| 1. |
- Ekendahl, Susanne, 1965, et al.
(author)
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Characterisation of Yeasts isolated from deep igneous rock aquifers of the fennoscandian shield
- 2003
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In: Microbial Ecology. - : Springer Science and Business Media LLC. - 0095-3628 .- 1432-184X. ; 46:4, s. 416-428
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Journal article (peer-reviewed)abstract
- The diversity of prokaryotes in the groundwater deep below the surface of the Baltic Sea at the Aspo Hard Rock Laboratory (HRL) in southeast Sweden is well documented. In addition, there is some evidence that eukaryotes, too, are present in the deep groundwater at this site, although their origins are uncertain. To extend the knowledge of eukaryotic life in this environment, five yeast, three yeastlike, and 17 mold strains were isolated from Aspo HRL groundwater between 201 and 444 m below sea level. Phenotypic testing and phylogenetic analysis of 18S rDNA sequences of the five yeast isolates revealed their relationships to Rhodotorula minuta and Cryptococcus spp. Scanning and transmission electron microscopy demonstrated that the strains possessed morphological characteristics typical for yeast, although they were relatively small, with an average length of 3 mum. Enumeration through direct counting and most probable number methods showed low numbers of fungi, between 0.01 and 1 cells mL(-1), at some sites. Five of the strains were characterized physiologically to determine whether they were adapted to life in the deep biosphere. These studies revealed that the strains grew within a pH range of 4-10, between temperatures of 4degreesC and 25-30degreesC, and in NaCl concentrations from 0 to 70 g L-1. These growth parameters suggest a degree of adaptation to the groundwater at Aspo HRL. Despite the fact that these eukaryotic microorganisms may be transient members of the deep biosphere microbial community, many of the observations of this study suggest that they are capable of growing in this extreme environment.
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| 2. |
- Flowers, Sarah A., et al.
(author)
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Decrease of core 2 O-glycans on synovial lubricin in osteoarthritis reduces galectin-3 mediated crosslinking
- 2020
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In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 295:47, s. 16023-16036
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Journal article (peer-reviewed)abstract
- The synovial fluid glycoprotein lubricin (also known as proteoglycan 4) is a mucin-type O-linked glycosylated biological lubricant implicated to be involved in osteoarthritis (OA) development. Lubricin's ability to reduce friction is related to its glycosylation consisting of sialylated and unsialylated Tn-antigens and core 1 and core 2 structures. The glycans on lubricin have also been suggested to be involved in crosslinking and stabilization of the lubricating superficial layer of cartilage by mediating interaction between lubricin and galectin-3. However, with the spectrum of glycans being found on lubricin, the glycan candidates involved in this interaction were unknown. Here, we confirm that the core 2 O-linked glycans mediate this lubricin-galectin-3 interaction, shown by surface plasmon resonance data indicating that recombinant lubricin (rhPRG4) devoid of core 2 structures did not bind to recombinant galectin-3. Conversely, transfection of Chinese hamster ovary cells with the core 2 GlcNAc transferase acting on a mucin-type O-glycoprotein displayed increased galectin-3 binding. Both the level of galectin-3 and the galectin-3 interactions with synovial lubricin were found to be decreased in late-stage OA patients, coinciding with an increase in unsialylated core 1 O-glycans (T-antigens) and Tn-antigens. These data suggest a defect in crosslinking of surface-active molecules in OA and provide novel insights into OA molecular pathology.
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| 3. |
- Johansson, Malin E V, 1971, et al.
(author)
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Composition and functional role of the mucus layers in the intestine.
- 2011
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In: Cellular and Molecular Life Sciences. - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 68, s. 3635-3641
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Research review (peer-reviewed)abstract
- In discussions on intestinal protection, the protective capacity of mucus has not been very much considered. The progress in the last years in understanding the molecular nature of mucins, the main building blocks of mucus, has, however, changed this. The intestinal enterocytes have their apical surfaces covered by transmembrane mucins and the whole intestinal surface is further covered by mucus, built around the gel-forming mucin MUC2. The mucus of the small intestine has only one layer, whereas the large intestine has a two-layered mucus where the inner, attached layer has a protective function for the intestine, as it is impermeable to the luminal bacteria.
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| 4. |
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| 5. |
- Nagao-Kitamoto, H., et al.
(author)
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Interleukin-22-mediated host glycosylation prevents Clostridioides difficile infection by modulating the metabolic activity of the gut microbiota
- 2020
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In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 26, s. 608-617
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Journal article (peer-reviewed)abstract
- In germ-free mice colonized with human microbiota, mucosal IL-22 signaling promotes the growth of succinate-consuming commensal bacteria via host mucus glycosylation, and transplantation of these bacteria limits Clostridioides difficile infection. The involvement of host immunity in the gut microbiota-mediated colonization resistance to Clostridioides difficile infection (CDI) is incompletely understood. Here, we show that interleukin (IL)-22, induced by colonization of the gut microbiota, is crucial for the prevention of CDI in human microbiota-associated (HMA) mice. IL-22 signaling in HMA mice regulated host glycosylation, which enabled the growth of succinate-consuming bacteria Phascolarctobacterium spp. within the gut microbiome. Phascolarctobacterium reduced the availability of luminal succinate, a crucial metabolite for the growth of C. difficile, and therefore prevented the growth of C. difficile. IL-22-mediated host N-glycosylation is likely impaired in patients with ulcerative colitis (UC) and renders UC-HMA mice more susceptible to CDI. Transplantation of healthy human-derived microbiota or Phascolarctobacterium reduced luminal succinate levels and restored colonization resistance in UC-HMA mice. IL-22-mediated host glycosylation thus fosters the growth of commensal bacteria that compete with C. difficile for the nutritional niche.
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| 6. |
- Prakobphol, A, et al.
(author)
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Human low-molecular-weight salivary mucin expresses the sialyl lewisx determinant and has L-selectin ligand activity.
- 1998
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In: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 37:14, s. 4916-27
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Journal article (peer-reviewed)abstract
- Previously we showed that the low-molecular-weight mucin (MG2, encoded by MUC7), a major component of human submandibular/sublingual saliva, is a bacterial receptor that coats the tooth surface. Here we tested the hypothesis that the structure of its carbohydrate residues contains important information about its function. Purified MG2 (Mr 120 000) was digested with trypsin, and the resulting Mr 90 000 fragment, which carried primarily O-linked oligosaccharides, was subjected to reductive beta-elimination. The released oligosaccharides were characterized by using nuclear magnetic resonance spectroscopy and mass spectrometry. Of the 41 different structures we detected, the most prominent included NeuAcalpha2-->3Galbeta1-->3GalNAc-ol (sialyl-T antigen), Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->6(Galbeta1 -->3)GalNAc-ol [type 2 core with Lewisx (Lex) determinant], and NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6(Galbeta1--> 3) GalNAc-ol [type 2 core with sialyl Lex (sLex) determinant]. We also detected di-, tri-, and pentasaccharides with one sulfate group. Lex, sLex, and related sulfated structures are ligands for selectins, adhesion molecules that mediate leukocyte trafficking. Therefore, we investigated whether MG2 was a selectin ligand. In an enzyme-linked immunosorbent assay, L-selectin chimeras interacted with immobilized MG2 in a Ca2+-dependent manner. L-Selectin chimeras also bound to MG2 immobilized on nitrocellulose. Together, these results suggest that the saccharides that MG2 carries could specify some of its important functions, which may include mediating leukocyte interactions in the oral cavity.
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| 7. |
- Thomsson, Kristina A, 1969, et al.
(author)
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MUC5B glycosylation in human saliva reflects blood group and secretor status.
- 2005
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In: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 15:8, s. 791-804
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Journal article (peer-reviewed)abstract
- This study aimed to characterize human salivary glycoforms and the natural glycosylation variation of the major ABO blood group bearing high molecular weight glycoprotein fraction MG1, which mainly consists of MUC5B mucin. Reduced and alkylated mucins from individuals of blood group A, B, and O were purified by sodium dodecyl sulfate-agarose/polyacrylamide composite gel electrophoresis (SDS-AgPAGE), blotted to polyvinylidene fluoride (PVDF) membranes, and visualized with alcian blue. O-linked oligosaccharides were released from MUC5B glycoform bands by reductive beta-elimination and analyzed by liquid chromatography (LC) electrospray ion trap mass spectrometry (MS). Slow electrophoretically migrating MUC5B components (sm) were found to be dominated by neutral oligosaccharides, and fast-migrating (fm) components were dominated by sulfated oligosaccharides. ABO blood group-specific sequences were found on all glycoforms, and novel oligosaccharides containing blood group A and B type sequences were sequenced. This is the first molecular description of the influence of the blood group ABO system on salivary MUC5B oligosaccharides. Expanding these results from the three A, B, and O individuals into larger population (29 individuals), we found oligosaccharide sequences corresponding to the blood group of the donor on MUC5B from 23 individuals. The remaining six individuals were characterized by a high degree of sialylation. These individuals were assigned as nonsecretors, whereas blood group-expressing individuals were assigned as secretors. Western blot assays with antibodies confirmed increased expression of Sialyl Lewis a (Si-Le(a)) in the nonsecretors. Our results highlight that salivary MUC5B consists of glycoforms with distinct glycosylation that vary extensively between individuals and that some of this variation is owing to blood group and secretor status.
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| 8. |
- Thomsson, Kristina A, 1969, et al.
(author)
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Sequencing of sulfated oligosaccharides from mucins by liquid chromatography and electrospray ionization tandem mass spectrometry.
- 2000
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In: Analytical chemistry. - 0003-2700. ; 72:19, s. 4543-9
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Journal article (peer-reviewed)abstract
- As part of a strategy for profiling diverse mixtures of sulfated mucin-derived oligosaccharides, liquid chromatography coupled to electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the negative ion mode has been explored. Two mixtures of sulfated oligosaccharide alditols from porcine stomach and large intestine were analyzed by straight phase chromatography using an amino-bonded column connected to a Q-TOF instrument. Nine sulfated mucin-derived oligosaccharide alditols from porcine stomach underwent extensive fragmentation allowing determination of their sequence. The fragmentation generated primary, secondary, and tertiary fragment ions informative for the elucidation of the saccharide sequence and localization of the sulfate group. From a single chromatographic analysis, the sequences of 28 different sulfated mucin oligosaccharide alditols purified from porcine large intestine were elucidated, revealing information concerning prominent core sequences and terminal blood group-type epitopes. Analysis of these two sulfated oligosaccharide mixtures demonstrated the usefulness of HPLC-ESI-MS/MS: the on-line separation of multiple isomeric suffated oligosaccharides as present in biological samples, informative fragmentation allowing the identification of the sequence of nonderivatized oligosaccharides, and a sensitivity sufficient for the analysis of quantities as obtained from natural sources.
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| 9. |
- Wada, Yoshinao, et al.
(author)
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Comparison of methods for profiling O-glycosylation: Human Proteome Organisation Human Disease Glycomics/Proteome Initiative multi-institutional study of IgA1.
- 2010
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In: Molecular & cellular proteomics. - 1535-9484. ; 9:4, s. 719-727
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Journal article (peer-reviewed)abstract
- The Human Proteome Organisation Human Disease Glycomics/Proteome Initiative recently coordinated a multi-institutional study that evaluated methodologies that are widely used for defining the N-glycan content in glycoproteins. The study convincingly endorsed mass spectrometry as the technique of choice for glycomic profiling in the discovery phase of diagnostic research. The present study reports the extension of the Human Disease Glycomics/Proteome Initiative's activities to an assessment of the methodologies currently used for O-glycan analysis. Three samples of IgA1 isolated from the serum of patients with multiple myeloma were distributed to 15 laboratories worldwide for O-glycomics analysis. A variety of mass spectrometric and chromatographic procedures representative of current methodologies were used. Similar to the previous N-glycan study, the results convincingly confirmed the pre-eminent performance of MS for O-glycan profiling. Two general strategies were found to give the most reliable data, namely direct MS analysis of mixtures of permethylated reduced glycans in the positive ion mode and analysis of native reduced glycans in the negative ion mode using LC-MS approaches. In addition, mass spectrometric methodologies to analyze O-glycopeptides were also successful.
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| 10. |
- Wilkinson, H., et al.
(author)
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The O-Glycome of Human Nigrostriatal Tissue and Its Alteration in Parkinson's Disease
- 2021
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In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 20:8, s. 3913-3924
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Journal article (peer-reviewed)abstract
- O-Glycosylation changes in misfolded proteins are of particular interest in understanding neurodegenerative conditions such as Parkinson's disease (PD) and incidental Lewy body disease (ILBD). This work outlines optimizations of a microwave-assisted nonreductive release to limit glycan degradation and employs this methodology to analyze O-glycosylation on the human striatum and substantia nigra tissue in PD, ILBD, and healthy controls, working alongside well-established reductive release approaches. A total of 70 O-glycans were identified, with ILBD presenting significantly decreased levels of mannose-core (p = 0.017) and glucuronylated structures (p = 0.039) in the striatum and PD presenting an increase in sialylation (p < 0.001) and a decrease in sulfation (p = 0.001). Significant increases in sialylation (p = 0.038) in PD were also observed in the substantia nigra. This is the first study to profile the whole nigrostriatal O-glycome in healthy, PD, and ILBD tissues, outlining disease biomarkers alongside benefits of employing orthogonal techniques for O-glycan analysis. © 2021 The Authors. Published by American Chemical Society.
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