cross-reactivity of MAb 2528 with P. stutzeri, P. alcaligenes, P. mendocina and P. pseudoalcaligenes. To elucidate the molecular structure for these cross-reactions, we cloned the P. stutzeri hsp60 gene in Escherichia coli and determined the nucleotide sequence of the gene. In addition, the hsp60 gene of further Pseudomonas species was amplified and sequenced and amino acid substitutions within the epitope recognized by MAb 2528 were determined. The decapeptide QADIEARVLQ is unique to the P. aeruginosa Hsp60 protein, and cross-reaction of MAb 2528 reflects the phylogenetic relationship of Pseudomonas species as P. aeruginosa and all four cross-reacting species constitute a DNA homology group within the rRNA group I of the family Pseudomonadaceae, which belong to the γ- subclass of the Proteobacteria.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Non-culture diagnosis and serogroup determination of meningococcal infection is important in contact management where vaccination may be possible. A serogroup B and C PCR ELISA assay for the non-culture diagnosis and serogroup determination has proved invaluable for enhanced epidemiological surveillance and contact management. A polymerase chain reaction assay, based on a restriction fragment length polymorphism in the meningococcal serogroup Y and W135 sialyltransferase (siaD) gene, was developed to enhance the range of non-culture diagnosis of meningococcal infection from clinical samples. The PCR assay was adapted to an ELISA format incorporating hybridisation with serogroup-specific Y and W135 oligonucleotide probes. The serogroup-specific W135 and Y PCR ELISA is a useful addition to currently available serogroup B and C assay for non-culture diagnosis of meningococcal infection and outbreak investigation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We recently described the phase-variable expression of a virulence-associated lipopolysaccharide (LPS) epitope in Legionella pneumophila. In this study, the molecular mechanism for phase variation was investigated. We identified a 30 kb unstable genetic element as the molecular origin for LPS phase variation. Thirty putative genes were encoded on the 30 kb sequence, organized in two putative opposite transcription units. Some of the open reading frames (ORFs) shared homologies with bacteriophage genes, suggesting that the 30 kb element was of phage origin. In the virulent wild-type strain, the 30 kb element was located on the chromosome, whereas excision from the chromosome and replication as a high-copy plasmid resulted in the mutant phenotype, which is characterized by alteration of an LPS epitope and loss of virulence. Mapping and sequencing of the insertion site in the genome revealed that the chromosomal attachment site was located in an intergenic region flanked by genes of unknown function. As phage release could not be induced by mitomycin C, it is conceivable that the 30 kb element is a non-functional phage remnant. The protein encoded by ORF T on the 30 kb plasmid could be isolated by an outer membrane preparation, indicating that the genes encoded on the 30 kb element are expressed in the mutant phenotype. Therefore, it is conceivable that the phenotypic alterations seen in the mutant depend on high-copy replication of the 30 kb element and expression of the encoded genes. Excision of the 30 kb element from the chromosome was found to occur in a RecA-independent pathway, presumably by the involvement of RecE, RecT and RusA homologues that are encoded on the 30 kb element.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Oxford BSL : Blackwell Science Ltd, UK
    Molecular microbiology 27 (1998), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Neisseria meningitidis possesses a repertoire of surface adhesins that promote bacterial adherence to and entry into mammalian cells. Here, we have identified heparan sulphate proteoglycans as epithelial cell receptors for the meningococcal Opc invasin. Binding studies with radiolabelled heparin and heparin affinity chromatography demonstrated that Opc is a heparin binding protein. Subsequent binding experiments with purified 35SO4-labelled epithelial cell proteoglycan receptors and infection assays with epithelial cells that had been treated with heparitinase to remove glycosaminoglycans confirmed that Opc-expressing meningococci exploit host cell-surface proteoglycans to gain access to the epithelial cell interior. Unexpectedly, Opa28-producing meningococci lacking Opc also bound proteoglycans. These bacteria also bound CEA receptors in contrast to the Opc-expressing phenotype, suggesting that Opa28 may possess domains with specificity for different receptors. Opa/Opc-negative meningococci did not bind either proteoglycan or CEA receptors. Using a set of genetically defined mutants with different lipopolysaccharide (LPS) and capsular phenotype, we were able to demonstrate that surface sialic acids interfere with the Opc–proteoglycan receptor interaction. This effect may provide the molecular basis for the reported modulatory effect of capsule and LPS on meningococcal adherence to and entry into various cell types.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 8 (1993), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Lipopolysaccharide is an essential component of the outer membrane of Gram-negative bacteria and an important virulence factor of many pathogens, such as Neisseria gonorrhoeae. We have cloned the gonococcal galE gene which was found to be located in the gonococcal homologue of the meningococcal capsule gene complex region D. Sequence alignment indicated extensive homology with the Escherichia coli and Salmonella GalE proteins. Mutants with insertions in the galE gene were used as a tool to characterize the structure and function of gonococcal lipopolysaccharide. They displayed deep rough phenotypes, and chemical analysis confirmed the loss of galactose from the mutant lipopolysaccharide. Functional analysis indicated that the terminal oligosaccharides contain galactose and that these are lost in galE mutants. The importance of these oligosaccharides in gonococcal biology is clear from the fact that they contain the epitopes that are the targets for killing by normal human serum, and the acceptor site for sialic acid, which acts to protect the gonococcus from this killing. Furthermore, infection experiments in vitro indicate that the galE mutants exhibit unaltered intergonococcal adhesion as well as adhesion to, and invasion of, epithelial cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 8 (1993), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Within the capsule gene complex (cps) of Neisseria meningitidis two functional regions B and C are involved in surface translocation of the cytoplasmically synthesized capsular polysaccharide, which is a homopolymer of α-2,8 polyneuraminic acid. The region-C gene products share characteristics with transporter proteins of the ABC (ATP-binding cassette) superfamily of active transporters. For analysis of the role of region B in surface translocation of the capsular polysaccharide we purified the polysaccharides of region B- and region C-defective Escherichia coli clones by affinity chromatography. The molecular weights of the polysaccharides were determined by gel filtration and the polysaccharides were analysed for phospholipid substitution by polyacrylamide gel electrophoresis and immunoblotting. The results indicate that the full-size capsular polysaccharide with a phospholipid anchor is synthesized intracellularly and that lipid modification is a strong requirement for translocation of the poly saccharide to the cell surface. Proteins encoded by region B are involved in phospholipid substitution of the capsular polysaccharide. Nucleotide sequence analysis of region B revealed two open reading frames, which encode proteins with molecular masses of 45.1 and 48.7 kDa.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: A central step in the pathogenesis of bacterial meningitis caused by Neisseria meningitidis (the meningococcus) is the interaction of the bacteria with cells of the blood–brain barrier. In the present study, we analysed the invasive potential of two strains representing hypervirulent meningococcal lineages of the ET-5 and ET-37 complex in human brain-derived endothelial cells (HBEMCs). In contrast to previous observations made with epithelial cells and human umbilical vein-derived endothelial cells (HUVECs), significant internalization of encapsulated meningococci by HBMECs was observed. However, this uptake was found only for the ET-5 complex isolate MC58, and not for an ET-37 complex strain. Furthermore, the uptake of meningococci by HBMECs depended on the presence of human serum, whereas serum of bovine origin did not promote the internalization of meningococci in HBMECs. By mutagenesis experiments, we demonstrate that internalization depended on the expression of the opc gene, which is present in meningococci of the ET-5 complex, but absent in ET-37 complex meningococci. Chromatographic separation of human serum proteins revealed fibronectin as the uptake-promoting serum factor, which binds to HBMECs via α5β1 integrin receptors. These data provide evidence for unique molecular mechanisms of the interaction of meningococci with endothelial cells of the blood–brain barrier and contribute to our understanding of the pathogenesis of meningitis caused by meningococci of different clonal lineages.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Oxford BSL : Blackwell Science Ltd
    Molecular microbiology 32 (1999), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Pathogenic Neisseria use a variety of mechanisms to survive the bactericidal action of the complement system. Serum resistance is a crucial virulence factor for the development of severe meningococcal disease, meningococcal meningitis and disseminated gonococcal infection. Furthermore, local inflammation at the site of gonococcal infection exposes the bacteria to moderate concentrations of complement factors. We review current concepts of neisserial serum resistance with emphasis on porins and polysaccharides exposed on the neisserial surface and their interaction with components of normal human serum.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...