Degradation by bacterial enzymes of colonic mucus from normal subjects and patients with inflammatory bowel disease: The role of sialic acid metabolism and the detection of a novel <i>O</i>-acetylsialic acid esterase

Herrmann

Journal of Biological Chemistry

et al. 1997

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 (GalNAc␣1-3(Fuc␣1-2)Gal␤1-, and structures related to the blood group Sd a /Cad-related epitope NeuAc/NeuGc␣1-3(GalNAc␤1-4)Gal␤1-, were found in GOT-BW small intestine, and also in both large intestines. Blood group Hdeterminants and NeuAc/NeuGc␣1-3Gal␤1-were found in all samples. Core 1 (Gal␤1-3GalNAc␣1-), core 2 (Gal␤1-3(GlcNAc␤1-6)GalNAc␣1-), core 3 (GlcNAc␤1-3-GalNAc␣1-), and core 4 (GlcNAc␤1-3(GlcNAc␤1-6)GalNAc␣1-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.The family of highly glycosylated glycoproteins found at the mucosal surfaces are known as mucins (1). Characteristic for mucins is the high degree of O-linked glycosylation known as the mucin-type, where ␣-N-acetylgalactosamine is linked to serine or threonine of the protein backbone. These amino acids together with proline are mainly found in long and often repeated protein sequences, called mucin domains, that become a scaffold for the glycosylation. The mucins are largely responsible for the physical properties of mucus that serves as a lubricant for the mucosal surface and protects the underlying epithelium from mechanical and chemical stress. However, the identification of several different encoded mucins, and an enormous repertoire of possible mucin oligosaccharides indicates that the tasks for these glycoproteins may be more subtle than the macroscopic properties suggest.Mucins produced in the intestine are mainly derived from the goblet cells. The major part (at least 80%) of the rat intestinal mucins, measured as protease-resistant mucin domains, can be recovered as an "insoluble" glycoprotein complex in as denaturating conditions as 6.0 M guanidinium chloride (2), providing that shear homogenization is avoided. Two highly glycosylated peptides, named glycopeptide A (gpA) 1 and B (gpB), 650 kDa and 335 kDa, respectively, were isolated by trypsin digestion of subunits from this insoluble mucin complex. A polyclonal antiserum raised against the deglycosylated gpA was used to isol...

Section: Fig 9 Negative Ion Fab-ms/ms Of the Two Perdeuteroacetylatmentioning

confidence: 99%

The Glycosylation of Rat Intestinal Muc2 Mucin Varies between Rat Strains and the Small and Large Intestine

Herrmann

Journal of Biological Chemistry

et al. 1997

“…It plays a crucial role in cellular interactions in eukaryotes and is also described as a key molecule in host/pathogen adhesion (7,(10)(11)(12). This major component, present in the mucous layer of the human digestive tract, can also be used as an energy source by the commensal bacteria of the human microbiota (8). In several pathogenic bacteria, sialic acid or its use is associated with virulence (8,10,13).…”

mentioning

confidence: 99%

“…N-acetylneuraminic acid, or Neu-5Ac (NANA), is the most common such sugar in the living world. Indeed, it is found in mammalian cells as a component of glycoproteins, and most abundantly in mucins, which are glycoproteins of very high molecular weight secreted by mucosa and some exocrine glands into the lumen of the respiratory, gastrointestinal, and reproductive tracts (7)(8)(9)(10). It plays a crucial role in cellular interactions in eukaryotes and is also described as a key molecule in host/pathogen adhesion (7,(10)(11)(12).…”

mentioning

confidence: 99%

“…This major component, present in the mucous layer of the human digestive tract, can also be used as an energy source by the commensal bacteria of the human microbiota (8). In several pathogenic bacteria, sialic acid or its use is associated with virulence (8,10,13). Previous studies, mainly on human-pathogenic bacteria, showed that, after its internalization, sialic acid is either catabolized as a nutrient source or incorporated into polymers for display at the bacterial cell surface, in order to escape the bactericidal effect of serum, subsequently allowing bacterial proliferation within the host (12,(14)(15)(16).…”

mentioning

confidence: 99%

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Catabolism of N -Acetylneuraminic Acid, a Fitness Function of the Food-Borne Lactic Acid Bacterium Lactobacillus sakei, Involves Two Newly Characterized Proteins

Anba‐Mondoloni

Chaillou

Zagorec

et al. 2013

Appl Environ Microbiol

In silico analysis of the genome sequence of the meat-borne lactic acid bacterium (LAB) Lactobacillus sakei 23K has revealed a repertoire of potential functions related to the adaptation of this bacterium to the meat environment. Among these functions, the ability to use N-acetyl-neuraminic acid (NANA) as a carbon source could provide a competitive advantage for growth on meat in which this amino sugar is present. In this work, we proposed to analyze the functionality of a gene cluster encompassing nanTEAR and nanK (nanTEAR-nanK). We established that this cluster encoded a pathway allowing transport and early steps of the catabolism of NANA in this genome. We also demonstrated that this cluster was absent from the genome of other L. sakei strains that were shown to be unable to grow on NANA. Moreover, L. sakei 23K nanA, nanT, nanK, and nanE genes were able to complement Escherichia coli mutants. Construction of different mutants in L. sakei 23K ⌬nanR, ⌬nanT, and ⌬nanK and the double mutant L. sakei 23K ⌬(nanA-nanE) made it possible to show that all were impaired for growth on NANA. In addition, two genes located downstream from nanK, lsa1644 and lsa1645, are involved in the catabolism of sialic acid in L. sakei 23K, as a L. sakei 23K ⌬lsa1645 mutant was no longer able to grow on NANA. All these results demonstrate that the gene cluster nanTEAR-nanK-lsa1644-lsa1645 is indeed involved in the use of NANA as an energy source by L. sakei.

“…Increased sialyation and sulphate increases the charge of the mucus, and thereby the tenacity, aiding in resistance of the mucus to bacterial enzymatic attack [79,97]. As a result bacteria have to produce sialidase (neuraminidase) and sulphatase which can remove the sialic acid and ester sulphate before further oligosaccharide degradation can proceed [79,[98][99][100][101]. Gram positive gut bacteria from the genera Clostridium and Streptococcus have been found to produce more than one sialidase as isoenzymes [102].…”

Section: Discussionmentioning

confidence: 99%

Acidic Conditions in the NHE2^-/-Mouse Intestine Result in an Altered Mucosa-Associated Bacterial Population with Changes in Mucus Oligosaccharides

Engevik

Hickerson

Shull

et al. 2013

Cell Physiol Biochem

This is an Open Access article licensed under the terms of the Creative Commons AttributionNonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only. Acidic Conditions in the NHE2- Abstract:Background: The mechanisms bacteria use to proliferate and alter the normal bacterial composition remain unknown. The ability to link changes in the intestinal micro-environment, such as ion composition and pH, to bacterial proliferation is clinically advantageous for diseases that involve an altered gut microbiota, such as Inflammatory Bowel Disease, obesity and diabetes. In human and mouse intestine, the apical Na + /H + exchangers NHE2 and NHE3 affect luminal Na + , water, and pH. Loss of NHE2 results in acidic luminal pH. Since acid resistance systems in gram-positive bacteria are well documented, we hypothesize that grampositive bacteria would increase in representation in the acidic NHE2 -/-intestine. Methods: Intestinal ion composition was measured by flame photometry and chloridometry and pH measured electrochemically. DNA extracted from intestinal flushes or from mucosal scrapings was analyzed by qRT-PCR to examine luminal and mucosa-associated bacterial populations. Epithelial mucus oligosaccharide patterns were examined by histology with FIT-C labeled lectins. Results: Although total luminal and mucosa-associated bacteria were unchanged in NHE2 -/-intestine, gram-positive bacterial phyla were increased in the mucosa-associated bacterial population in a region-specific manner. The genera Clostridium and Lactobacillus were increased in the cecum and colon which corresponded to changes in NHE2 -/-mucus oligosaccharide composition of mannose, N-acetyglucosamine, N-acetygalactosamine and galactose. Conclusions: Together these data indicate that changes in ion transport induce region-specific bacterial changes, which alter host mucus oligosaccharide patterns. These hostbacterial interactions provide a possible mechanism of niche-development and shed insight on how certain groups proliferate in changing environments and maintain their proliferation by altering the host.