| 1. |
- Malmsten, M, et al.
(författare)
-
Ellipsometry studies of the mucoadhesion of cellulose derivatives
- 1994
-
Ingår i: Colloids and Surfaces B. - 0927-7765 .- 1873-4367. ; 2, s. 463-470
-
Tidskriftsartikel (refereegranskat)abstract
- The mucoadhesion of three different cellulose derivatives, ethyl(hydroxyethyl)cellulose (EHEC), hydrophobically modified hydroxyethyl cellulose (h-HEC) and a cationic cellulose derivative (amino cellulose), was investigated with in situ ellipsometry. In the measurements, gastric mucin from rat was first adsorbed onto hydrophobized silica, which provided good anchorage for the mucin layer and allowed a large amount of mucin to be adsorbed. Significant mucoadhesion was obtained for all three cellulose derivatives, indicating that either overall solvency effects, electrostatic interactions or hydrophobic groups may be used to obtain mucoadhesion in cellulose systems. Of the polymers used, EHEC showed the greatest tendency for adsorption, which may indicate that the first approach is preferable for obtaining efficient mucoadhesion. The addition of SDS was found to counteract mucoadhesion of EHEC.
|
|
| 2. |
- Malmsten, M, et al.
(författare)
-
Mucin layers on hydrophobic surfaces studied with ellipsometry and surface force measurements
- 1992
-
Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 151, s. 579-590
-
Tidskriftsartikel (refereegranskat)abstract
- The forces acting between layers of gastric mucins from rat (RGM) and pig (PGM) adsorbed on to hydrophobized mica surfaces were investigated by using the surface force technique, whereas information on the kinetics and the reversibility of the adsorption process was obtained with ellipsometry. From the surface force measurements, we found that the amount adsorbed from a 0.1 mg/ml RGM solution was 3.5±1.5 mg/m2 at adsorption equilibrium, within experimental error equal to that (about 3 mg/m2) found with ellipsometry. The forces obtained with RGM were purely repulsive, whereas those displayed by PGM were partially attractive. Dilution of the bulk solution caused only minor desorption and the interaction force between the RGM layers was only weakly dependent on the excess electrolyte concentration. Hence, steric forces predominate the interaction in the RGM system. Both RGM and PGM adsorb in a flat conformation, with compressed adsorbed layer thicknesses of 10-20 nm and 3-4 nm, respectively. The interaction force was essentially reversible on approach and separation for RGM, whereas 'relaxation effects' were prominent for PGM layers.
|
|
| 3. |
- 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.
|
|
| 4. |
|
|
| 5. |
- Caramori, G, et al.
(författare)
-
Mucin expression in peripheral airways of patients with chronic obstructive pulmonary disease
- 2004
-
Ingår i: Histopathology. - : Wiley. - 0309-0167 .- 1365-2559. ; 45:5, s. 477-484
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: To study the expression of mucins in peripheral airways in patients with chronic obstructive pulmonary disease (COPD). Methods and results: Peripheral lung sections from smokers with COPD (n = 9) and age-matched controls including smokers (n = 11) and lifelong non-smokers with normal lung function (n = 6) were stained with alcian blue, periodic acid-Schiff (PAS) and by immunohistochemistry of mucins (MUC): MUC2, MUC4, MUC5AC, MUC5B and MUC6. Histochemical staining and immunoreactivity of bronchiolar epithelium were graded and the presence or absence of stained mucus in the bronchiolar lumen was evaluated. There were no differences in alcian blue and PAS epithelial staining between the three groups. Intraluminal PAS staining was significantly more frequent among COPD subjects (P < 0.05). The expression of MUC5AC was significantly higher in the bronchiolar epithelium of patients with COPD (P < 0.05). Within the bronchiolar lumen, the predominant mucin was MUC5B. Intraluminal MUC5B was significantly more frequent among COPD patients (P < 0.05). Conclusions: COPD is specifically associated with increased expression of MUC5B in the bronchiolar lumen and of the mucin MUC5AC in the bronchiolar epithelium. These changes in mucin production in the peripheral airways may contribute to the pathophysiology of COPD.
|
|
| 6. |
- Carlstedt, I, et al.
(författare)
-
Characterization of two different glycosylated domains from the insoluble mucin complex of rat small intestine.
- 1993
-
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 268:25, s. 18771-81
-
Tidskriftsartikel (refereegranskat)abstract
- The highly glycosylated domains of rat small intestinal mucins were isolated after reduction and trypsin digestion and separated into two populations (A and B) by gel chromatography. The molecular mass values were 650 and 335 kDa, respectively, and the relative yields suggest that the two glycopeptides occur in equimolar proportions. Electron microscopy revealed linear structures with weight average lengths of 230 nm (A) and 110 nm (B) corresponding to a mass/unit length of about 3 kDa/nm. The protein cores (17-19%) contain large amounts of threonine (over 40%), serine (17-24%), and proline (18-19%). Carbohydrate and sulfate account for approximately 80 and 0.5%, respectively, and gas chromatography-mass spectrometry showed that the patterns of neutral and sialic acid-containing glycans are very similar in the two glycopeptides. Both contain a significant amount (7-10 mol %) of single GalNAc residues, the average oligosaccharide is about 4 sugar residues long, and the largest species observed are heptasaccharides. The major neutral and sialic acid-containing oligosaccharides are Fuc1-2Gal1-3GalNAcol and GlcNAc1-6(NeuGc2-Gal1-3)GalNAcol, respectively. Sialic acid is present as both N-acetyl- and N-glycoloyl-neuraminic acid. Repeated extractions of the tissue with guanidinium chloride left approximately 80% of the mucus glycoproteins as an insoluble glycoprotein complex whereas exposure to dithiothreitol or high speed homogenization accomplished complete solubilization. The "subunits" obtained after reduction with dithiothreitol are larger than glycopeptides A and B, and fragments corresponding in size to the latter are obtained after cleavage with trypsin. Most of the mucins from rat small intestine thus occurs as an insoluble glycoprotein complex composed of subunits joined with disulfide bonds. The subunits contain two highly glycosylated regions with different lengths substituted with very similar oligosaccharides.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Hansson, Gunnar C., 1951, et al.
(författare)
-
Molecular cloning of a cDNA coding for a region of an apoprotein from the 'insoluble' mucin complex of rat small intestine.
- 1994
-
Ingår i: Biochemical and biophysical research communications. - 0006-291X. ; 198:1, s. 181-90
-
Tidskriftsartikel (refereegranskat)abstract
- The major part of rat small intestinal mucins occurs as an 'insoluble' glycoprotein complex unextractable in 6 M guanidinium chloride unless disulfide bonds are cleaved. One of the trypsin-resistant high-glycosylated domains of this complex (glycopeptide A) was recently isolated. We have now deglycosylated it with HF, injected it into rabbits and the obtained antiserum was used for expression cloning providing a cDNA clone (VR-1A). This clone contained an open reading frame of 235 amino acids composed of two regions. The deduced N-terminal 53 amino acids included seven Cys residues and only one Ser, followed by a region of 182 residues with 64% Ser and Thr but devoid of Cys residues. Analysis of mRNA revealed a transcript of about 12 kb, identical in size to a band labelled with a probe based on the rat mucin-like protein (MLP/Muc2) cDNA. Pulsed-field gel electrophoresis of genomic rat DNA showed identical bands (380 and 500 kb) when blots were sequentially probed with the MLP/Muc2 probe and VR-1A. A panel of mouse x rat hybrids was used to localize the gene corresponding to both VR-1A and Muc2 to rat chromosome 1. The results strongly suggest that the 'insoluble' mucin complex of the rat small intestine is encoded by the Muc2 gene.
|
|
| 10. |
- Karlsson, Niclas G., 1966, et al.
(författare)
-
Glycosylation differences between pig gastric mucin populations: a comparative study of the neutral oligosaccharides using mass spectrometry.
- 1997
-
Ingår i: The Biochemical journal. - 0264-6021. ; 326 ( Pt 3), s. 911-7
-
Tidskriftsartikel (refereegranskat)abstract
- Five mucin populations were isolated from the cardiac region,corpus and antrum of pig gastric mucosa. The released neutral oligosaccharides were permethylated and analysed using high-temperature gas chromatography-mass spectrometry (GC-MS) as well as matrix-assisted laser-desorption mass spectrometry (MALDI-MS). Thirty different oligosaccharides with up to six monosaccharide residues were characterized using both techniques, but the presence of an additional 49 structures was suggested on the basis of their molecular mass by MALDI-MS. Oligosaccharides based on core-1 (Galbeta1-3GalNAcalpha1-) and core-2 [Galbeta1-3(GlcNAcbeta1-6)GalNAcalpha1-] structures were widely distributed, whereas core-3 structures (GlcNAcbeta1-3GalNAcalpha1-) were present only in mucins from the cardiac region and corpus, and core-4 structures [GlcNAcbeta1-3(GlcNAcbeta1-6)GalNAcalpha1-] were present exclusively in mucins from the cardiac region. Furthermore the oligosaccharides from one of the mucins from the corpus were significantly longer than those from the other populations. The results illustrate vast structural diversity, but the relative abundances show only a few dominating structures, suggesting that many oligosaccharides may be quite rare in pig gastric mucins. Well-defined mucin populations with distinctly different glycosylation can thus be identified in pig stomach, suggesting that glycosylation of the large secreted mucins from this tissue is not a random event.
|
|
| 11. |
- Karlsson, Niclas G., 1966, et al.
(författare)
-
Molecular characterization of the large heavily glycosylated domain glycopeptide from the rat small intestinal Muc2 mucin.
- 1996
-
Ingår i: Glycoconjugate journal. - 0282-0080. ; 13:5, s. 823-31
-
Tidskriftsartikel (refereegranskat)abstract
- The largest high-glycosylated domain, glycopeptide A, of the "insoluble' mucin complex of the rat small intestine has earlier been purified and characterized (Carlstedt et al., 1993, J Biol Chem 268: 18771-81). A rabbit antiserum raised against deglycosylated glycopeptide A was used to clone part of a mucin showing homology to the human MUC2 mucin (Hansson et al., 1994, Biochem Biophys Res Commun 198. 181-90). This serum specifically stained goblet cells (paranuclear) in the mouse small intestine. The size of the coding sequence of glycopeptide A was estimated by using reversed transcriptase PCR of mRNA from an inbred rat strain (GOT-W) using primers in the unique central and C-terminal parts of the proposed rat Muc2 sequences. The PCR and Southern blot of the PCR products showed a fragment of about 5.5 kb corresponding to about 1700 amino acids when the known Cys-rich sequences used for the primers were subtracted. This is slightly larger than the size estimated earlier by biochemical studies. The mRNA encoding the rat Muc2 was slightly smaller than the mRNA encoding the human MUC2 in a colorectal cell line. Although the size of glycopeptide A estimated from biochemical results and by PCR is not identical, the results obtained here further support that the "insoluble' mucin of the rat small intestine is encoded by the Muc2 gene. Most of the oligosaccharides in glycopeptide A were either neutral (40%) or sialylated (40%). The remaining ones were sulfated with the sulfate group attached to C-6 of N-acetylglucosamine linked to C-6 of the N-acetylgalactosaminitol as revealed by tandem mass spectrometry of the perdeuteroacetylated oligosaccharides. Eighteen oligosaccharides were found of which fourteen were characterized and found to be mostly novel. Our findings thus expand the current knowledge of the core peptide of the rat intestinal goblet cell mucin and provide a relatively complete picture of the glycosylation of a defined mucin domain.
|
|
| 12. |
- Karlsson, Niclas G., 1966, et al.
(författare)
-
The glycosylation of rat intestinal Muc2 mucin varies between rat strains and the small and large intestine. A study of O-linked oligosaccharides by a mass spectrometric approach.
- 1997
-
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 272:43, s. 27025-34
-
Tidskriftsartikel (refereegranskat)abstract
- The large glycosylated domains obtained from the rat intestinal mucin Muc2 were isolated from the large and small intestine of the inbred rat strains GOT-W and GOT-BW. The expression of the rat Muc2 in the large intestine was confirmed immunochemically and by Northern blotting. Released oligosaccharides were structurally characterized by gas chromatography-mass spectrometry (neutral and sialylated species) or by tandem mass spectrometry (sulfated species), and a total of 63 structures was assigned. The large intestinal oligosaccharides were found to be identical between the strains, while the small intestinal glycosylation differed. Until now, detailed structural analysis of oligosaccharides isolated from a single mucin core or mucin domain with different origin have not been performed, and the information of different mucin glycoforms has been limited to immunochemistry. Blood group A-determinants (GalNAcalpha1-3(Fucalpha1-2)Galbeta1-, and structures related to the blood group Sda/Cad-related epitope NeuAc/NeuGcalpha1-3(GalNAcbeta1-4)Galbeta1-, were found in GOT-BW small intestine, and also in both large intestines. Blood group H-determinants and NeuAc/NeuGcalpha1-3Galbeta1- were found in all samples. Core 1 (Galbeta1-3GalNAcalpha1-), core 2 (Galbeta1-3(GlcNAcbeta1-6)GalNAcalpha1-), core 3 (GlcNAcbeta1-3GalNAcalpha1-), and core 4 (GlcNAcbeta1-3(GlcNAcbeta1-6)GalNAcalpha1- were also found in all the samples. The large intestine were enriched in sulfated oligosaccharides and the small intestine contained higher amounts of sialylated species. Sulfation were found exclusively on C-6 of GlcNAc.
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
- Nordman, H, et al.
(författare)
-
Mucus glycoproteins from pig gastric mucosa: identification ofdifferent mucin populations from the surface epithelium.
- 1997
-
Ingår i: The Biochemical journal. - 0264-6021. ; 326 ( Pt 3), s. 903-10
-
Tidskriftsartikel (refereegranskat)abstract
- Pig gastric mucins were isolated from the surface epithelium of the cardiac region, corpus and antrum using density-gradient centrifugation after extraction in 6 M guanidinium chloride. In CsCl/0.5 M guanidinium chloride, mucins solubilized from the cardiac region appeared as a broad unimodal band at 1.52 g/ml whereas those from the corpus and antrum occurred as high- and low-density populations at 1.50 and 1.45 g/ml respectively. High-iron diamine reacted more strongly with the cardiac mucins and the high-density populations from corpus and antrum than with the two low-density ones. In keeping with this, approx. 60% of the oligosaccharides from the former mucins and 20% from the latter contained sulphate. All surface epithelial cells of the cardiac region stained with high-iron diamine, whereas in the corpus only the epithelium in the bottom of the pits reacted, suggesting that the high-density population from this region originates from these cells. Mucins from all regions were composed of subunits, each containing highly glycosylated domains. The mucins from the cardiac region were larger than those from the corpus and antrum, and reduced subunits as well as high-molecular-mass glycopeptides from the cardiac mucins were larger than the corresponding fragments from the other regions. Ion-exchange HPLC showed that reduced subunits from the cardiac mucins and the high-density populations from the corpus and antrum were more 'acidic' than reduced subunits from the two low-density ones. All mucins contained a 'neutral'fraction, in particular those from the antrum. Pig gastric mucus thus contains a number of distinctly different mucin populations varying in buoyant density, size, 'acidity', glycosylation, sulphation and tissue origin.
|
|
| 17. |
|
|
| 18. |
- Thomsson, Kristina A, 1969, et al.
(författare)
-
Different O-glycosylation of respiratory mucin glycopeptides from a patient with cystic fibrosis.
- 1998
-
Ingår i: Glycoconjugate journal. - 0282-0080. ; 15:8, s. 823-33
-
Tidskriftsartikel (refereegranskat)abstract
- The O-linked oligosaccharides from three fractions of highly glycosylated mucin glycopeptides obtained from sputum of a patient with cystic fibrosis were characterized and compared regarding size, composition, sequence and when possible linkage positions. Neutral and sialic acid-containing glycans were permethylated and analyzed by high-temperature GC-MS and MALDI-MS, showing more than 60 different oligosaccharides with a size of up to 15 monosaccharide units. Some of the observed oligosaccharides are novel for respiratory secretions, one being a trifucosylated heptasaccharide with the proposed structure: Fuc-Gal-4(Fuc-3)GlcNAc-(Fuc-)Gal-3GalNAcol. The glycosylation of two of the glycopeptide fractions was similar with regard to the neutral and sialylated oligosaccharides despite their different origins from the sol or gel phase. Analysis of the sulfated oligosaccharides by FAB-MS/MS indicated that the gel fraction contained C-6 linked sulfate groups while the two sol fractions also contained C-3 linked sulfate. The results suggest the presence of different glycosylated mucin domains, probably originating from different mucin glycoforms and/or apoproteins in the airway of cystic fibrosis patients.
|
|
| 19. |
|
|
