| 1. |
- Chahal, Gurdeep, et al.
(author)
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A Complex Connection Between the Diversity of Human Gastric Mucin O-Glycans, Helicobacter pylori Binding, Helicobacter Infection and Fucosylation
- 2022
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In: Molecular & Cellular Proteomics. - : Elsevier BV. - 1535-9476 .- 1535-9484. ; 21:11
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Journal article (peer-reviewed)abstract
- Helicobacter pylori colonizes the stomach of half of the human population. Most H. pylori are located in the mucus layer, which is mainly comprised by glycosylated mucins. Using mass spectrometry, we identified 631 glycans (whereof 145 were fully characterized and the remainder assigned as compositions) on mucins isolated from 14 Helicobacter spp.-infected and 14 Helicobacter spp.-noninfected stomachs. Only six identified glycans were common to all individuals, from a total of 60 to 189 glycans in each individual. An increased number of unique glycan structures together with an increased intra-individual diversity and larger interindividual variation were identified among O-glycans from Helicobacter spp.-infected stomachs compared with noninfected stom-achs. H. pylori strain J99, which carries the blood group antigen-binding adhesin (BabA), the sialic acid-binding adhesin (SabA), and the LacdiNAc-binding adhesin, bound both to Lewis b (Leb)-positive and Leb-negative mucins. Among Leb-positive mucins, H. pylori J99 bind-ing was higher to mucins from Helicobacter spp.-infected individuals than noninfected individuals. Statistical corre-lation analysis, binding experiments with J99 wt, and J99 Delta babA Delta sabA and inhibition experiments using syn-thetic glycoconjugates demonstrated that the differences in H. pylori-binding ability among these four groups were governed by BabA-dependent binding to fucosylated structures. LacdiNAc levels were lower in mucins that bound to J99 lacking BabA and SabA than in mucins that did not, suggesting that LacdiNAc did not significantly contribute to the binding. We identified 24 O-glycans from Leb-negative mucins that correlated well with H. pylori binding whereof 23 contained alpha 1,2-linked fucosylation. The large and diverse gastric glycan library identified, including structures that correlated with H. pylori binding, could be used to select glycodeterminants to experimen-tally investigate further for their importance in host- pathogen interactions and as candidates to develop glycan-based therapies.
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| 2. |
- Padra, János T, et al.
(author)
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Atlantic Salmon Mucins Inhibit LuxS-Dependent A. Salmonicida AI-2 Quorum Sensing in an N-Acetylneuraminic Acid-Dependent Manner
- 2022
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 23:8
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Journal article (peer-reviewed)abstract
- One of the most important bacterial diseases in salmonid aquaculture is furunculosis, caused by Aeromonas salmonicida. Bacterial communication through secreted autoinducer signals, quorum sensing, takes part in the regulation of gene expression in bacteria, influencing growth and virulence. The skin and mucosal surfaces, covered by a mucus layer, are the first point of contact between fish and bacteria. Mucins are highly glycosylated and are the main components of mucus. Here, we validate the Vibrio harveyi BB170 bioreporter assay for quantifying A. salmonicida quorum sensing and study the effects of Atlantic salmon mucins as well as mono-and disaccharides on the AI-2 levels of A. salmonicida. Atlantic salmon mucins from skin, pyloric ceca, proximal and distal intestine reduced A. salmonicida AI-2 levels. Among the saccharides abundant on mucins, fucose, N-acetylneuraminic acid and GlcNAcβ1-3Gal inhibited AI-2 A. salmonicida secretion. Removal of N-acetylneuraminic acid, which is the most abundant terminal residue on mucin glycans on Atlantic salmon mucins, attenuated the inhibitory effects on AI-2 levels of A. salmonicida. Deletion of A. salmonicida luxS abolished AI-2 production. In conclusion, Atlantic salmon mucins regulate A. salmonicida quorum sensing in a luxS and N-acetylneuraminic acid-dependent manner.
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| 3. |
- Padra, János T, et al.
(author)
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Optimization of Alcian blue pH1.0 histo-staining protocols to match mass spectrometric quantification of sulfomucins and circumvent false positive results due to sialomucins.
- 2022
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In: Glycobiology. - : Oxford University Press (OUP). - 1460-2423. ; 32:1, s. 6-10
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Journal article (peer-reviewed)abstract
- Sulfomucins are in some body-locations and species a normal occurrence, whereas in other situations a sign of pathology. Sulfomucin content on histological sections and isolated material is frequently analyzed with Alcian blue staining at pH1.0. However, since the stain detects the charge, a high density of other charged molecules, such as sialic acids has potential to impede specificity. Here, we compared the outcome from four staining protocols with the level of sulfation determined by liquid chromatography-tandem mass spectrometry analysis (MS) on samples from various tissues with variable sulfation and sialylation levels. We found that a protocol we designed, including rinsing with MetOH and 0.5M NaCl buffer at pH1.0 eliminates false positive staining of tissues outperforming commonly recommended solutions. In tissues with low to moderately sulfated mucins (e.g. human stomach and salmonid epithelia) this method enables accurate relative quantification (e.g. sulfate scoring comparisons between healthy and diseased tissues) whereas the range of the method is not suitable for comparisons between tissues with high sulfomucin content (e.g. pig stomach and colon).
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