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 19 of 19 for “"chemical defenses"”.
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Marine natural products as antimicrobial chemical defenses and sources of potential drugs
… The heterogeneous presentation of antimicrobial chemical defenses on host surfaces suggests the potential importance of spatial scale in understanding host-pathogen interactions, and illustrates the capacity of mass spectrometry imaging in understanding chemically-mediated biological processes. …
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The Role of Plant Chemical Defenses in The Nutritional Ecology of Voles
… conducted to examine the effects of plant chemical defenses on the individual performance, food habits, and population dynamics of voles. Results from laboratory feeding trials (Chapter One) with prairie voles (Microtus ochrogaster) showed that plant phenolics (quercetin, tannic acid, and …
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Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A.
<p>Sessile organisms employing inducible defenses may receive protection from consumers while simultaneously minimizing the metabolic costs of maintaining these defenses. To investigate if reef sponges in the South Atlantic Bight employ inducible chemical defenses, I tested two predictions with …
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Genetic Constraints and the Evolution of Chemical Defenses in Multiple Tissues of Boechera stricta
<p>In order to deter herbivores, plants evolve defenses suited to different tissues and varying patterns of herbivory. If the defense profiles of different tissues share common genetic controls but differ in selective pressures, evolution of effective defenses within the whole plant may be …
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Are Chemical Defenses Allocated within Sponges to Defend Regions Most at Risk to Predator Attack?
The allocation of chemical defenses to regions most at risk to predator attack may provide adequate protection at minimal metabolic cost. This study examined chemical defense allocation within three sponge species from a temperate reef by investigating the predictions that: concentrations of …
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Ecology of chemical defenses of algae against the herbivorous snail, Littorina littorea, in the New England rocky intertidal community
… first direct evidence that these algae produce chemicals which inhibit feeding by the snails. Polyphenols in Fucus vesiculosus and Ascophyllum nodosum were shown to be effective chemical defenses against the snails. Feeding experiments demonstrated that the presence in the diet of as little as …
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Multi-component chemical defense in seahares (Gastropoda:Opisthobranchia): antipredator compounds act as both honest and deceptive signals to multiple predator species
Many organisms produce chemical defenses to deter predation, yet the behavioral, neurophysiological, and cellular mechanisms of chemical defenses are largely unexplored. Animals do not face a single hypothetical predator, but rather a diversity of predators whose behaviors and sensory systems can …
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Sponge Community Structure and Anti-Predator Defenses on Temperate Reefs of the South Atlantic Bight
… interaction between predation and anti-predator defenses of prey is important in shaping community structure in all ecosystems. This study examined the relationship between sponge predation and the distribution of sponge anti-predator defenses on temperate reefs in the South Atlantic Bight. …
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Functional characterization and expression of molluscan detoxification enzymes and transporters involved in dietary allelochemical resistance
… with potentially toxic or fitness-reducing allelochemicals is important for understanding patterns of predation and herbivory in the marine environment. The ability of marine consumers to tolerate dietary toxins may involve biochemical resistance mechanisms, which increase the hydrophilicity of …
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Carbon based secondary metabolites in African savanna woody species in relation to anti-herbivore defense
Chemical defense in African savanna woody species have been inferred from foliar condensed tannin and total phenolic concentrations. However these measures are controversial since condensed tannin chemical heterogeneity compromises its simple quantification and total phenolics, which is a measure …
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Culture-independent analysis of the bacterial community shifts in a macroalgal disease
… when seawater temperature rises and the algal’s chemical defenses are reduced. The role of bacteria in the disease has been implied by difference in the microbial community composition between healthy and bleached algae and by two bacterial strains that can cause bleaching in vitro. In the …
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Dose Dependent Survivability of Gfp-Expressing Escherichia Coli in the Alimentary Canal of House Flies (<i>Musca domestica L.</i>)
… response, the fly gut has other physical and chemical defenses, which may serve in immobilizing and lysing ingested bacteria. This study investigated the dose dependent survivability of GFP-expressing Escherichia coli (GFP E. coli) in the fly alimentary canal and transmissibility of each …
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Ecological significance of seed traits in the genus Macaranga
… requirements for germination, investment in seed chemical and physical defense, and seed persistence in the soil. Empirical measurements of germination and seed persistence in the soil were made at Lambir Hill National Park in Borneo, and coupled with analyses of the physical and chemical defense …
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THE ROLE OF MICROBIAL ENDOSYMBIONTS IN SORGHUM HALEPENSE INVASIONS: EVIDENCE OF A NEW INVASION STRATEGY, MICROBIALLY ENHANCED COMPETITIVE ABILITY (MECA)
… growth rates, increased biomass, and enhanced chemical defenses have been documented in many invasive plants. When expanding into new ranges, these traits frequently allow invasive plants to outcompete native plant communities. Current theories suggest these invasive attributes are …
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THE ROLE OF MICROBIAL ENDOSYMBIONTS IN SORGHUM HALEPENSE INVASIONS: EVIDENCE OF A NEW INVASION STRATEGY, MICROBIALLY ENHANCED COMPETITIVE ABILITY (MECA)
… growth rates, increased biomass, and enhanced chemical defenses have been documented in many invasive plants. When expanding into new ranges, these traits frequently allow invasive plants to outcompete native plant communities. Current theories suggest these invasive attributes are …
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Identification, Characterization, and Functional Analysis of Terpenoid Specialized Metabolism in Switchgrass (Panicum virgatum) and Carrot (Daucus carota)
… sesquiterpenes that likely function in direct chemical defense or in the attraction of insect predators or parasitoids. Drought stress application caused switchgrass roots to accumulate a larger amount of oxygenated terpenes and presumably non-volatile terpenes, the function of which in direct …
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Establishment and trait variation of a range expanding Brassicaceae species under various growth conditions
… of leaf glucosinolates, known for their chemical defense properties and commonly found in the Brassicaceae family.<br /> Additionally, I analyzed the leaf peroxidase activity, which is known to play a role in plant-pathogen interactions, and compared the trichome densities on leaves in …
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Variação nas concentrações de compostos fenólicos e nas taxas de herbivoria em Aspidosperma pyrifolium Mart. em áreas antropizadas de Caatinga
A herbivoria é o consumo de partes das plantas que pode afetar negativamente seu fitness, sendo um dos fatores responsáveis pela estruturação e composição das comunidades vegetais. Fatores, como disponibilidade de recursos e perturbações antrópicas, possuem papel relevante nas respostas à atuação …
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Unravelling multidimensions of the flora of Kenya floristics, herbivory defences, and phylogenetic diversity
… Kenya; (3) to evaluate structural and chemical plant defense manifestations between woody plants of the broad-leaved non-spiny Combretum – Terminalia and narrow-leaved spiny Acacia – Commiphora woodlands studied in Objective 2; and (4) to infer age, phylogenetic diversity and structure …