Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 69 for “"bacterial diversity"”.
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Freshwater bacterial diversity, functions and stability.
Biodiversity is declining worldwide with detrimental effects on ecosystems functions and services that it sustains. The relationship between biodiversity and freshwater purification remains unclear. Freshwater purification is of paramount importance for humankind as eighty percent of the worlds …
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Ecology of Root Nodule Bacterial Diversity: Implications for Soybean Growth
… and irrigation. Second, how changes in these bacterial diazotrophs are related to levels of BNF, and N-related soybean molecular markers. Finally, as my colleagues and I found non-diazotrophs in the nodules of some soybean plants, I was curious about the role they are playing inside the …
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Site effects on wildlife enteric bacterial diversity: you are where you eat?
… capacity to document microscopic biodiversity at the community, population and genomic levels. In this dissertation, we apply a combination of molecular and cultivation approaches to the study of enteric microbial diversity in a unique system of sister iguanid species, the Galápagos …
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Structural and functional characterization of bacterial diversity in the rhizospheres of three grain legumes
… this study was to increase the understanding of diversity and activity of dominant bacterial populations in the rhizospheres of three economically important grain legumes (Vicia faba, Lupinus albus and Pisum sativum). A cultivation-independent approach was employed to achieve this aim bearing in …
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The Effect of Condensed Tannins on Bacterial Diversity and Metabolism in the Intestinal Tract
To increase the proportion of tannin-resistant bacteria it is necessary to know the mechanism of tannin-resistance. Wattle condensed tannins were determined to be toxic to Escherichia coli in aerobic medium primarily because they generate hydrogen peroxide. The oxidative stress response helps E. …
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Bacterial Diversity of the Atacama Desert, Chile: The Challenges of Characterizing the Community Dynamics of Extreme Oligotrophic Ecosystems
This dissertation examines the bacterial diversity of hyperarid and arid regions of the Atacama Desert, Chile, as a first step towards understanding the global biogeochemical significance of arid-land microbial communities. The specific objectives were to characterize bacterial diversity and infer …
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Comparison of Subterranean Termite (Rhinotermitidae: Reticulitermes) Gut Bacterial Diversity Within and Between Colonies and to Other Termite Species Using Molecular Techniques (ARDRA and 16S rRNA Gene Sequencing)
… work has been done, however, to describe the diversity and function of the bacteria in the economically important eastern subterranean termite, Reticulitermes flavipes. The first object of this study was to characterize the bacterial diversity in the gut of R. flavipes using amplified rDNA …
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The Influence of Land Coverage and Soil Chemical Factors on Soil Bacterial Community Diversity and Structure in Cedartown, GA, USA
… metal stress, but the response of different bacterial groups may vary depending on the level and type of heavy metal contamination. When subjected to heavy metal stress, many bacterial species or populations may become extirpated, while some may survive to form the foundations of a new …
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Soil Microbial Diversity and Litter Decomposition Increase with Time Since Land Use Disturbance in Tropical Montane Forests of Malaysian Borneo
… disturbances alter soil chemistry, microbial diversity, and disrupt carbon cycling through shifts in litter decomposition. Direct links between microbial diversity and soil properties such as pH are well established; however, the indirect impacts of logging and forest conversion on microbial …
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The bacterial ecology and function from a sub-surface critical zone
… unavailable to flora and fauna. Yet, the diversity and role of microorganisms in weathering at the critical zone is not well understood. This thesis examines microbial communities in vegetated and unvegetated critical zones near Skorradalur Lake, Iceland. A suite of analyses were carried …
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Aquatic microenvironments in bacterial ecology and diversity
Molecular surveys have revealed tremendous bacterial diversity in the world's oceans; yet how do these diverse bacteria with the same essential nutrient requirements co-exist in the same environment? This study examines the role of aquatic microenvironments in generating bacterial diversity: …
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A potential energy-saving heat treatment for re-circulated irrigation water and its biological mechanisms
… temperature on the survival of Phytophthora and bacterial species, two major groups of plant pathogens in water recycling systems, and (2) elucidate the underlying biological mechanisms by which plant pathogens are killed at those temperatures. Lab assays were performed to determine the survival …
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Changes in vaginal microbiome of beef cows enrolled in estrous synchronization protocols and its relation to fertility
… However, at CIDR withdrawal, there was decreased bacterial diversity, increased vaginal pH, increased bacterial abundance, and increased vaginal inflammation when compared to what was observed prior to CIDR insertion. Furthermore, abundance of bacteria, vaginal inflammation, and bacterial …
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Physiological and ecological studies of mannitol utilizing marine bacteria
… Acinetobacter and Flavobacterium species. Bacterial diversity in adjacent kelp dominated habitats was examined using numerical analysis, and it was found that nearshore and offshore isolates were similar, whereas bacteria isolated from beached kelp and interstitial waters were dissimilar …
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An Insight Into the Microbial Diversity and Expression of Cysteine Protease Inhibitors (Cystatin) in <i>Rickettsia parkeri</i> Infected <i>Amblyomma maculatum</i>
… the spotted fever group of rickettsial diversity in <em>A. maculatum</em> based on rickettsial <em>ompA</em> gene PCR. Our results showed <em>A. maculatum </em>harbors <em>R. parkeri, R. amblyommii, </em>and <em>R. endosymbiont of A. maculatum.</em> While only <em>R. parkeri</em> was …
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Prevotella Phylogeny: Genomic And Molecular Insights Into The Role Of The Human Commensal Prevotella In Cystic Fibrosis
… often the dominant species in samples of higher bacterial diversity, which is associated with higher lung function but is also differentially enriched in samples of lower lung function, where bacterial diversity is low. We attempt to explain this contradictory result by exploring the genomic …
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The role of the skin microbiome in amphibian pathogen susceptibility in Turnbull National Wildlife Refuge
… Bd infection intensities would have higher skin bacterial diversity and more abundant anti-Bd bacteria, indicative of a more protective function. Our study combined cultureindependent and culture-dependent methods to assess the relationship between Bd and the microbiome of the Columbia Spotted …
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Simultaneous partial Nitritation, Anammox and Denitrification (SNAD) process for treating ammonium-rich wastewaters
… digester effluent and old landfill leachate. The bacterial diversity in the reactor was investigated by analysis of specific gene clone libraries, Polymerase Chain Reaction (PCR) and fluorescence in situ hybridization (FISH). SNAD process is a complex biological process where different populations …
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Effect of invasive phragmites australis and its control on microbial community composition in a freshwater wetland
<p>Wetlands support great species diversity and perform important ecosystem services like carbon and nutrient cycling, largely facilitated by microorganisms. Invasive plants, like Phragmites australis, reduce biodiversity and alter ecosystem services. I hypothesized that changes in soil bacterial …
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