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At least 775 records · Page 43Linked to original sources
PubMed1993

Oat bran but not a beta-glucan-enriched oat fraction enhances butyrate production in the large intestine of pigs.

Digestibility of polysaccharides and other macronutrients and the metabolic response of the microflora in the large intestine to a low dietary fiber wheat flour diet and three enriched diets with equal amounts of added dietary fiber (oat bran, a beta-glucan-enriched oat fraction and insoluble oat residues) were studied in ileal-cannulated pigs. The digestibility of starch was high in the small intestine (98-100%). At this site of the gastrointestinal tract there was also a significant degradation of mixed linked beta (1 --> 3; 1 --> 4)-D-glucan (beta-glucan) (45-54%), whereas arabinoxylan was quantitatively recovered in ileal effluent. Type and amount of polysaccharides passing the ileal-cecal junction had little effect of the density of microorganism in the large intestine (approximately 10(10) viable counts/g digesta) but did have a high impact on the activity of the flora in colon as measured by the concentration of ATP in digesta. The relative proportion of butyrate in the short-chain fatty acids in the luminal contents of the large intestine was 6.6-8.4% when the low dietary fiber wheat flour diet was fed. However, when either oat bran or insoluble residues were included in the diet, the level was raised to 9.3-11.2%. No effect was seen after the addition of the beta-glucan-enriched fraction. This study showed that arabinoxylan and not beta-glucan in the cell walls of oat bran was responsible for the enhanced butyrate production of oat bran.

Animals↗
PubMedDate not supplied

[Comparative microbiological study of fresh and heat-treated yoghurt in an in vivo animal model].

In an acute assay, rats fasted for 24 h were sounded with 2 ml of fresh yogurt, sterilised yogurt or distilled water, and sacrificed at 2, 4, 8 and 24 h. They were compared with non-sounded rats. The survival of the lactic bacteria of the yogurt administered in the animals' stomach and intestines was determined, and the bacteria isolated were to the Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus profiles belonging to the strains isolated originally from the yogurt. Counts of the total number of microorganisms that were grown in lactobacilli and lactic streptococci media were also made. Analyses of the different types of resulting colonies in the lactobacilli and lactic streptococci media was performed. No L. delbrueckii subsp. bulgaricus or S. thermophilus were characterized in this acute assay. The statistical analysis of the results did not show significant differences in the log UFC. g-1, of the intestinal microbiota microorganisms of the three groups of animals in any of the times. In a chronic assay, three groups of animals, after 30 days of nourishment ad libitum with either a semisynthetic diet with 10% of fresh yogurt, or with 10% of sterilised yogurt or controls, housed in individual metabolism cells, were sacrificed. The results did not show meaningful differences in the long UFC. g-1 of the intestinal microbiota microorganisms from the three groups of animals in any of the times. In turn, in the study of the different types of colonies resulting in the lactobacilli and lactic streptococci media, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay. The results did not show meaningful differences in the log CFU. g-1 of the intestinal flora microorganisms from the three groups of animals in any of the times. In turn, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay.

Animals↗
PubMed2006

The front line of enteric host defense against unwelcome intrusion of harmful microorganisms: mucins, antimicrobial peptides, and microbiota.

The intestinal tract is a complex ecosystem that combines resident microbiota and the cells of various phenotypes with complex metabolic activities that line the epithelial wall. The intestinal cells that make up the epithelium provide physical and chemical barriers that protect the host against the unwanted intrusion of microorganisms that hijack the cellular molecules and signaling pathways of the host and become pathogenic. Some of the organisms making up the intestinal microbiota also have microbicidal effects that contribute to the barrier against enteric pathogens. This review describes the two cell lineages present in the intestinal epithelium: the goblet cells and the Paneth cells, both of which play a pivotal role in the first line of enteric defense by producing mucus and antimicrobial peptides, respectively. We also analyze recent insights into the intestinal microbiota and the mechanisms by which some resident species act as a barrier to enteric pathogens. Moreover, this review examines whether the cells producing mucins or antimicrobial peptides and the resident microbiota act in partnership and whether they function individually and/or synergistically to provide the host with an effective front line of defense against harmful enteric pathogens.

Animals↗
PubMed1986

[Colonizing resistance of rats born of animals with experimental dysbacteriosis].

It was shown that long-term oral administration of rifampicin (40 mg/kg) to rats was accompanied by a marked decrease in the number of enterococci and staphylococci in their large intestine. A significant decrease in the number of colibacilli and anaerobic nonsporulating gramnegative bacteria was also observed. Discontinuation of the antibiotic administration resulted in rapid recovery of the intestinal flora with respect to all the indices tested. It was found for the first time that pregany of rats with experimental disbacteriosis was characterized by lowered colon resistance in spite of similarity in the intestinal flora of the experimental and control pregany. This was evident from increased periods of indicator microorganism retention in the animal intestine.

Animals↗
PubMedDate not supplied

[Study of the parietal microflora in the rat intestine].

The article deals with the adaptation of the existing method of the isolation of microorganisms from parietal mucin of the intestine of experimental animals (rats) with a view to ensure the methodological uniformity of investigations. The effectiveness of the method of sparing disintegration of parietal mucin taken from the mucous membrane of the gastrointestinal tract, specially developed for human biomaterial, and its adequacy for microbiological investigations of the digestive organs of rats have been confirmed. A certain similarity between the microbiocenosis of the parietal mucin in the intestine of humans and rats has been established.

Animals↗
PubMed1996

Clinical uses of probiotics for stabilizing the gut mucosal barrier: successful strains and future challenges.

Probiotic bacteria are used to treat disturbed intestinal microflora and increased gut permeability which are characteristic to many intestinal disorders. Examples include children with acute rotavirus diarrhoea, subjects with food allergy, subjects with colonic disorders and patients undergoing pelvic radiotherapy and sometimes changes associated with colon cancer development. In all such disease states altered intestinal microflora, impaired gut barrier and different types of intestinal inflammation are present. Successful probiotic bacteria are able to survive gastric conditions and colonize the intestine, at least temporarily, by adhering to the intestinal epithelium. Such probiotic microorganisms appear to be promising candidates for the treatment of clinical conditions with abnormal gut microflora and altered gut mucosal barrier functions. They are also promising ingredients to future functional foods and clinical foods for specific disease states provided that basic requirements for strains and clinical studies are carefully followed.

Animals↗
PubMed1985

Connections between Ascaridia galli and the bacterial flora in the intestine of hens.

Parasitological dissections of 502 intestinal tracts of hens deriving from big private chicken-farms have been done. In the jejunum of 146 hosts (ext. 29.1%) from 1 to 21 individuals of A. galli were detected. Using bacterial selective media and biochemical tests, the microorganisms from the hen's intestinal tracts as well as from the cuticle surface of the nematodes were identified. Among them were: grampositive (+) Lactobacillus, Bacillus, Staphylococcus, Streptococcus, Micrococcus, Sarcina, Clostridium, Corynebacterium; gramnegative (-) Enterobacteriaceae, Pseudomonas, Pasteurella, and fungi Candida and others. The lower frequency of microorganisms and the smaller amount of bacteria in the intestinal content in infected hens than in uninfected show that A. galli has antibacterial properties.

Animals↗
PubMed2000

Small intestinal adenomatous polyposis resulting in protein-losing enteropathy in a horse.

A 4-year-old Quarter Horse gelding was presented with a history of weight loss of 6 months duration, along with extensive ventral subcutaneous edema. Clinicopathologic findings included a markedly low serum total protein (2.9 g/dl) and a low packed cell volume (24%). The mucosal surface of the distal jejunum and entire ileum were carpeted with numerous polypoid, papillary, and glandular masses comprised of pseudostratified tall columnar cells and large numbers of interspersed goblet cells. Neoplastic change was diffuse throughout the mucosa of each mass, but abrupt demarcation occurred between neoplastic masses and adjacent mucosa. Immunohistochemical staining for protein of the p53 tumor suppressor gene revealed only occasional cytoplasmic reactivity within polyps and normal mucosa. Nuclear staining for papillomavirus antigens was not observed. Electron microscopic examination revealed features of well-differentiated intestinal epithelial cells, including apical tight junctions and microvilli, desmosomes, and the presence of numerous goblet cells. Microorganisms were not detected. Small intestinal polyposis should be considered as a rare differential diagnosis for protein-losing enteropathy in the horse.

Adenomatous Polyps↗
PubMed1999

Gastrointestinal flora and its alterations in critical illness.

The normal indigenous flora of the human gastrointestinal tract comprises a remarkably complex yet stable colony of more than 400 separate species, living in a symbiotic relationship with the human host. Stability of that flora is accomplished by multiple mechanisms including gastric acidity, gut motility, bile, products of immune cells in the gut epithelium, and competition between microorganisms for nutrients and intestinal binding sites. The indigenous flora influences multiple aspects of physiologic homeostasis and forms a key component of normal host defenses against infection by exogenous pathogens. Critical illness is associated with striking changes in patterns of microbial colonization, best described in the oropharynx and upper gastrointestinal tract. Pathological colonization occurs with the same species that is predominate in nosocomial infections, and descriptive studies suggest that such colonization is a risk factor for infection. Moreover, prophylactic measures that prevent pathological gut colonization in experimental circumstances reduce rates of nosocomial infection in critically ill patients and, in the case of selective decontamination of the digestive tract, reduce mortality risk. Conventional approaches to infectious diseases have conceptualized microorganisms as inimical and focused on eradicating them as rapidly and fully as possible. Insights from the study of critically ill patients suggest that that relationship is better understood as a symbiotic one and that preservation, rather than elimination, of the indigenous flora provides the greatest promise of clinical benefit to this vulnerable population.

Critical Illness↗
PubMed1982

[Intestinal mucosa of gnotobiotic rats administered lactobacilli].

When lactobacilli are administered to gnotobiotic rats (Fischer strain), a gradual increase of lymphocytic, eosinophilic and mast cell infiltration of the intestinal connective tissue stroma, dilatation of vessels and their filling with lymphocytes is observed. Radioautographically 7 months later, migration and differentiation of enterocytes in the crypta--villus system of the iliac mucous tunic increases. In the mesenteric lymph nodes the postcapillary venules increase in number, lymphocytes migrate out of them, focal plasmocytic reaction with presence of some blastic forms takes place. Specific antibodies for lactobacilli in the blood serum either are absent or occur in low titers (1:2-1:8). Owing to the data obtained, a conclusion can be made on a weak immunogenecity of the lactobacilli. Their administration to the germ-free rats produces a certain cellular reaction, probably T-dependent, though any definite signs of hormonal response are absent. One--14 days after lactobacilli have been injected, in the rat intestine mucous tunic no microorganisms are revealed to fix to enterocytes. In cytoplasm of the absorbtive cell villi, the Golgi complex is subjected to hyperplasia and occupies an essential area over the nucleus. Within its cysterns, as well as in the mitochondrial and nuclear membrane areas, myelin-like bodies are revealed; evidently, they demonstrate certain changes in peroxidic oxidation of lipids..

Animals↗
PubMed1990

[Etiologic interpretation of acute intestinal diseases].

The authors suggest a scheme for the detection of the etiologic factor of an acute intestinal condition; this scheme permits detecting dysbiotic changes in the microbiocenosis, finding pathogenic or opportunistic microorganisms in fecal culture. Classification of acute intestinal diseases into those induced by pathogenic and opportunistic microorganisms, as well as those resultant from acute imbalance of the normal ratio of intestinal bacteria helps carry out differential therapy of patients. The results of such bacteriologic studies may be useful for epidemiologists.

Acute Disease↗
PubMed1998

The role of interdigestive small bowel motility in the regulation of gut microflora, bacterial overgrowth, and bacterial translocation in rats.

OBJECTIVE: To clarify the role of the migrating motor complex (MMC) in the regulation of small intestinal microflora and bacterial translocation. SUMMARY BACKGROUND DATA: The intestinal microflora may serve as a source of infectious microorganisms. Failure of regulatory mechanisms of the intestinal flora could therefore play an important role in the pathogenesis of gut-derived infections. METHODS: Rats were fitted with small intestinal myoelectrodes. MMCs were measured on a control day and 3 consecutive days during continuous administration of morphine or placebo. Mesenteric lymph nodes, liver, spleen, peripheral blood, duodenum, and ileum samples were cultured quantitatively. RESULTS: The mean MMC cycle length in placebo-treated animals was 15.1+/-0.5 minutes. MMCs were completely disrupted after morphine treatment. Total bacterial growth in the duodenum was 7.27+/-0.34 10log colony-forming units (CFU)/g with placebo and 8.28+/-0.27 CFU/g with morphine. In placebo-treated animals, the mean MMC cycle length the day before culturing correlated with total bacterial growth in the duodenum. Translocation incidences to the mesenteric lymph nodes, liver, spleen, and blood were 0/8, 1/8, 0/8, and 0/8 with placebo and 7/8, 6/8, 5/8, and 0/8 with morphine. The overall translocation incidence was 1/8 in placebo-treated animals and 8/8 in morphine-treated animals. CONCLUSIONS: The MMC is an important mechanism controlling bacterial growth in the upper small bowel. Its disruption with morphine promotes duodenal bacterial overgrowth and bacterial translocation.

Animals↗
PubMed1996

Effects of omeprazole and amoxycillin on the human oral and gastrointestinal microflora in patients with Helicobacter pylori infection.

Fourteen patients with Helicobacter pylori infection were treated with omeprazole capsules 20 mg and amoxycillin capsules 1000 mg twice daily for 14 days and 14 patients with omeprazole capsules 20 mg and placebo twice daily for 14 days. Samples from saliva, dental plaque and faeces and biopsies from antrum and corpus were analysed in order to determine the ecological changes in the normal microflora. Several microorganisms were affected by both treatment regimens. Two patients were colonised with enterobacteria in the oral cavity and stomach during the omeprazole plus amoxycillin treatment. A general increase in the number of microorganisms from gastric mucosa was observed in both treatment groups. A selection of resistant enterobacteria and an increase in beta-lactamase production was observed in the faecal samples during the omeprazole plus amoxycillin treatment. Eradication of H. pylori in the omeprazole-amoxycillin group was 50% and in the omeprazole placebo group 0% four weeks after treatment. No viable H. pylori were cultivated in the saliva, dental plaque or faecal samples. Treatment with omeprazole 20 mg and amoxycillin 1000 mg twice daily for 14 days altered the normal microflora in the oral, gastric and intestinal tract and antibiotic resistant microorganisms increased in numbers in the intestinal microflora.

Adult↗
PubMed2006

Importance of the host specificity in the selection of probiotic bacteria.

The gastrointestinal tract is a complex and dynamic ecosystem. Commensal microorganisms (C), which proliferate in the intestine from birth, are crucial for gut homeostasis while non commensal (NC) microorganisms are transient and enter the organism from the environment and foods. We studied comparatively the influence of oral administration of C and NC Lactobacillus fermentum and Lactobacilus acidophilus on the gut-associated lymphoid tissue (GALT) of conventional mice. To determine the importance of the selection of probiotic host-specificity bacteria with immunomodulating capacity, we examined the interaction with the gut by transmission electron microscopy and FITC-labelled bacteria. We compared the immunomodulation capacities of C and NC strains by studying the number of IgA secreting cells and cytokine profile. No differences were found in the number of IgA+ cells; however, the pattern of cytokine response to C and NC bacteria was different. With regard to proinflammatory cytokine (IFNgamma and TNFalpha), we found that TNFalpha was mainly produced by NC bacteria, while C bacteria were able to elicit mainly IFNgamma. The regulatory cytokines (IL-10 and IL-4) were induced with different patterns for both C and NC strains. No differences in the pathway of internalization to the gut between C and NC were found. In summary, we determined that C and NC bacteria interact with the intestine in the same way; both C and NC bacteria were able to reinforce the surveillance of the gut mucosal immune system. The cytokine profile showed that C bacteria would be involved in the regulation of intestinal homeostasis rather than in the immune activation as the NC bacteria.

Administration, Oral↗
PubMed1960

Bilirubin and urobilins in germfree, ex-germfree, and conventional rats.

No urobilinogens are present in the feces or urine of germfree rats. After contamination of germfree animals with feces from conventional animals the exgermfree rats produced urobilins to the same extent as conventional animals on the same diet. The negative urobilin test turned positive in germfree animals infected with a single Clostridium-like microorganism isolated from the intestinal contents of rats with urobilins in the feces. The output increased in these monoinfected animals after superinfection with a strain of E. coli but never reached the values of conventional animals.

Animals↗
PubMed1966

The role of the microbial flora in uremia. I. Survival times of germfree, limited-flora, and conventionalized rats after bilateral nephrectomy and fasting.

Germfree rats were used in 3 experiments to study the effects of the microbial flora on survival time after acute uremia produced by a one-stage bilateral nephrectomy. Germfree rats, limited-flora rats, and conventionalized rats (all maintained continuously in isolators) were subjected to nephrectomy or to sham nephrectomy, deprived of food and water until they died, respectively, of uremia or of starvation, and their survival times compared. To establish a limited defined flora in advance of nephrectomy, germfree rats were either monocontaminated (Staphylococcus albus), dicontaminated (S. albus and Proteus mirabilis) or tetracontaminated (S. albus, S. faecalis, P. mirabilis, and E. coli); to conventionalize germfree rats, they were exposed to the mixed microbial flora contained in the cecal contents of ordinary rats, which was the source of the aforementioned bacteria and which included other uncharacterized microorganisms as well. The intestine of all rats with a limited flora persisted in a morphologic state that was virtually no different from that of the germfree rat, including the presence of an enlarged, thin-walled cecum; by contrast, the intestine of the conventionalized rats permanently assumed the morphological characteristics of ordinary, open-laboratory rats with the cecum reduced to normal size. After nephrectomy and food and water deprivation (death from anuria): (a) All germfree rats but one outlived their conventionalized counterparts in each of the 3 experiments; the 21 germfree rats (127 hr) lived, on the average, 2 days longer than did the 24 conventionalized rats (75 hr). No sex difference was demonstrated. (b) The rats with a limited flora died correspondingly sooner as the complexity of their flora increased; survival time of the tetracontaminated rats was significantly shorter than that of the germfree rats, and statistically no different from that of the conventionalized rats. After sham nephrectomy and food and water deprivation (delayed death from starvation): (a) All rats, irrespective of microbial status or sex, outlived their fasting nephrectomized partners. The conventionalized rats endured starvation approximately 2.5 wk longer than they did anuria and the germfree rats 1 wk longer. (b) All conventionalized rats, both male and female, outlived their respective germfree counterparts by about 1 wk. (c) All males, irrespective of microbial status, survived longer than did the females; the average difference was 4 days. The differences in tolerance to anuria or starvation did not correlate with initial body weight or rate of weight loss.

Animals↗
PubMed2002

Enterococcus faecalis produces extracellular superoxide and hydrogen peroxide that damages colonic epithelial cell DNA.

Enterococcus faecalis is a commensal microorganism of the human intestinal tract that produces substantial extracellular superoxide (O(-)(2)), and derivative reactive oxygen species such as H(2)O(2) and hydroxyl radical, through autoxidation of membrane-associated demethylmenaquinone. Because these oxidants may be important as a cause of chromosomal instability (CIN) associated with sporadic adenomatous polyps and colorectal cancer, the ability of E.faecalis to damage eukaryotic cell DNA was examined using the alkaline lysis single cell gel electrophoresis (comet) assay. Both Chinese hamster ovary and HT-29 intestinal epithelial cells showed increased DNA damage after co-incubation with wild-type E. faecalis strain OG1RF, but not a transposon-inactivated mutant with attenuated extracellular O(-)(2) production. E. faecalis-mediated DNA damage was prevented by catalase, but not manganese superoxide dismutase, indicating H(2)O(2) arising from O(-)(2) was the genotoxin. In a rat model of intestinal colonization, OG1RF resulted in significantly higher stool concentrations of H(2)O(2) and 5,5-dimethyl-1-pyrroline N-oxide adducts of hydroxyl and thiyl radicals, as identified by electron spin resonance-spin trapping, compared with rats colonized with a mutant strain having attenuated O(-)(2) production. Using the comet assay, luminal cells from the colon of rats colonized with O(-)(2)-producing E. faecalis showed significantly increased DNA damage compared with control rats colonized with the mutant. These findings suggest a potentially profound role for extracellular free radical production by E. faecalis in promoting CIN associated with sporadic adenomatous polyps and colorectal cancer.

Animals↗
PubMed1998

Helicobacter--species classification and identification.

The genus Helicobacter was created in 1989 with H. pylori as the type species. Since then the genus has expanded to include about 18 species. Some species were reclassified from Campylobacter, but most were newly discovered microorganisms from gastric or intestinal sites in mammalian host animals. The essential property of almost all helicobacters is the presence of sheathed flagella. Most species possess strong ureolytic ability, particularly those associated with gastric mucosa, and exhibit considerable diversity in cell morphology with respect to cell length, number and location of flagella, and presence of periplasmic fibrils. H. pylori has a global distribution and infects human gastric mucosa exclusively but there is some evidence for infection in cats. Genomes of isolates from different individuals are unusual in their diversity in gene order and sequences within individual genes. 'H. heilmannii' is another gastric spiral shaped organism less frequently infecting humans but commonly found in cat and dog gastric tissue. H. felis is important in the mouse model of infection. A range of conventional phenotypic tests as well as some new PCR based assays are available for identifying isolates of Helicobacter from clinical specimens.

Animals↗