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PubMed1977

Some characteristics of cytosol binding protein for 1alpha,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol in rat intestinal mucosa.

Cytosol binding protein for 1alpha,25-(OH)2D3 and 25-OHD3 was demonstrated in rat intestinal mucosa using sucrose density gradient ultracentrifugation analysis, Sephadex G-200 column chromatography and polyacrylamide disc gel electrophoresis. The binding protein has a sedimentation constant of 5-6S, a molecular weight of 100,000-120,000 daltons and a mobility in electrophoresis of Rf 0.42. Further analysis of binding behavior by DEAE-cellulose filter assays revealed that the bindig protein had a higher affinity for 25-OHD3 than for 1alpha,25-(OH)2D3, and that 1alpha,25-(OH)2D3 competed with 25-OHD3 for the same binding site on the protein. The apparent dissociation constant for 1alpha,25-(OH)2D3 and 25-OHD3 was 9.2 X 10(-9) M and 1.5 X 10(-9) M, respectively. The binding capacity was 3.1 pmoles/mg protein for both 1alpha,25-(OH)2D3 and 25-OHD3. The order of binding affinity was 25-OHD3 greater than 1alpha,25-(OH)2D3 greater than D3 = 1alpha-OHD3.

Animals↗

PubMed2004

The biogenic amine tyramine modulates the adherence of Escherichia coli O157:H7 to intestinal mucosa.

The environmental factors that influence the ability of Escherichia coli O157:H7 to attach to the intestinal mucosa are incompletely understood. In the present study, the ability of one of the most common biogenic amines present in food, tyramine, to influence the ability of E. coli O157:H7 to adhere to murine cecal mucosa was examined. Ex vivo full-thickness sheets of murine cecum were mounted in Ussing chambers, which preserved the enteric nervous system innervation of the luminal epithelia and thereby allowed us to achieve a closer approximation of bacterial adherence than would be encountered in vivo. After exposure of the luminal aspect of the cecum to tyramine, E. coli O157:H7 was added for 90 min. The cecal tissue was then removed and washed, and adhered E. coli O157:H7 was enumerated using a selective medium. Tyramine significantly increased E. coli O157:H7 adherence to cecal mucosa when compared to that of controls. The 50% effective concentration of tyramine was 92.6 microM. Specific adrenergic antagonists were then employed to examine whether the effect of tyramine was mediated through alpha- or beta-adrenergic receptors on the intestinal tissue. Pretreatment of tissues with either the alpha-adrenergic receptor antagonist phentolamine or the beta-adrenergic receptor antagonist propranolol prevented the action of tyramine. Measurement of active transepithelial ion transport and ionic permeability in the cecal sheets before and after the addition of tyramine and E. coli O157:H7 did not show any impairment of tissue viability or transepithelial conductance. Further, tyramine did not influence either the growth of E. coli O157:H7 or the expression of the intimin attachment factor. The present findings suggest that biogenic amines, such as tyramine, present within the food matrix influence host susceptibility to E. coli O157:H7 infection.

Animals↗

PubMed1977

Biosynthesis of brush border glycoproteins by human small intestinal mucosa in organ culture.

The incorporation of [14C]glucosamine into brush border glycoproteins by human small intestinal mucosa in organ culture has been investigated. The experiments were based on the observations that (1) isolated brush border membrane fragments from cultured explants showed an unchanged pattern of protein bands and brush border enzyme activities on sodium dodecyl sulfate/polyacrylamide gels after electrophoresis and (2) the rate of overall [14C]glucosamine incorporation measured in the tissue homogenate remained constant up to 48 h. After 24 h of culture, the radioactivity peaks on gels due to incorporation of [14C]glucosamine were found exclusively in the high molecular weight region and corresponded to protein bands identified as maltase-glucoamylase, lactase, sucrase-isomaltase, enterokinase and alkaline phosphatase. Enzymatic activity could not be assigned to the three remaining labelled bands. Most of these glycoproteins were already labelled after 5 h. Newly glycosylated brush border enzymes remained predominantly associated with the brush border membrane of intact cells with little release into the medium up to 24 h.

Cell Membrane↗

PubMed2003

Amylolytic activity in fish intestinal mucosa: temperature effects.

The activity, temperature characteristics and energy of activation of amylolytic enzymes in the intestinal mucosa were studied in six species of fish living in a boreal zone [burbot (Lota lota L.), northern pike (Exos lucius L.), perch (Perca fluviatilis L.), bream (Abramis brama L.), roach (Rutilis rutilis L.), and carp (Cyprinus carpio L.)] and in three species from tropical and subtropical areas [pilchard (Sardina pilchardus W.), jack mackerel (Trachurus trecae C.) and round sardinella (Sardinella aurita V.)]. The amylolytic activity correlated with the feeding habits: it was essentially lower in predators. The enzyme activity at low temperature, relative to the maximal activity, was correlated with the natural environmental temperature where the species lived. At low temperature the relative activity was higher in boreal fish than in tropical and subtropical fish. We found a breakpoint in the Arrhenius plots in all fish species, except for jack mackerel. The energy of activation in predators decreased below the breakpoint in the low-temperature region. The energy of activation in benthophages of the Aral-Ponto-Caspian area was lower at higher temperatures above the breakpoint. A reduction in activation energy in the range of physiological temperatures might indicate adaptation to the environmental temperature.

Amylases↗

PubMed1989

Investigations on the influence of copper succinate on the production of superoxide anion radicals by bovine small intestinal mucosa cells.

The effect of an experimental ischemia lasting for 45 minutes and a subsequent period of reperfusion of equal length on the activity of xanthine oxidase (XO) and microsomal NADPH-cytochrome P450 reductase (NADPH-CR) were investigated in the small intestinal mucosa of male neonatal calves of the breed German "Schwarzbunte". The activity of the NADPH-CR was determined by chemiluminescence. The activity of XO decreased during ischemia, but rose to values above the control level following reperfusion. 5 mg of Cu2(succinate)2 (CuSu) administered either intraarterially or intraluminally during reperfusion prevented the rise in XO. Formation of malondialdehyde decreased in the presence of CuSu. The NADPH-CR likewise showed subnormal activity values during ischemia, but also remained at a low level during reperfusion. The activity of this enzyme was further lowered by local intraarterial or intraluminal administration of 5 mg of CuSu and by 120 mg of CuSu administered intravenously during the reperfusion. These results are discussed with regard to the superoxide anion radical induced tissue lesions observed during reperfusion.

Animals↗

PubMed1987

Binding of amino beta-lactam antibiotics to soluble protein from rat intestinal mucosa--II. Mutual inhibition of binding among amino beta-lactam antibiotics and binding characteristics.

The characteristics of binding of amino beta-lactam antibiotics including ampicillin, amoxicillin, cephalexin and cephradine to fraction b obtained from the 105,000 g supernatant of rat small intestinal mucosa was investigated. The mutual inhibition of binding among these antibiotics was observed, and these were dependent on the concentration of inhibitors. It was found that dipeptides such as L-carnosine and glycylglycine significantly reduced the binding of cephalexin to fraction b, but the binding of cephradine was only slightly decreased by these dipeptides. Furthermore, the binding of cephalexin and cephradine was not influenced by amino acids (L-phenylalanine, glycine). Although ANS(1-anilino-8-naphthalenesulfonic acid magnesium salt), which is a hydrophobic probe, bound to the fraction b, there was no competitive inhibition in binding between ANS and amino beta-lactam antibiotics. The Scatchard plot of binding data of cephalexin gave two dissociation constant (Kd) values (1.37 and 15.7 microM). On the other hand, one Kd value (11.2 microM) was obtained for ampicillin.

Ampicillin↗

PubMed1983

[Characteristics of the development of the small intestine mucosa in man and rat].

The process of the small intestine tunica mucosa embryonal development has been studied in 75 rat embryos from 10 to 21 days of development and in 82 human embryos at equivalent stages of development (from 28 days up to 13 weeks). The changes observed in the tunica mucosa structure and indices of the cellular activity [mitotic index, nuclear volumes, RNA content, alkaline phosphatase (APh), acid phosphatase (AcPh), succinic dehydrogenase (SDG), lactate dehydrogenase (LDG) activity] make it possible to distinguish 3 periods in the process of the small intestine tunica mucosa embryonal development: 1 - period of the germinal differentiation, 2 - prespecific and 3 - specific differentiation period, the latter is characterized by common signs for the man and the rat. Together with some retardation in the rat organogenesis (postnatal formation of criptae) its tunica mucosa is characterized by a higher, than in the man, activity of all the enzymes studied; AcPh and LDG activities are the most intensive, that is connected with low content of glycogen. This low content of glycogen and 4-5 times higher LDG activity than in the man demonstrate a more intensified utilization of glycogen, evidently, connected with a high level of anaerobic respiration in the rat embryos.

Acid Phosphatase↗

PubMedDate not supplied

[Synthesis of prostaglandins E2 and F2alpha and quantitative changes in lipids in small intestinal mucosa in normal piglets and in piglets with diarrhea].

Small intestine mucose inflammation and diarrhea syndrome in piglets affected by salmonella endotoxin enhanced prostaglandin E2 synthesis and decreased prostaglandin F2 alpha synthesis. Under these conditions the share of free cholesterol decreased and the share of diacylglycerols increased in total lipid content in thin intestine mucose of piglets. The share of phosphatidic acid decreased and the share of lysophosphatidylcholine and phosphatidylinositol increased in the total content of phospholipids.

Animals↗

PubMed1980

Secretory immune response in intestinal mucosa and salivary gland after experimental infection of pigs with transmissible gastroenteritis virus.

Pigs 8 to 10 weeks of age were orally infected with transmissible gastroenteritis (TGE) virus or infected by inoculation of the virus into Thirty-Vella loops of jejunum. Concentrations of immunoglobulin (Ig) A, IgM, and IgG in serum, saliva, jejunal secretions, loop secretions, and bile were determined by solid-phase radioimmunoassay for TGE virus-infected and control pigs. A multiple-staining fluorescent antibody technique was used to determine the relative numbers of IgA-, IgM-, and IgG-producing plasma cells in intestinal mucosa, mesenteric lymph node, spleen, iliac lymph node, and submandibular salivary gland. The numbers of IgA- and IgM-producing plasma cells were greater in the jejunal mucosa of pigs infected and reinfected orally with TGE virus than in that of the control pigs. There was also an increase of IgA- and probably of IgM-cells in the submandibular salivary glands. Similar numerical increases of IgA- and IgM-cells were observed in jejunal mucosa and salivary glands of all pigs with intestinal loops whether exposed to TGE virus or not. Increases in plasma cells in mucosa or salivary gland were not associated with increases in concentrations of IgA or IgM in the respective secretions or serum. The data support the hypothesis that after stimulation, IgA- and IgM-producing cells leave the intestinal mucosa and are trapped by distant secretory epithelial. The absence of a simultaneous increased concentration of IgA and IgM in saliva and intestinal secretions indicates that in an intact epithelium, the transport of IgA and IgM mediated by secretory component is probably saturable.

Animals↗

PubMed1999

Changes in number of serotonin-containing cells and serotonin levels in the intestinal mucosa of rats with colitis induced by dextran sodium sulfate.

The role of serotonin in the pathogenesis of inflammatory bowel disease has not been fully studied. We examined the changes in the serotonin level and the density of serotonin-containing enterochromaffin (EC) and mast cells in the intestinal mucosa of dextran sodium sulfate (DSS)-induced colitis in rats. Rats were treated with 1.5% DSS for 1 month. Serotonin levels were biochemically measured and the density of epithelial EC cells and mucosal mast cells was quantified by serotonin immunohistochemistry. DSS caused malnutrition due to chronic diarrhea. Infiltrated inflammatory cells were microscopically observed in the colonic wall with intact epithelium. The serotonin content in the mucosa/submucosa tissue was increased in the proximal and distal colon in DSS-treated rats, compared to that in control rats. The density of EC cells in the epithelium also increased in the proximal and distal colon in DSS-treated rats. In contrast, the density of mast cells in the lamina propria dramatically increased in the distal, but not in the proximal colon in DSS-treated rats. This discrepancy implies the serotonin released from EC cells and from mast cells may play different roles in the pathogenesis of DSS-induced colitis.

Animals↗

PubMed1980

Peptide hydrolases of the human small intestinal mucosa: distribution of activities between brush border membranes and cytosol.

Brush border membranes from frozen human small intestine have been purified using a method which did not involve the use of EDTA-containing buffers or the disruption of brush border fragments with high concentrations of Tris. On average a 24-fold increase in specific activity of alpha-glucosidase (brush border marker) was obtained in the final preparation which contained insignificant traces of enzyme marker activities from cytosol and lysosomes. The homogenates of human small intestinal mucosa were shown to contain enzymes capable of hydrolysing di-, tri-, and tetrapeptides as well as amino acid- and peptide-2-nephthylamides. Assuming a 100% location of alpha-glucosidase in the brush border membrane, distribution studies indicated that activities against tetrapeptides and leucyl-2-naphthylamide were located exclusively in the brush border membrane. A large proportion of activity against alpha-glutamyl-2-naphthylamide, gamma-glutamyl-2-naphthylamide and glycyl-prolyl-2-naphthylamide were also recovered in the brush border membrane fraction. Depending on the substrate utilized, 33-87% of tripeptidase activity was located in the brush border membrane. However, 58-87% of dipeptidase activity was recovered in the soluble fraction.

Amino Acids↗

PubMed1994

Purification and characterization of a novel membrane-bound arginine-specific serine proteinase from porcine intestinal mucosa.

A novel membrane-bound serine proteinase has been purified from the microsomal membranes of porcine intestinal mucosa. It was solubilized from the microsomal membrane fraction with 1% sodium deoxycholate, then purified by a series of column chromatographic steps on DE52, butyl-Toyopearl, Bio-Gel P-150, Mono Q, and benzamidine-Sepharose in the presence of 0.02% Lubrol PX. Its molecular mass was estimated to be 50 kDa both by SDS-polyacrylamide gel electrophoresis under non-reducing conditions and by gel filtration, and to be 32 kDa by SDS-polyacrylamide gel electrophoresis under reducing conditions, suggesting that the enzyme may exist as a homodimer in which two subunits are linked by disulfide bond(s). It had a pH optimum at around 9 and did not require Ca2+ for activity. It cleaved several peptide 4-methylcoumaryl-7-amide substrates almost exclusively after arginine residues, the best substrate among those tested being t-butyloxycarbonyl-Gln-Ala-Arg-4-methylcoumaryl-7-amide. Various neuropeptides were also cleaved by this enzyme after arginine, mainly between paired basic amino acid residues, Arg-Arg or Arg-Lys. Activity toward protein substrates was scarcely detected. Further, its partial amino acid sequences were highly homologous, but not identical, with those of trypsin-type serine proteinases. These results indicate that the present enzyme is a novel arginine-specific trypsin-like endopeptidase, possibly involved as a processing proteinase in the production of certain gastrointestinal neuropeptides or peptide hormones from their precursors, or their specific degradation.

Amino Acid Sequence↗

PubMed2003

[The effects of bifidobacterium on the intestinal mucosa of the patients with ulcerative colitis].

OBJECTIVE: To investigate the effects of bifidobacterium (Bf) on the intestinal mucosa of the patients with ulcerative colitis (UC). METHODS: Thirty patients in clinical and endoscopic remission by sulphasalazine and glucocorticoid were randomized to receive either Bifid Triple Viable capsule (BIFICO), 420 mg/d, or an identical placebo (starch) for 8 weeks. Fecal samples were collected for stool culture before and after treatment. Patients were assessed clinically endoscopically and histologically after 2 months or in the case of a relapse. p65 and IkappaB expression was determined by Western blot analysis DNA-binding activity of NF-kappaB in colonic nuclear extracts was detected by electrophoretic mobility shift assay. The mRNA expression of cytokines were identified by a semi-quantitative assay, reverse transcription-polymerase chain reaction. RESULTS: Three patients in the BIFICO group had relapses within the 2-month follow-up period, compared with 14 in the placebo group (P < 0.01). Fecal concentration of lactobacilli, bifidobacteria, increased significantly from baseline levels only in the BIFICO-treated group (P < 0.01). The expression of NF-kappaB p65 and DNA binding activity of NF-kappaB were significantly attenuated in the treat group than that in control (P < 0.05). The mRNA expression of anti-inflammatory cytokines elevated obviously comparable of control group. CONCLUSIONS: The Bf maybe impede the activation of NF-kappaB, decrease the expression of TNF-alpha and IL-1beta and elevate the expression of IL-10. These results suggest that oral administration of this new probiotic preparation is effective in preventing flare-ups of chronic UC. It will become a prophylactic drug delaying the relapse of UC.

Adolescent↗

PubMed1963