Dissertationen zum Thema „In vitro gut model“
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Coussa-Charley, Michael. „A novel «in vitro» mucosal gut bacterial adhesion model“. Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106420.
Der volle Inhalt der QuelleLa flore intestinale est un organe dynamique et complexe qui se trouve à l'intérieur du tube digestif. Bien qu'il y ait un flux d'activité constant, la microflore peut être considérée comme un bioréacteur ayant un quasi état d'équilibre durant toute la vie d'une personne. En fait, la composition relative des différents types de bactéries est directement reliée à la santé de l'individu. En comprenant comment l'intestin est colonisé et ce qui peut être administré pour modifier sa composition générale, on serait en mesure de l'utiliser comme une cible légitime pour la livraison de médicaments. Des modèles in-vitro d'adhérence intestinale ont été mis au point exactement à cette fin. Un modèle comprenant plusieurs éléments clés associés à l'adhésion bactérienne sur la muqueuse intestinale a été développé pour cette thèse. Tout d'abord, des capsules d'alginates recouvertes de mucus ont été utilisées afin de simuler la muqueuse intestinale. En outre, ces capsules ont été incubés avec les bactéries intestinales à partir d'un échantillon frais provenant des fécales humaines. De cette façon, on serait en mesure d'observer les interactions entre les différentes bactéries dans l'intestin, et l'interaction que ces bactéries ont avec tout autre traitement. Finalement, ce modèle est continu, permettant une analyse en temps réel de la muqueuse associée à la flore et nous permet de comprendre l'éffet de différents facteurs environnementaux sur de longues périodes de temps. Les résultats ont démontré que la plate-forme a été très efficace dans la fourniture d'un écosystème stable microbien pour une seule souche bactérienne ou pour un grand nombre de bactéries aérobies ou anaérobies. Le modèle a également montré de très bonnes performances au cours des études à long terme en utilisant plusieurs échantillons pendant l'expérience. Les applications de ce modèle sont pratiquement infinies, et permettent notamment d'enquêter sur l'effet que les probiotiques, les prébiotiques, et les antibiotiques ont sur la modification d'une microflore associée à la muqueuse.
GARUGLIERI, ELISA. „EFFECTS OF SILVER NANOPARTICLES ON IN VITRO GUT MICROBIAL MODELS AND OTHER ANAEROBIC ENVIRONMENTS“. Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/488359.
Der volle Inhalt der QuelleGérémie, Lauriane. „Development of an in-vitro intestinal model featuring peristaltic motion“. Thesis, Sorbonne université, 2019. http://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS118.pdf.
Der volle Inhalt der QuelleMy PhD work is part of the organ-on-chip field, and more precisely part of the gut-on-chip field. It is in line with the main objective of this field, which is the development of in-vitro models recapitulating as faithfully as possible the intestinal micro-environment. Through my PhD work I first developed a versatile gut-on-chip platform recapitulating the intestinal 3D architecture as well as its dynamic micro-environment. Therefore, this platform allows us to study the influence of the intestinal dynamic, especially the peristalsis, on cellular behavior in function of the 3D architecture of the scaffold. For this study Caco2 cells have been seeded either on a 2D or a 3D scaffold coated with laminin and submitted to a cyclic stretching (at 0.2 Hz and 10%) for 2, 5, 8, 16, 24 and 48 hours. Our main observation was the cellular reorientation induced by the stretching, therefore we characterized the cell behavior in function of the coating condition, the initial confluency, the stretching time and the scaffold geometry. Interestingly, the strongest cellular response was obtained when the 3D geometry and the stretching was combined illustrating the need of these two stimuli to better mimic the intestinal in vivo conditions
Crowther, Grace. „Development and characterisation of an in vitro human gut model to study the biofilm mode of growth of Clostridium difficile and the indigenous gut microbiota“. Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5736/.
Der volle Inhalt der QuelleVERDILE, NICOLE. „MORPHOLOGICAL AND FUNCTIONAL CHARACTERIZATION OF THE RAINBOW TROUT GUT (ONCORHYNCHUS MYKISS) TO DEVELOP A PREDICTIVE IN VITRO INTESTINAL MODEL“. Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/928771.
Der volle Inhalt der QuelleTuohy, K. „Measurement of DNA transfer in the gut using in vitro and in vivo models“. Thesis, University of Surrey, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322465.
Der volle Inhalt der QuelleShah, Pranjul, Joëlle V. Fritz, Enrico Glaab, Mahesh S. Desai, Kacy Greenhalgh, Audrey Frachet, Magdalena Niegowska et al. „A microfluidics-based in vitro model of the gastrointestinal human–microbe interface“. NATURE PUBLISHING GROUP, 2016. http://hdl.handle.net/10150/614760.
Der volle Inhalt der QuelleVangala, Swathi. „Human Cytochrome P450 3A4 Over-Expressing IEC-18 and MDCK Cell Lines as an In-Vitro Model to Assess Gut Permeability and the Enzyme Metabolism“. Scholarly Commons, 2013. https://scholarlycommons.pacific.edu/uop_etds/273.
Der volle Inhalt der QuelleDeschamps, Charlotte. „Impact du poids corporel et d'une perturbation antibiotique sur le microbiote intestinal du chien : simulation in vitro et stratégies de restauration“. Electronic Thesis or Diss., Université Clermont Auvergne (2021-...), 2023. http://www.theses.fr/2023UCFA0055.
Der volle Inhalt der QuelleDifferent dog sizes are associated with variations in digestive physiology, mainly related to the large intestine and its resident microorganisms. This gut microbiota plays a key role in animal health, supporting nutritional, immunological and physiological processes. Nevertheless, diseases or antibiotherapy can disturb microbial equilibrium and induce a perturbated state called dysbiosis. To restore microbiota eubiosis, new restorations strategies have been developed such as pre-, pro- or postbiotics. However, very few studies have evaluated their effects on gut microbiota in the context of antibiotherapy. This joint PhD between the Microbiology, Digestive Environment and Health unit from Université Clermont Auvergne and the two compagnies Lallemand Animal Nutrition and Dômes Pharma, aimed to investigate the impact of body weight and antibiotic disturbance on canine colonic microbiota, as well as the potential of microbial restoration strategies, using in vitro gut models.This thesis started by evaluating the impact of different methods for faecal sample storage (48-h freezing -80°C, 48-h -80°C with glycerol or lyophilization with maltodextrin/trehalose) on the kinetics of microbiota colonization and metabolic activities in the Mucosal Artificial Colon (M-ARCOL). Compared to fresh stools, inoculating with raw frozen stool without cryoprotectant was the best option among those tested. Second, thanks to a large literature review, the M-ARCOL model was adapted to reproduce the main nutritional, physicochemical and microbial parameters specific from small, medium and large size conditions in a new model called Canine M-ARCOL (CANIM-ARCOL), further validated through in vitro-in vivo comparisons. This adaptation allowed to reproduce in vitro the increase in Bacteroidota and Firmicutes abundances and higher main short-chain fatty acid (SCFA) concentrations observed in vivo. Then, we used the CANIM-ARCOL to perform a mechanistic study, which revealed that nutritional and physicochemical parameters are enough to shape microbiota activity according to dog size, but faecal inoculum was necessary to reproduce size-related microbiota composition. The next step was to adapt the CANIM-ARCOL to diseased situation, focusing on antibiotic-induced dysbiosis. In accordance with in vivo data, antibiotherapy induced an increase in Enterobacteriaceae, Streptococcaceae and Lactobacillaceae relative abundances while alpha-diversity and SCFA production decreased. Similar but lower effects were observed in mucus-associated microbiota. Lastly, we evaluated the effect of the live probiotic yeast Saccharomyces boulardii CNCM I-1079 and the heat-inactivated bacteria Lactobacillus helveticus HA-122 on microbiota resistance during antibiotic treatment and resilience afterwards. Of interest, both microbial strategies decreased the Enterobacteriaceae bloom during antibiotherapy and allowed, in the first two days, a quicker recovery of microbiota composition and activity, in both the luminal and mucosal compartments.This PhD work provided pioneering and significant insights into the impact of dog size and antibiotherapy on canine colonic luminal and mucus-associated microbiota composition and activity, filling gaps in knowledge in these fields. This work also contributed to a better understanding of microbiota resilience in response to antibiotic disturbance. In a near future, in accordance with the European 3R's rules aiming to reduce at a maximum animal experiments, our in vitro approaches could be used for mechanistic studies on the interactions between nutrients, feed additives or veterinary products and canine colonic microbiota. Such experiments could be performed under healthy but also disturbed gut microbial situations (including obesity, inflammatory bowel diseases or chronic enteropathies), always considering interindividual variabilities to move towards personalized nutrition and medicine
MANCINO, ROBERTA. „Influence of cow diet on nutritional profile of milk and dairy products and effects on alterations of human gut microbiota by an in vitro digestion model“. Doctoral thesis, Università di Foggia, 2018. http://hdl.handle.net/11369/363264.
Der volle Inhalt der QuelleHealth-conscious consumers are demanding milk with higher proportions of healthy fatty acids as polyunsatured fatty acids (PUFA), and lower proportion of saturated fatty acids (SFA). Milk and dairy products contribute significantly to the consumption of essential nutrients in human populations. Despite its important roles in human nutrition, consumption of milk has declined, because nutritional guidelines have limited capita consumption of SFA, which to a significant proportion originate from milk and dairy products (USDA and HHS, 2010). A strategy to improve the FA profile of milk and dairy products is the supplementation of cow’s diet with oilseeds, which decrease the proportion of SFA, by decreasing de novo FA synthesis in the mammary gland. Feeding flaxseed to dairy cows decreases the concentrations of short-chain fatty acids and medium chain fatty acids and increases the long-chain fatty acid content in milk fat. However, oilseeds, and in particular flaxseed, have a very high costs that discourage farmers in their utilization. It’s necessary, therefore to find a compromise between costs and the right amount to be administered in the diet to the animals to ameliorate milk yield and composition. In Italy, about 80% of dairy farms produce milk of Friesian cows both for direct consumption and for cheese production. Jersey breed and it has been used to improve the efficiency of the cheesemaking sector in different part of the world, and is characterized by improved longevity, superior udder health, higher cheese yield, reduced feed and water requirement. The gastrointestinal tract constitutes the body’s largest interface with the external environment and is exposed to a vast amount of foreign material, including pathogenic and commensal bacteria, as well as food antigens. Oral tolerance is an important property of the gut immune system; intestinal homeostasis requires balanced interactions between the gut microbiota, dietary antigens. At birth, we are colonized with a complex community of microbes that reaches up to a density of 1 × 1012 bacterial cells per grams of content in the adult colon. These microbes live in a symbiotic relationship with the host and they are determinants in health and disease influencing nutrient absorption, barrier function and immune development. On the basis of the previous considerations and considering that oil seeds are expensive and many farmers are reluctant to use them the aims of this PhD thesis are: 1. trying to reduce the daily amount of flaxseed administered to animals in order to increase the content of polyunsaturated fatty acids in milk at the expense of saturated fatty acids, and to encourage its utilization by farmers as supplements to dairy cows with a reduction of management costs; 2. testing the effects of flaxseed administration on two different dairy cows breeds: Friesian and Jersey; 3. evaluating the transferring of polyunsaturated fatty acids in two different dairy products (Caciotta vs Caciocavallo) at different ripening time; 4. evaluating the effects of dairy products naturally enriched in polyunsaturated fatty acids on human health by an in vitro digestion model with the evaluation of changes in: a) fatty acid profile of dairy products after in vitro digestion; b) short chain fatty acids (SCFA) produced by gut microbiota; c) changes in gut microbiota populations by fecal fermentation followed by pyrosequencing. The higher milk content of C18:3n3 in milk suggests that the reduction in the amount of flaxseed supplementation can also improve milk fatty acid profile with a consistent reduction of production costs; however, Friesian and Jersey cows replied differently to the same flaxseed supplementation; Polyunsatured fatty acids are transferred into dairy products, especially in Caciotta cheese, suggesting that probably the different cheese making influenced the transferring. After in vitro digestion, fatty acids remain in the digest; their presence can have beneficial effects on the gastrointestinal tract and consequently on human health. Moreover the presence and the amount of short chain fatty acids (SCFA) could suggest some changes of microbiological populations that could have beneficial effects on human health.
Cordonnier, Charlotte. „Survie et pathogénicité des EHEC dans l'environnement digestif : Interactions avec le microbiote et l'épithélium intestinal. : Influence de l'administration de levures probiotiques“. Thesis, Clermont-Ferrand 1, 2015. http://www.theses.fr/2015CLF1MM21/document.
Der volle Inhalt der QuelleThe enterohemorrhagic Escherichia coli (EHEC) are major zoonotic pathogens responsible for food-borne infectionwhich leads to life-threatening complications in humans. The main virulence determinant of EHEC is the production of Shigatoxins (Stx), even if other factors seem to play an important role in virulence, such as adhesion factors. Survival and virulenceof EHEC strains in the human digestive environment are a key factor in bacterial pathogenesis but remains unclear owing tolack of relevant model. Moreover, no specific treatment has led to interest in preventative and / or curative alternatives, suchas using probiotics. The objective of this study is to better understand the behavior of the reference strain EHEC O157:H7EDL933 in the entire digestive tract, and in particular its interaction with the resident microbiota and the intestinal epithelium,and to evaluate the antagonistic effect of the probiotic yeast, Saccharomyces cerevisiae CNCM I-3856, using in vitro and in vivo complementary approaches.In vitro, bacterial mortality was noticed in the stomach, whereas bacterial growth resumption was observed in thedistal parts of the small intestine and the pathogen was not able to maintain in the human colonic conditions. Virulence genesencoding Stx and adhesins (intimin and “Long polar fimbriae”) are upregulated in the upper parts of the digestive tract. A ten-time higher amount of cells was found in the ileal effluents of infant compared to adult. stx genes were over-expressed (up to25-fold) in infant conditions compared to the adult ones. This results show that differences in digestive physicochemicalparameters of the upper gastrointestinal tract may partially explain why infants are more susceptible to EHEC infection thanadults. And finally, Lpf seem to play a key role in the interactions of EHEC with murine Peyer’s patches and are needed for anactive translocation of the pathogen across M cells, and both in vitro (M cells culture) and in vivo (murine ileal loops).S. cerevisiae had not effect on EHEC survival in the colonic environment but (i) favorably influenced gut microbiotaactivity through beneficial modulation of short chain fatty acid production, (ii) leading to significantly decrease stx expressionand (iii) significantly reduced EHEC translocation through M cells and inhibited in vivo interactions of the pathogen withPeyer’s patches and the associated hemorrhagic lesions. Probiotic had donor-dependent effect on the gut microbiota strengthenthe hypothesis that host-associated factors such as microbiota could influence the clinical evolution of EHEC infection and theeffectiveness of a probiotic strategy.This work contributes to a better understanding of the behavior of EHEC in the human digestive environment andconfirms the interest of probiotic strategy in controlling EHEC infections. Further transcriptome studies are warranted for thepathogen in the human digestive environment, with or without probiotics for the better understanding of the pathophysiologyof EHEC and so on the mechanisms involved in the antagonistic effect of probiotics
Müller, Jakob Verfasser], Heinrich H. D. [Akademischer Betreuer] [Meyer, Michael W. [Akademischer Betreuer] Pfaffl und Andrea K. [Akademischer Betreuer] Büttner. „Secondary plant metabolites and gut health: functional studies on porcine small intestine in vitro models / Jakob Müller. Gutachter: Michael W. Pfaffl ; Andrea K. Büttner. Betreuer: Heinrich H. D. Meyer“. München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1030099545/34.
Der volle Inhalt der QuelleLi, Yingchuan. „A SUSY SO(10) GUT model with lopsided structure“. College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6703.
Der volle Inhalt der QuelleThesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Kuwahara, M., T. Ogaeri, R. Matsuura, H. Kogo, T. Fujimoto, S. Torihashi und 茂子 鳥橋. „In vitro organogenesis of gut-like structures from mouse embryonic stem cells“. Blackwell, 2004. http://hdl.handle.net/2237/7446.
Der volle Inhalt der QuelleJaiyeola, Etana Joy. „Gut microbiota in human type 2 diabetes : in-vivo and in-vitro studies“. Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/844975/.
Der volle Inhalt der QuelleAgans, Richard Thomas. „Modeling Effects of Diet on Human Gut Microbiota“. Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1472128769.
Der volle Inhalt der QuelleJiang, Lei. „On human gut microbial ecosystem : in vitro experiment, in vivo study and mathematical modelling“. Thesis, Swansea University, 2013. https://cronfa.swan.ac.uk/Record/cronfa42214.
Der volle Inhalt der QuelleNistor, Nicolae, und Monika Schustek. „Wie gut sind die guten alten FAQs?“ Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-76312.
Der volle Inhalt der QuelleHand, K. V. „Studies investigating in vitro nutrient stimulated secretion of gut satiety signals and potential mechanisms of release“. Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546355.
Der volle Inhalt der QuelleFIORE, WALTER. „OVERALL ASSESSMENT OF A MODEL PROBIOTIC BACTERIUM: FROM GUT COLONIZATION TO CLINICAL EFFICACY“. Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/737193.
Der volle Inhalt der QuelleJoesten, William C. „Exploring the relationships between gut bacteria, gut permeability, and bacterial metabolism in the Non Obese Diabetic (NOD) mouse model of Type 1 Diabetes (T1D)“. Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1574423689823958.
Der volle Inhalt der QuelleWang, Xuedan. „Effect of inulin type fructans on protein fermentation by gut bacteria : in vitro and in vivo studies“. Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/79980/.
Der volle Inhalt der QuellePoh, Zijie. „Model Building in the LHC Era: Vector-like Leptons and SUSY GUTs“. The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1502809360161742.
Der volle Inhalt der QuelleKelsall, Ashlie Peta. „Studies on optimising the everted gut sac model (EGSM) in rat and possum tissue to compare selective drug movement across the intestinal wall“. Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14578.
Der volle Inhalt der QuelleChohan, M. B. N. „The impact of digestion and gut bioavailability, in vitro, on the polyphenolic associated activity of cooked culinary herbs“. Thesis, Kingston University, 2011. http://eprints.kingston.ac.uk/22530/.
Der volle Inhalt der QuelleHolt, Marie Kragelund Bachmann. „In vitro and in vivo properties of GLP-1 producing neurons : the brain actions of a gut hormone“. Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/10039312/.
Der volle Inhalt der QuelleChase, Teena D. „An in vitro model of reactive astrogliosis“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ49329.pdf.
Der volle Inhalt der QuelleWorrall, Lisa Kirsty. „A 3D in vitro breast cancer model“. Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436812.
Der volle Inhalt der QuelleMistry, Rupal. „Host-gut microbiota interaction in health and disease using Drosophila melanogaster as a model organism“. Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c5add9af-9abf-4664-8c62-4b462c35e2c2.
Der volle Inhalt der QuelleFois, Chiara Anna Maria. „A Gut-on-a-chip Model for Testing the Anti-inflammatory Effects of Active Compounds“. Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25967.
Der volle Inhalt der QuelleEisa, Osama Eltayeb Idris. „Modulators of innate gut immunity to enteric viral infections : murine norovirus (MNV) as a model“. Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271239.
Der volle Inhalt der QuelleDjamiatun, Kis. „In vitro studies on induction of lymphocyte and cytokine responses to the gut protozoans Giardia lamblia and Giardia muris“. Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23882.
Der volle Inhalt der QuelleSaxton, Katie. „Development and mechanisms of fluoroquinolene resitance in epidemic clostridium difficile strians in a human gut model“. Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511177.
Der volle Inhalt der QuelleGoggans, Mallory. „Elucidating Tomato Steroidal Glycoalkaloid Metabolism and Effects of Consumption onthe Gut Microbiome in a Pig Model“. The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594824484770731.
Der volle Inhalt der QuelleRich, Barbara Sharon. „Development of an in vitro model for accommodation“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28982.pdf.
Der volle Inhalt der QuelleAldsworth, Timothy Grant. „Microbial in vitro model of root surface caries“. Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360285.
Der volle Inhalt der QuelleOhene-Abuakwa, Yaw. „In vitro erythroid model for diamond blackfan anaemia“. Thesis, St George's, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420364.
Der volle Inhalt der QuelleOwen, Robert. „Tissue engineering an in vitro model of osteoporosis“. Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19265/.
Der volle Inhalt der QuelleDavern, Jordan W. „Development of a bioengineered microvascular in vitro model“. Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/201653/1/Jordan_Davern_Thesis.pdf.
Der volle Inhalt der QuelleRebelo, Sandra da Silva. „Desenvolvimento de um modelo in vitro para avaliação de um biogel antimicrobiano com potencial para o controlo da doença periodontal canina“. Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2020. http://hdl.handle.net/10400.5/20210.
Der volle Inhalt der QuelleA doença periodontal (DP) é uma das doenças mais frequentes na espécie canina, afetando cerca de 80-85% destes animais. Esta doença, de etiologia multifatorial, inicia-se com o desenvolvimento, na superfície do dente, de placa bacteriana, um biofilme composto maioritariamente por bactérias contidas numa matriz de polissacáridos extracelulares, com o potencial de inibir a ação antimicrobiana e as defesas naturais do hospedeiro. Os processos de agregação bacteriana constituem um fenómeno bastante importante na formação de biofilme ao contribuir para a interação bacteriana durante a evolução da DP. O principal objetivo do controlo da DP é controlar a formação da placa bacteriana. Estudos realizados com isolados de Enterococcus faecalis, obtidos a partir de amostras da cavidade oral canina, demonstraram atividade antimicrobiana de um gel de goma de guar suplementado com nisina (biogel de nisina) contra esta espécie bacteriana, demonstrando a sua potencial eficácia para o controlo da DP canina. Este estudo teve como objetivos o desenvolvimento de um modelo de biofilme polimicrobiano in vitro, que seja representativo da placa bacteriana presente na cavidade oral canina, e a avaliação do potencial inibitório e de erradicação do biogel de nisina relativamente ao biofilme polimicrobiano estabelecido. As espécies bacterianas incluídas foram: Porphyromonas cangingivalis, Neisseria zoodegmatis, Corynebacterium canis, Peptostreptococcus canis e E. faecalis. Durante a primeira fase deste projeto, foi avaliada a capacidade de agregação entre os cinco isolados bacterianos. Todos os isolados demonstraram capacidade de agregação, revelando o seu potencial para a formação de biofilmes polimicrobianos. De seguida, promoveu-se a formação de um biofilme polimicrobiano constituído pelas cinco espécies bacterianas em estudo. A presença das espécies bacterianas no biofilme estabelecido in vitro foi confirmada através da sua observação direta ao microscópio de fluorescência após aplicação da técnica de “Fluorescent In Situ Hybridization”. Os resultados da avaliação do potencial inibitório e de erradicação do biogel de nisina revelaram um valor de concentração mínima inibitória de biofilme de 25 μg/mL e um valor de concentração mínima de erradicação de biofilme superior a 100 μg/mL. Ambos os valores correspondem a concentrações de nisina abaixo do limite da dose diária aceitável definida pela Organização Mundial de Saúde, que corresponde a 0 – 2 mg/Kg. Este estudo demonstrou mais uma vez a eficácia do biogel de nisina para a inibição de biofilmes polmicrobianos confirmando o potencial para a sua utilização no controlo da DP canina.
ABSTRACT - Development of an in vitro model for the evaluation of an antimicrobial biogel with potential for the control of canine periodontal disease - Periodontal disease (PD) is one of the most common diseases in dogs, affecting around 80 to 85% of the canine population. It refers to a group of conditions caused by the development of a dental plaque in the tooth surface. The dental plaque is characterized by a microbial biofilm formed by a multi-species community of microorganisms enclosed in a self-producing extracellular matrix, which protects bacteria from the host immune system and reduces the action of antimicrobial therapy. It is a well-known fact that aggregation is a specific process that plays an important role in the bacterial interactions during biofilm formation. This process contributes to the changes on bacterial composition of the biofilm during the progression of PD. Periodontal therapy aims to control the formation of bacterial plaque. Previous studies have demonstrated that, when incorporated within a guar-gum biogel (nisin-biogel), antimicrobial peptide nisin can inhibit and eradicate mono-species biofilms formed by canine oral enterococci, rendering it a potential agent for PD control. The main objectives of this project were to establish a five-species biofilm model aiming to simulate dental biofilms from dogs with PD and to use the established model to evaluate the inhibitory potential of the nisin-biogel, previously developed by our research team. The bacterial species included were: Porphyromonas cangingivalis, Neisseria zoodegmatis, Corynebacterium canis, Peptostreptococcus canis and Enterococcus faecalis. During the first task, aggregation rates between all the isolates were calculated two by two and individually. All the isolates showed aggregation ability after either a 2h or 24h incubation, showing their potential to form multi-species biofilms. Later, a five-species biofilm model was successfully established and the presence of the five bacterial species was confirmed by Fluorescent In Situ Hybridization using specific probes. The susceptibility of the multi-species biofilm to the nisin-biogel was evaluated by determination of the Minimum Biofilm Inhibitory Concentration (MBIC) and of the Minimum Biofilm Eradication Concentration (MBEC). The nisin-biogel presented inhibitory activity against the polymicrobial biofilm, with a MBIC value of 25 μg/mL and a MBEC value > 100 μg/mL, both corresponding to nisin dosages lower than the acceptable daily intake, 0 – 2 mg/Kg, set by the World Health Organization. This study demonstrated that the nisin-biogel developed by our research team can inhibit the formation of multi-species biofilms, reinforcing its potential to control canine PD.
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Farran, B. „Developing a recombinant model of the P2Y1 and P2Y11 receptor interactions mediating relaxation in gut smooth muscle“. Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1464076/.
Der volle Inhalt der QuelleHoffman, Jared D. „THE PREBIOTIC INULIN BENEFICIALLY MODULATES THE GUT-BRAIN AXIS BY ENHANCING METABOLISM IN AN APOE4 MOUSE MODEL“. UKnowledge, 2018. https://uknowledge.uky.edu/pharmacol_etds/24.
Der volle Inhalt der QuelleMangwana, Noluxabiso. „The in vitro faecal evaluation of prebiotic effects of rooibos phenolic compounds on the gut microbiota of vervet monkeys (Chlorocebus pygerythrus)“. Thesis, Cape Peninsula University of Technology, 2020. http://hdl.handle.net/20.500.11838/3109.
Der volle Inhalt der QuelleBackground: The development of metabolic disease is accompanied by changes in gut microbiota phenotype, including a decrease of beneficial bacteria and increase of pernicious bacteria of the gastrointestinal tract. A Western (high-fat and high-sugar) diet, sedentary lifestyle and altered gut microbiota diversity have been associated with an increased risk of developing metabolic diseases such as type 2 diabetes and its associated risk factor, obesity. Many researchers have studied the link between the gut microbiota and diet. Hence our in vitro study is aimed at investigating the potential prebiotic effect of an aspalathin-rich unfermented rooibos extract, Afriplex GRT™ and aspalathin on the faecal bacterial diversity of vervet monkeys fed Western diet. Methodology: A total of six vervet monkeys (Chlorocebus pygerythrus) were selected from monkeys fed either a maize based normal diet (standard diet group; n=3) or a high fat diet (Western diet group; n=3) for more than 5-years. Faecal samples were collected from the animals in both groups at the Primate Unit and Delft Animal Centre (PUDAC) between 7 – 9 AM. Faecal samples from the two groups were divided into culture-independent baseline samples (before culture) and culture-dependent samples (after anaerobic culture). The culture-dependent samples were cultured under anaerobic conditions at 37°C for 10 hours, with or without Afriplex GRT™ extract or aspalathin. Bacterial genomic DNA (gDNA) was extracted from all samples using the NucleoSpin® DNA Stool extraction kit. Purified gDNA was sent for metagenomic sequencing for 16S rRNA gene analysis of microbial diversity using an Ion Torrent Next-generation Sequencing platform. Results: Results indicated that the Western diet affects the abundance of several bacterial species. Afriplex GRT™ and aspalathin significantly enhanced the relative abundance of health promoting butyrate-producing bacteria such as Faecalibacterium prausnitzii in both standard and Western diet groups (p= 0.02 and p=0.04, respectively). A similar trend was observed in other beneficial bacteria such as Eubacterium spp., Sutterella spp., and Dorea longicatena. Conclusion: Based on the data observed, it can be suggested that Afriplex GRT™ has a beneficial prebiotic effect on gut microbiota diversity and gut health.
Ogue, Bon Eva. „In vitro investigations of the effects of dietary fibres and prebiotics on probiotic growth, antimicrobial activity and the canine gut microbiota“. Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511667.
Der volle Inhalt der QuelleTRETOLA, MARCO. „FORMER FOODSTUFFS PRODUCTS INTENDED FOR PIG NUTRITION: IN VITRO AND IN VIVO NUTRITIONAL EVALUATION, IMPACT ON GROWTH PERFORMANCES AND GUT HEALTH“. Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/609808.
Der volle Inhalt der QuelleLivestock play a key role in food security, through food provision, agricultural production, and by providing employment and income. However, with the diminishing availability of farmland, climate change and the threat of declining water resources, the goal is to meet the growing demand for food and feed by using fewer resources. Exploiting alternative ingredients for livestock, feed could be one way of increasing livestock sustainability. This thesis focused on processed and ready-to-eat food products that are no longer suitable for human consumption due to logistical, manufacturing or packaging defects. Such products would normally go to a landfill yet actually have a high potential of being used as sustainable feed ingredients. The first part of this thesis investigated the chemical composition of six different former foodstuff products (FFPs). Based on the FFP composition data, the digestible energy and metabolisable energy values for pigs were estimated. In addition, the in vitro digestibility values of FFPs were evaluated using a multi-step enzymatic technique. The in vitro predicted glycaemic index and hydrolysis index of the same samples were examined using a two-step in vitro digestion assay. In the second part, the safety issues linked to the use of FFPs were investigated. FFP samples were thus analysed in relation to the microbial load and the presence of presumed remnants of packaging materials. For this purpose, two different methods were used: stereomicroscopy, according to published methods; and stereomicroscopy coupled with a computer vision system. The final part addressed the effects of a diet in which common cereal grains were partially replaced by FFPs in post weaning piglet diets. Specifically, pig growth performance and selected plasma biochemical variables were evaluated in twelve post-weaning piglets. The apparent total tract digestibility of dry matter and the faecal microbiota were also characterized. When compared with common cereal grains used in pig feed formulations, FFPs can be considered a fortified version of cereals, with comparable in vitro digestibility values and with higher glycaemic and hydrolysis indexes, thus characterizing them as an excellent source of carbohydrates. All FFP samples were safe from a microbiological point of view, showing a limited microbial load and were always Salmonella free. Regarding the presumed remnants of packaging materials, the contamination level was always below the safety threshold set by German authorities, and the validated method demonstrated that packaging remnants were mainly from the 1-mm sieve mesh fraction. In order to find a more rapid and objective method for evaluating the packaging remnants, the innovative computer vision system was a rapid alternative for the detection of packaging remnants in ex-food samples when combined with a stereomicroscope. The in vivo study revealed that both in vitro and in vivo digestibility values were higher for the diet based on FFPs compared to the control diet. At the end of the experiment, no differences in growth performance were observed, however the plasma glucose increased in piglets fed FFPs compared to piglets fed the control diet, while the urea concentration decreased. The sequencing analysis of the variable regions V3 and V4 of the 16S rRNA gene showed that the use of FFPs in the post-weaning period decreased the bacterial richness and evenness in the large intestine. The unweighted beta diversity analysis also resulted in a statistically significant difference between the two groups in terms of the taxa composition. The linear discriminant analysis of effect size also demonstrated an increased amount of Proteobacteria phylum and a decreased amount of Lactobacillales genus in the FFP compared to the control group. The results highlighted the potential of these alternative feed ingredients and their safe use in pig nutrition. This is essential for establishing the best scientific practices for the use of FFPs in animal nutrition and feeding. Given the increasing need to obtain a more sustainable livestock sector, research in animal sciences should focus not only on increasing the efficiency of the animal production chain but also on the efficiency of the entire food system in ensuring sustainable nutrition. By recognizing that former foodstuffs that are not suitable for human consumption are a resource for animal nutrition and not a waste product, food and feed industries could reduce the amount of waste sent to landfill or deposed-off every year, thus saving costs, and reducing the environmental impact of the food production chain.
Patient, J. D. „Development of an in-vitro epithelial-myofibroblast intestinal model“. Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33617/.
Der volle Inhalt der QuelleHung, Chao-Chun. „In Vitro Model Systems of a-Synuclein Over-Expression“. Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485237.
Der volle Inhalt der QuelleTurner, Andrew. „Vitamin D metabolism in an In Vitro mineralisation model /“. Title page and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09SB/09sbt9438.pdf.
Der volle Inhalt der QuelleSung, Hsing-Wen. „In vitro velocity measurements in a pulmonary artery model“. Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/13388.
Der volle Inhalt der QuelleTretiak, Tania. „A bovine in vitro model of human cerebral vasospasm“. Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22819.
Der volle Inhalt der QuelleThis project was designed to examine the effects of oxyhemoglobin on the vascular tone of the middle and basilar cerebral arteries in vitro and to evaluate the validity of using bovine vessels as an animal model of the human cerebral vasculature in which to study cerebral vasospasm. Human vessels were studied in parallel with the bovine arteries to test the validity of the animal model. To further evaluate the model, some experiments were also carried out on canine vessels, because the dog has frequently been used for cerebrovascular studies in the past.
The cow is a better model of the human cerebral vasculature than the dog. Arteries respond to a variety of vasoactive stimuli, in a manner closely resembling human vessels, and can be induced into a prolonged vasospastic state by exposure to oxyhemoglobin. Vasospasm in all three species was independent of endothelial status, functional innervation, or morphological evidence of atherosclerosis. Vasospasm could not be prevented by diltiazem, nicardipine or ascorbic acid, but was partially reversed in some samples by verapamil. Bovine vessels would appear to be exceptionally useful for studies designed to test pharmacological agents for the prevention or therapy of post-hemorrhagic vasospasm and also to determine the pathophysiological mechanisms involved.