liu.seSök publikationer i DiVA
Ändra sökning
Avgränsa sökresultatet
1 - 8 av 8
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Richter, Katrin
    et al.
    Justus Liebig Univ Giessen, Germany.
    Koch, Christian
    Justus Liebig Univ Giessen, Germany.
    Perniss, Alexander
    Justus Liebig Univ Giessen, Germany.
    Wolf, Philipp M.
    Justus Liebig Univ Giessen, Germany.
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Wichmann, Sven
    Justus Liebig Univ Giessen, Germany.
    Wilker, Sigrid
    Justus Liebig Univ Giessen, Germany.
    Magel, Ilona
    Justus Liebig Univ Giessen, Germany.
    Sander, Michael
    Justus Liebig Univ Giessen, Germany.
    McIntosh, J. Michael
    Univ Utah, UT 84112 USA; George E Wahlen Vet Affairs Med Ctr, UT 84148 USA; Univ Utah, UT 84108 USA.
    Padberg, Winfried
    Justus Liebig Univ Giessen, Germany.
    Grau, Veronika
    Justus Liebig Univ Giessen, Germany.
    Phosphocholine-Modified Lipooligosaccharides of Haemophilus influenzae Inhibit ATP-Induced IL-1 beta Release by Pulmonary Epithelial Cells2018Ingår i: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, nr 8, artikel-id 1979Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Phosphocholine-modified bacterial cell wall components are virulence factors enabling immune evasion and permanent colonization of the mammalian host, by mechanisms that are poorly understood. Recently, we demonstrated that free phosphocholine (PC) and PC-modified lipooligosaccharides (PC-LOS) from Haemophilus influenzae, an opportunistic pathogen of the upper and lower airways, function as unconventional nicotinic agonists and efficiently inhibit the ATP-induced release of monocytic IL-1 beta. We hypothesize that H. influenzae PC-LOS exert similar effects on pulmonary epithelial cells and on the complex lung tissue. The human lung carcinoma-derived epithelial cell lines A549 and Calu-3 were primed with lipopolysaccharide from Escherichia coli followed by stimulation with ATP in the presence or absence of PC or PC-LOS or LOS devoid of PC. The involvement of nicotinic acetylcholine receptors was tested using specific antagonists. We demonstrate that PC and PC-LOS efficiently inhibit ATP-mediated IL-1 beta release by A549 and Calu-3 cells via nicotinic acetylcholine receptors containing subunits alpha 7, alpha 9, and/or alpha 10. Primed precision-cut lung slices behaved similarly. We conclude that H. influenzae hijacked an endogenous anti-inflammatory cholinergic control mechanism of the lung to evade innate immune responses of the host. These findings may pave the way towards a host-centered antibiotic treatment of chronic airway infections with H. influenzae.

    Ladda ner fulltext (pdf)
    fulltext
  • 2.
    Hecker, Andreas
    et al.
    University of Giessen, Germany.
    Kuellmar, Mira
    University of Giessen, Germany.
    Wilker, Sigrid
    University of Giessen, Germany.
    Richter, Katrin
    University of Giessen, Germany; University of Giessen, Germany.
    Zakrzewicz, Anna
    University of Giessen, Germany.
    Atanasova, Srebrena
    University of Giessen, Germany.
    Mathes, Verena
    University of Giessen, Germany.
    Timm, Thomas
    University of Giessen, Germany.
    Lerner, Sabrina
    University of Giessen, Germany.
    Klein, Jochen
    Goethe University of Frankfurt, Germany.
    Kaufmann, Andreas
    University of Marburg, Germany.
    Bauer, Stefan
    University of Marburg, Germany.
    Padberg, Winfried
    University of Giessen, Germany.
    Kummer, Wolfgang
    University of Giessen, Germany.
    Janciauskiene, Sabina
    Hannover Medical Sch, Germany.
    Fronius, Martin
    University of Giessen, Germany; University of Otago, New Zealand.
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Lochnit, Guenter
    University of Giessen, Germany.
    Grau, Veronika
    University of Giessen, Germany.
    Phosphocholine-Modified Macromolecules and Canonical Nicotinic Agonists Inhibit ATP-Induced IL-1 beta Release2015Ingår i: Journal of Immunology, ISSN 0022-1767, E-ISSN 1550-6606, Vol. 195, nr 5, s. 2325-2334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    IL-1 beta is a potent proinflammatory cytokine of the innate immune system that is involved in host defense against infection. However, increased production of IL-1 beta plays a pathogenic role in various inflammatory diseases, such as rheumatoid arthritis, gout, sepsis, stroke, and transplant rejection. To prevent detrimental collateral damage, IL-1 beta release is tightly controlled and typically requires two consecutive danger signals. LPS from Gram-negative bacteria is a prototypical first signal inducing pro-IL-1 beta synthesis, whereas extracellular ATP is a typical second signal sensed by the ATP receptor P2X7 that triggers activation of the NLRP3-containing inflammasome, proteolytic cleavage of pro-IL-1 beta by caspase-1, and release of mature IL-1 beta. Mechanisms controlling IL-1 beta release, even in the presence of both danger signals, are needed to protect from collateral damage and are of therapeutic interest. In this article, we show that acetylcholine, choline, phosphocholine, phosphocholine-modified LPS from Haemophilus influenzae, and phosphocholine-modified protein efficiently inhibit ATP-mediated IL-1 beta release in human and rat monocytes via nicotinic acetylcholine receptors containing subunits alpha 7, alpha 9, and/or alpha 10. Of note, we identify receptors for phosphocholine-modified macromolecules that are synthesized by microbes and eukaryotic parasites and are well-known modulators of the immune system. Our data suggest that an endogenous anti-inflammatory cholinergic control mechanism effectively controls ATP-mediated release of IL-1 beta and that the same mechanism is used by symbionts and misused by parasites to evade innate immune responses of the host.

  • 3.
    Skarp-de Haan, Caroline P. A.
    et al.
    University of Helsinki, Finland .
    Culebro, Alejandra
    University of Helsinki, Finland .
    Schott, Thomas
    University of Helsinki, Finland .
    Revez, Joana
    University of Helsinki, Finland .
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Hanninen, Marja-Liisa
    University of Helsinki, Finland .
    Rossi, Mirko
    University of Helsinki, Finland .
    Comparative genomics of unintrogressed Campylobacter coli clades 2 and 32014Ingår i: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 15, nr 129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Campylobacter jejuni and C. coli share a multitude of risk factors associated with human gastrointestinal disease, yet their phylogeny differs significantly. C. jejuni is scattered into several lineages, with no apparent linkage, whereas C. coli clusters into three distinct phylogenetic groups (clades) of which clade 1 has shown extensive genome-wide introgression with C. jejuni, yet the other two clades (2 and 3) have less than 2% of C. jejuni ancestry. We characterized a C. coli strain (76339) with four novel multilocus sequence type alleles (ST-5088) and having the capability to express gamma-glutamyltranspeptidase (GGT); an accessory feature in C. jejuni. Our aim was to further characterize unintrogressed C. coli clades 2 and 3, using comparative genomics and with additional genome sequences available, to investigate the impact of horizontal gene transfer in shaping the accessory and core gene pools in unintrogressed C. coli. Results: Here, we present the first fully closed C. coli clade 3 genome (76339). The phylogenomic analysis of strain 76339, revealed that it belonged to clade 3 of unintrogressed C. coli. A more extensive respiratory metabolism among unintrogressed C. coli strains was found compared to introgressed C. coli (clade 1). We also identified other genes, such as serine proteases and an active sialyltransferase in the lipooligosaccharide locus, not present in C. coli clade 1 and we further propose a unique scenario for the evolution of Campylobacter ggt. Conclusions: We propose new insights into the evolution of the accessory genome of C. coli clade 3 and C. jejuni. Also, in silico analysis of the gene content revealed that C. coli clades 2 and 3 have genes associated with infection, suggesting they are a potent human pathogen, and may currently be underreported in human infections due to niche separation.

    Ladda ner fulltext (pdf)
    fulltext
  • 4.
    Vitiazeva, Varvara
    et al.
    Karolinska Institute, Sweden .
    Li, Jianjun
    National Research Council Canada, Canada .
    Hood, Derek W.
    MRC Harwell, England .
    Moxon, Richard E.
    University of Oxford Nuffield, England .
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    A novel branching pattern in the lipopolysaccharide expressed by non-typeable Haemophilus influenzae strain 12322013Ingår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 378, s. 114-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the novel branching pattern in lipopolysaccharide (LPS) expressed by non-typeable Haemophilus influenzae (NTHi) strain 1232. The strain expressed the beta-D-Glcp-(1 -andgt; 4)-[alpha-D-Galp-(1 -andgt; 4)-beta-D-Galp-(1 -andgt; 7)]-D-alpha-D-Hepp-(1 -andgt; 6)-beta-D-Glcp chain linked to the proximal heptose (HepI) of the conserved triheptosyl inner-core moiety of NTHi LPS: L-alpha-D-HepIIIp-(1 -andgt; 2)-[PEtn -andgt; 6]-L-alpha-D-HepIIp-(1 -andgt; 3)-L-alpha-D-HepIp-(1 -andgt; 5)-[PPEtn -andgt; 4]-alpha-Kdop-(2 -andgt; 6)-lipid A. The structure has been elucidated using NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and capillary electrophoresis coupled to electrospray ionization tandem mass spectrometry (CE-ESI-MSn) on O-deacylated LPS and core oligosaccharide (OS) materials, as well as HPLC-ESI-MSo on permethylated, dephosphorylated OS. It was also found that a tetrasaccharide unit bearing sialic acid [alpha-Neu5Ac-(2 -andgt; 3)-beta-D-Galp-(1 -andgt; 4)-beta-D-GlcNAcp-(1 -andgt; 3)-beta-D-Galp-(1 -andgt;] could substitute O-4 of the beta-D-Glcp linked to HepI. In addition, the distal heptose (HepIII) was substituted by PCho -andgt; 6-beta-D-Galp-(1 -andgt; at the O-2 position.

  • 5.
    Young, Rosanna E. B.
    et al.
    UCL, England University of Oxford, England .
    Twelkmeyer, Brigitte
    Karolinska Institute, Sweden .
    Vitiazeva, Varvara
    Karolinska Institute, Sweden .
    Power, Peter M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan. University of Oxford, England.
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Hood, Derek W.
    University of Oxford, England MRC Harwell, England .
    Haemophilus parainfluenzae expresses diverse lipopolysaccharide O-antigens using ABC transporter and Wzy polymerase-dependent mechanisms2013Ingår i: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 303, nr 8, s. 603-617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lipopolysaccharide O-antigens are the basis of serotyping schemes for Gram negative bacteria and help to determine the nature of host-bacterial interactions. Haemophilus parainfluenzae is a normal commensal of humans but is also an occasional pathogen. The prevalence, diversity and biosynthesis of O-antigens were investigated in this species for the first time. 18/18 commensal H. parainfluenzae isolates contain a O-antigen biosynthesis gene cluster flanked by glnA and pepB, the same position as the hmg locus for tetrasaccharide biosynthesis in Haemophilus influenzae. The O-antigen loci show diverse restriction digest patterns but fall into two main groups: (1) those encoding enzymes for the synthesis and transfer of Fuc-NAc4N in addition to the Wzy-dependent mechanism of O-antigen synthesis and transport and (2) those encoding galactofuranose synthesis/transfer enzymes and an ABC transporter. The other glycosyltransferase genes differ between isolates. Three H. parainfluenzae isolates fell outside these groups and are predicted to synthesise O-antigens containing ribitol phosphate or deoxytalose. Isolates using the ABC transporter system encode a putative O-antigen ligase, required for the synthesis of O-antigen-containing LPS glycoforms, at a separate genomic location. The presence of an O-antigen contributes significantly to H. parainfluenzae resistance to the killing effect of human serum in vitro. The discovery of O-antigens in H. parainfluenzae is striking, as its close relative H. influenzae lacks this cell surface component.

    Ladda ner fulltext (pdf)
    fulltext
  • 6.
    Kumar Kondadi, Pradeep
    et al.
    University of Helsinki.
    Rossi, Mirko
    University of Helsinki.
    Twelkmeyer, Brigitte
    Huddinge Hospital.
    Schur, Melissa J
    National Research Council Canada.
    Li, Jianjun
    National Research Council Canada.
    Schott, Thomas
    University of Helsinki.
    Paulin, Lars
    University of Helsinki.
    Auvinen, Petri
    University of Helsinki.
    Hanninen, Marja-Liisa
    University of Helsinki.
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Wakarchuk, Warren
    National Research Council Canada.
    Identification and Characterization of a Lipopolysaccharide alpha,2,3-Sialyltransferase from the Human Pathogen Helicobacter bizzozeronii2012Ingår i: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 194, nr 10, s. 2540-2550Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Terminal sialic acid in the lipopolysaccharides (LPSs) of mucosal pathogens is an important virulence factor. Here we report the characterization of a Helicobacter sialyltransferase involved in the biosynthesis of sialylated LPS in Helicobacter bizzozeronii, the only non-pylori gastric Helicobacter species isolated from humans thus far. Starting from the genome sequences of canine and human strains, we identified potential sialyltransferases downstream of three genes involved in the biosynthesis of N-acetylneuraminic acid. One of these candidates showed monofunctional alpha,2,3-sialyltransferase activity with a preference for N-acetyllactosamine as a substrate. The LPSs from different strains were shown by SDS-PAGE and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to contain sialic acid after neuraminidase treatment. The expression of this sialyltransferase and sialyl-LPS appeared to be a phase-variable characteristic common to both human and canine H. bizzozeronii strains. The sialylation site of the LPSs of two H. bizzozeronii strains was determined to be NeuAc-Hex-HexNAc, suggesting terminal 3-sialyl-LacNAc. Moreover, serological typing revealed the possible presence of sialyl-Lewis X in two additional strains, indicating that H. bizzozeronii could also mimic the surface glycans of mammalian cells. The expression of sialyl-glycans may influence the adaptation process of H. bizzozeronii during the host jump from dogs to humans.

  • 7.
    Langereis, Jeroen D
    et al.
    Radboud University of Nijmegen, Netherlands .
    Stol, Kim
    Radboud University of Nijmegen, Netherlands .
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Twelkmeyer, Brigitte
    Karolinska Institute, Sweden .
    Bootsma, Hester J
    Radboud University of Nijmegen, Netherlands .
    de Vries, Stefan P W
    Radboud University of Nijmegen, Netherlands .
    Burghout, Peter
    Radboud University of Nijmegen, Netherlands .
    Diavatopoulos, Dimitri A
    Radboud University of Nijmegen, Netherlands .
    Hermans, Peter W M
    Radboud University of Nijmegen, Netherlands .
    Modified Lipooligosaccharide Structure Protects Nontypeable Haemophilus influenzae from IgM-Mediated Complement Killing in Experimental Otitis Media2012Ingår i: mBio, ISSN 2161-2129, E-ISSN 2150-7511, Vol. 3, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative, human-restricted pathogen. Although this bacterium typically colonizes the nasopharynx in the absence of clinical symptoms, it is also one of the major pathogens causing otitis media (OM) in children. Complement represents an important aspect of the host defense against NTHi. In general, NTHi is efficiently killed by complement-mediated killing; however, various resistance mechanisms have also evolved. We measured the complement resistance of NTHi isolates isolated from the nasopharynx and the middle ear fluids of OM patients. Furthermore, we determined the molecular mechanism of NTHi complement resistance. Complement resistance was strongly increased in isolates from the middle ear, which correlated with decreased binding of IgM. We identified a crucial role for the R2866_0112 gene in complement resistance. Deletion of this gene altered the lipooligosaccharide (LOS) composition of the bacterium, which increased IgM binding and complement-mediated lysis. In a novel mouse model of coinfection with influenza virus, we demonstrate decreased virulence for the R2866_0112 deletion mutant. These findings identify a mechanism by which NTHi modifies its LOS structure to prevent recognition by IgM and activation of complement. Importantly, this mechanism plays a crucial role in the ability of NTHi to cause OM. less thanbrgreater than less thanbrgreater thanIMPORTANCE Nontypeable Haemophilus influenzae (NTHi) colonizes the nasopharynx of especially young children without any obvious symptoms. However, NTHi is also a major pathogen in otitis media (OM), one of the most common childhood infections. Although this pathogen is often associated with OM, the mechanism by which this bacterium is able to cause OM is largely unknown. Our study addresses a key biological question that is highly relevant for child health: what is the molecular mechanism that enables NTHi to cause OM? We show that isolates collected from the middle ear fluid exhibit increased complement resistance and that the lipooligosaccharide (LOS) structure determines IgM binding and complement activation. Modification of the LOS structure decreased NTHi virulence in a novel NTHi-influenza A virus coinfection OM mouse model. Our findings may also have important implications for other Gram-negative pathogens harboring LOS, such as Neisseria meningitidis, Moraxella catarrhalis, and Bordetella pertussis.

    Ladda ner fulltext (pdf)
    fulltext
  • 8.
    Vitiazeva, Varvara
    et al.
    Karolinska Institute, Sweden .
    Li, Jianjun
    National Research Council Canada, Canada .
    Hood, Derek W.
    University of Oxford Nuffield, England .
    Moxon, E .Richard
    University of Oxford Nuffield, England .
    Schweda, Elke
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    The structural diversity of lipopolysaccharide expressed by non-typeable Haemophilus influenzae strains 1158 and 11592012Ingår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 357, s. 98-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A heterogeneous population of glycoforms expressed by NTHi strains 1158 and 1159 has been elucidated using NMR spectroscopy and capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) on O-deacylated LPS (LPS-OH) and core oligosaccharide (OS) materials, as well as HPLC-ESI-MSn on dephosphorylated and methylated OS samples. The most abundant glycoform contained a disaccharide chain: PCho -greater than 7)-D-alpha-D-Hepp-(1 -greater than 6)-beta-D-Glcp linked to HepI from the common structural element of H. influenzae LPS: L-alpha-D-HepIIIp-(1 -greater than 2)-[PEtn -greater than 6]-L-alpha-D-HepIIp-(1 -greater than 3)-L-alpha-D-HepIp-(1 -greater than 5)[PPEtn -greater than 4]-alpha-Kdop-(2 -greater than 6)-lipid A. Phosphocholine (PCho) was found at two positions in the LPS glycoforms; PCho substituted the 6-position of beta-D-Glcp attached to HepIII and was also located at a novel position linked to D-alpha-D-Hepp; this latter position was determined by structural analysis of LPS from a 1158lpsA mutant strain. Additionally, HPLC-ESI-MSn experiments indicated glycoforms that have chain elongation from HepII, this was found only in glycoforms, which lack the additional heptose in the outer core region. Structural details of these glycoforms were confirmed by analyses of LPS from a 1158losB2 mutant strain; the losB2 gene is required for addition of the D,D-Hep to the outer core region in strain 1158.

1 - 8 av 8
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf