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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Binding mechanism of K88ab pili produced by enterotoxigenic Escherichia coli

Choi, Suk Ho January 1987 (has links)
Binding of K88ab pili by brush border membrane and mucus from pig small intestine was characterized by inhibition assay and Western blot. In Western blot, K88ab pili were bound by two major brush border membrane polypeptides with molecular weight of 61,500 and 57,000 in addition to numerous minor polypeptides and a major mucus polypeptide with molecular weight of 27,500. The results from Western blot assays with periodate oxidized and carbamylated brush border membrane and inhibition assay with brush border membrane glycopeptide suggest that amino groups (rather than carbohydrate) present on the protein moiety are a part of the recognition site for K88ab pili of receptor polypeptides in brush border membrane. Differences were obtained in the binding patterns of K88ab pili when brush border membranes were prepared from small intestines obtained from 2-, 21-, and 42-day-old piglets as well as adult hogs. Binding of K88ab pili by mucus polypeptides was greater when prepared from small intestines obtained from 2-day-old piglets than from piglets of other ages and adult hogs. In inhibition assay, most fractions from sow milk and colostrum inhibited binding of K88ab pili. After gel filtration of colostral whey, fractions which contained IgG, IgA, and IgM produced the strongest inhibition of K88ab binding. Among fractions prepared from cow milk, casein and skim milk significantly inhibited binding of K88ab pili. In Western blot, α<sub>s1</sub>-casein, immunoglobulin chains, and MFGM polypeptides in sow milk and colostrum were shown to be able to bind K88ab pili. Additionally, α<sub>s1</sub>-casein was the major protein in bovine milk responsible for binding K88ab pili. In dot blot assay, IgG as well as brush border membrane could strongly bind K88ab pili. However, bovine α<sub>s1</sub>-casein showed only weak binding of K88ab pili. Binding of K88ab pili to these proteins and brush border membrane was inhibited by carbamylation and by addition of 100 mM D-galactosamine. The results suggest that the K88ab-binding proteins in milk and colostrum compete to bind K88ab pili with the receptors in the brush border membrane and that mechanisms involved in binding of K88ab pili by these proteins is similar to that by brush border membrane. / Ph. D.
12

The development in mice of local intestinal immunity to enterobactericeae / Vichai Marneerushapisal

Marneerushapisal, Vichai January 1984 (has links)
Some ill. mounted / Bibliography: leaves 109-129 / xiii, 129, [ca. 60] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1984
13

Probiotics and prebiotics as a therapeutic strategy for inflammatory bowel disease.

Geier, Mark Steven January 2007 (has links)
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The primary aim of this thesis was to identify probiotics and/or prebiotics with the potential to reduce the severity of experimental colitis. The specific aims were to i) screen a range of candidate pro biotic strains for capacity to reduce symptoms of DSS-colitis, ii) characterize the effects of DSS within the small intestine, iii) assess, in vitro, the effect of probiotics on intestinal epithelial cell integrity, iv) assess the potential for the prebiotic, fructooligosaccharide, to reduce the severity of DSS-colitis alone, and in synbiotic combination with a probiotic strain. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280844 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Sciences, 2007
14

Probiotics and prebiotics as a therapeutic strategy for inflammatory bowel disease.

Geier, Mark Steven January 2007 (has links)
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The primary aim of this thesis was to identify probiotics and/or prebiotics with the potential to reduce the severity of experimental colitis. The specific aims were to i) screen a range of candidate pro biotic strains for capacity to reduce symptoms of DSS-colitis, ii) characterize the effects of DSS within the small intestine, iii) assess, in vitro, the effect of probiotics on intestinal epithelial cell integrity, iv) assess the potential for the prebiotic, fructooligosaccharide, to reduce the severity of DSS-colitis alone, and in synbiotic combination with a probiotic strain. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280844 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Sciences, 2007
15

La flore commensale bactérienne de l'enfant: impact et prévention /cpar Sarah Jourdain

Jourdain, Sarah January 2012 (has links)
Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished
16

Dietary modulation of the human colonic microbiota through plant-derived prebiotic compounds

Kassim, Muhammad Arshad January 2007 (has links)
Thesis (M.Tech.: Biotechnology)- Dept. of Biotechnology, Durban University of Technology, 2007 xv, 127 leaves / The human gut microbiota play a major role in host health, and attempts are being made to manipulate the composition of the gut microbiota-increase the composition of bacterial groups, such as lactobacilli and bifidobacteria that are perceived as exerting health promoting properties. These bacteria defined as food supplements (probiotics) beneficially affect the host by improving the intestinal microbial balance, and have been used to change the composition of the colonic microbiota. However, such changes may be transient, and the implantation of exogenous bacteria therefore becomes limited. In contrast, prebiotics are naturally occurring carbohydrates that are classified as non-digestible oligosaccharides present in edible plants. These carbohydrates enter the colon as intact compounds, elicit systemic physiological functions and act as fermentable substrates for colonic microflora-influencing the species composition and metabolic characteristics of intestinal microflora providing important health attributes. Currently, a widely marketed prebiotic, inulin is extracted from plants of the family Asteraceae. There are many unexploited plants that are regularly consumed and that may have a prebiotic effect or can have very high levels of inulin which could make them commercially viable. In this study, we investigated prebiotic compounds, especially inulin from locally growing, non-commercialised leafy plants. The aqueous extracts of 22 plants from the families Asparagaceae, Alliaceae, Asteraceae, Solanaceae, Cucurbitaceae, Amaranthaceae, Acanthaceae, Polygonaceae, Portulaceae, Fabaceae, Chenopodiaceae, Pedaliaceae and Apiaceae from Kwa-Zulu Natal were investigated for a prebiotic effect using a modified batch-culture technique with Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus reuteri and Bifidobacterium longum, four common probiotics and the inulin content of the plants was determined using high performance liquid chromatography. Of the 22 plants studied, Solanum nigrum, Amaranthus spinosus, Amaranthus hybridus, Asystasia gangetica, Senna occidentalis, Cerathoteca triloba, Asparagus sprengeri, Tulbaghia violacea, Sonchus oleraceus and Taraxacum officinale exhibited a prebiotic effect. The prebiotic effect of the Taraxacum officinale, Sonchus oleraceus and Asparagus sprengeri extracts on L. lactis and L. reuteri was higher than or equivalent to inulin-a commercial prebiotic. In this study, Sonchus oleraceus exhibited the best prebiotic effect-was the only plant to stimulate all the probiotics including B. longum. Of all the plants analysed, Asparagus sprengeri tuber contained the highest amount of inulin (3.55%).
17

Dietary modulation of the human colonic microbiota through plant-derived prebiotic compounds

Kassim, Muhammad Arshad January 2007 (has links)
Thesis (M.Tech.: Biotechnology)- Dept. of Biotechnology, Durban University of Technology, 2007 xv, 127 leaves / The human gut microbiota play a major role in host health, and attempts are being made to manipulate the composition of the gut microbiota-increase the composition of bacterial groups, such as lactobacilli and bifidobacteria that are perceived as exerting health promoting properties. These bacteria defined as food supplements (probiotics) beneficially affect the host by improving the intestinal microbial balance, and have been used to change the composition of the colonic microbiota. However, such changes may be transient, and the implantation of exogenous bacteria therefore becomes limited. In contrast, prebiotics are naturally occurring carbohydrates that are classified as non-digestible oligosaccharides present in edible plants. These carbohydrates enter the colon as intact compounds, elicit systemic physiological functions and act as fermentable substrates for colonic microflora-influencing the species composition and metabolic characteristics of intestinal microflora providing important health attributes. Currently, a widely marketed prebiotic, inulin is extracted from plants of the family Asteraceae. There are many unexploited plants that are regularly consumed and that may have a prebiotic effect or can have very high levels of inulin which could make them commercially viable. In this study, we investigated prebiotic compounds, especially inulin from locally growing, non-commercialised leafy plants. The aqueous extracts of 22 plants from the families Asparagaceae, Alliaceae, Asteraceae, Solanaceae, Cucurbitaceae, Amaranthaceae, Acanthaceae, Polygonaceae, Portulaceae, Fabaceae, Chenopodiaceae, Pedaliaceae and Apiaceae from Kwa-Zulu Natal were investigated for a prebiotic effect using a modified batch-culture technique with Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus reuteri and Bifidobacterium longum, four common probiotics and the inulin content of the plants was determined using high performance liquid chromatography. Of the 22 plants studied, Solanum nigrum, Amaranthus spinosus, Amaranthus hybridus, Asystasia gangetica, Senna occidentalis, Cerathoteca triloba, Asparagus sprengeri, Tulbaghia violacea, Sonchus oleraceus and Taraxacum officinale exhibited a prebiotic effect. The prebiotic effect of the Taraxacum officinale, Sonchus oleraceus and Asparagus sprengeri extracts on L. lactis and L. reuteri was higher than or equivalent to inulin-a commercial prebiotic. In this study, Sonchus oleraceus exhibited the best prebiotic effect-was the only plant to stimulate all the probiotics including B. longum. Of all the plants analysed, Asparagus sprengeri tuber contained the highest amount of inulin (3.55%).
18

Probióticos e simbiótico sobre o desempenho zootécnico e morfometria intestinal de frangos de corte desafiados com Salmonella Enteritidis / Probiotics and synbiotic about performance and intestinal morphometry of broilers challenged with Salmonella Enteritidis

Santos, José Rodolfo dos 20 February 2013 (has links)
No Brasil, nas últimas décadas uma das grandes preocupações são as toxinfecções alimentares, sendo que uma das mais preocupantes vem a estar relacionada com as salmonellas. Esta doença destaca-se com grande importância pela sua ampla e variada ocorrência no homem e em animais; em que as aves ocupam o ponto central na epidemiologia das Salmonellas entéricas, representando um reservatório de grande importância sanitária e difícil controle. A Salmonella Enteritidis que é um patógeno entérico pertencente à família Enterobateriaceae, vindo a ser entre os mais de 2.500 sorotipos de Salmonellas spp., uma das mais frequentes de origem alimentar descrita na literatura. Uma das medidas profiláticas que tem sido empregada para controlar a infecção desta doença na produção de aves inclui o uso de antibióticos, seleções genéticas de linhagens de frangos para melhor resposta imunológica, desenvolvimento de vacinas e uso de produtos probióticos por meio de inclusão competitiva. A principal preocupação com o uso contínuo de antibióticos, principalmente pelas diversas organizações mundiais, é quanto ao surgimento e disseminação de populações bacterianas patogênicas, que trazem riscos tanto para a saúde animal quanto humana. Procurando alternativas que garantam o desempenho produtivo e a segurança alimentar dos consumidores, temos os probióticos que são suplementos alimentares, normalmente presentes no trato gastrointestinal (ex.: Bacillus subtilis e Bacillus licheniformis). Quando administrados de forma correta produzem efeitos benéficos ao hospedeiro, favorecendo o equilíbrio de sua microbiótica intestinal, podendo ser constituídos por microorganismos de culturas definidas, indefinidas ou simbióticos. Contudo não dispomos de estudos que possam comprovar qual das constituições de probióticos é a mais eficaz no combate as salmonellas entéricas e na melhor obtenção do desempenho zootécnico, o que requer maiores estudos em relação as diferentes constituições de probióticos disponíveis e suas formas de utilização. O objetivo do presente estudo foi abordar por meio de uma revisão bibliográfica a utilização de probióticos e simbióticos como auxiliares na qualidade intestinal e ferramenta no combate a salmonella. Um segundo objetivo é elaborar um capítulo com um artigo intitulado: “Probióticos e Simbiótico sobre o desempenho zootécnico e morfometria intestinal de frangos de corte desafiados com Salmonella Enteritidis”. / In Brazil, in the last decades a of great concerns have been about the food poisoning, being that a of the most worrying comes to be related with the Salmonella. This disease stands out with great importance for its wide and varied occurrence in the man and animals; in which birds occupy the central point the epidemiology of Salmonella Enteric, representing a reservoir of great importance health and difficult to control. Salmonella Enteritidis is a pathogen belonging to the family intérico Enterobateriaceae, it comes to be among the more than 2,500 serotypes Salmonellas sp., one of the most common foodborne described in the literature. An prophylactic measures that is has been used to control the infection of the disease in poultry production, including antibiotics, selection of genetic strains of chickens to better immune response, development of the vaccine and use of probiotic products by inclusion competitive. The main concern with the continuous use of antibiotics, especially by various organizations worldwide is on the emergence and spread of pathogenic bacterial populations, bringing risks to both animal and human health. Seeking alternatives to ensure the production performance and food safety for consumers, we probiotcs foods supplements that are normally present in the gastrointestinal tract (ex.: Bacillus Subtilis e Bacillus Licheniformis), when they are administered correctly produce beneficial effects to the host, favoring the balance of their intestinal microbiota, may consist of microorganisms defined, undefined or synbiotics culture. However we do not have studies to prove which of the constitutions of probiotics is most effective in combating the Salmonella Enteric and in obtaining the best zootechinical performance, which requires larger studies regarding the different constitutions of probiotics available and ways of use. The aim of this study was approach by means of a bibliographic review the use of probiotics and synbiotics acting as auxiliary tool in combating intestinal Salmonella. A second goal is to develop a chapter with an article entitled: "Probiotics and synbiotic about zootechinical performance and intestinal morphometry of broilers challenged with Salmonella Enteritidis."
19

The Effects of Air Pollution on the Intestinal Microbiota: A Novel Approach to Assess How Gut Microbe Interactions with the Environment Affect Human Health

Fitch, Megan N. 05 1900 (has links)
This thesis investigates how air pollution, both natural and anthropogenic, affects changes in the proximal small intestine and ileum microbiota profile, as well as intestinal barrier integrity, histological changes, and inflammation. APO-E KO mice on a high fat diet were randomly selected to be exposed by whole body inhalation to either wood smoke (WS) or mixed vehicular exhaust (MVE), with filtered air (FA) acting as the control. Intestinal integrity and histology were assessed by observing expression of well- known structural components tight junction proteins (TJPs), matrix metallopeptidase-9 (MMP-9), and gel-forming mucin (MUC2), as well known inflammatory related factors: TNF-α, IL-1β, and toll-like receptor (TLR)-4. Bacterial profiling was done using DNA analysis of microbiota within the ileum, utilizing 16S metagenomics sequencing (Illumina miSeq) technique. Overall results of this experiment suggest that air pollution, both anthropogenic and natural, cause a breach in the intestinal barrier with an increase in inflammatory factors and a decrease in beneficial bacteria. This evidence suggests the possibility of air pollution being a potential causative agent of intestinal disease as well as a possible contributing mechanism for induction of systemic inflammation.

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