No description available.

No description available.

The sulphate-reducing bacteria (SRB) are a diverse group of organisms which use sulphate as a terminal electron acceptor and produce the highly toxic gas, hydrogen sulphide. The deleterious effects of this include hydrocarbon reservoir souring, formation damage and microbial corrosion. The SRB are of major economic importance to the oil industry. However, knowledge of the microbial ecology of the deep subsurface remains limited. The aim of this project was to investigate whether organisms are indigenous to the hydrocarbon formation and/or are introduced during drilling operations. A range of molecular techniques such as 16S rDNA sequence analysis, probing with labelled oligonucleotides, and denaturing gradient gel electrophoresis (DGGE) were employed to investigate the microbial diversity in oil field samples. A wide range of bacterial 16S rDNA sequences were identified using these molecular methods. An analysis of drilling mud samples revealed a diverse range of bacterial 16S rDNA sequences confirming that bacteria, including SRB, can be introduced to the reservoir during drilling operations. A number of bacterial 16S rDNA sequences were recovered from a geological core sample taken from a depth of 9,770 feet. The microbial diversity was remarkable in such a high temperature, high pressure environment. This lends credence to the theory that certain bacteria may be indigenous to the subsurface environment. Scanning electron micrographs of core which had been incubated in growth medium indicated the presence of 'nannobacteria'. These tiny coccoids, with a diameter of only 0.1 μm are far smaller than the generally accepted minimum size for cellular life forms. The nannobacteria grew in regular colony shaped structures and were seen only in sections taken from inside the rock. This study indicates that hydrocarbon reservoirs provide an environment in which bacteria, if introduced during drill operations, may become established. However, the subsurface also contains complex indigenous microbial populations that demonstrate considerable species diversity and may include unrecognised life forms.

Osteopontin (OPN) is a matricellular cytokine found in most tissues and body fluids. It is involved in a variety of cell processes by binding to integrins and CD44 receptors, and it modulates immune responses. To investigate the functions of OPN during colitis the DSS acute colitis model in OPN-/- and WT control mice was utilized. OPN-/- mice were more susceptible to DSS-induced colitis than the DSS-treated WT control mice. The increased susceptibility of the OPN-/- mice was characterized by greater intestinal crypt destruction; high myeloperoxidase activity of infiltrating neutrophils; lack of differentiation of inflammatory cells such as lymphocytes subsets (CD4+, CD8+) and macrophages (F4/80); reduced production of certain cytokines, especially TNF-alpha; and non-programmed cell death of enterocytes. It is postulated that the hyperactivity of neutrophils may explain the increased tissue destruction during experimental colitis in the absence of OPN. Analysis of OPN’s impact on neutrophil function showed that while OPN may be important for the recruitment and migration of neutrophils, the expression of OPN by neutrophils is not required for manifestation of their destructive capabilities. This would suggest that OPN administration may protect the intestines from the adverse effects of colitis. Exogenous bovine milk OPN (20 μg/ml), administered for 8 days dissolved in the drinking water, ameliorated DSS-induced colitis. It diminished signs of disease, with a greater impact in the WT than the OPN-/- mice. It reduced the levels of neutrophils, macrophages, and pro-inflammatory mediators in the colon tissue. Recombinant OPN failed to reproduce the beneficial effects of milk OPN, which suggests that post-translational modifications of OPN are crucial to ameliorate experimental colitis. Collectively, these studies demonstrate that OPN has a protective effect during experimental colitis and that the oral administration of bovine milk OPN (20 μg/ml) ameliorates acute DSS-induced colitis. The results of this study also imply that the protective effect probably depends on a post-translationally modified form of OPN, and may require intracellular-OPN as a cofactor for significant attenuation of colitis. Future research could concentrate on more detailed investigation of these latter findings to determine OPN’s mechanism of action.

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "Inland acidic sulfate soils under fresh water conditions where contemporary clearning of native vegetation has caused erosion, rising of local water tables and excess discharge of saline-sulfatic groundwater. A new systematic and interactive web-based approach was used to improve acquisition, collation, integration and communication of diverse soil-regolith data ... Successful application of the interactive web-based data site, as part of this study, resulted in its uptake as a standard tool for coordinating and reporting on a number of current and future national and international soil-regolith studies." -- from Abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289208 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Enviromental Sciences, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "Inland acidic sulfate soils under fresh water conditions where contemporary clearning of native vegetation has caused erosion, rising of local water tables and excess discharge of saline-sulfatic groundwater. A new systematic and interactive web-based approach was used to improve acquisition, collation, integration and communication of diverse soil-regolith data ... Successful application of the interactive web-based data site, as part of this study, resulted in its uptake as a standard tool for coordinating and reporting on a number of current and future national and international soil-regolith studies." -- from Abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289208 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Enviromental Sciences, 2007

Thesis (M.A.)--University of Hong Kong, 1977. / Also available in print.

Thesis (PH. D.)--University of Michigan, 1928.

Thesis (Ph. D.)--Columbia University, 1935. / Vita. Bibliography: p. [35].

No description available.