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 93 for “"symbiont"”.
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Microbiology of marine sponges: from community structure to symbiont function
… an in-depth investigation of an enigmatic sponge symbiont which has largely escaped attention until now. Analysis of the marine sponge microbiota poses unique conceptual and analytical challenges, as microbial species may number in the thousands. One way to overcome this issue is to consider only …
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Mobile genetic elements as modulators of the human gut symbiont Bacteroides
Mobile genetic elements (MGEs) facilitate horizontal gene transfer (HGT) in all cellular hosts. In microbial systems, MGEs (e.g. phages, integrative and conjugative elements) are potent drivers of host evolution. Within hosts from the bacterial genus Bacteroides, one of the most common and abundant …
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Symbiont-Mediated Modification of Mosquitocide Toxicity in the Dengue Vector, Aedes aegypti
… Recent evidence also suggests that bacterial symbionts of mosquitoes, known to be essential in nutritional homeostasis and pathogen defense, may play a significant role in facilitating mosquitocide resistance. Here, I examined the metabolic detoxification and toxicity of two mosquitocides, …
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Novel genes required for proper cell envelope function in the plant symbiont Rhizobium leguminosarum
… proper cell envelope development in the legume symbiont Rhizobium leguminosarum. In R. leguminosarum there is a positive correlation between mutations that affect cell envelope structure and sensitivity to peptide-rich media; therefore, I implemented an innovative transposon mutagenesis approach …
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Signaling between Two Sensor Kinases Controls Biofilms and Host Colonization in a Bacterial Symbiont
<p>Organisms within all domains of life must acclimate to fluctuating environments to survive. To do this, cells utilize sensory circuits, which function to connect environmental stimuli to an intracellular response. One common sensory pathway utilized by bacteria is two-component signaling (TCS), …
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Drivers of burrow symbiont distribution in a softsediment system: host abundance or burrow trophic environment?
… Their burrows are home to various burrow symbionts including a commensal shrimp (Betaeus jucundus), a six-legged crab (Spiroplax spiralis) and a scaleworm (Antinoe lactea). Little work has been conducted on these burrow symbionts, and the mechanisms influencing their abundance and …
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Towards an understanding of symbiont natural history through studies of crayfish and their annelid associates
… host resistance creates predictable patterns of symbiont diversity and composition throughout host ontogeny. Host resistance limits within-host symbiont communities to a few weakly interacting species, whereas relaxed resistance leads to more diverse symbiont communities that have strong …
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The evolution of immune genes in tsetse flies (Glossina) and insights into tsetse-symbiont-trypanosome interactions
… and Toll-like receptor 2 (TLR2), in relation to symbionts and parasitic interactions. This could in turn lay the foundations for genetic control methods The successful identification of novel attacin orthologues confirmed the previous descriptions of attacin clusters within the Glossina genome, …
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Mixing it up: Multiple symbiont acquisition strategies as an adaptive mechanism in the coral Stylophora pistillata
… on the successful acquisition and maintenance of symbionts, which can be transferred from parent to offspring via direct inheritance (vertical transmission) or acquired anew each generation from the environment (horizontal transmission). Vertical transmission ensures progeny acquire their obligate …
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Functional diversity of fungal symbiont communities and the impact of biotic and abiotic factors on their composition and assembly
Plants harbor tremendously diverse microbial symbiont communities (“the microbiome”) that affect the host fitness and response to environmental changes. Despite their importance, less attention has been given to the response of microbial symbionts to environmental difference, the understanding of …
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The double life of an insect pathogen: Metarhizium as a plant symbiont and its genetic diversity in coffee agroecosystems
… but more recently was recognized as a plant symbiont, being able to transfer nitrogen from insect cadavers to plants, act as plant pathogen antagonist and plant growth promoter. All those functions could be valuable as ecosystem services provided by these fungi to plants in sustainable …
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Multi-scale Transmission Ecology: How Individual Host Characteristics, Host Population Density, and Community Structure Influence Transmission in a Multi-host Snail Symbiont System
… spread of these infectious agents and other symbionts through host populations and communities, we need dynamic mathematical models that accurately portray host-symbiont transmission. But transmission is an inherently difficult process to measure or study, because it is actually a series of …
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Invasive Hosts and their Context Dependent Relationships with Native Symbionts
… variety of factors that include host properties, symbiont densities, and environmental conditions. Invasive species can affect symbiotic relationships by introducing invasive symbionts, reducing the population of native symbionts, or competing for native symbionts as a resource. There is an …
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The Evolution of Symbiosis in Communities
All organisms host a menagerie of symbionts. While harmful pathogens have historically held the attention of researchers, recent technological advances have revealed a cornucopia of benign, and even beneficial, symbionts. Observations that most organisms are party to a wide variety of harmless …
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Partners in space: Discordant population structure between legume hosts and Rhizobium symbionts in their native range
… distance. Overall genetic variation across the symbiont genome is less spatially structured than that of its host, and variation in the two species is uncorrelated, indicating comparatively higher levels of gene flow among sampling sites in these bacterial symbionts relative to host plants. …
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Establishing Sodalis species as a laboratory model of endosymbionts
… diversity found in the natural world. Microbial symbionts, being some of the longest living organisms on the planet with the largest distribution, offer the best opportunity to understand the complex mechanisms behind host-symbiont interactions and evolutionary processes. The insect kingdom, …
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The Prevalence and Effect of Wolbachia Infection on the Brown Widow Spider (Latrodectus Geometricus)
… Spider (<em>Latrodectus geometricus</em>). This symbiont has not previously been found in this genus, therefore the consequences on the host’s population dynamics are unknown. The frequency of endosymbiont infection can provide insight into the population dynamics of the host as this bacteria is …
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Ecology and behaviour of burrowing prawns and their burrow symbionts
… and trophic functions (e.g. food) for burrow symbionts, however, the relative importance of these functions for symbionts is poorly understood. The behavioural interactions between burrowing engineers and their burrow symbionts are also poorly understood, mainly due to the difficulty in …
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Mountain Lake Revisited: Impacts of Invasion on Native Symbiotic Systems
… invasions through the perspective of native symbiont communities. In the Mountain Lake region of Virginia, crayfish host diverse assemblages of obligate cleaning symbionts known as branchiobdellida. This cleaning symbiosis has been found to result in significant fitness benefits for native …
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Downstream Dilemma: Navigating Microplastic's Impact on Freshwater Symbiosis in the Anthropocene
… tire wear particle morphologies while varying symbiont densities. We used the crayfish-branchiobdellidan model system in our study due to its amenability to laboratory monitoring and manipulation. The crayfish C. appalachiensis, common in the Virginia New River Basin, served as hosts to …
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