Thesis (M.A.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references. Also available on the Internet.

Efforts to discover an efficient yet environmentally friendly mode of metal nanoparticle (NP) synthesis are increasing rapidly. A ‘green’ route that avoids the high costs, toxic wastes and complicated protocols associated with chemical synthesis methods is therefore highly sought after. A biologically based protocol will provide the possibility of gaining control over the mechanism merely by manipulating the experimental conditions of the system. Given that the properties of nanoparticles are highly dependant on the morphology of the particles themselves, this mechanistic control will provide significant industrial advantages with regards to tailoring specific properties of the nanoparticles produced. The key objectives of this study were to: a) determine whether a consortium of sulfate-reducing bacteria was capable of platinum nanoparticle synthesis, b) elucidate the bioreductive, enzymatic mechanism responsible, and c) attempt to control the morphologies of the particles produced. A consortium of sulfate-reducing bacteria (SRB), isolated from sewage sludge, was used in these investigations due to the advantages a consortium provides in comparison to pure cultures. The syntrophic relationships established within the constituent species not only prevent the growth of contaminant microbes, but increases the oxygen-tolerance of the system as a whole. The sulfate-reducing consortium was shown to possess an aerobic mechanism for Pt(IV) reduction which, though different from the anaerobic bioreductive mechanism previously identified in literature, did not require an exogenous electron donor. It was demonstrated that the Pt(IV) ion becomes reduced to Pt(0) via a two-cycle mechanism involving Pt(II) as the intermediate. Further investigation elucidated the reduction of Pt(IV) to Pt(II) to be dependant on a novel Pt(IV) reductase which becomes upregulated in the presence of Cu(II), while the reduction of Pt(II) to Pt(0) occurred by means of a periplasmic hydrogenase. To our knowledge, this is the first time a coupled mechanism for Pt(IV) reduction by micro-organisms has been proposed. A cell-free, crude protein solution from the consortium produced both geometric and irregular platinum nanoparticles. The wavelength of 334 nm was chosen as a nonquantitative indicator of Pt(0) nanoparticle formation over time. The optimum conditions for nanoparticle synthesis were pH 9.0, 65 ˚C and 0.75 mM Pt(IV) as H2PtCl6 salt. In the absence of a buffer a Pt(IV) concentration > 1 mM resulted in the precipitation of protein-nanoparticle bioconjugates, due to unfavourable acidic conditions. This demonstrated that the nanoparticles were binding to and becoming stabilised by general protein in the cell-free solution. Upon addition of a sodium-bicarbonate buffer, a general increase in Pt(IV) reduction to Pt(II) was observed. The addition of the buffer also resulted in an unexplained change in particle morphology and for this reason was not used in subsequent investigations. Polyvinylpyrrolidone (PVP) was shown to compromise the reduction rate of the Pt(IV) ion by SRB cells. The presence of extracellular NP’s was suggested by the colour of the supernatant turning brown and the A334 increasing over time. Attempts to visualise the particles by transmission electron microscopy (TEM) resulted in an unexpected phenomenon where nanoparticles could be observed to form dynamically upon irradiation by the electron beam. Extended irradiation by the electron beam also resulted in structural changes of the particles occurring during observation. An increase in temperature was shown to increase the reduction rate which in turn resulted in particles decreasing in size. The starting pH was shown to have a significant effect on the reduction rate and particle morphology although specific trends could not be identified. In conclusion, the cell-soluble extract from the sulfate-reducing consortium investigated, is capable of Pt(0) nanoparticle synthesis. Precise control over the particle morphology was not attained although the mechanism was further clarified and optimal conditions for nanoparticle synthesis were determined.

The purpose of this study was to evaluate the changes in work capacity, personality and body fat in obese women undergoing training. Twenty-six subjects from the Vancouver Y.W.C.A. "180-Plus Club" voluntarily participated in the study. The subjects were tested before and after a nine month program. The pretraining and posttraining test environments and test procedures were standardized for all subjects. The experimental group met once per week, until halfway through the program, and then met twice a week. The program consisted of a gymnasium and pool exercise session. A control group of eleven subjects was used to help establish the reliability of the Astrand test of physical work capacity. The following variables were measured as follows: (a) physical work capacity -- Astrand submaximal test, (b) personality -- Cattell's Sixteen Personality Factor Questionnaire, Forms A and B, and (c) body fat -- determination of body density by underwater weighing and the use of Brozek and Keys formula, as well as subcutaneous fat measurements taken at six sites. Three groups were formed on the basis of attendance. The results of the study show that there was a slight improvement associated with a higher frequency of attendance, however, even the group with the highest frequency of attendance failed to show any physiologically important change in work capacity or 'percent body fat’. The combined group results showed a departure from the general female adult population for intelligence, which was higher than the population mean, and for ego strength, which was lower at pretest. The poorest attenders, Group I, showed evidence of departures from the population in factors which described them as being happy-go-lucky, absent-minded, casual and undependable. It is, therefore, not unexpected that persons with these characteristics would drop out of the program. Groups II and III, with respective higher frequencies of attendance, showed significant changes from pretest to posttest in factors which indicated that they became more emotionally mature (Group II) and more sensitive and composed (Group III). These would appear to be desirable changes in view of the Y.W.C.A.'s objectives for psychological as well as physical changes. On the basis of the findings of this study, it does not appear that the time, money and effort required to run the "180-Plus Club" program can be justified. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

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Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: A laboratory-scale model was used to simulate biological sulfate removal. The focus of the research was microbial community response, such as the relative abundance of functional groups to changes in influent medium composition. Specific oligonucleotide probes were obtained that recognised sulfate reducing bacteria (SRB) within the biofilm community. Terminal restriction fragment length polymorphism (T-RFLP) and BIOLOG™ Ecoplate analyses were used to study the SRB community when provided with sodium lactate, sucrose or ethanol as carbon sources in complex Postgate C broth. These two analyses, as well as conventional methods, were applied to follow succession patterns in the laboratory scale reactors, and to determine the possible presence and relative abundance of microorganisms other than bacteria under sulfate reducing conditions. T-RFLP and BIOLOG™ Ecoplate analyses indicated a few dominant organisms in the community and a slight decline after a shift to another carbon source. Fluorescent hybridization showed higher numbers of SRB relative to the total microbial community than conventional culturing techniques. Furthermore, microscopic observations showed that not only SRB and other bacteria, but also yeast and filamentous fungi were integrated in a biofilm under sulfate reducing conditions. These microscopic observations were verified with fluorescent in situ hybridization (FISH) and yeast Live I Dead viability probes. / AFRIKAANSE OPSOMMING: Biologiese sulfaat-verwydering is met behulp van "n laboratoriumskaalmodel gesimuleer. Die doel van die navorsing was om die respons van "n mikrobiese gemeenskap met byvoorbeeld die relatiewe hoeveelheid van funksionele groepe op veranderinge in invloeiende medium samestelling te bestudeer. Spesifieke oligonukleotiedpeilers wat sulfaatreduserende bakterieë (SRB) in "n biofilmgemeenskap kan opspoor is gebruik. Die SRB gemeenskap is bestudeer met behulp van terminale-restriksiefragmentlengtepolimorfisme (TRFLP) en BIOLOGTM Ecoplate analise waar natriumlaktaat, sukrose of etanol as koolstofbronne toegevoeg is. Hierdie twee tipes analise en konvensionele metodes is aangewend om suksessiepatrone in die laboratoriumskaalreaktor te volg en die moontlike teenwoordigheid en relatiewe hoeveelheid van organismes, uitsluitende bakterieë, onder sulfaatreduserende kondisies te bepaal. Analise van T-RFLP en BIOLOGTM Ecoplate het aangedui dat In paar dominante organismes in die gemeenskap teenwoordig was, wat effens afgeneem het na verskuiwing na 'n ander koolstofbron. Fluoresserende hibridisasie het hoër getalle van SRB relatief tot die totale mikrobiese gemeenskap aangedui as konvensionele kultuur tegnieke. Mikroskopiese analises het verder getoon dat benewens SRB en ander bakterieë ook giste en filamentagtige swamme onder sulfaatreduserende kondisies in "n biofilm geïntegreer was. Hierdie mikroskopiese waarneminge is bevestig deur fluoresserende in situ hibridisasie (FISH) en gis Lewe / Dood lewensvatbaarheid peilers.

A number of methods are being undertaken in New Zealand to achieve sustainable land transport outcomes. Lower urban speeds (less than 50 km/h) are increasingly being used to improve safety, but may also contribute to other sustainable land transport outcomes. This research includes: a literature review, case studies, a survey of industry professionals and comparative analysis, to consider the potential effectiveness and efficiency of reducing urban speeds1 to achieve sustainable land transport outcomes. There is reasonable consistency between the findings of the survey, case studies and literature review. The key areas of difference relate to the survey responses potentially under-estimating political and public support for reducing speeds. The responses also over-estimate the current contribution of industry knowledge, and the adverse effects of travel times, vehicle emissions, and fuel usage. In respect to efficiency, reducing urban speeds can be successfully implemented in New Zealand, time and cost requirements are achievable, and legislation is permissive, but additional guidance and industry knowledge is required. Political and public opinions are difficult to determine but there is nothing to suggest that there is widespread opposition to reducing urban speeds, particularly in residential, high pedestrian and business areas. In respect to effectiveness, reducing urban speeds can contribute to improving: safety, public health, accessibility, integrated urban form, environmental sustainability2 and economic development. The impact of increased travel times on functional transport networks is likely to result in some adverse effects, but these are not likely to be significant. Compared to the provision of walking and cycling infrastructure, from the information available, reducing urban speeds is considered to be at least as effective at achieving sustainable land transport outcomes. Reducing urban speeds could also be as efficient, as provision of walking and cycling infrastructure, with more consistent political support, more guidance on the use of legislation, and once the level of industry knowledge improves.

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Metal-reducing microorganisms reduce a variety of metals in metabolic processes coupled to the oxidation of organic compounds. These bacteria play an important role in the biogeochemical cycling of metals and organic matter in anaerobic aquatic and sediment ecosystems. It has been proposed recently that metal-reducing microorganisms also are active in deep subsurface environments such as petroleum reservoirs. Only two metal-reducing bacteria have been isolated from petroleum reservoir fluids, Shewanella putrefaciens and Deferribacter thermophilus. This project studied the occurrence and distribution of metal-reducing microorganisms in petroleum reservoirs. The research focused on the isolation, characterisation and identification of anaerobic bacteria from petroleum reservoirs that were capable of reducing metals and the potential roles of these isolates in the microbial ecology and biogeochemical cycling of petroleum reservoirs. Petroleum reservoirs were selected for this study on the basis of physio-chemical conditions such as temperature, salinity, pH and the presence of organic and inorganic compounds, that were likely to provide a suitable environment for anaerobic bacteria capable of reducing metals. Factors such as the stratigraphic features of the sedimentary basin, age of reservoir and past oil field practices also were considered in choosing the reservoir for study. Seven petroleum reservoirs in the USA and Azerbaijan were chosen for extensive investigations. The physico-chemical conditions in these reservoirs varied substantially. A systematic study of the production water from these petroleum reservoirs revealed a consistent presence of iron- and manganese-reducing microorganisms. It was found that salinity and temperature play a significant and defining role in the occurrence and distribution of these metal-reducing microorganisms. Biotic metal reduction was detected from production waters from all but one of the oil wells sampled. It was significant that the water from this well (Neftcala #1074) was the most saline (78 g/l NaCI). Metal-reducing activity was detected at temperatures up to 70°C. Two pure cultures, strains RED1 for Redwash petroleum reservoir (USA) and NEF1 from the Neftcala petroleum reservoir (Azerbaijan) were isolated and characterized. The strains had diverse physiological and metabolic properties including the ability to oxidize a wide range of carbon compounds and reduce a variety of metals. Their temperature, salinity and pH optima varied markedly. Phylogenetic analyses of the 16S rRNA of strain RED1 showed that the strain represented a new species of a new genus in the domain Bacteria. The bacterium most closely related to strain RED1 is the fermentative Fe(III)-reducer, Pelobacter acetylenicus (similarity value, 92.8%). Strain NEF1 possesses a unique combination of phenotypic traits and a low mol % G+C. From preliminary analyses and comparative biochemistry, NEF1 appears to be a novel metal-reducing bacterium of the Flexistipes group. The bacteria isolated in this study were able to grow at temperatures and salinities consistent with the reservoir from which they were isolated. This indicated that petroleum reservoirs are a new source of physiologically diverse, novel, metal-reducing microorganisms. The bacteria isolated also demonstrated a number of characteristics that would enable them to survive and persist in extreme subsurface conditions and develop a selective ecological advantage in petroleum reservoir environments. Significantly, the metal-reducing bacteria isolated were able to utilize an array of metabolic products produced by bacteria indigenous to petroleum reservoirs. This has resulted in a new proposed model for the ecological succession of bacteria in petroleum reservoirs.