Interleukin-11 (IL-11) is a cytokine that promotes intestinal epithelial resistance to injury, however the mechanisms remain incompletely understood. Evidence from the Ropeleski Lab supports IL-11 dependent activation of the transcription factor Nuclear Factor кB (NFкB), without the degradation of the inhibitor кB (IкB), which deviates from the classical mechanism involving proteolytic processing of IкB. Also, IL-11 mediates the modulation of genes associated with healing, such as cyclooxygenase-2 (COX-2). It was hypothesized that IL-11 activates NFкB in intestinal epithelial cells by direct modulation of NFкB which, in a physiological setting, stimulates restitution during the healing response in the gut. Both cultured rat IEC-18 and human HIEC epithelial crypt cells were used as models to investigate whether the effect of IL-11 was species-specific. Activated NFкB is targeted to the nucleus therefore immunoblotting of nuclear extracts for expression of NFкB protein subunits including p65, activated p65 (phospho-p65Ser536), p50, and RelB, as well as by immunofluorescent detection of p65 were used. Inhibition of IL-11 signaling was carried out using various pharmacological inhibitors in order to determine their effect on p65 phosphorylation. Mechanically wounded cells were used as a model of gut injury and restitution where immunoblotting was used to examine IL-11 dependent effects on phospho-p65Ser536 and COX-2 expression. The binding of p65 to the кB binding site on DNA was detected with an ELISA-based system. IL-11 treatment was associated with the nuclear accumulation of phospho-p65ser536 in epithelial cell lines. Inhibition of PI3K/Akt signaling with LY294002 and AktiVIII suggested a partial reduction in phospho-p65Ser536 while inhibition of MEK1,2 signaling with U0126 indicated almost a complete abrogation of phospho-p65Ser536 accumulation in the nucleus. Inhibition of inhibitor of кB kinase-β (IKKβ) with SC-514 also revealed a strong attenuation of IL-11 induced phospho-p65Ser536. Inhibition of p90RSK1 with SL0101 was inconsistent but suggested a partial blockage of phospho-p65Ser536 whereas inhibition of Src kinase with PP2, did not affect phospho-p65Ser536 in IL-11 treated IEC-18 cells. There was no increased binding of p65 to the кB binding motif on DNA after IL-11 treatment. In mechanically wounded cells treated with IL-11, nuclear phospho-p65Ser536 was unaffected; however there was an evident potentiation of wound-induced COX-2 expression compared to untreated cells. In conclusion, IL-11 activates NFкB signaling in a non-classical manner through the phosphorylation of the p65 subunit. The predominant pathway appears to involve IKK and MEK signaling. Also, IL-11 modulates COX-2 expression in response to wounding in intestinal epithelial cells. / Thesis (Master, Anatomy & Cell Biology) -- Queen's University, 2008-07-31 10:12:18.794

No description available.

The aims of this study were to screen an array of plant families for novel lectins, to isolate candidate lectins whose reactivity suggested may be functionally useful and to assess the reactivity and modulatory effects of the novel lectins on the cells of the gastrointestinal tract (including the immune regions) and lymphocytes. Few of the seed and bulb samples screened had significant levels of lectin. However, the seeds, roots, stem and bark of <I>Morus nigra</I>, the black mulberry tree from the Moraceae plant family, were found to contain particularly high lectin activity. Two new lectins <I>Morus nigra</I> agglutinin-I (MNAI) and <I>Morus nigra</I> agglutinin-II (MNAII) were isolated. They were found to differ significantly from each other in their sugar specificity, subunit structure, amino acid sequence identity, glycosylation and haemagglutinating activity. MNAI has similarities in sugar inhibition characteristics (GalNAc) and amino acid identity to both MPA and jacalin, which also belong to the Moraceae family. MNAI recognises the similar intestinal glycan structures as jacalin and recognises T/Tn blood group antigen, both with and without sialylation. However, it differs significantly from MPA and jacalin in its lymphocyte stimulatory properties. MNAII appears to be novel and did not show amino acid sequence identity with any known proteins contained in the deltamass database. It is inhibitable by α-D-methyl mannoside. It may have an affinity for structures such as some form of N-linked glycans and appears to have low affinity for α2,6 sialylated structures. It labelled glycan structures present on the villus brush border, dome FAE and most M cells of many of the species tested <I>in vitro</I>.

No description available.

No description available.

Recent 16S rRNA gene sequencing studies of the duodenal and fecal microbiota have revealed alterations in the abundance of specific bacterial groups in dogs with gastrointestinal (GI) disorders. The aim of this study was to establish a panel of quantitative real-time PCR (qPCR) assays for the evaluation of specific bacterial groups in fecal samples of healthy dogs, dogs with chronic enteropathies (CE), and dogs with acute hemorrhagic diarrhea (AHD). Fecal samples from 242 healthy dogs, 118 dogs with CE, and 57 dogs with AHD were analyzed using qPCR assays targeting Faecalibacterium spp., Turicibacter spp., Bifidobacterium spp., Lactobacillus spp., Streptococcus spp., Ruminococcaceae, C. perfringens, E. coli, gamma-Proteobacteria, Bacteroidetes, and Firmicutes). Differences in bacterial abundance among the three groups were evaluated using a Kruskal-Wallis test followed by a Dunn's post-test. A Bonferroni correction was used to correct for multiple comparisons and an adjusted p<0.05 was considered for statistical significance. Faecalibacterium spp., Turicibacter spp., and Ruminococcaceae were significantly decreased in CE and AHD compared to healthy dogs (p<0.001 for all). Lactobacillus spp. and Streptococcus spp. were significantly increased in dogs with CE (p<0.001 for both) when compared to the healthy dogs. In contrast, Lactobacillus spp. and Streptococcus spp. were significantly decreased in dogs with AHD compared to healthy dogs (p<0.01 and p<0.05, respectively) and also when compared to the dogs with CE (p<0.001 for both). C. perfringens and E. coli were significantly increased in dogs with AHD (p<0.001 and p<0.01, respectively), when compared to healthy dogs. E. coli was also significantly increased in dogs with CE when compared to the healthy dogs (p<0.001). Bacteroidetes were significantly lower in dogs with CE compared to healthy dogs (<0.001). Firmicutes were significantly higher in healthy dogs in comparison to dogs with AHD (p<0.05). Bifidobacterium spp. and gamma-Proteobacteria were not significantly different among all three groups of dogs. In conclusion, the qPCR panel employed here revealed a fecal dysbiosis in dogs with CE and AHD when compared to healthy dogs. These results are similar to recently reported findings using molecular sequencing approaches. Quantification of these bacterial groups by qPCR may be a useful adjunct for the diagnosis or monitoring of gastrointestinal disease in dogs.

Bibliography: leaves 322-368. / xii, 368 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Presents studies relating to normal and disordered gastric motility and the role of the gastrointestinal tract in appetite regulation in humans. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 1997

Bibliography: leaves 206-251. / xii, 251 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The motor and sensory interactions between nutrients and proximal gut in humans are not well understood, despite the pivotal importance of these interactions on appetite, absorption and thus, nutrition. In part, this lack of knowledge results from technical difficulties in studying motor function in the human gut. In particular, the inability to continuously measure intraluminal flow with any degree of temporal resolution, has impeded progress in this field. The studies described in this thesis focus on nutrient-gut interactions, and also on the development of novel methodologies aimed at advancing the understanding and interpretation of the relationships between intraluminal pressures and flows. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2000

Includes bibliographical references (leaves 349-440). / 440 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The broad areas addressed are: the effect of physiological changes in the blood glucose concentration in the regulation of gastroduodenal motor and sensory function; the effect of acute hyperglycaemia on gastric motor and sensory function in patients with diabetes mellitus and the motor response to prokinetic therapy; the relationships between small intestinal nutrient exposure, gastrointestinal peptide hormone release, antropyloric motility and appetite; and, the effect of aging on the proximal gastric response to distension and food intake. / Thesis (Ph.D.)--Adelaide University, Dept. of Medicine, 2001

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Assessment of gastric emptying in animals is hampered by the lack of a technique that is noninvasive and does not involve sacrificing the animal. The primary aims of these studies therefore were to develop the breath test for the mouse and then investigate gastric emptying rates in physiological, pathological and pharmacological studies. After an overnight fast, mice were fed a solid or liquid meal that contained a ¹³C-labelled substrate, and placed in breath collection chambers. Breath samples collected at intervals were analysed for levels of ¹³C0₂, with the rate of appearance in the breath giving a measure of the gastric emptying rate. The breath testing technique was shown to be reproducible and sensitive enough to be able to detect induced alterations to gastric emptying, with results comparable to those obtained from other techniques. The breath test was used to assess gastric emptying in mice and showed that: (1) H. pylori infection accelerated gastric emptying in the initial weeks of infection, whilst a more severe stomach inflammation caused dysmotility; (2) baclofen (a potential reflux therapy) accelerated gastric emptying of solids and delayed liquid emptying in a dosedependent manner; and (3) mice with a high daily food intake had faster emptying compared to those with low intake, which resulted in the same weight gain of the two groups. Breath testing was also used in adults and children and showed that: (1) increasing the caloric content of a solid meal delayed the emptying of the solid, but not of a liquid given simultaneously; (2) gastric emptying rate is correlated to the amount of colonic gas produced; and (3) improvement in pancreatic lipase activity with pancreatic enzyme replacement is inversely related to the gastric emptying time. Breath testing was also used to show that substrates with a natural ¹³C-enrichment can be used to assess small intestinal enzyme activity. Breath testing is a sensitive and reproducible tool to investigate gastric emptying in mice. Its noninvasive nature allows it to be repeated within each subject which is useful for follow-up investigations. It can now be applied further to a range of disease, pharmacological and nutritional investigations. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1082934 / Thesis (Ph.D.) -- University of Adelaide, Dept. of Physiology, 2002