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Östberg, Yngve
Publications (10 of 14) Show all publications
Avican, U., Doruk, T., Östberg, Y., Fahlgren, A. & Forsberg, Å. (2017). The Tat substrate SufI is critical for the ability of Yersinia pseudotuberculosis to cause systemic infection. Infection and Immunity, 85(4), Article ID e00867-16.
Open this publication in new window or tab >>The Tat substrate SufI is critical for the ability of Yersinia pseudotuberculosis to cause systemic infection
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2017 (English)In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 85, no 4, article id e00867-16Article in journal (Refereed) Published
Abstract [en]

The twin arginine translocation (Tat) system targets folded proteins across the inner membrane and is crucial for virulence in many important humanpathogenic bacteria. Tat has been shown to be required for the virulence of Yersinia pseudotuberculosis, and we recently showed that the system is critical for different virulence-related stress responses as well as for iron uptake. In this study, we wanted to address the role of the Tat substrates in in vivo virulence. Therefore, 22 genes encoding potential Tat substrates were mutated, and each mutant was evaluated in a competitive oral infection of mice. Interestingly, a.sufI mutant was essentially as attenuated for virulence as the Tat-deficient strain. We also verified that SufI was Tat dependent for membrane/periplasmic localization in Y. pseudotuberculosis. In vivo bioluminescent imaging of orally infected mice revealed that both the.sufI and Delta tatC mutants were able to colonize the cecum and Peyer's patches (PPs) and could spread to the mesenteric lymph nodes (MLNs). Importantly, at this point, neither the Delta tatC mutant nor the Delta sufI mutant was able to spread systemically, and they were gradually cleared. Immunostaining of MLNs revealed that both the Delta tatC and Delta sufI mutants were unable to spread from the initial infection foci and appeared to be contained by neutrophils, while wild-type bacteria readily spread to establish multiple foci from day 3 postinfection. Our results show that SufI alone is required for the establishment of systemic infection and is the major cause of the attenuation of the Delta tatC mutant.

Keywords
Yersinia pseudotuberculosis, Tat pathway, virulence, SufI, mesenteric lymph nodes, neutrophils
National Category
Microbiology Immunology
Identifiers
urn:nbn:se:umu:diva-128087 (URN)10.1128/IAI.00867-16 (DOI)000397581800003 ()28115509 (PubMedID)
Available from: 2016-11-22 Created: 2016-11-22 Last updated: 2018-06-09Bibliographically approved
Park, H.-S., Östberg, Y., Johansson, J., Wagner, E. G. & Uhlin, B. E. (2010). Novel role for a bacterial nucleoid protein in translation of mRNAs with suboptimal ribosome-binding sites. Genes & Development, 24(13), 1345-1350
Open this publication in new window or tab >>Novel role for a bacterial nucleoid protein in translation of mRNAs with suboptimal ribosome-binding sites
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2010 (English)In: Genes & Development, ISSN 0890-9369, E-ISSN 1549-5477, Vol. 24, no 13, p. 1345-1350Article in journal (Refereed) Published
Abstract [en]

In Escherichia coli, the major nucleoid protein H-NS limits transcription by acting as a repressor or transcriptional silencer, presumably by its ability to close the looped chromosome domains in the nucleoid through DNA-protein-DNA bridging. Here, we demonstrate the direct involvement of H-NS as a positive factor stimulating translation of the malT mRNA. In vitro studies showed that H-NS facilitates a repositioning of the 30S preinitiation complex on the malT mRNA. H-NS stimulation of translation depended on the AU-rich -35 to -40 region of the mRNA. Several additional examples were found demonstrating a novel function for H-NS in translation of genes with suboptimal ribosome-binding sequences.

Keywords
Bacterial nucleoid; gene expression; translation; ribosome-binding sites; 5 '-untranslated region
National Category
Medical Genetics
Identifiers
urn:nbn:se:umu:diva-43193 (URN)10.1101/gad.576310 (DOI)000279405000004 ()
Available from: 2011-04-22 Created: 2011-04-22 Last updated: 2018-06-08Bibliographically approved
Bunikis, I., Denker, K., Östberg, Y., Andersen, C., Benz, R. & Bergström, S. (2008). An RND-type efflux system in Borrelia burgdorferi is involved in virulence and resistance to antimicrobial compounds. PLoS Pathogenicity, 4(2), e1000009
Open this publication in new window or tab >>An RND-type efflux system in Borrelia burgdorferi is involved in virulence and resistance to antimicrobial compounds
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2008 (English)In: PLoS Pathogenicity, ISSN 1553-7374, Vol. 4, no 2, p. e1000009-Article in journal (Refereed) Published
Abstract [en]

Borrelia burgdorferi is remarkable for its ability to thrive in widely different environments due to its ability to infect various organisms. In comparison to enteric Gram-negative bacteria, these spirochetes have only a few transmembrane proteins some of which are thought to play a role in solute and nutrient uptake and excretion of toxic substances. Here, we have identified an outer membrane protein, BesC, which is part of a putative export system comprising the components BesA, BesB and BesC. We show that BesC, a TolC homolog, forms channels in planar lipid bilayers and is involved in antibiotic resistance. A besC knockout was unable to establish infection in mice, signifying the importance of this outer membrane channel in the mammalian host. The biophysical properties of BesC could be explained by a model based on the channel-tunnel structure. We have also generated a structural model of the efflux apparatus showing the putative spatial orientation of BesC with respect to the AcrAB homologs BesAB. We believe that our findings will be helpful in unraveling the pathogenic mechanisms of borreliae as well as in developing novel therapeutic agents aiming to block the function of this secretion apparatus.

Keywords
Amino Acid Sequence, Animals, Anti-Bacterial Agents/pharmacology, Bacterial Outer Membrane Proteins/genetics/*metabolism, Bacterial Proteins/genetics/*metabolism, Borrelia burgdorferi/genetics/metabolism/*pathogenicity, DNA; Bacterial, Drug Resistance; Microbial/*physiology, Gene Expression Regulation; Bacterial/genetics, Gene Silencing, Ion Channels/drug effects/metabolism, Membrane Transport Proteins/genetics/*metabolism, Mice, Mice; Inbred C3H, Microbial Sensitivity Tests, Models; Molecular, Molecular Sequence Data, Organisms; Genetically Modified, RNA; Messenger/metabolism, Virulence
National Category
Cell and Molecular Biology
Research subject
Molecular Biology
Identifiers
urn:nbn:se:umu:diva-10115 (URN)18389081 (PubMedID)
Available from: 2008-06-17 Created: 2008-06-17 Last updated: 2018-06-09Bibliographically approved
Östberg, Y., Berg, S., Comstedt, P., Wieslander, Å. & Bergström, S. (2007). Functional analysis of a lipid galactosyltransferase synthesizing the major envelope lipid in the Lyme disease spirochete Borrelia burgdorferi. FEMS Microbiology Letters, 272(1), 22-29
Open this publication in new window or tab >>Functional analysis of a lipid galactosyltransferase synthesizing the major envelope lipid in the Lyme disease spirochete Borrelia burgdorferi
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2007 (English)In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 272, no 1, p. 22-29Article in journal (Refereed) Published
Abstract [en]

One of the major lipids in the membranes of Borrelia burgdorferi is monogalactosyl diacylglycerol (MGalDAG), a glycolipid recently shown to carry antigenic potency. Herein, it is shown that the gene mgs (TIGR designation bb0454) of B. burgdorferi encodes for the protein bbMGS that, when expressed in Escherichia coli, catalyzes the glycosylation of 1,2-diacylglycerol with specificity for the donor substrate UDP-Gal yielding MGalDAG. Related lipid enzymes were found in many Gram-positive bacteria. The presence of this galactosyltransferase activity and synthesis of a cholesteryl galactoside by another enzyme were verified in B. burgdorferi cell extract. Besides MGalDAG, phosphatidylcholine, phosphatidylglycerol, and cholesterol were also found as major lipids in the cell envelope. The high isoelectric point of bbMGS and clustered basic residues in its amino acid sequence suggest that the enzyme interacts with acidic lipids in the plasma membrane, in agreement with strong enzymatic activation of bbMGS by phosphatidylglycerol. The membrane packing and immunological properties of MGalDAG are likely to be of great importance in vivo.

National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-48648 (URN)10.1111/j.1574-6968.2007.00728.x (DOI)17456185 (PubMedID)
Available from: 2011-10-26 Created: 2011-10-26 Last updated: 2018-06-08Bibliographically approved
Pinne, M., Östberg, Y., Comstedt, P. & Bergström, S. (2004). Molecular analysis of the channel-forming protein P13 and its paralogue family 48 from different Lyme disease Borrelia species. Microbiology, 150(Pt 3), 549-559
Open this publication in new window or tab >>Molecular analysis of the channel-forming protein P13 and its paralogue family 48 from different Lyme disease Borrelia species
2004 (English)In: Microbiology, ISSN 1350-0872, E-ISSN 1465-2080, Vol. 150, no Pt 3, p. 549-559Article in journal (Refereed) Published
Abstract [en]

The aetiological agent of Lyme disease, Borrelia burgdorferi cycles between its tick vector and mammalian hosts, implying that it can sense different environments and consequently change the expression of genes encoding several surface-associated proteins. The genome of the type strain B. burgdorferi B31 has revealed 175 different gene families. The p13 gene, situated on the chromosome, encodes a channel-forming protein that belongs to the gene family 48 consisting of eight additional paralogous genes. The heterogeneity of the P13 protein from different Lyme disease Borrelia strains was investigated. The predicted surface-exposed domains are the most heterogeneous regions and contain probable epitopes of P13. The membrane-spanning architecture of P13 was determined and a model for the location of this protein in the outer membrane is presented. The transcription of the paralogues of gene family 48 during in vitro culturing and in a mouse infection model was also analysed. The bba01 gene is the only p13 paralogue present in all three Lyme-disease-causing genospecies; it is stable during cultivation in vitro and the BBA01 protein was expressed in all Borrelia strains investigated. Conversely, paralogues bbi31, bbq06 and bbh41 were only detected in B. burgdorferi and the corresponding plasmids harbouring bbi31 and bbh41 were lost during in vitro passage. Finally, p13 and bbi31 are the only members of gene family 48 that are transcribed in mice, suggesting their importance during mammalian infection.

Keywords
Amino Acid Sequence, Animals, Bacterial Outer Membrane Proteins/chemistry/genetics/physiology, Bacterial Proteins/chemistry/*genetics/physiology, Base Sequence, Borrelia/*genetics/pathogenicity/physiology, DNA; Bacterial/genetics, Epitope Mapping, Genes; Bacterial, Humans, Ion Channels/chemistry/genetics/physiology, Lyme Disease/microbiology, Mice, Mice; Inbred C3H, Models; Molecular, Molecular Sequence Data, Multigene Family, Sequence Homology; Amino Acid, Species Specificity
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-12966 (URN)10.1099/mic.0.26728-0 (DOI)14993304 (PubMedID)
Available from: 2008-01-10 Created: 2008-01-10 Last updated: 2018-06-09Bibliographically approved
Östberg, Y., Carroll, J. A., Pinne, M., Krum, J. G., Rosa, P. & Bergström, S. (2004). Pleiotropic effects of inactivating a carboxyl-terminal protease, CtpA, in Borrelia burgdorferi. Journal of Bacteriology, 186(7), 2074-2084
Open this publication in new window or tab >>Pleiotropic effects of inactivating a carboxyl-terminal protease, CtpA, in Borrelia burgdorferi
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2004 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 186, no 7, p. 2074-2084Article in journal (Refereed) Published
Abstract [en]

The aetiological agent of Lyme disease, Borrelia burgdorferi cycles between its tick vector and mammalian hosts, implying that it can sense different environments and consequently change the expression of genes encoding several surface-associated proteins. The genome of the type strain B. burgdorferi B31 has revealed 175 different gene families. The p13 gene, situated on the chromosome, encodes a channel-forming protein that belongs to the gene family 48 consisting of eight additional paralogous genes. The heterogeneity of the P13 protein from different Lyme disease Borrelia strains was investigated. The predicted surface-exposed domains are the most heterogeneous regions and contain probable epitopes of P13. The membrane-spanning architecture of P13 was determined and a model for the location of this protein in the outer membrane is presented. The transcription of the paralogues of gene family 48 during in vitro culturing and in a mouse infection model was also analysed. The bba01 gene is the only p13 paralogue present in all three Lyme-disease-causing genospecies; it is stable during cultivation in vitro and the BBA01 protein was expressed in all Borrelia strains investigated. Conversely, paralogues bbi31, bbq06 and bbh41 were only detected in B. burgdorferi and the corresponding plasmids harbouring bbi31 and bbh41 were lost during in vitro passage. Finally, p13 and bbi31 are the only members of gene family 48 that are transcribed in mice, suggesting their importance during mammalian infection.

Keywords
Amino Acid Sequence, Bacterial Proteins/chemistry/genetics/metabolism, Borrelia burgdorferi/*enzymology/genetics, Carboxypeptidases/chemistry/*genetics/*metabolism, Electrophoresis; Polyacrylamide Gel, Immunoblotting, Molecular Sequence Data, Mutation, Sequence Analysis; DNA, Sequence Homology; Amino Acid, Spectrometry; Mass; Matrix-Assisted Laser Desorption-Ionization, Substrate Specificity
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-12965 (URN)10.1099/mic.0.26728-0 (DOI)15028692 (PubMedID)
Available from: 2007-10-03 Created: 2007-10-03 Last updated: 2018-06-09Bibliographically approved
Östberg, Y., Bunikis, I., Bergström, S. & Johansson, J. (2004). The etiological agent of Lyme disease, Borrelia burgdorferi, appears to contain. Journal of Bacteriology, 186(24), 8472-8477
Open this publication in new window or tab >>The etiological agent of Lyme disease, Borrelia burgdorferi, appears to contain
2004 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 186, no 24, p. 8472-8477Article in journal (Refereed) Published
Abstract [en]

Small regulatory RNAs (sRNAs) have recently been shown to be the main controllers of several regulatory pathways. The function of sRNAs depends in many cases on the RNA-binding protein Hfq, especially for sRNAs with an antisense function. In this study, the genome of Borrelia burgdorferi was subjected to different searches for sRNAs, including direct homology and comparative genomics searches and ortholog- and annotation-based search strategies. Two new sRNAs were found, one of which showed complementarity to the rpoS region, which it possibly controls by an antisense mechanism. The role of the other sRNA is unknown, although observed complementarities against particular mRNA sequences suggest an antisense mechanism. We suggest that the low level of sRNAs observed in B. burgdorferi is at least partly due to the presumed lack of both functional Hfq protein and RNase E activity.

Keywords
Animals, Borrelia burgdorferi/*genetics, Computational Biology/methods, Endoribonucleases, Genome; Bacterial, Genomics, Host Factor 1 Protein, Humans, Lyme Disease/*microbiology, MicroRNAs/*genetics, RNA; Bacterial/*genetics, Rabbits
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-12945 (URN)15576797 (PubMedID)
Available from: 2007-10-03 Created: 2007-10-03 Last updated: 2018-06-09Bibliographically approved
Nilsson, C. L., Cooper, H. J., Håkansson, K., Marshall, A. G., Östberg, Y., Lavrinovicha, M. & Bergström, S. (2002). Characterization of the P13 membrane protein of Borrelia burgdorferi by mass spectrometry.. Journal of the American Society for Mass Spectrometry, 13(4), 295-299
Open this publication in new window or tab >>Characterization of the P13 membrane protein of Borrelia burgdorferi by mass spectrometry.
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2002 (English)In: Journal of the American Society for Mass Spectrometry, ISSN 1044-0305, E-ISSN 1879-1123, Vol. 13, no 4, p. 295-299Article in journal (Refereed) Published
Abstract [en]

Borrelia burgdorferi sensu lato is a tick-borne pathogen that causes Lyme disease. The characterization of membrane proteins from this and other pathogens may yield a better understanding of the mechanisms of infection and information useful for vaccine design. Characterization of the highly hydrophobic Borrelia outer membrane component P13 from a mutant (OspA- OspB- OspC- and OspD-) strain was undertaken by use of a combination of mass spectrometric methods. In a previous investigation, an electrospray ionization (ESI) mass spectrum of the intact protein provided an average molecular weight that was 20 Da lower than the predicted molecular weight. The mass deviation could be explained by a modification of the N-terminus of the protein such as pyroglutamylation (-17 Da) in combination with the experimental error of measurement, however more information was required. New structural information for this membrane protein was provided by peptide mapping with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) and sequencing with ESI-quadrupole-TOF tandem MS.

National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-48654 (URN)10.1016/S1044-0305(01)00365-8 (DOI)11951966 (PubMedID)
Available from: 2011-10-26 Created: 2011-10-26 Last updated: 2018-06-08Bibliographically approved
Ornstein, K., Östberg, Y., Bunikis, J., Noppa, L., Berglund, J., Norrby, R. & Bergström, S. (2002). Differential immune response to the variable surface loop antigen of P66 of Borrelia burgdorferi sensu lato species in geographically diverse populations of lyme borreliosis patients. Clinical and diagnostic laboratory immunology, 9(6), 1382-1384
Open this publication in new window or tab >>Differential immune response to the variable surface loop antigen of P66 of Borrelia burgdorferi sensu lato species in geographically diverse populations of lyme borreliosis patients
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2002 (English)In: Clinical and diagnostic laboratory immunology, ISSN 1071-412X, Vol. 9, no 6, p. 1382-1384Article in journal (Refereed) Published
Abstract [en]

We have studied the immune response to a variable surface-exposed loop region of the P66 outer membrane protein from Borrelia burgdorferi sensu lato by using an enzyme immunoassay. Lyme borreliosis populations found in North America and Sweden were preferentially more seroreactive to P66 from their respective regional species, namely, B. burgdorferi sensu stricto and B. garinii and B. afzelii, respectively.

National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-48653 (URN)10.1128/CDLI.9.6.1382-1384.2002 (DOI)12414780 (PubMedID)
Available from: 2011-10-26 Created: 2011-10-26 Last updated: 2018-06-08Bibliographically approved
Östberg, Y., Pinne, M., Benz, R., Rosa, P. & Bergström, S. (2002). Elimination of channel-forming activity by insertional inactivation of the p13 gene in Borrelia burgdorferi. Journal of Bacteriology, 184(24), 6811-6819
Open this publication in new window or tab >>Elimination of channel-forming activity by insertional inactivation of the p13 gene in Borrelia burgdorferi
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2002 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 184, no 24, p. 6811-6819Article in journal (Refereed) Published
Abstract [en]

P13 is a chromosomally encoded 13-kDa integral outer membrane protein of the Lyme disease agent, Borrelia burgdorferi. The aim of this study was to investigate the function of the P13 protein. Here, we inactivated the p13 gene by targeted mutagenesis and investigated the porin activities of outer membrane proteins by using lipid bilayer experiments. Channel-forming activity was lost in the p13 mutant compared to wild-type B. burgdorferi, indicating that P13 may function as a porin. We purified native P13 to homogeneity by fast performance liquid chromatography and demonstrated that pure P13 has channel-forming activity with a single-channel conductance in 1 M KCl of 3.5 nS, the same as the porin activity that was lost in the p13 mutant. Further characterization of the channel formed by P13 suggested that it is cation selective and voltage independent. In addition, no major physiological effects of the inactivated p13 gene could be detected under normal growth conditions. The inactivation of p13 is the first reported inactivation of a gene encoding an integral outer membrane protein in B. burgdorferi. Here, we describe both genetic and biophysical experiments indicating that P13 in B. burgdorferi is an outer membrane protein with porin activity.

Place, publisher, year, edition, pages
American Society for Microbiology, 2002
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-5029 (URN)10.1128/JB.184.24.6811-6819.2002 (DOI)000179529200008 ()12446631 (PubMedID)
Available from: 2006-03-31 Created: 2006-03-31 Last updated: 2019-01-22Bibliographically approved
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