Identification of bacterial glycosidases in rat cecal contents

Abstract

Cecal contents of conventional and germfree rats were examined for glycosidases which may have a role in degrading glycoprotein oligosaccharides. Utilizing p-nitrophenylglycosides as substrates, we identified glycosidases in bacteria-free supernatants from cecal contents which act on beta-linkages. These cecal glycosidases appear to be of bacterial origin since: (1) direct comparisons of the enzymes in similar contents from germfree rats showed negligible activities; (2) most of the glycosidase levels in bacterial extracts were at least as high as those of soluble supernatants; and (3) disk gel electrophoresis of contents and bacterial extracts revealed in both preparations a beta-N-acetylglucosaminidase band with similar Rfs. Also, the blood group B antigenicity of germfree cecal glycoproteins was greatly decreased by conventional cecal contents. These findings indicate that beta-galactosidase and beta-N-acetylgalactosaminidase in cecal contents are bacterial in origin, and they may have a role in the bacterial catabolism of intestinal glycoproteins.

Binding of proteolytically-degraded human colonic mucin glycoproteins to the Gal/GalNAc adherence lectin of Entamoeba histolytica.

“…A dose response for the effect of trypsin-digested void volume mucins, compared with undigested control mucins (Fig 3), on amoebic adherence to Chinese hamster ovary cells indicated 15 digested mucins eluted in the void volume under reducing conditions showed no low molecular weight proteins entering the running gel (Fig 4). Native (A), trypsin (B), and pronase (C)digested mucins from the excluded fractions (15)(16)(17) of Sephacryl S-200 chromatography ran as a faint diffuse band in the stacking gel (4%) and confirm their identity as high molecular weight mucin glycoproteins with no disulphidelinked lower molecular weight subunits. Periodic acid Schiff reagent positive staining material was only observed in the stacking gel (data not shown).…”

“…Mucin glycoproteins in the excludedfractions(15)(16)(17) ofSephacryl S-200 chromatography in control (undigested) and trypsindigested were testedfor inhibition ofamoebic adherence as described under Methods. *p<0.05, **p<0.01 by Student's t test compared with undigested mucin controls.…”

Increased Faecal Glycosidases in Patients with Crohn’s Disease

“…We reported previously a 6-fold increase of B. vulgatus in patients [2]. It has been shown that Bacteroides species are very active fermentors of dietary fiber and mucus glycoproteins [6][7][8], and several hydrolytic enzymes produced by Bacteroides have been characterized [23][24][25]. This may indicate that the increased enzyme level in patients with CD is due to the high numbers of Bac teroides.…”

Chitosan as a pore former in coated beads for colon specific drug delivery of 5-ASA

“…The contents were then subjected to a literature differential centrifugation technique at 0–4 °C (Prizont and Konigsberg, 1981; Zhang and Neau, 2002). The contents were first weighed in centrifuge tubes and then diluted with 0.05 M ice cold isotonic phosphate buffer at pH 6.8.…”