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1
Broome, Malcolm Charles, and mikewood@deakin edu au. "Aspects of milk protein catabolism by lactobacilli." Deakin University. School of Sciences, 1988. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050902.120502.
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Lactobacillus plantarum and subspecies of Lactobacillus casei were isolated from good quality mature Cheddar cheese and characterized with respect to metabolic functions that would allow their use in cheesemaking. In this way microbiological control of the maturation process with particular emphasis on protein catabolism was achieved. The lactobacilli isolated were selected for low growth rates (and acid production) in milk, and low proteinase activity to allow for their addition in high numbers to cheesemilk together with the normal starter flora (group N streptococci). The growth and acid production of the starter bacteria were unaffected by the presence of the lactobacilli during cheese manufacture and it was found that the added lactobacilli were able to grow and function under the conditions prevalent in Cheddar cheese during maturation. It was also demonstrated that the lactobacilli could be grown in an artificial medium to high numbers under controlled conditions and could be harvested for the preparation of cell concentrates, a necessary characteristic for commercialization. The lactobacilli also metabolized citrate, a potential problem in cheese maturation associated with C02 production but this did not adversely affect the maturation process under the conditions used.
Compared to the group N streptococci the non-starter lactobacilli possessed a proteinase system that had a higher temperature optimum and was less affected by heat and sodium chloride. They also possessed a more active peptidase system although both the lactobacilli and the starter organisms possessed a similar range of peptidases.
Non-starter lactobacilli were added to normal cheese and cheese made with proteinase negative starter. The added organisms did not adversely affect manufacturing parameters and did not metabolize citrate or lead to the formation of biogenic amines. However protein catabolism rates, particularly with respect to peptide degradation,
were increased, as was flavour development and intensity. It was observed that the body and texture of the cheeses was unaffected by the treatment. By controlling both the starter and non-starter microflora in the cheeses a practical system for favourably influencing cheese maturation was possible.
The investigation has demonstrated that carefully selected and characterized non-starter lactobacilli can be incorporated into Cheddar cheese manufacture in order to influence flavour development during maturation. Moreover the organisms can be added to the vat stage of manufacture without causing problems to the manufacturing process. This approach is a simple cost effective means of improving the cost of Cheddar cheese production and provides an unique opportunity to improve and control quality of all Cheddar cheese produced.
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Bridson, Eric Youlden. "Quantal microbiology." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312059.
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Osman, Shaiesta. "Oral microbiology." Thesis, University of North Texas, 1998. http://catalog.hathitrust.org/api/volumes/oclc/48128254.html.
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Aljohny, Bassam Ouda. "Studies on silicon microbiology." Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548645.
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Kehe, Jared Scott. "Massively parallel combinatorial microbiology." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127886.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, May, 2020Cataloged from PDF version of thesis.
Includes bibliographical references (pages 203-216).
Reductionist biology of the 20th century rooted pure culture methods and antibiotics as pillars of humankind's interaction with microbiology, igniting a revolution in medicine and biotechnology. The revolution was not without cost. By overlooking complex biological interactions, it introduced new problems--from the sharp rise in immune disorders to the antibiotic resistance crisis--that 21st century tools must address. While 'omics methods have fundamentally expanded our understanding of biological complexity, we lack a generalized method for measuring how the parts of a complex system, such as the individual strains of a microbial community, interact with each other. In this thesis, I present kChip, a new platform for constructing massively parallel combinatorial arrays of these parts in order to measure their interactions directly. I describe how kChip has been used to reveal patterns in microbial community assembly, unearth minimal microbial combinations with desirable functions, and screen for compounds that potentiate antibiotic activity. I demonstrate how kChip can advance the development of new technologies like microbial consortia and combinatorial drug therapies.
by Jared Scott Kehe.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Biological Engineering
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White, Lorraine. "The microbiology of death." Thesis, University of Sheffield, 2009. http://etheses.whiterose.ac.uk/10361/.
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The main aim of this research was an attempt to clarify whether the protagonists of bacterial bone destruction were of a bodily origin as opposed to environmental contamination by soil bacteria and furthermore to demonstrate a time frame for such attack. It is hypothesised that bacteria from the gut commensal flora are responsible for micro-focal destruction (MFD) of bone postmortem that leaves distinctive tunnels. Microorganisms live with a person throughout their life and somewhat ironically after death persist to exploit this now nonoperational substrate. They continue to thrive and without a working immune system are capable of crossing mucosal barriers and invading both soft and hard body tissues. Experimental protocol using pigs as human analogues were combined with archaeological sections of both humans and animals. The experimental research was almost absolute in the conclusion that only the fetal material was free of MFD one year post-mortem; these were entirely skeletonised and open to contamination by soil bacteria. All of the other pigs had suffered some form of attack, including those that had not skeletonised and were not therefore subjected to soil bacteria. The archaeological material tended to support the hypothesis that endogenous gut bacteria were the cause of MFD as both fetal material and animal bones were much less likely to be affected. It is suggested that soil bacteria are not normally accountable for MFD although their involvement cannot be ruled out entirely and they may be involved at a later stage. It is therefore likely that endogenous gut bacteria having access to a dead body immediately are most often the cause of MFD and that this occurs well within the early postmortem period. This has negative implications for biomolecular studies and positive implications for in-situ preservation.
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Grant, Irene Ruth. "The microbiology of irradiated pork." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335332.
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Robinson, Tobin. "The microbiology of food microenvironments." Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387586.
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Athukorala, Arachchi Seneviratne Chaminda Jayampath. "Molecular microbiology of candida biofilms." Thesis, Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B4068751X.
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Frau, Alessandra. "Molecular microbiology of hydrocarbon polluted groundwater." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676470.
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The thesis is focused on the study of the microbiology of groundwater contaminated by diesel with three main goals. Firstly, to characterize the natural attenuation process, secondly, to increase knowledge of the role of microorganisms in the remediation of polluted environments and thirdly, to evaluate the efficacy of molecular biology methods to assess the in situ biodegradation potential of the microorganisms in such contaminated areas. This study includes the metagenomic characterization of the microbial community through the exploitation of next-generation sequencing techniques and the quantification of key biodegrative genes as biomarkers. Moreover, several strategies were put in place to understand the role of an uncultivated bacterial phylum (the OD1 candidate division) in the biodegradation of organic pollutants. These included the design of primer sets for the amplification of a functional gene specific for OD1 and the phylogenetic analysis of 16S rRNA sequences assigned to OD1 from several studies and a public database. A main outcome has been the characterization of the natural attenuation process in the site. A network of fermentative syntrophic bacteria and methanogenic archaea are the likely the protagonists of this process. The role of OD1 in the fermentation process was proposed. A thorough analysis of OD1 distribution has been carried out and phylogenetic cluster of ODl clades involved in this complex trophic network of fermentative bacteria and methanogens was identified.
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Jeffery, Simon. "The microbiology of arable soil surfaces." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/2245.
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Whilst much is known about the physics and erosion of soil surfaces on a millimetre scale, little is known about the associated microbiology, particularly in temperate arable systems. The vast majority of research regarding microbial interactions at soil surfaces has concerned microbiotic crusts. However, such surface crusts take many years to form and then only in relatively undisturbed soil systems. Arable soil surfaces are subject to relatively extreme environmental conditions, potentially undergoing rapid changes in relation to temperature, water status and solar radiation compared to deeper soil zones. These extreme environmental parameters are likely to have a large impact on the biota found at the arable soil surface when compared to that which occurs in deeper soil zones. Phenotypic profiling using phospholipid fatty acid (PLFA) analysis, microbial biomass, and chlorophyll concentration were used to characterise soil microbial communities with the aim of quantifying differences within the surface layers of arable systems on a millimetre scale. This field work was supported with a series of microcosm-scale studies in which parameters such as length of time between disturbance events and the quality of light reaching the soil surface were controlled. Using microcosms subjected to simulated rainfall and imaged using X-ray computed tomography scanning, the effects of the soil surface microbiota on associated physical properties including structural integrity, porosity, erodibility and hydrological properties were investigated. This research showed that given sufficient time between disturbance events, environmental parameters such as temperature and wet:dry cycling were sufficient to drive the formation of a distinct soil surface phenotype, which appeared to be consistently confined to an order of depth of circa 1 mm. It was notable that the PLFA 16:0 was consistently associated with discrimination between phenotypes between soil surface layers. Calculation of the ratio of fungal to bacterial PLFA biomarkers showed a consistently higher ratio of fungi to bacteria present in the soil surface layer to a depth of circa 1 mm, providing evidence that fungi grow preferentially over the soil surface compared to through the soil matrix. Further investigation demonstrated that light, particularly at photosynthetically active wavelengths, was the main driving factor in the establishment of the distinct soil surface phenotypes. The inocula which drove the formation of such soil-surface community phenotypes, especially the photoautotrophic components, was demonstrated to derive predominantly from aerial sources. Functionally the nature of the soil surface community was found to affect run-off generation and shear strength at the surface. There was no significant impact of the soil surface microbiota on erodibility or water infiltration rates, although whilst distinct surface phenotypes had developed in this experimental circumstance, these were relatively deficient in photoautotrophs compared to other microcosm experiments and field circumstances, and hence extrapolation of this conclusion is not sound. This project has demonstrated that a soil surface ecological niche may exist in other unexplored soil surfaces and highlights the needs to explore this possibility and to examine any associated functional consequence should such niches be found to exist.
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Al-Wajeeh, Khaled Mohsen. "Studies on the microbiology of silicon." Thesis, University of Sheffield, 1999. http://etheses.whiterose.ac.uk/10225/.
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A study was made of the interactions between the element silicon, mainly as silicic acid, and various microbial processes. The effect of silicon compounds on fungal growth was determined under both oligotrophic and nutrient-rich (copiotrophic) conditions. Mycelium of Aspergillus oryzae was grown from a spore inoculum added to ultra-pure water (upw) containing silicon compounds, but not in upw alone. Growth of other fungi also only occurred in upw when silicon compounds were added. Increased growth of fungi also followed the addition of silicon compounds to Czapek Dox medium. Silicic acid also increased the protein content of fungi grown under such nutrient-rich conditions. The fungi solubilised the insoluble silicon compounds under both oligotrophic and copiotrophic conditions. Silicon was not however, accumulated by fungi as electron-dense hyphal bodies. Addition of silicic acid to nutrient rich media also increased the growth of species of Streptomyces but decreased the chlorophyll content of the alga, Dunaliella parva; the growth of two yeasts and the bacteria, E. colt and S. aureus also was not affected by silicon addition; the observed stimulatory effect therefore appears to be restricted to filamentous microorganisms. The effect of silicon compounds on various microbial processes was also investigated. Silicic acid stimulated the production of citric acid by Aspergillus niger, but decreased nitrification and sulphur oxidation in this fungus. Silicic acid addition also led to a reduction in antibiotic production by species of Streptomyces. Studies were initiated to study the possibility that fungi and bacteria can erode the surface of both bulk and porous silicon wafers. While no such surface erosion was evident, we observed that E. coif underwent extensive extreme pleomorphism when growing under starvation conditions for up to 14 days. Such pleomorphism consisted of the formation of bulbous protrusions from the normal rod, dumbbell-shaped cells and long filaments, these were up to 50g in length (compared to the normal 1-3μ, rods). Such filamentation was clearly caused by the inability of the bacterial cells (rods) to separate on division. The observed bacterial pleomorphism was not however, silicon-specific, as it was also found to occur on titanium and glass surfaces. Such extreme pleomorphism may have important implications in relation to the growth of E. coli in low nutrient environments and may influence the bacterium's ability to affect pathogenesis. While the microbiology of silicon has largely been neglected the results of this thesis show that there is considerable interaction between this element and microbial growth. Future studies should in particular be directed towards determining if silicon can be used as an energy source by microorganisms. Additionally, the observed phenomenon of extreme pleomorphism in E. coil is clearly worthy of further study.
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Nagano, Yuriko. "Application of molecular techniques in medical microbiology." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479415.
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Jones, Frances Patricia. "The microbiology of lean and obese soil." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/69408/.
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The bacterial genus Bradyrhizobium is biologically important within soils, with different representatives found to perform a range of functions including nitrogen fixation through symbioses, photosynthesis and denitrification. The Highfield experiment at Rothamsted provides an opportunity to study the impact of plants on microbial communities as it has three long-term contrasting regimes; permanent grassland, arable and bare fallow (devoid of plants). The bare fallow plots have a significant reduction in soil carbon and microbial biomass. Bradyrhizobium has been shown by metagenomic studies on soil to be one of the most abundant and active groups including in bare fallow soil indicating that some phenotypes are adapted to survive in the absence of plants. A culture collection was created with isolates obtained from contrasting soil types from Highfield in addition to woodland soil, gorse (Ulex europeaus) and broom (Cytisus scoparius) root nodules. The collection’s phylogeny has been explored by sequencing housekeeping genes to determine whether soil treatment affects the core genome. One grassland and one bare fallow isolate had their genome sequenced and differences have been assessed to establish their potential for a range of functions and to direct future experiments. The functional diversity of the collection has been investigated using carbon metabolism assays to identify key substrates and determine whether the isolates group according to soil treatment. Symbiosis capacity and role in nitrogen cycling has been examined using nodulation tests, anaerobic growth on nitrate and nitrous oxide production and reduction through denitrification. A high level of diversity can be seen throughout the collection with differences being linked to niche adaptation. Understanding more about Bradyrhizobium could give clues on how above ground management impacts a key group within the soil community. Furthermore, the first assembled genomes of two non-symbiotic Bradyrhizobium strains isolated from soil provide an important resource for microbiology and soil ecology.
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Pitt, Sarah Jane. "Managing for quality in clinical microbiology services." Thesis, Liverpool John Moores University, 2001. http://researchonline.ljmu.ac.uk/5526/.
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The technical quality of the work performed in clinical microbiology laboratories is regularly monitored, by external and internal schemes. Among the factors which might affect quality, attitudes of the laboratory staff are rarely considered. In this study, three concepts recognised by occupational psychologists as being important in the work place, Job Satisfaction, Commitment and Climate, were measured among microbiology biomedical scientists (BMSs) in the United Kingdom A self-report questionnaire was developed through preliminary interviews and two pilot studies. The perceptions of Job Satisfaction, Commitment (to both Profession and Organisation) and Climate were measured using established models from the occupational psychology literature. Three scales were devised specifically during this study to assess an individual BMS's perceptions of the standard of their own performance, the attitudes of their colleagues towards their work and the quality within their laboratory. A fourth measure was developed which collated all the ways that technical quality in clinical microbiology laboratories is currently measured in the UK into one scale. A total of 2415 questionnaires were posted to BMSs employed in National Health Service, Public Health Laboratory Service, Privately funded and University laboratories between November 1998 and February 1999. By March 1999,931 replies had been received, a response rate of 39%. BMSs reported lower Job Satisfaction than Medical Laboratory Technologists (the equivalent profession) in the United States. The results supported Meyer and Allen's (1991) three-component model of commitment and showed that BMSs experienced Professional Commitment more strongly than Organisational Commitment. An eight dimension model of Climate was developed, for clinical microbiology staff, from Newman's (1977) Perceived Work Environment scale. BMSs' perceptions of Individual Climate were affected by a number of demographic factors, but the most important was the size of the laboratory. The optimal number of people in a clinical microbiology department for positive Individual Climate was found to be less than 30. Affective Commitment to the Profession was the component of Commitment which most strongly influenced technical quality, through its positive relationship with an individual BMS's performance at work. Through aggregation of Climate scores for selected laboratories, it was shown that Laboratory Climate correlated positively with technical quality. From BMSs' perceptions of their laboratory's quality, a scale to assess `A Climate for Laboratory Quality' was developed. There was a strong positive relationship between `A Climate for Laboratory Quality' and a department's score on the measure of technical quality. Interviews with staff in four clinical microbiology laboratories supported the questionnaire findings with respect to Laboratory Climate. Qualitative data collected from a representative group of users of each of the four microbiology services showed that users' main concern was rapid turnaround time for results. Comments also highlighted the need for more effective communication between laboratory staff their colleagues working directly with patients.
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Dharod, Meghna. "Diabetic foot : microbiology, pathogenesis and glycan studies." Thesis, University of Westminster, 2010. https://westminsterresearch.westminster.ac.uk/item/9057z/diabetic-foot-microbiology-pathogenesis-and-glycan-studies.
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Complications of type 2 diabetes mellitus are one of the major causes of morbidity and mortality around the world. Diabetic foot infections remain one of the major complications leading to a leg loss every 3 seconds due to amputations causing mental trauma and distress. In diabetic foot ulcers aerobes, anaerobes and fungus often interact with each other and form biofilms which is difficult to treat, enhancing antimicrobial resistance and lead to a non-healing ulcer. Co-existing peripheral vascular disease and neuropathy exacerbate the problems. In T2DM patients’ minor cuts and wounds, often lead to hard to treat and chronic ulcers which can worsen to gangrene formation which may lead to osteomyelitis compromising the mechanics of the foot. It is necessary to identify the virulence factors of these clinically significant microbes and to identify the resistance patterns regularly to limit the antibiotic usage and target to the specific organisms. A Cohort studies were carried out in India and in the UK to identify the risk factors among the diabetic foot patients along with their microbial aetiology and antibiotic resistance patterns from the tissue and pus samples. This part of the research has shown the presence of mixed cultures mainly from the Indian diabetic foot ulcer specimens with higher percentages of anaerobes than aerobes. Multi-drug resistant organisms were one of the peculiar characteristics of the diabetic foot ulcer profiles of Indian patients. As compared to the Indian patients, UK patients had few resistant organisms and the patients admitted to hospitals in India were at the last stage of foot ulcers whereas in the UK, surveillance and preventative strategies allow early detection and intervention. Currently there is a lack of rapid, robust and an inexpensive diagnostic method for the rapid typing and identification of clinically significant anaerobes. Another part of the research focussed on utilising the glycan-lectin interactions by developing a simple enzyme linked lectin sorbent assay by employing biotinylated lectins to develop to an enzyme linked lectin sorbent assay (ELLA) on whole cells, Proteinase K treated cells and glycolipids of clinically significant aerobes and anaerobes. This study is concluded by utilising the glycan-lectin interactions and to develop a rapid typing method for clinically significant Methicillin resistant and sensitive Staphylococcus aureus and epidermidis species. The rapid identification of anaerobes and typing of Peptostreptococcus species was also by facilitated by the developed ELLA method. Finegoldia magna is one of the most significant anaerobes from soft tissue infections and the Gas Chromatography – mass spectrometry (GC-MS) of the glycolipids of Finegoldia magna on composition analysis using show the presence of sialic acid which could be involved in pathogenesis. This sugar may be one of virulence factor employed by this organism in either attachment to the host or to other organisms.
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Guermonprez, Cyprien. "Droplet-based Microfluidic Platform for Quantitative Microbiology." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX106/document.
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Développement d'une plateforme microfluidique pour la microbiologie quantitative. La plateforme permet la culture de milliers de colonies en parallèle dans des micro-gouttes. L'utilisation de tableau statique pour stocker les gouttes permet non seulement leur observation dans le temps pour des analyses dynamiques mais également la récupération de n'importe quelle goutte pour des études complémentaires. Nous avons également développé un outil permettant de soumettre les gouttes à des gradients chimiques directement sur la plateforme dont nous présentons les mécanismes physiques. Nous avons développé un software d'analyse des données générées par la plateforme pour l'étude de modèles de croissance bactérienne ainsi que l'impact des antibiotiques sur leur proliférationDevelopment of a microfluidic chip for quantitative microbiology. The chip allow for parallel culture of thousands bacterial colonies in micro-droplets stored in static array. The 2D-array enable not only the visualisation of each colonies in timelapse experiment but also the extraction of any of them out of the chip at any time for further analysis (PCR, re-culture,...). The platform is adaptable to a concentration gradient producer, for which we present the physical understanding of working mechanism, that can apply different chemical environments to each colony. We developed in parallel a software that perform the analysis of the data generated by the platform to adress bacteria growth studies as well as the impact of antibiotics on bacteria proliferation
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Yuan, Heyang. "Bioelectrochemical Systems: Microbiology, Catalysts, Processes and Applications." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/79910.
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The treatment of water and wastewater is energy intensive, and there is an urgent need to develop new approaches to address the water-energy challenges. Bioelectrochemical systems (BES) are energy-efficient technologies that can treat wastewater and simultaneously achieve multiple functions such as energy generation, hydrogen production and/or desalination. The objectives of this dissertation are to understand the fundamental microbiology of BES, develop cost-effective cathode catalysts, optimize the process engineering and identify the application niches. It has been shown in Chapter 2 that electrochemically active bacteria can take advantage of shuttle-mediated EET and create optimal anode salinities for their dominance. A novel statistical model has been developed based on the taxonomic data to understand and predict functional dynamics and current production. In Chapter 3, 4 and 5, three cathode catalyst (i.e., N- and S- co-doped porous carbon nanosheets, N-doped bamboo-like CNTs and MoS2 coated on CNTs) have been synthesized and showed effective catalysis of oxygen reduction reaction or hydrogen evolution reaction in BES. Chapter 6, 7 and 8 have demonstrated how BES can be combined with forward osmosis to enhance desalination or achieve self-powered hydrogen production. Mathematical models have been developed to predict the performance of the integrated systems. In Chapter 9, BES have been used as a research platform to understand the fate and removal of antibiotic resistant genes under anaerobic conditions. The studies in this dissertation have collectively demonstrated that BES may hold great promise for energy-efficient water and wastewater treatment.Ph. D.
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Silva, João Carlos Tenente da. "Huambo Microbiology Laboratory : economical and financial viability." Master's thesis, Instituto Superior de Economia e Gestão, 2016. http://hdl.handle.net/10400.5/11857.
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Mestrado em FinançasEste trabalho foi realizado no âmbito de um projeto para uma empresa sediada em Huambo, na qual foi pedido uma análise de viabilidade económica e financeira para a construção de um laboratório de microbiologia de alimentos. Esta será a primeira empresa localizada em Huambo, na qual irá testar a qualidade dos produtos importados e exportados em Angola. Numa primeira fase foi estudado o valor inicial para este investimento, a nível de infraestruturas e equipamentos. Para conseguir uma previsão deste investimento, foram analisados alguns laboratórios concorrentes em Portugal, apesar da difícil comparação em termos de dimensão e custos. Este será um investimento realizado exclusivamente através de financiamento bancário. A taxa de juro para este empréstimo foi calculada com base nas taxas de juro aplicadas em casos e valores de financiamento semelhantes. De seguida, foi elaborado uma projeção do volume de negócios baseado na informação recolhida relativamente às importações e exportações neste sector. Com esse volume de negócio, foram calculados todos os custos inerentes ao funcionamento da empresa, como por exemplo, custos fixos e variáveis e custos com salários. Os custos do investimento irão ser depreciados ao longo dos cinco anos previstos. Para melhorar a análise, foram realizados três cenários, de forma, a perceber o quanto poderá influenciar algumas alterações nas previsões. Para perceber a viabilidade económica e financeira deste projeto foi utilizado o método do desconto dos Cash-Flow. Com este método foi também possível obter a taxa interna de rentabilidade e o período no qual o investimento será pago.
This work was carried out for a project in a company based in Huambo, which was asked for an economic and financial viability study for the construction of a food microbiology laboratory. This will be the first company located in Huambo, which will test the quality of imported and exported products in Angola. In a first phase the initial value was studied for this investment, such as buildings, frame-work and equipment. To get the investment’s provision, some competitors’ laboratories were analyzed in Portugal, despite the difficult comparison in terms of size and cost. This will be an investment made exclusively through bank financing. The interest rate for this loan was calculated based on the interest rates applied in similar cases and financing values. Then a turnover projection based on information collected on imports and exports in this sector was prepared. With this turnover, they calculated all the costs of operation of the business, such as fixed and variable costs and wage costs. The investment costs will be depreciated over the five year period. To improve the analysis, there were three scenarios (pessimistic, average and optimistic), in order, to realize how much changes on quantity and costs can influence the forecasts. To realize the economic and financial viability of this project we used the discount method of Cash Flow. With this method it was also possible to obtain the internal rate of return and payback period.
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Song, Hao En. "Some suggestions on developing the Chinese microbiology market." Thesis, University of Macau, 2000. http://umaclib3.umac.mo/record=b1636668.
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Dumas, Eve-Marie. "Development of new imaging tools for environmental microbiology." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95020.
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Environmental microbiology is a field that has been explored for years using tools which are limited in their ability to adapt to the environment studied. The goal of this thesis is to develop new tools for in situ imaging of microorganisms. The first of these tools is a class of photoluminescent probes for fluorescence microscopy. Many microscopic dyes have been used with light microscopes to label microorganisms, but the protocol of each of these techniques limits either the type of organism targeted or the type of environment that can be studied. Most of these probes also only work for a short time due to photobleaching or degrade if stored. An emerging class of fluorophores in the field of cellular and microbiology is the quantum dot (QD), a semiconductor nanoparticle which has recently been made biocompatible. The use of QDs as bacterial probe I studied here, and characterized by studying the particles' interaction with and cytotoxicity to several test organisms, both Gram positive and Gram negative. We find that QDs are toxic to most bacteria due, among other things, to their production of reactive oxygen species. However, this affect varies from one strain to another, suggesting the existence of resistance mechanisms. Although QDs are more toxic to Gram negative strains, electron transfer and depolarisation does not seem to be the source of the toxicity. QDs have a promising future in microbiology as both labeling and anti-microbial agents. In the second part of the thesis, a new microscopic technology was explored for field use: live in-line holographic microscopy. A custom, laser-based holographic microscope was used in a Mars analogue site in order to determine whether it was capable of surviving the harsh conditions and of providing valid data. We experimented in automating the system by combining it with an amphibious robot which was shown to be able to pull the holographic microscope while the latter was recording. Overall, these findingsLa microbiologie environnementale est une discipline qui a longtemps été explorée à l'aide d'outils qui sont limités par leur habileté à s'adapter à l'environnement. Le but de cette thèse est de développer de nouveaux outils pour l'imagerie de microorganismes in situ. Le premier de ces outils est une classe de sonde photolumineuse pour la microscopie fluorescente. Plusieurs teintures ont été utilisé avec des microscopes à lumière afin d'étiqueter des microorganismes, mais chacune de ces techniques est limitée par son protocole. Ces techniques peuvent soit seulement cibler certains types d'organismes, soit sont limitée au niveau de l'environnement étudié. De plus, La plupart de ces teintures sont blanchient par la lumière et ne peuvent être entreposée très longtemps. Les points quantiques (PQ), une nanoparticule semiconductrice qui est maintenant biocompatible, sont maintenant utilisés en microbiologie. J'ai explore ici, l'utilisation de PQs comme sonde bactérienne et les est caractérisée en étudiant leur interaction avec et la toxicité causée à plusieurs microorganismes. Nous avons démontré que la toxicité des PQs est causée, entre autre, par la libération d'espèces d'oxygène réactive. Cependant, l'effet observé varie selon la souche, suggérant l'existence d'un procédé de résistance aux PQs. Nous avons conclus que malgré le fait que les bactéries Gram négatives sont plus affectée par les particules que les Gram positives, le transfère d'électron et la dépolarisation ne sont pas en cause. Les PQs ont un futur prometteur en microbiologie entant que sonde et agent antimicrobien. Dans la seconde partie de cette thèse, l'utilisation d'une nouvelle technologie microscopique sur le terrain a été explorée. Un microscope holographique au laser modifié a été utilisé sur un site analogue à la planète Mars afin de s'assurer que l'instrument pouvait subir ces conditions extrêmes sans dommage et pouvait
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Hole, Stephen J. W. "Biology, microbiology and management of enhanced carbetamide biodegradation /." Title page, abstract and contents only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phh729.pdf.
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Schuurman, Timothy. "Developments and clinical applications in diagnostic molecular microbiology." [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2008. http://hdl.handle.net/1765/13137.
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Doherty, C. J. "Cystic fibrosis microbiology : molecular fingerprinting of microbial pathogens." Thesis, University of Edinburgh, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649603.
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CF lung infections are caused by a surprisingly narrow spectrum of pathogens and include Staphylococcus aureus, non-capsulate Haemophilus influenzae, Pseudomonas aeruginosa and Burkholderia cepacia. Stenotrophomonas maltophila is recovered from respiratory secretions with increasing frequency; however, its pathogenic role remains unclear. The primary aims of this thesis include the development and use of genomic fingerprinting systems to assist epidemiological investigations of CF pathogens, including S. maltophilia. Genomic fingerprinting is based on digestion of total bacterial chromosomal DNA with rare cutting enzymes, chosen on the basis of the bacterium's GC content. Separation of the DNA fragments, is then achieved by pulsed-field gel electrophoresis (PFGE) in an appropriate apparatus such as the Bio-Rad contour clamped homogeneous electric field (CHEF) system. Although a variety of other genomic typing systems are available, the thesis focused on PFGE, potentially the most discriminating system at present. Another major theme of the thesis concerned the epidemiology of B. cepacia. This highly adaptable plant and human pathogen causes great anxiety in the CF community on account of its inherent resistance, transmissibility and association with cepacia syndrome, a rapidly fatal pneumonia affecting approximately 30% of colonised patients. PFGE is technically demanding, time consuming and relatively expensive, thus attempts were made to assess the reliability and potential of other systems, in particular, PCR-ribotyping as a simple and rapid screening system for clonal analyses. The project provided a limited opportunity for fingerprinting and other microbiological studies of the commensal and pathogenic respiratory flora in CF patients participating in the first human trials of CF gene therapy. Specimens were examined before, during and after local nasal administration of a DNA/liposome complex. Although only a Phase 1 study was achieved during the duration of the thesis, microbiological analyses provided interesting results, in particular an unexpected lack of clonal relationship between S. aurens colonising the upper and lower airways.
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Petters, Hannah Itam. "Studies on the microbiology of barley malt production." Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/978.
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Populations of aerobic heterotrophic bacteria, niycelial fungi and yeasts occurring in the production of barley malt were examined by plating on agar media and by scanning electron microscopy. There was an increase in the total number of micro-organisms during germination of barley, although populations declined after kilning. Bacteria dominated numerically in all samples, with progressively lower populations of yeasts and filamentous fungi. There was no obvious pattern of spatial distribution of micro-organisms On/in the samples, although there appeared to be high populations of bacteria and fungal hyphae on the inner surface of kernels. The dominant groups of aerobic heterotrophic bacteria were presumptively identified as Alcaligenes sp., Arthrobacter globiformis, Clavibacter iranicuin, Erwinia herbicola, Lactobacillus spp. and Pseudomonas fluorescens. The principal filainentous fungi were Alternaria alternata, Aspergillus glaucus group, Cladosporium macrocarpum, Epicoccum purpurascens, Fusarium avenaceum, Geotrichum candidum and Penicillium spp. The yeasts isolated most frequently were Candida catenulata, Q. vini, Debaryomyces hansenii, Hansenula polyniorpha, Kloeckera apiculata, Rhodotorula nrncilaginosa, Sporobolomyces roseus and Trichosporon bei gelii. Representative bacteria, mycelial fungi and yeasts were examined for the ability to degrade 8-glucan, starch or arabinoxylan. Approximately 50% of the fungi, <50% of the bacteria and <25% of the yeasts degraded these substrates. A culture filtrate of nivale demonstrated marked ability to reduce -glucan viscometrically and colorimetrically. The organism also degraded raffinose and sucrose. In micro-malting experiments the addition of Fusarium nivale and Geotrichum candidum did not produce substantial changes in terms of the physical and chemical characteristics of the finished malts.
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Bintsis, Thomas. "Aspects of the microbiology of Feta cheese brine." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366049.
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Mendoza, L. S. "The microbiology of cooked rice and fish fermentation." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356490.
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Watts, Ngaire Una. "The microbiology of chlorophenol degradation in mushroom composts." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338633.
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Khayat, Fahad Ali Abdulghany. "Detection of Abnormal Milk with Impedance Microbiology Instrumentation." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/5332.
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Mastitic milk was detected by obtaining conductance measurements using an impedance microbiology Bactometer® 120 SC instruments. Conductance readings taken after 30 min at 25'C separated normal and abnormal milks when readings differed by more than 3% from the variance among instrument module wells. Samples blended from four quarters of a cow indicated milk from one quarter was abnormal if the salt level in the abnormal quarter raised the blend conductivity above that of normal samples and variance among the wells. Either solid or liquid substrates that contained bacterial stimulants could be used to accelerate bacterial acid production or to reduce impedance detection times, each without adversely affecting the ability to detect abnormal milk. However, measurements with liquid substrates varied with the volume of sample in the well. Results suggested that a fixed volume of one ml be used. Such a volume would allow simultaneous detection of abnormal milk and bacterial load on the same sample.
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Arat, Seda. "A Systems Biology Approach to Microbiology and Cancer." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75149.
Full textAbstract:
Systems biology is an interdisciplinary field that focuses on elucidating complex biological processes (systems) by investigating the interactions among its components through an iterative cycle composed of data generation, data analysis and mathematical modeling. Our contributions to systems biology revolve around the following two axes:
- Data analysis: Two data analysis projects, which were initiated when I was a co-op at GlaxoSmithKline, are discussed in this thesis. First, next generation sequencing data generated
for a phase I clinical trial is analyzed to determine the altered microbial community in human
gut before and after antibiotic usage (Chapter 2). To our knowledge, there have not been
similar comparative studies in humans on the impacts on the gut microbiome of an antibiotic
when administered by different modes. Second, publicly available gene expression data is
analyzed to investigate human immune response to tuberculosis (TB) infection (Chapter 3).
The novel feature of this study is systematic drug repositioning for the prevention, control
and treatment of TB using the Connectivity map.
- Mathematical modeling: Polynomial dynamical systems, a state- and time- discrete logical
modeling framework, is used to model two biological processes. First, a denitrification pathway
in Pseudomonas aeruginosa is modeled to shed light on the reason of greenhouse gas
nitrous oxide accumulation (Chapter 4). It is the first mathematical model of denitrification
that can predict the effect of phosphate on the denitrification performance of this bacterium.
Second, an iron homeostasis pathway linked to iron utilization, oxidative stress response and
oncogenic pathways is constructed to investigate how normal breast cells become cancerous
(Chapter 5). To date, our intracellular model is the only expanded core iron model that can
capture a breast cancer phenotype by overexpression and knockout simulations.Ph. D.
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Dabdoub, Shareef Majed. "Applied Visual Analytics in Molecular, Cellular, and Microbiology." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322602183.
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Schöne, Nadine [Verfasser]. "A new probabilistic approach in predictive microbiology / Nadine Schöne." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1025550803/34.
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Iker, Brandon Charles. "Application of Advanced Molecular Techniques in Applied Environmental Microbiology." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301699.
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Recent advancements in molecular biology such as next generation sequencing and more sensitive and rapid molecular detection methods like qPCR, have historically been developed for clinical applications in human genetics and for health care diagnostic purposes. The high demand for faster and more accurate molecular assays in the health care field has driven rapid development of inexpensive molecular techniques that when applied to the science of environmental microbiology, provides an unprecedented level of understanding of the microbial world around us. The goal of this dissertation is to begin to apply more advanced molecular technologies to problems in applied environmental microbiology. Appendix A is a brief literature review of next generation sequencing technologies for applications in environmental microbiology. Appendix B focuses on the development of a more robust virus nucleic extraction kit for the detection of viral genomes from environmental samples found to contain high concentrations of qPCR inhibitors, such as humic acids or heavy metals. Appendix C summarizes one of the largest virus surveys done in the US, using state of the art qPCR technologies in both wastewater influent and effluent from two wastewater treatment plants in the Southwest. Data suggests that traditional virus indicators may not be a viable tool to evaluate fecally impacted source water or virus removal during water treatment. The third study summarized in Appendix D, provides one of the first insights into the microbial ecology of biofilms utilized as biological treatment media using Roche 454 amplicon sequencing of the 16S rRNA gene.
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Innocenti, Nicolas. "Data Analysis and Next Generation Sequencing : Applications in Microbiology." Doctoral thesis, KTH, Beräkningsbiologi, CB, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173219.
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Next Generation Sequencing (NGS) is a new technology that has revolutionized the way we study living organisms. Where previously only a few genes could be studied at a time through targeted direct probing, NGS offers the possibility to perform measurements for a whole genome at once. The drawback is that the amount of data generated in the process is large and extracting useful information from it requires new methods to process and analyze it. The main contribution of this thesis is the development of a novel experimental method coined tagRNA-seq, combining 5’tagRACE, a previously developed technique, with RNA-sequencing technology. Briefly, tagRNA-seq makes it possible to identify the 5’ ends of RNAs in bacteria and directly probe for their type, primary or processed, by ligating short RNA sequences, the tags, to the beginnings of RNA molecules. We used the method to directly probe for transcription start and processing sites in two bacterial species, Escherichiacoli and Enterococcus faecalis. It was also used to study polyadenylation in E. coli, where the ability to identify processed RNA molecules proved to be useful to separate direct and indirect regulatory effects of this mechanism. We also demonstrate how data from tagRNA-seq experiments can be used to increase confidence on the discovery of anti-sense transcripts in bacteria. Analyses of RNA-seq data obtained in the context of these experiments revealed subtle artifacts in the coverage signal towards gene ends, that we were able to explain and quantify based Kolmogorov’s broken stick model. We also discovered evidences for circularization of a few RNA transcripts, both in our own data sets and publicly available data. Designing the tags used in tagRNA-seq led us to the problem of words absent from a text. We focus on a particular subset of these, the minimal absent words (MAWs), and develop a theory providing a complete description of their size distribution in random text. We also show that MAWs in genomes from viruses and living organisms almost always exhibit a behavior different from random texts in the tail of the distribution, and that MAWs from this tail are closely related to sequences present in the genome that preferentially appear in regions with important regulatory functions. Finally, and independently from tagRNA-seq, we propose a new approach to the problem of bacterial community reconstruction in metagenomic, based on techniques from compressed sensing. We provide a novel algorithm competing with state-of-the-art techniques in the field.QC 20150930
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Juwah, Charles Isitoa. "The microbiology and biochemistry of commercial pre-fermented doughs." Thesis, University of Strathclyde, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389697.
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Payler, Samuel Joseph. "Microbiology and the limits to life in deep salts." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33076.
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Deep subsurface evaporites are common terrestrial deep subsurface environments found globally. These deposits are known to host communities of halophilic organisms, some of which have been suggested to be millions of years old. The discovery of evaporite minerals on Mars has led to these environments becoming of interest to astrobiology, particularly because the subsurface of Mars represents the best chance of finding more clement conditions conducive to life. Despite this interest, deep subsurface evaporites remain poorly understood and we have little insight into how different salts shape the Earth's biosphere, much of which is underground. This thesis addresses several knowledge gaps present in the literature by sampling a selection of brine seeps and rock salt samples taken from Boulby Potash Mine, UK. The origin and evolution of the brines is determined with geochemical techniques, showing the majority to have been sourced from an aquifer above where they were intersected in the mine. These brines appear to have taken a variety of pathways through the subsurface leading to the presence of a range of different ions dissolved within them. The majority are Na/Cl dominated, whilst one is K/Cl dominated. One brine appears to have a different origin and probably interacted with dolomite becoming very concentrated in Mg. This variety in brine origins and migration pathways has impacted the habitability of the brines. Physicochemical measurements for chaotropicity, water activity and ionic strength, combined with culturing experiments suggest brines from the Sherwood Sandstone were habitable, but the brine from a distinct unknown source was uninhabitable. DNA was successfully extracted from three of the habitable brines and their metagenomes sequenced. These revealed communities largely functionally and phylogenetically similar to surface near saturation brines, indicating that the structure of the communities present in saturated Na/Cl brines are controlled almost exclusively by these ions rather than any other environmental difference between the surface and subsurface. Organisms were also taken from these brines and culturing experiments carried out to determine if any carbon sources were present in ancient salt that might promote growth in the absence of other carbon sources. Controls showed that the geochemical changes to the growth media induced by solving the salts, particularly sylvinite, were responsible for the increases in growth observed, indicating certain salt minerals effectively fertilise the growth of halophiles. Culturing on hydrocarbon seeps collected in the mine suggested they may provide a carbon source periodically to some organisms within the deposit. Work was done to show the presence of dissimilatory sulphate and iron reducing halophiles. Overall this significantly advances our understanding of how salts shape the Earth's biosphere, particularly its deep subsurface component, and what functional capabilities life has to persist in these environments. This work provides a new window on the potential habitability of deep subsurface extraterrestrial environments and how we might go about investigating these environments for habitable conditions.
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Gyamfi-Brobbey, George. "The microbiology of diabetic foot infections : a Ghanaian perspective." Thesis, University of Westminster, 2016. https://westminsterresearch.westminster.ac.uk/item/9yz27/the-microbiology-of-diabetic-foot-infections-a-ghanaian-perspective.
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Diabetic foot ulcer (DFU), a major complication of both types 1 and 2 diabetes, develops in about 15–25% of people living with the disease. In Ghana, DFUs contribute to most hospital admissions (53%) among diabetics with high rates of amputation (33.3%) and death (8.8%). Diabetic foot ulcers are predisposed to infections from bacteria in the environment which normally colonise these wounds as multicellular communities called biofilms. Biofilms have been found to have increased resistance to antimicrobial agents probably due to the presence of an extracellular matrix that retards or prevents the entry of antimicrobial agents into the bacterial community, antibiotic resistance genes and/or the presence of persister cells that are unresponsive to antimicrobial agents. The work presented here studied the role of 2 multidrug resistant DFU isolates, Klebsiella pneumoniae and Proteus mirabilis in maintaining the chronicity of diabetic foot ulcers. Using 3 in vitro biofilm models; the conventional microtitre plate and Minimum Biofilm Eradication Concentration (MBEC™) High-Throughput assays and the Quasi–Vivo® continuous flow system, K. pneumoniae and P. mirabilis were found to be positive for acyl–homoserine lactone production, biofilm and persister cell producers and could resist and/or tolerate antibiotics such as ceftazidime and levofloxacin up to 1280 times their minimum inhibitory concentration. K. pneumoniae and P. mirabilis were also found to express the interspecies AI–2 quorum sensing molecules which significantly increased biofilm formation and fold induction of bioluminescence in a luxS mutant V. harveyi reference strain. Quorum sensing (QS) inhibition assays using baicalin hydrate, cinnamaldehyde and 2(5H)–furanone showed considerable inhibition of K. pneumoniae and P. mirabilis biofilm formation but failed to completely inhibit their growth. The combinatorial effects of antibiotics and QS inhibitors/antimicrobial peptides such as polymyxin B and polymyxin B nonapeptide determined as fractional inhibitory concentration (FIC) index suggests that, additive and synergistic effects produced by the combination of two antimicrobial agents have the potential to eradicate biofilms. Data from the FIC indices determined from the combination assays can provide the basis for the formulation of topical treatment for DFUs.
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Olaonipekun, Basirat Arinola. "Application of predictive food microbiology to reduce food waste." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65935.
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Universal food insecurity continue to be a challenge that needs attention from all stakeholders. The problem of food waste however is highly important as it slows down the effort to improve food security, most especially in the world’s poorest countries. Conservative shelf life estimation of RTE foods by food producers is one of the major contributor to food waste. After a survey was carried out on the different RTE food products (n=195) available on the shelf of 3 supermarkets in Hatfield, with their set shelf life and storage instructions. Microbiological quality (Total viable count, LAB, Enterobacteriaceae, yeasts and moulds, and Pseudomonas spp.) and safety (E. coli, Staphylococcus aureus, Listeria spp. and Salmonella spp.) was conducted on selected RTE products (used as a reference point) during storage at ± 5o C. This wass to evaluate the validity of the set shelf life of beef lasagne (3 days), egg noodles (3 days), pre-cut mango (4 days) and pre-cut papaya (4 days) by food producers. Challenge test study was also conducted on representative RTE food products (beef lasagne, egg noodles, and pre-cut mango) with relevant food borne pathogens (L. monocytogenes, Salmonella Typhimurium, and E. coli) during storage for 12 days at ± 5oC. Growth potential (?) of these pathogens in the RTE foods were calculated using the concept of EU-CRL technical guidance on shelf life for L. monocytogenes on RTE foods as ? values can be very useful in potential food safety risk evaluation. Performance of 4 different types of software (ComBase, PMP, MicroHibro & FSSP) was evaluated for use in shelf life estimation of these selected RTE foods. These software were selected based on different criteria (User-friendly, accessibility and availability and types of pathogens for its application). The predicted growth from these software were compared to observed growth (generated from experimental data got from challenge test) of L. monocytogenes in beef lasagne and egg noodles. Indices of performance; Coefficient of determination (R2), root mean square error (RMSE), bias factor (Bf) and accuracy factor (Af) were used to evaluate the performance of these software. All the RTE food products reviewed had no specific refrigeration storage temperature instruction on the product package. Storage test study indicated that some of these RTE foods (beef lasagne, pre-cut mango and papaya) could have longer shelf life (5, 13 and 5 days respectively), while egg noodles could be a potential public health risk due to the presence of food borne pathogens right from day of purchase. However, the challenge test results also confirmed the conservative shelf life estimation by food producers in that the shelf life of all the products evaluated can be extended (Beef lasagne by 6 days, Egg noodles by 6 days and pre-cut mango by 9 days) with no food safety risk associated with the extension. On the other hand. RTE egg noodles and beef lasagne may support the growth of L. monocytogenes (? > 0.5 log10 cfu/g) if present in the food while egg noodles may not support the growth of S. Typhimurium (? ? 0.5 log10 cfu/g). Beef lasagne and pre-cut mango may also not support the growth of E. coli (? ? 0.5 log10 cfu/g). Growth of L. monocytogenes predicted by ComBase, PMP, MicroHibro & FSSP in beef lasagne and egg noodles was in agreement with the observed growth from the challenge test study, with a fail-safe prediction. However, ComBase predictor had the closest prediction to the observed growth. Hence, it had overall best performance for prediction compared to the other software. Notwithstanding, all the software evaluated in this study can be applied in shelf life prediction of RTE food products. Predictive microbiology is a field of food microbiology that can be looked into and implemented by the authorities. Its use by the South African food industry to scientifically estimate the shelf life of RTE food products is thereby encouraged. This will assist in decision making with regards to food quality and safety, thereby reducing the problem of food waste as result of product shelf life and at the same time protect public health.Dissertation (MSc)--University of Pretoria, 2017.
Food Science
MSc
Unrestricted
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Walker, Candace Lynette. "Implementing Inquiry-Based Learning in a General Microbiology Laboratory." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/43973.
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In recent years there has been an increased interest in inquiry-based learning, also known as experiential learning or problem-based learning, as a more appropriate model of teaching science. The purpose of this study was to incorporate inquiry-based learning in a college sophomore-level General Microbiology Laboratory. The goal of this laboratory course is to introduce students to basic techniques and procedures necessary for the study of microorganisms. Laboratory sections were randomly assigned to an experimental group or a control/reference group. The experimental group was taught the concept of serial dilutions using an inquiry-based learning approach whereas the control group was taught using traditional teaching methods. Analysis of the data generated from the students' involvement in the investigation during the fall semester indicated that the experimental group had a slightly greater improvement in their knowledge of serial dilution. The study continued in the spring semester and involved close to 300 students. During the spring semester both the experimental and the control groups had similar attitudes about their learning experience as evaluated by a Lickert Scale survey. However, a statistical analysis of the quiz scores of the students with values within the interquartiles indicated the experimental classes' quiz scores were significantly higher on quiz 2 taken at the midpoint in the study. Thus an inquiry-based learning approach was found to be beneficial to the middle 50% of the class.Master of Science
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Gilfillan, Joanne Criseyde. "The structure and microbiology of floating sulphide oxidising biofilms." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1003962.
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Floating sulphur biofilms are observed as surface layers in numerous aquatic sulphide-rich environments, and apparently play an important role in the cycling of sulphur in its various oxidation states. In addition to the conversion of sulphide to sulphur and/or sulphate species, it has been suspected that subsequent reduction back to sulphide may occur within the floating sulphur biofi1m in organic-rich environments. The use of sulphur biofilms for the harvesting of elemental sulphur from wastewater treatment systems has also been suggested. There is, however, little documented information in the literature on the structure of floating sulphur biofilms, or the microbial species responsible for their occurrence. In this study, floating sulphur biofilms were generated in a continuous flow baflle reactor and their structure was examined using scanning electron microscopy. It was found that they occur as layered structures with morphologically distinct bacterial forms present in different layers of the biofilm. The biofilpl structure was also found to be dynamic, with structural changes observed as feed conditions were altered. An enriched culture derived from the biofi1m demonstrated rates of sulphide oxidation comparable to values reported in the literature for liquid culture systems. The microbiology of the biofi1m was studied using traditional plate culture techniques and analysis ofrRNA genes. Identification of plate culture isolates as representatives of the biofi1m community proved to be limited, leading to a PeR-based cloning approach. The majority of the organisms present in the sulphur biofi1m were classified as species in the genus ~eudomonas, and a number of other bacterial species whose sulphide oxidising capacity has been noted previously. Surprisingly, only 2% of the clone library consisted of Thiobacillus spp., and no sulphate reducing bacteria were identified in the biofilm at all. These results indicate that in organic sulphide-rich environments facultative chemolithoheterotrophic bacterial forms predominate in floating sulphur biofilms, and that the complete biological cycling of sulphur may not occur in these systems.
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Jaber, Salah. "Canine faeces : the microbiology of an environmental health problem." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3849/.
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The overall aim of the research work reported in this Thesis was to study a variety of aspects of dog faeces in relation to public health, their fertilizer potential and possibility that such faeces might be remediated using larvae, ultimately to provide a source of biodiesel. The results can be summarized as follows: 1) Dog faeces were shown to be source of pathogenic bacteria, notably Escherichia. coli and Salmonella. These bacteria were shown to be transferred to the soil of a local playing field by direct, in situ, transfer from dog faeces undergoing weathering. E. coli and Salmonella enterica were isolated from all four sites while no such isolates were obtained from the fifth location which was uncontaminated with dog faeces 2) It was shown here that “common or garden” slugs can transfer potentially pathogenic bacteria from dog faeces to lettuce. 3) The feeding of Black Soldier Fly Larvae on faeces led to a statistically significant increase in the number of bacteria inside the BSFL gut and the same trend was seen in relation to dog faeces fed Fruit Beetle Larvae. This trend of increasing bacterial numbers in larvae fed on dog faeces is particularly worrying in relation to the potential feeding of these larvae to animals- post exposure to faeces. 4) Dog faeces were shown to have potential inherent fertilizer content; the nutrients present being released over a time period mimicking the natural weathering of dog faeces in the environment. 5) As a generalization, the addition of both types of larvae to dog faeces significantly reduced the concentration of indigenous plant nutrients over the entire four week incubation period; exceptions to this were nitrate and phosphate concentrations in BSFL treated faeces, where significant increases were seen at week 4 and 3 respectively and in faeces treated with FBL, where ammonium concentrations were significantly increased at weeks 2-4, and phosphate at week 4. While the addition of both larvae therefore IV initially decreased levels of indigenous plant nutrients there was a trend in some of the nutrients to increase the longer the incubation went on. This suggests that perhaps a longer term exposure of dog faeces to the two larvae might have lead to increase in ammonium, nitrate, sulphate and phosphate concentrations. The addition of ammonium, elemental sulphur an insoluble phosphate to dog faeces which had been modified by the two larvae led to significant increases in nitrate, sulphate and plant-available phosphate, results which shows that that dog faeces contains the indigenous microflora required for the transformation of these amendments (which simulate fertilizer addition). The results suggest the possibility that larval modified dog faeces could be used as compost additive fertilizer, or perhaps even be used as an agricultural soil fertilizer. 6) The potential for using fly larvae for the bioremediation of dog faeces was investigated. Black Soldier Fly (BSFL) and Fruit Beetle (FBL) Fly larvae were shown to dramatically improve the physical nature of canine faeces, even after only a short exposure period, giving a bioremediated product which is markedly improved in terms of texture, reduced odour and overall reduced offensiveness. The bioremediated dog faeces product was also found to be suitable as potting compost when “diluted” with proprietary potting compost. 7) The haemolymph and total body extracts of BSFL and FBL were shown to be antibacterial. 8) The potential for using dog faeces and dog faeces which had been treated with BSFL and FB as a source of biodiesel was determined. It was shown that potential biodiesel precursors) (mainly fatty acids) were present both in the raw dog faeces and in faeces which were treated with the two different larvae. 9) The number of bacteria present in dog faeces disposed of in plastic bags dramatically increased over exposure to the UK summer, when temperatures were recorded between 10-270C.
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Shaheen, Babar. "Effect of photodynamic therapy on the microbiology of acne." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/69644/.
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Light-based therapies, including photodynamic therapy (PDT), for acne are gaining popularity in dermatology. Based largely upon in vitro data, their beneficial outcome in acne is thought to be related to their bactericidal effects on Propionibacterium acnes. This randomised controlled study sought to determine the efficacy and tolerability of 610-950 nm IPL (administered as IPL-Placebo) and IPL-assisted methyl aminolaevulinate PDT (IPL-MAL) vs. adapalene 0.1% gel in the treatment of acne and to identify their mode of action, looking specifically at the effect on surface density of P. acnes. Thirty seven patients (31% of target due to slow recruitment) with mild to moderate facial acne were randomly allocated to IPL-MAL treatment, IPL-Placebo or adapalene. Both IPL groups received four treatments to the whole face, 2 weeks apart, while the third group was given adapalene nightly for 12 weeks. Assessments performed at baseline and weeks 8, 11, and 16 included inflamed, noninflamed and total lesion counts, Leeds grading, follicular porphyrin fluorescence, the Family Dermatology Life Quality Index and Dermatology Life Quality Index scores, and patient’s perspective of clinical improvement by the visual analogue scale (VAS). Cutaneous microflora was collected from all patients at similar intervals. Of the 37 patients randomised, only 30 completed the trial (10 in each group) and were included in the final analyses. Adapalene was found to be significantly superior to IPL-MAL and IPL-Placebo in reducing the noninflamed (adapalene 37.6% vs. IPL-MAL 3.4% vs. IPL-Placebo −9.7%) and total lesion counts (adapalene 35.7% vs. IPL-MAL 4.3% vs. IPL-Placebo −8.4%) at week 16. This was accompanied by a significant decrease (52.9%) in the DLQI score in this group (p = 0.031). The maximum improvement in inflamed lesion counts from baseline was seen at week 11 in the IPL-MAL (20.7%) and IPL-Placebo (13.4%) groups but occurred at week 16 in the adapalene group (26.5%). Statistical significance, however, was not reached in any group. There was no significant difference within or between the groups in the VAS, Leeds, FDLQI and porphyrin fluorescence results pre- and post- treatment. A significant increase in the density of propionibacteria (p = 0.021) and xxi coagulase-negative staphylococci (p = 0.039) was seen in the IPL-Placebo and IPL- MAL groups at week 16 and week 8, respectively; however, there was no significant difference between the groups. All the treatments were well tolerated. Adapalene remains an effective first line treatment in mild to moderate facial acne. However, the present study has remained indecisive (due to being underpowered) in drawing any firm conclusions regarding the efficacy of IPL and IPL-MAL on inflamed acne lesions. Further research is therefore warranted before their use can be advocated for acne treatment. An alternative mode of action for IPL and IPL-assisted MAL-PDT other than photodynamic destruction of P. acnes is suggested from the results of this study.
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Kuhn, Eloise M. R. "Microbiology of fly ash-acid mine drainage co-disposal processes." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The waste products acid mine drainage formed during coal mining and fly ash from coal burning power generation, pose substantial environmental and economic problems for South Africa. Eskom has developed a remediation system employing alkaline fly ash to neutralize and precipitate heavy metals from toxic acidic acid mine drainage streams. The aim of this study was to assess the microbial diversity in and microbial impact on this remediation system.
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Jepras, Robert Ian. "Applications of photon correlation spectroscopy and flow cytometry to microbiology." Thesis, Open University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290872.
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Wegmüller, Bernhard. "Applications of modern DNA techniques in microbiology and mutation detection /." [S.l.] : [s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Mlaga, Kodjovi Dodji. "Real-time genomics to decipher atypical bacteria in clinical microbiology." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0594/document.
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L'objectif de notre thèse est d'appliquer la génomique en temps réel pour déchiffrer les caractéristiques génomiques bactériennes et les événements de recombinaison du génome des bactéries atypiques ainsi que leur impact sur les maladies infectieuses. Au cours de ma thèse, nous avons effectué une revue sur les outils bioinformatiques les plus courants utilisés en microbiologie clinique et mis en évidence l’impact de la recombinaison sur le comportement des bacteries. Le deuxième projet de notre thèse est de déchiffrer une epidémis de Staphylococcus saprophyticus causant des infections urinaires en utilisant la technologie MALDI-TOF MS et une analyse comparative du génome de S. saprophyticus pour comprendre leur évolution génomique. Nous avons démontré qu'il existe un groupe de S. saprophyticus géographiquement restreint à Marseille comparé au souches de Nice. De plus, nous avons montré que S. saprophyticus qui était initialement considéré comme une bactérie saprophyte a evolué pour devenir une bactérie pathogène à travers des recombinaisons massives et des « single nucleotide polymorphism », résultant d'une perte significative de gènes. Le troisième projet de notre thèse est une analyse comparative des génomes d'Enterococcus faecalis et d'E.faecium isolé chez l'homme, les animaux et l'environnement pour déchiffrer la différence de propagation et l'acquisition de déterminants antimicrobiens. Nous avons démontré qu'il existe une association directe entre l'absence de système CRISPR, la présence du gène ardA et l'acquisition de gènes de résistance à la vancomycine, qui différencient E. faecalis de E. faecium. Enfin nous avons decrit un nouveau genre bacterien NissabacterThe objective of our thesis is to applied the Real-time genomic approaches to decipher bacterial genomic features and genome recombination events of atypical bacteria and their impact on infectious diseases. During my thesis, we have reviewed the most common bioinformatics tools applicable in clinical microbiology and highlight how bacterial genome recombination have impacted their behaviour. The second project of our PhD is to decipher a community outbreak of Staphylococcus saprophyticus involved in (UTI) using MALDI-TOF MS technology and a comparative genome analysis of clinical and non-clinical S. saprophyticus to understand their genomic evolution. We demonstrated that there is a geographically restricted cluster of S. saprophyticus circulating in Marseille community as compared to Nice. Moreover, we showed that S. saprophyticus which was initially considered as a saprophytic bacterium has drifted to becoming a pathogenic bacterium through massive genome recombination and single nucleotide polymorphism events, resulting from a significant loss of genes. The third project of our work is a comparative genome evolutionary analysis of Enterococcus faecalis and Enterococcus faecium isolated from human, animals, and environment to decipher the difference in spread and the acquisition of antimicrobial determinants. We demonstrated that there is a direct association between the absence of CRISPR system, the presence of gene ardA and the acquisition of vancomycin resistance genes, which differentiate E. faecalis from E. faecium. Our final project was focused on the discovering of a new genus Nissabacter and its description
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Al-Luaibi, Yasin Y. Y. "Molecular genetics and microbiology of bioremediation using methane-oxidising bacteria." Thesis, Sheffield Hallam University, 2015. http://shura.shu.ac.uk/17361/.
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Methanotrophic bacteria can grow on methane as their sole source of carbon and energy. Methylosinus trichosporium OB3b is a Gram negative, methanotrophic bacterium, which can convert methane to methanol by either particulate (pMMO) or soluble (sMMO) methane monooxygenase. The sMMO comprises three polypeptides; hydroxylase (αβγ)2, regulator/coupling protein (protein B), and reductase. The hydroxylase contains the diiron active site. The three components of sMMO are found to be indispensable for full enzyme activity. In the present study, the sMMO hydroxylase was purified by anion exchange chromatography and protein B fused with GST was purified by using affinity chromatography. Attempts to purify the reductase were unsuccessful although the reductase was detected during the purification steps. To shorten the long purification protocol of the hydroxylase and minimize the loss of its activity during multiple purification steps, a new system was developed by inserting a His-tag in the wild type hydroxylase β-subunit. The His-tag hydroxylase was then purified in one step by using an affinity column. The new His-tag system yields hydroxylase with detectable activity when it was tested toward propylene. Solid phase microextraction (SPME) was used for the first time in the present study to detect the product propylene oxide from propylene oxidation for the wild type His-tagged hydroxylase. Crystallographic studies have suggested roles for a number of amino acids within and around the active site. The present study used site-directed mutagenesis to create four new mutants in addition to performing further characterization of another two. The mutation C151S preserved activity toward a range of substrates, and indicated that radical chemistry at this position is not xviii essential for monooxygenase activity toward a number of aliphatic and aromatic hydrocarbons. Results from other mutations included stabilising a previously unstable mutant (C151Y) with a secondary mutation to gain the double mutant E114D C151Y. The mutant R98L showed activity toward the monoaromatic substrate ethyl benzene and the diaromatic substrate naphthalene. Mutation of one of the diiron site coordinating residues E114D resulted in a stable hydroxylase with activity toward naphthalene. In terms of the oxidation of the triaromatic hydrocarbons anthracene and phenanthrene, no activity could be detected for the mutants tested in the present study or the wild type.
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Khan, Intisar Chowdhury. "Spreads microbiology in association with product matrix, structure and chemistry." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28996/.
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The overall aim of this study was to eliminate the root cause of the ‘cheese flavour’ in spread caused by four key microbes Bacillus spp, Staphylococcus spp, yeasts and moulds. The major sources of these bacteria were in the product ingredients mainly sweet cream buttermilk and skimmed milk along with environmental aerosols. The causative organisms were present in about 63% of the products and mainly ‘feed’ on the oil element of the recipe, containing high level C12 that generates the distinctive cheese flavour when broken down by bacteria. The key hurdle factor in spread preventing microbial growth is water droplet size. The spread showing cheese off flavour had a droplet size distribution of 95% <10 micron. To achieve finer droplet size distribution, trial products were made in the Scrape Surface Heat Exchanger (SSHE) over the current churning method with a distribution of droplet size 98% <5 micron. The trial product showed a 50% reduction in the generation of the ‘cheese flavour’ methyl ketones. The Staphylococcus spp cross contamination source where from personnel with direct food contact processing area. Further education on personal hygiene helped to reduce the level of Staphylococcus spp contamination in the product. The trial product from the SSHE was further challenge tested with Listeria monocytogenes over a 10 week shelf life period to evaluate product robustness against microbial growth and spoilage. The organism did not show any growth over the period of time. The liquid phase of the emulsion was further modified with various salts at different concentrations and challenged with L. monocytogenes isolated from various parts of the dairy environment. It was observed that a pH range of 5.5 or lower with added 0.063% potassium sorbate showed significant antibacterial affect compared to the nutrient enriched MPC-broth and the unsalted liquid phase of the emulsion with no added potassium sorbate. To understand L. monocytogenes survival within a dairy process, the organism was further challenged by exposure to pasteurisation heat treatments and the standard CIP cycle of acid and caustic treatment. No recovery rate of the organism was observed. Therefore it could be concluded that the contamination within the industry is more likely to be post process or environmental contamination rather than survival through the plant itself as per RASFF alert of Listeria spp outbreak in dairy. Therefore, reducing the available water in the liquid phase of the spread and achieving a <5 μm droplet size and a finer distribution within the product will be limiting factors to microbial growth. An air purifier system BAXX has reduced the level of environmental contaminants, especially yeast and mould.
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Silva, Ana Filipa. "Microbiology of membrane bioreactors for wastewater treatment: a molecular approach." Doctoral thesis, Universidade Nova de Lisboa. Instituto de Tecnologia Química e Biológica, 2013. http://hdl.handle.net/10362/12030.
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Dissertation presented to obtain the Ph.D degree in Engineering and Technology Sciences, Biotechnology.Water is a natural resource essential for life maintenance of the human kind and the ecosystems found in Nature. Currently the natural resources of water are increasingly exhausted with the constant water demand. Biological wastewater treatment processes are green, economic and efficient ways to remove pollutants from wastewater and recycle the water back into the environment. Membrane bioreactors (MBRs) in the last two decades have gained special attention due to the small footprint and the high quality of the treated effluent, helping meeting the requirements of increasingly stricter legislations. MBRs combine the activated sludge process with membrane filtration and have specific features that likely affect the microbial structure and ecophysiology.(...)
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Yilmaz, Pelin [Verfasser]. "Improving the Usage of ribosomal RNA Gene in Microbiology and Microbial Ecology: Importance of Standardization and Biocuration / Pelin Yilmaz. Max Planck Institute for Marine Microbiology." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2012. http://d-nb.info/1035211068/34.
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