| 1. |
- Mahdavi, Jafar, et al.
(författare)
-
Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation
- 2002
-
Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 297:5581, s. 573-578
-
Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.
|
|
| 2. |
- Aspholm-Hurtig, Marina, et al.
(författare)
-
Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
-
Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
-
Tidskriftsartikel (refereegranskat)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
|
|
| 3. |
- Borén, Thomas, 1967-
(författare)
-
Meeting-places of Transformation : Urban Identity, Spatial Representations and Local Politics in St Petersburg, Russia
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study develops a model for understanding spatial change and the construction of space as a meeting-place, and then employs it in order to show an otherwise little-known picture of (sub-)urban Russia and its transformation from Soviet times to today. The model is based on time-geographic ideas of time-space as a limited resource in which forces of various kinds struggle for access and form space in interaction with each other. Drawing on cultural semiotics and the concepts of lifeworld and system, the study highlights the social side of these space-forming forces. Based on a long-term fieldwork (participant observation) in Ligovo/Uritsk, a high-rise residential district developed around 1970 and situated on the outskirts of Sankt-Peterburg (St Petersburg), the empirical material concerns processes of urban identity, spatial representations and local politics. The study explicates three codes used to form the image of the city that all relate to its pre-Revolutionary history, two textual strategies of juxtaposition in creating the genius loci of a place, and a discussion of what I call Soviet "stiff landscape" in relation to Soviet mental and ordinary maps of the urban landscape. Moreover, the study shows that the newly implemented self-governing municipalities have not realised their potential as political actors in forming local space, which raises questions on the democratisation of urban space. Finally, the study argues that the model that guides the research is a tool that facilitates the application of the world-view of time-geography and the epistemology of the landscape of courses in concrete research. The study ends with an attempt to generalise spatial change in four types.
|
|
| 4. |
|
|
| 5. |
- Lundén, Thomas, et al.
(författare)
-
A hundred years later. Streetcars are still rattling in Baltic cities
- 2012
-
Ingår i: Baltic Worlds. - 2000-2955 .- 2001-7308. ; 5:3-4, s. 37-44
-
Tidskriftsartikel (refereegranskat)abstract
- A young geographer by the name of Sten DeGeer mapped the cities around the Baltic Sea in an article published in 1912. As an attempt to capture the urban structure of Baltic region cities, his paper is unique. In this article, we comment on his meticulous descriptions of these cities, with a century long perspective.
|
|
| 6. |
|
|
| 7. |
- Prakobphol, A, et al.
(författare)
-
Salivary agglutinin, which binds Streptococcus mutans and Helicobacter pylori, is the lung scavenger receptor cysteine-rich protein gp-340.
- 2000
-
Ingår i: The Journal of biological chemistry. - 0021-9258 .- 1083-351X. ; 275:51, s. 39860-6
-
Tidskriftsartikel (refereegranskat)abstract
- Salivary agglutinin is a high molecular mass component of human saliva that binds Streptococcus mutans, an oral bacterium implicated in dental caries. To study its protein sequence, we isolated the agglutinin from human parotid saliva. After trypsin digestion, a portion was analyzed by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which gave the molecular mass of 14 unique peptides. The remainder of the digest was subjected to high performance liquid chromatography, and the separated peptides were analyzed by MALDI-TOF/post-source decay; the spectra gave the sequences of five peptides. The molecular mass and peptide sequence information showed that salivary agglutinin peptides were identical to sequences in lung (lavage) gp-340, a member of the scavenger receptor cysteine-rich protein family. Immunoblotting with antibodies that specifically recognized either lung gp-340 or the agglutinin confirmed that the salivary agglutinin was gp-340. Immunoblotting with an antibody specific to the sialyl Le(x) carbohydrate epitope detected expression on the salivary but not the lung glycoprotein, possible evidence of different glycoforms. The salivary agglutinin also interacted with Helicobacter pylori, implicated in gastritis and peptic ulcer disease, Streptococcus agalactiae, implicated in neonatal meningitis, and several oral commensal streptococci. These results identify the salivary agglutinin as gp-340 and suggest it binds bacteria that are important determinants of either the oral ecology or systemic diseases.
|
|
| 8. |
- Roche, Niamh, 1969, et al.
(författare)
-
Helicobacter pylori and complex gangliosides.
- 2004
-
Ingår i: Infection and immunity. - 0019-9567. ; 72:3, s. 1519-29
-
Tidskriftsartikel (refereegranskat)abstract
- Recognition of sialic acid-containing glycoconjugates by the human gastric pathogen Helicobacter pylori has been repeatedly demonstrated. To investigate the structural requirements for H. pylori binding to complex gangliosides, a large number of gangliosides were isolated and characterized by mass spectrometry and proton nuclear magnetic resonance. Ganglioside binding of sialic acid-recognizing H. pylori strains (strains J99 and CCUG 17874) and knockout mutant strains with the sialic acid binding adhesin SabA or the NeuAcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta-binding neutrophil-activating protein HPNAP deleted was investigated using the thin-layer chromatogram binding assay. The wild-type bacteria bound to N-acetyllactosamine-based gangliosides with terminal alpha3-linked NeuAc, while gangliosides with terminal NeuGcalpha3, NeuAcalpha6, or NeuAcalpha8NeuAcalpha3 were not recognized. The factors affecting binding affinity were identified as (i) the length of the N-acetyllactosamine carbohydrate chain, (ii) the branches of the carbohydrate chain, and (iii) fucose substitution of the N-acetyllactosamine core chain. While the J99/NAP(-) mutant strain displayed a ganglioside binding pattern identical to that of the parent J99 wild-type strain, no ganglioside binding was obtained with the J99/SabA(-) mutant strain, demonstrating that the SabA adhesin is the sole factor responsible for the binding of H. pylori bacterial cells to gangliosides.
|
|
| 9. |
|
|
| 10. |
- Adiels, Martin, 1976, et al.
(författare)
-
Optimization of N-methyl-N-[tert-butyldimethylsilyl]trifluoroacetamide as a derivatization agent for determining isotopic enrichment of glycerol in very-low density lipoproteins.
- 2010
-
Ingår i: Rapid communications in mass spectrometry : RCM. - : Wiley. - 1097-0231 .- 0951-4198. ; 24:5, s. 586-592
-
Tidskriftsartikel (refereegranskat)abstract
- Stable isotope kinetic studies play an important role in the study of very-low density lipoprotein (VLDL) metabolism, including basic and clinical research. Today, [1,1,2,3,3-(2)H(5)]glycerol is the most cost-effective alternative to measure glycerol and triglyceride kinetics. Recycling of glycerol from glycolysis and gluconeogenesis may lead to incompletely labelled tracer molecules. Many existing methods for the measurement of glycerol isotopic enrichment involve the production of glycerol derivatives that result in fragmentation of the glycerol molecule after ionization. It would be favourable to measure the intact tracer molecule since incompletely labelled tracer molecules may be measured as fully labelled. The number of methods available to measure the intact tracer in biological samples is limited. The aim of this project was to develop a gas chromatography/mass spectrometry (GC/MS) method for glycerol enrichment that measures the intact glycerol backbone and is suitable for electron ionization (EI), which is widely available. A previously published method for N-methyl-N-[tert-butyldimethylsilyl]trifluoroacetamide (MTBSTFA) derivatization was significantly improved; we produced a stable derivative and increased recovery 27-fold in standards. We used the optimized MTBSTFA method in VLDL-triglyceride and found that further modification was required to take matrix effects into account. We now have a robust method to measure glycerol isotopic enrichment by GC/EI-MS that can be used to rule out the known problem of tracer recycling in studies of VLDL kinetics. Copyright (c) 2010 John Wiley & Sons, Ltd.
|
|
