No description available.

No description available.

Wong King Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 117-131). / Abstracts in English and Chinese. / Committee Memebers --- p.i / Acknowledgement --- p.ii / Abstract --- p.iii / 摘要 --- p.vi / List of Tables --- p.viii / List of Figures --- p.xiii / Abbreviations --- p.xv / Content --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Colonic fermentation --- p.1 / Chapter 1.1.1 --- The large intestine and the intestinal microflora --- p.1 / Chapter 1.1.2 --- Major substrates and products of colonic fermentation --- p.2 / Chapter 1.1.3 --- Beneficial bacteria --- p.6 / Chapter 1.2 --- Prebiotics --- p.7 / Chapter 1.2.1 --- Definitions of probiotics and prebiotics --- p.7 / Chapter 1.2.2 --- General characteristics of prebiotics --- p.8 / Chapter 1.2.3 --- Current studies on prebiotics --- p.9 / Chapter 1.2.3.1 --- Non-β3-glucan typed prebiotics --- p.9 / Chapter 1.2.3.2 --- β-glucan type prebiotics --- p.11 / Chapter 1.3 --- Potential β-glucan type prebiotics --- p.12 / Chapter 1.3.1 --- Commercial sources of β (l→3) glucans as potential prebiotics --- p.12 / Chapter 1.3.1.1 --- Pachyman (PAC) and carboxymethylated-pachyman (CM-PAC)… --- p.13 / Chapter 1.3.1.2 --- Curdlan (CUR) and carboxymethylated curdlan (CM-CUR) --- p.13 / Chapter 1.3.1.3 --- Laminarian (LAM) --- p.14 / Chapter 1.3.2 --- Non-digestible carbohydrates (NDC) from mushroom --- p.14 / Chapter 1.3.2.1 --- Mushroom sclerotia as a good source of β-glucan --- p.14 / Chapter 1.3.2.2 --- Poria cocos (PC) sclerotia --- p.15 / Chapter 1.3.2.3 --- Oligosaccharide preparation from PC sclerotium --- p.16 / Chapter 1.4 --- Microbial analysis by molecular methods --- p.19 / Chapter 1.4.1 --- Traditional cultural techniques --- p.19 / Chapter 1.4.2 --- Newly emerging molecular techniques --- p.23 / Chapter 1.5 --- Objectives and significance of the present study --- p.27 / Chapter Chapter 2 --- Materials and Methods --- p.28 / Chapter 2.1 --- Materials --- p.28 / Chapter 2.1.1 --- Commercial β-glucans --- p.28 / Chapter 2.1.2 --- β-glucan from Poria cocos sclerotium --- p.28 / Chapter 2.2 --- Chemical characterization of Poria cocos sclerotium --- p.30 / Chapter 2.2.1 --- Lowry method for soluble protein determination --- p.30 / Chapter 2.2.1.1 --- Reagents --- p.30 / Chapter 2.2.1.2 --- Determination of soluble protein content --- p.30 / Chapter 2.2.2 --- Total sugar content analysis (Phenol-sulphuric acid method) --- p.31 / Chapter 2.2.3 --- Total dietary fiber analysis --- p.31 / Chapter 2.2.3.1 --- Digestible carbohydrate and protein removal by enzyme treatment --- p.32 / Chapter 2.2.3.2 --- Total dietary fiber content determination --- p.32 / Chapter 2.3 --- Structural characterization of PSS and other commercial β-glucans --- p.35 / Chapter 2.3.1 --- Monosaccharide profile study by gas chromatography (GC) --- p.35 / Chapter 2.3.1.1 --- Acid depolymerisation --- p.35 / Chapter 2.3.1.2 --- Neutral and amino sugar derivatization --- p.35 / Chapter 2.3.1.3 --- Determination of neutral sugars by gas chromatography (GC) --- p.36 / Chapter 2.3.2 --- Structural study of polysaccharides by methylation --- p.37 / Chapter 2.3.2.1 --- Preparation of dry dimethyl sulfoxide (DMSO) --- p.37 / Chapter 2.3.2.2 --- Preparation of methylsulfinyl methyl sodium (CH3SOCH2-Na+) from the dry DMSO and sodium hydride --- p.37 / Chapter 2.3.2.3 --- Methylation procedure --- p.38 / Chapter 2.3.2.4 --- Preparation of partially methylated alditol acetates (PMAAs) --- p.39 / Chapter 2.3.2.5 --- Analysis of the PMAAs by GC-MS --- p.39 / Chapter 2.3.3 --- Intrinsic viscosity determination --- p.40 / Chapter 2.4 --- Enzymatic digestion of PSS --- p.43 / Chapter 2.4.1 --- Optimization of digestion Conditions --- p.43 / Chapter 2.4.2 --- Large scale oligosaccharide preparation by preparative HPLC --- p.43 / Chapter 2.5 --- In vitro fermentation of β-glucans --- p.45 / Chapter 2.5.1 --- Static Batch culture in vitro fermentation using human fecal inoculum --- p.45 / Chapter 2.5.2 --- Determination of organic matter disappearance (OMD) --- p.47 / Chapter 2.6 --- Gas chromatographic determination of SCFAs --- p.49 / Chapter 2.7 --- Microbial identification and enumeration --- p.52 / Chapter 2.7.1 --- Oligonucleotide probes for fluorescent in situ hybridization --- p.52 / Chapter 2.7.2 --- Fluorescent in situ hybridization (FISH) --- p.52 / Chapter 2.7.2.1 --- Cell Fixation --- p.53 / Chapter 2.7.2.2 --- In situ hybridization --- p.53 / Chapter 2.8 --- Statistical analysis --- p.54 / Chapter Chapter 3 --- Results and discussions --- p.55 / Chapter 3.1 --- Chemical characterization of Poria cocos sclerotium --- p.55 / Chapter 3.2 --- Structural characterization of PSS & other commercial β-glucans --- p.56 / Chapter 3.2.1 --- Monosaccharide profile --- p.56 / Chapter 3.2.2 --- Glycosidic linkages in polysaccharides --- p.58 / Chapter 3.2.3 --- Molecular weight comparison as determined by intrinsic viscosity --- p.59 / Chapter 3.3 --- Preparation of β (1→3) glucose-based oligosaccharides --- p.66 / Chapter 3.3.1 --- Enzymatic digestion of PSS --- p.66 / Chapter 3.3.2 --- Preparation of (3 (1 →3) glucose-based oligosaccharides by preparative HPLC --- p.66 / Chapter 3.4 --- Batch culture in vitro fermentation --- p.70 / Chapter 3.4.1 --- Organic matter disappearance (OMD) --- p.70 / Chapter 3.4.2 --- Time course study of SCFA production --- p.74 / Chapter 3.4.2.1 --- Total SCFA production --- p.74 / Chapter 3.4.2.2 --- "Individual SCFA (Acetate, Propionate and Butyrate)" --- p.76 / Chapter 3.4.3 --- Overall production of total and individual SCFA --- p.84 / Chapter 3.4.4 --- Molar ratio of SCFAs --- p.90 / Chapter 3.4.5 --- Summary --- p.94 / Chapter 3.5 --- Microbial identification and enumeration by FISH --- p.95 / Chapter 3.5.1 --- Time course relationship --- p.95 / Chapter 3.5.1.1 --- Total bacterial count --- p.95 / Chapter 3.5.1.2 --- Bifidobacteria --- p.97 / Chapter 3.5.2 --- Comparison of bifidogenic properties in the β-glucans --- p.105 / Chapter 3.5.3 --- Summary --- p.108 / Chapter 3.6 --- Correlation between various parameters during in vitro fermentation of β_ glucans --- p.110 / Chapter Chapter 4 --- Conclusions --- p.113 / Chapter 4.1 --- Prebiotic potential of β (1→3) glucans --- p.113 / Chapter 4.2 --- Future Work --- p.115 / List of References: --- p.117

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 72-82). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 72-82). Also available on the Internet.

No description available.

published_or_final_version / Community Medicine / Master / Master of Public Health

Appropriate early microbial colonisation of the gut dramatically affects the incidences of infectious, inflammatory and autoimmune diseases, a concept embraced by the ‘Hygiene Hypothesis’. Hence, factors which influence microbial colonisation and succession during early life have important implications for both human and animal health. This thesis addressed some of the basic principles of the ‘Hygiene Hypothesis’ by investigating how early-life environment impacts on microbial diversity of the adult gut, and how this in turn affects development of the mucosal immune system. The developing pig was used as an experimental model to study host-microbe interactions in early life. The mucosa-adherent microbiota was characterised using both 16S rRNA gene libraries and DGGE and the corresponding host response determined using Affymetrix microarray technology. Initial colonisation of animals derived from two rearing systems with distinct levels of hygiene (outdoor ‘organic/rural’ and indoor ‘hygienic/urban’) was characterised by a highly diverse microbiota that was similar between treatments. These early microbial colonisers were unrelated to those found colonising the adult gut. Establishment of the adult microbiota required continual environmental exposure which led to microbial succession and stabilisation at the adult life-stage. A natural microbiota dominated by Firmicutes reduced both microbial diversity and the number of pathogenic micro-organisms within the gut ecosystem. It also facilitated enhanced innate immune responses. The impact of long-term antibiotic use on the mucosal microbiota was also investigated. This resulted in a sustained disturbance of the gut microbiota which contained phylotypes of a pathogenic phenotype and correlated with altered host immune responses. The work presented supports the concept of the ‘Hygiene Hypothesis’ and has identified windows of opportunity during early life when appropriate manipulation of the mucosal microbiota may enhance immune function and natural disease resistance of the host. Prophylactic administration of broad-spectrum antibiotics in early life is not beneficial to the host.

No description available.

v, 315 leaves : ill., graphs, tables, photos ; 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, 1978