76,870 research outputs found

    Regional and global changes in TCR [alpha][beta] T cell repertoires in the gut are dependent upon the complexity of the enteric microflora

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    The repertoire of gut associated T cells is shaped by exposure to microbes, including the natural enteric microflora. Previous studies compared the repertoire of gut associated T cell populations in germ free (GF) and conventional mammals often focussing on intra-epithelial lymphocyte compartments. Using GF, conventional and monocolonised (gnotobiotic) chickens and chicken TCRbeta-repertoire analysis techniques, we determined the influence of microbial status on global and regional enteric TCRbeta repertoires. The gut of conventionally reared chickens exhibited non-Gaussian distributions of CDR3-lengths with some shared over-represented peaks in neighbouring gut segments. Sequence analysis revealed local clonal over-representation. Germ-free chickens exhibited a polyclonal, non-selected population of T cells in the spleen and in the gut. In contrast, gnotobiotic chickens exhibited a biased repertoire with shared clones evident throughout the gut. These data indicate the dramatic influence of enteric microflora complexity on the profile of TCRbeta repertoire in the gut at local and global levels

    TSE pathogenesis in cattle and sheep

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    Many studies have been undertaken in rodents to study the pathogenesis of transmissible spongiform encephalopathies (TSE). Only a few studies have focused on the pathogenesis of bovine spongiform encephalopathy (BSE) and scrapie in their natural hosts. In this review, we summarize the most recent insights into the pathogenesis of BSE and scrapie starting from the initial uptake of TSE agents and crossing of the gut epithelium. Following replication in the gut-associated lymphoid tissues (GALT), TSE agents spread to the enteric nervous system (ENS) of the gut. Infection is then carried through the efferent fibers of the post-ganglionic neurons of the parasympathetic and sympathetic nervous system to the pre-ganglionic neurons in the medulla oblongata of the brain and the thoracic segments of the spinal cord. The differences between the pathogenesis of BSE in cattle and scrapie in sheep are discussed as well as the possible existence of additional pathogenetic routes

    Surgical treatment of anomalies of fixing of left half large intestine at children

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    The purpose of surgical interventions at anomalies of fixing of the left bend colon at children is creation of physiological fixing of a thick gut within the anatomic sheaves warning displacement and omission of segments of a intestine in a combination to a resection of its superfluous segments

    The Suspensory Muscles in a Tipulid Larva, Tipula Abdominalis (Diptera: Tipulidae)

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    Author Institution: Biology Department, College of Wooster, Wooster, OhioThere are three pairs of suspensory muscles in the larva of Tipula abdominalis which originate dorso-laterally between body segments one through four and insert laterally along the mid-gut and on the mid-portion of the Malpighian tubules. Cytologically these muscles resemble body wall muscles more than gut muscles. In the living animal, the muscles probably take up slack and keep the gut and Malpighian tubules from being displaced unduly

    Characterization and comparisons of microbiota in different intestinal segments between adult Chinese Shanxi Black Pigs and Large White Pigs

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    The carcass weight of Chinese Shanxi Black Pigs is relatively lower in comparison with that of the counterparts, i.e., Large White Pigs, although the former are resistant to harsh conditions. Since gut microflora has been recognized to play a key role in pork production, it is of interest to explore the microbial communities in different intestinal segments of pigs and its potential relatedness with host features. In this study, 16S rRNA gene amplicon sequencing, accompanied by the inter- and intra-group comparisons, was implemented to investigate the structure composition and potential functions of microbial communities of four distinct intestinal segments [duodenum (D), jejunum (J), ileum (I), and cecum (C)] between adult Chinese Shanxi Black Pigs and Large White Pigs. Comparative survey revealed that the dominant phylum in both breeds was Firmicutes, followed by Proteobacteria, and Bacteroidetes. At the genus level, Lactobacillus was predominant in all samples, and Prevotella was specifically prevalent in the cecum. Further inspection showed the differences of dominant species in the same segments between these two groups. Notably, unique taxa in C and D segments were more than that in I and J segments. Additionally, each segment was characterized by specifically enriched genera, and distinctive pathways were predicted in certain intestinal segments. In short, the findings presented a coherent picture of structure composition and predicted functionalities of gut microbiota in diverse intestinal segments of adult Chinese Shanxi Black Pigs and Large White Pigs, and extend the understanding of potential link between intestinal microbiota and their hosts

    Intestinal Electric Stimulation Accelerates Whole Gut Transit and Promotes Fat Excrement in Conscious Rats

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    *_Introduction:_* Intestinal electric stimulation (IES) is proposed as a potential tool for the treatment of morbid obesity. Our previous study showed that IES with one pair of electrodes accelerated intestinal transit and decreased fat absorption in a segment of the jejunum in the anesthetized rats. The aims of this study were to assess the effects of IES on the whole gut transit and fat absorption in conscious rats, to examine the effects of multi-channel IES, and to explore the cholinergic mechanism behind the effects of IES. 
*_Methods:_* Thirty-eight male rats implanted with serosal electrodes were randomized into five groups: control without IES, 2/3 channel IES with short pulses, atropine and atropine plus IES. The whole gut transit and fat remained and emptied from the gut were analyzed after continuous 2-hour IES. 
*_Results:_* Two and three channel IES significantly accelerated phenol red (marker used for transit) excretion (ANOVA, P < 0.001). No significant difference was found between two and three channel IES. Two channel IES significantly increased the excretion of fat (P < 0.05). Atropine significantly blocked the accelerated transit induced by IES (ANOVA, P < 0.001). Correlation was found between the percentage of phenol red and fat retained in the whole gut (r = 0.497, P < 0.01). 
*_Conclusions:_* IES accelerates whole gut transit and promotes fat excrement in conscious rats, and these effects are mediated through the cholinergic nerves. These findings are in support of the concept that IES may be a promising treatment option for obesity

    Quantitative Comparison of Abundance Structures of Generalized Communities: From B-Cell Receptor Repertoires to Microbiomes

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    The \emph{community}, the assemblage of organisms co-existing in a given space and time, has the potential to become one of the unifying concepts of biology, especially with the advent of high-throughput sequencing experiments that reveal genetic diversity exhaustively. In this spirit we show that a tool from community ecology, the Rank Abundance Distribution (RAD), can be turned by the new MaxRank normalization method into a generic, expressive descriptor for quantitative comparison of communities in many areas of biology. To illustrate the versatility of the method, we analyze RADs from various \emph{generalized communities}, i.e.\ assemblages of genetically diverse cells or organisms, including human B cells, gut microbiomes under antibiotic treatment and of different ages and countries of origin, and other human and environmental microbial communities. We show that normalized RADs enable novel quantitative approaches that help to understand structures and dynamics of complex generalize communities

    Characterization of Thiosulphate: Cyanide sulphur transferase from the gut and body segments of Earthworm (Hyperiodrilus africanus)

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    Cyanide compounds that are by products of industrial activities are known to pose serious environmental pollution. The use of these cyanide compounds by the mining industry, along with limitations in the analysis and monitoring of these compounds, raises serious concerns regarding environmental protection and public safety. Hyperiodrilus africanus (earthworm) is directly employed within bioremediation strategies to promote biodegradation of organic contaminants and thus could be employed to rejuvenate cyanide contaminated soils. Cyanides detoxification could also prevent the risk of cyanide poisoning in poultry animals by converting cyanides in forages to a less toxic compound. This work is designed to extract and characterize rhodanese (thiosulphate: cyanide sulphur transferase, (EC 2.8.1.1) from the gut and body segments of H. africanus collected from the swampy area along Uren bank river in Ikenne community of Ogun State, Nigeria. Our results show total rhodanese activities of 1434.50 RU and 2274.28 RU and specific activities of 108.01 RUmg-1 and 83.1901 RUmg-1 in the gut and body segments of H. africanus respectively. The optimum temperature of 25 °C and optimum pH of 10.5 were obtained for both the gut and body segments enzymes. The enzyme obeyed Michaelis-Menten kinetics and the kinetic constants, Km and Vmax in the gut segment were 33.33 mM and 62.50 RU/ml for KCN substrate and 22.22 mM and 41.67 RU/ml for Na2S2O3 substrates. In the body segment, the Km and Vmax were 33.33 mM and 83.33 RU/ml; 15.38 mM and 4.00 RU/ml for the KCN and Na2S2O3 substrates respectively. Hence, we conclude that the enzyme is more specific for  Na2S2O3 than KCN as substrates, though maximum activity was observed in the body segment for KCN substrate. Ca2+, Mg2+, Ba2+, K+, Na+, Cu2+ and Zn2+ metal ion salts activated the body segment rhodanese at 1 mM and 5 mM concentrations while they have no effect on the gut segment rhodanese from earthworm. On the basis of these findings we conclude that earthworm could detoxify cyanide-containing wastes/forages and therefore promote biodegradation.Keywords: Rhodanese, earthworm, environmental protection, cyanide detoxification, bioremediatio

    Transmural intestinal wall permeability in severe ischemia after enteral protease inhibition.

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    In intestinal ischemia, inflammatory mediators in the small intestine's lumen such as food byproducts, bacteria, and digestive enzymes leak into the peritoneal space, lymph, and circulation, but the mechanisms by which the intestinal wall permeability initially increases are not well defined. We hypothesize that wall protease activity (independent of luminal proteases) and apoptosis contribute to the increased transmural permeability of the intestine's wall in an acutely ischemic small intestine. To model intestinal ischemia, the proximal jejunum to the distal ileum in the rat was excised, the lumen was rapidly flushed with saline to remove luminal contents, sectioned into equal length segments, and filled with a tracer (fluorescein) in saline, glucose, or protease inhibitors. The transmural fluorescein transport was determined over 2 hours. Villi structure and epithelial junctional proteins were analyzed. After ischemia, there was increased transmural permeability, loss of villi structure, and destruction of epithelial proteins. Supplementation with luminal glucose preserved the epithelium and significantly attenuated permeability and villi damage. Matrix metalloproteinase (MMP) inhibitors (doxycycline, GM 6001), and serine protease inhibitor (tranexamic acid) in the lumen, significantly reduced the fluorescein transport compared to saline for 90 min of ischemia. Based on these results, we tested in an in-vivo model of hemorrhagic shock (90 min 30 mmHg, 3 hours observation) for intestinal lesion formation. Single enteral interventions (saline, glucose, tranexamic acid) did not prevent intestinal lesions, while the combination of enteral glucose and tranexamic acid prevented lesion formation after hemorrhagic shock. The results suggest that apoptotic and protease mediated breakdown cause increased permeability and damage to the intestinal wall. Metabolic support in the lumen of an ischemic intestine with glucose reduces the transport from the lumen across the wall and enteral proteolytic inhibition attenuates tissue breakdown. These combined interventions ameliorate lesion formation in the small intestine after hemorrhagic shock

    Saccharomyces boulardii CNCM I-745 supplementation reduces gastrointestinal dysfunction in an animal model of IBS

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    We evaluated the effect of Saccharomyces boulardii CNCM I-745 on intestinal neuromuscular anomalies in an IBS-type mouse model of gastrointestinal motor dysfunctions elicited by Herpes Simplex Virus type 1 (HSV-1) exposure.Mice were inoculated intranasally with HSV-1 (102 PFU) or vehicle at time 0 and 4 weeks later by the intragastric (IG) route (108 PFU). Six weeks after IG inoculum, mice were randomly allocated to receive oral gavage with either S. boulardii (107 CFU/day) or vehicle. After 4 weeks the following were determined: a) intestinal motility using fluorescein-isothiocyanate dextran distribution in the gut, fecal pellet expulsion, stool water content, and distal colonic transit of glass beads; b) integrity of the enteric nervous system (ENS) by immunohistochemistry on ileal whole-mount preparations and western blot of protein lysates from ileal longitudinal muscle and myenteric plexus; c) isometric muscle tension with electric field and pharmacological (carbachol) stimulation of ileal segments; and d) intestinal inflammation by levels of tumor necrosis factor α, interleukin(IL)-1β, IL-10 and IL-4.S. boulardii CNCM I-745 improved HSV-1 induced intestinal dysmotility and alteration of intestinal transit observed ten weeks after IG inoculum of the virus. Also, the probiotic yeast ameliorated the structural alterations of the ENS induced by HSV-1 (i.e., reduced peripherin immunoreactivity and expression, increased glial S100β protein immunoreactivity and neuronal nitric oxide synthase level, reduced substance P-positive fibers). Moreover, S. boulardii CNCM I-745 diminished the production of HSV-1 associated pro-inflammatory cytokines in the myenteric plexus and increased levels of anti-inflammatory interleukins.S. boulardii CNCM I-745 ameliorated gastrointestinal neuromuscular anomalies in a mouse model of gut dysfunctions typically observed with irritable bowel syndrome
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