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 21 for “"host fitness"”.
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Characterizing the early stages of a novel host shift using host fitness and metabolomics
… contribute to successful colonization of a novel host species by a pathogen remain unclear. One likely factor determining host shift success is the early interaction between host and pathogen at the very moment of the host shift event. How does a novel host respond to a pathogen insult immediately …
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The gut microbiome of the wild great tit (Parus major): drivers and fitness consequences
The gut microbiome plays a vital role in its host’s ecology. Clinical studies have shown gut microbes increase host health and fitness by providing digestive and immune functions, as well as aiding development. Natural variation in the microbiome is widely believed to affect host fitness in the …
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Systems approaches to infer microbial community interactions and their impacts on ecosystem function
… where they can have profound effects on host fitness. Thus, understanding how microbial community interactions and environmental context shape the functional capabilities of microbiomes is of vital importance if we want to engineer these systems to address challenges in human health and …
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Understanding microbial communities through horizontal gene transfer
… demonstrated that the isolated MGEs enhance host fitness by providing defence against phage predators, and hijack jumbo bacteriophages for intercellular transfer. Together, this thesis reveals how diversity, HGT events and MGEs jointly modulate and are modulated by microbial community …
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Evolutionary and ecological consequences of chronic infection in Sulfolobus islandicus
… often considered from this perspective, virus-host interactions represent a symbiotic interaction that exists along a continuum from antagonistic to mutualistic. In microbial ecology and evolution, this relationship has mostly focused on antagonistic lytic viruses. Lytic viruses are …
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THE EVOLUTIONARY ECOLOGY OF HOST-MICROBIOME SYMBIOSIS IN ONTHOPHAGUS DUNG BEETLES
The effect of host-microbe interactions on diverse aspects of host biology are increasingly appreciated across biological disciplines, yet the roles played by these interactions in shaping host evolution remain poorly understood. My dissertation research seeks to address these and related issues …
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Friends or foes? Blood parasite costs and defence abilities in young raptor hosts
… primes a spectrum of long-term consequences for host fitness, that may ultimately regulate population dynamics. In this thesis, I intend to address aspects of this fundamental arc at increasing organizational scales, from gene, tissue, individual to population. I use multiple approaches such as …
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An investigation into the host-parasite interrelationship between Common Swifts and Hippoboscid Louse-Flies
… relationship where resource transfer between a host and parasite occurs. This results in the sub-optimal expression of host life-history traits and a consequent reduction in host fitness. The Louse Fly, Crataerina pallida (Diptera: Hippoboscidae), is a monoxenous haematophagous nest ectoparasite …
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The evolution and genetics of virus resistance in Drosophila
Parasites impose high selection pressure on host fitness and are thought to be a major selective factor that promotes the evolution of resistance in host populations. Much of the resistance is determined by genetic factors, however, it is unclear what genetic factors promote resistance to …
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The Evolution of Recombination Landscapes and Mechanisms in Drosophila in Light of Intragenomic Conflict
… can increase in abundance independently of their host organism and frequently at a cost to host fitness. Several types of selfish elements act during meiosis and therefore it is possible for recombination rates and mechanisms to evolve to counteract and ameliorate their negative effects. However, …
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Gregarine parasitism in dragonfly populations of Central Texas with an assessment of fitness costs in Erythemis simplicicollis.
… (Phylum Apicomplexa) in the gut of the host. Gregarines are ubiquitous protozoan parasites that infect arthropods worldwide. More than 1,600 gregarine species have been described, but only a small percentage of invertebrates have been surveyed for these apicomplexan parasites. Some …
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Exposure heterogeneity, host immunity and virulence evolution in a wild bird-bacterium system
… consequences of this heterogeneity on pathogen fitness and evolution. A major source of heterogeneity in free-living host populations is the degree of exposure to a pathogen, as well as a host's history of exposure to a pathogen, which can create variation in standing immunity. We sought to …
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Environmental and Biotic Drivers of Seaweed–Bacterial Interactions: Insights into the Seaweed Holobiont
Seaweeds are host to a wide variety of microbes with which they form chemically mediated relationships, operating as a unified holobiont - an integrated functional unit. Host fitness is reliant on this symbiosis, with interactions from epiphytic bacteria necessary for the correct physiological …
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The causes and consequences of variation in the cloacal microbiome of tree swallows (Tachycineta bicolor)
Animals are ecological landscapes that host communities of microbes often referred to as microbiomes. These microbes can be transferred between individuals when they come into contact, such as during mating. Microbes that reside in or on any aspect of a host that becomes exposed to the reproductive …
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Factores que determinan la virulencia del virus del mosaico del pepino (CMV) en Arabidopsis thaliana
… defined as the negative effect of infection on host fitness. Understanding virulence may be of socio-economic relevance due to the important impact of infectious diseases on human, animal and plant welfare, and is fundamental to understand the role of parasites in ecosystem composition and …
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Functional diversity of fungal symbiont communities and the impact of biotic and abiotic factors on their composition and assembly
… 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 which is crucial if we are to use these important …
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Effects of the antibiotic tetracycline on the honey bee gut microbiome
Host-associated microbial communities, also known as microbiomes, are essential to the health of their hosts, and disturbance of these communities can negatively impact host fitness. The honey bee gut microbiome is a relatively simple host-associated community that makes an excellent model system …
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Dynamic patterning of maternal mRNAs in the Early C. elegans embryo
… allele ordinarily depends on its contribution to host fitness. Occasionally, however, genetic elements arise that are able to gain a transmission advantage while simultaneously imposing a fitness cost on their hosts. Seidel et al. previously discovered one such element in C. elegans that gains a …
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Factors Influencing Ectoparasitism on Western Fence Lizards (Sceloporus occidentalis): Host Sex, Testosterone, Reproductive Condition, and Behavior
<p>Host-parasite relationships are one of the most common symbiotic relationships present in a diverse array of ecosystems. There are numerous factors that impact the dynamics of these relationships. Major factors that can influence the degree of parasitism include host sex, hormonal state, …
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