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Beyond The Fat: Protein Metabolism And Muscle Function As Part Of The Migratory Syndrome Of Songbirds, Cory R. Elowe

Doctoral Dissertations

Migration allows animals to seasonally exploit favorable habitats that are geographically disparate, and migratory animals have a suite of adaptations to complete their extraordinary journeys. This “migratory syndrome” of traits is comprised of seasonally-responsive adaptations that together result in changes to metabolism, body composition, and reproductive status, all of which act to increase the probability of a successful migration. The focus of my dissertation is to investigate the suite of changes in metabolism and muscle function that enable birds to undertake long-duration flights. In chapter 1, I compare fuel use in flight between two related migratory warbler species that migrate …

Drivers And Direct Impacts Of Lean Mass Dynamics On The Stopover Ecology And Migratory Pace Of Nearctic-Neotropical Migrant Songbirds In Spring, Mariamar Gutierrez Ramirez

Doctoral Dissertations

Annual migration in songbirds is one of the most demanding life-history stages. It represents a period of high mortality, yet there is still much unknown about the ecological correlates that influence its successful completion. After long non-stop migratory flights, birds require a stopover period to rest and replenish depleted energy reserves. Birds use fat as the primary fuel to power long-distance flights. However, birds also burn lean tissue, which results in significant reductions in muscle and organ masses. The discovery and quantification of lean mass catabolism represented a paradigm shift in migration ecology because non-fat components were thought to remain …

Characterizing The Role Bipa Plays During Cellular Adaptation In Escherichia Coli, Rebecca Bova

Doctoral Dissertations

BipA, also known as TypA, is a highly conserved protein originally identified in Salmonella typhimurium as a protein that is induced in response to bactericidal/permeability-inducing protein. Mutants lacking BipA exhibit a wide variety of phenotypes. Some of these phenotypes include: diminished pathogenicity, altered capsule biosynthesis, decreased resistance to antibiotics and antimicrobial peptides, as well as diminished growth at low temperatures. These data suggest that BipA affects multiple systems throughout the cell, suggesting that BipA plays a role in adaptation to various conditions within the cell. A similar role has been proposed for RelA although effecting transcription during adaptation rather than …

Life History And Contemporary Evolution: Implications For Managing A Hybrid Salamander Invasion, Evin Timothy Carter

Doctoral Dissertations

Predicting adaptive responses of populations is a primary goal of evolutionary ecology and conservation. While evolution on contemporary time scales is now apparent, the underlying mechanisms and whether change is adaptive or neutral often remain unclear. Typically, habitat modification, introduction of nonnative taxa, hybridization, or a combination of these factors is invoked to explain rapid evolution. I focus on an amphibian system of conservation concern to explore the interplay between ecology and evolution in shaping population genetic structure, including how habitat and physiology interact with life history to promote invasion success. I begin by using simulation to demonstrate that the …

Contemporary And Historic Effects Of Fishing On Largemouth Bass Populations, Using Unexploited Populations For Reference, Jan-Michael Hessenauer

Doctoral Dissertations

Recreational fisheries represent complex coupled human and natural systems subject to intricate feedback loops. These feedback loops can affect anglers, fish populations, and the ecosystem. I studied the effects of recreational angling on Largemouth Bass Micropterus salmoides populations, using unexploited populations for references. Exploited populations contained significantly more individuals with low metabolic rates than unexploited populations, consistent with predictions of fisheries induced evolution. Naïve individuals from unexploited and exploited populations had equal initial angling vulnerability in standardized trials. However, individuals from exploited populations learned lure avoidance faster than unexploited individuals. The cumulative number of catch events best predicted catch rates, …

Physiological Characterization Of Prochlorococcus Under Abiotic Stressors Temperature And Hydrogen Peroxide, Lanying Ma

Doctoral Dissertations

Cyanobacteria of the genus Prochlorococcus are the smallest and most abundant phytoplankters in the ocean. Temperature is a major influence on Prochlorococcus abundance and distribution in the ocean, but the physiological basis for this relationship is not well understood. In other microbes, lipid and fatty acid composition have been shown to be influenced by temperature, and temperature has also been proposed as a relevant factor for setting the elemental allocation in marine phytoplankton. In this study, we found that percentage of fatty acids unsaturation was negatively related with temperature in some Prochlorococcus strains, but this was not universal. Temperature had …

Linking Physiology And Biogeography: Disentangling The Constraints On The Distributions Of Ant Species, Lacy Danikas Chick

Doctoral Dissertations

Understanding the factors that limit the distribution of species is at the core of ecological and biogeographical research, and is critical if we are to predict the responses of key ecosystem components to ongoing climatic changes. My doctoral research seeks to provide an understanding of how thermal physiology influences species’ distributions and better define the mechanisms underlying geographic variation in biodiversity. By using natural temperature gradients (both elevational and latitudinal) and coupling controlled laboratory experiments with field observations and null modeling approaches, I was able to document the role of inter-specific variation in thermal physiology and, more interesting, inter-population variation …

The Role Of Astrocyte And Purinergic Signaling In Rtn Chemoreception, Ian C. Wenker

Doctoral Dissertations

Central chemoreception is the mechanism by which the brain regulates breathing in response to changes in tissue pH/CO2. It is particularly important during sleep and its disruption has been associated with certain pathologies, including central sleep apnea and central congenital hypoventilation syndrome. A region of the brainstem called the retrotrapezoid nucleus (RTN) is thought to be an important site of central chemoreception. Recent evidence suggests that RTN chemoreception involves two mechanisms. The first appears to be H+-mediated activation of neurons via inhibition of pH-sensitive potassium channels. More recently, a second sensing mechanism has been identified; paracrine release of ATP in …

Inorganic Carbon And Nitrogen Utilization In Mixotrophic Ciliates, Donald M. Schoener

Doctoral Dissertations

Mixotrophy is a common nutritional strategy that uses both heterotrophy and photosynthesis. Kleptoplastidic mixotrophs do not make their own plastids but acquire them from their algal prey. Before we can add mixotrophs to standard ecological models we need to understand how much each nutritional mode contributes to mixotrophic growth, and how this balance may be influenced by plastid acquisition, retention, and turnover.

In order to examine the role of captured chloroplasts in the metabolism of the oligotrich ciliate Strombidium rassoulzadegani. I evaluated the uptake and retention of chloroplasts, the ability of two different algae to supply functional chloroplasts, and …

Cellular Uptake And Actions Of Bilberry Anthocyanins In Retinal Pigment Epithelial Cells, Paul Everett Milbury Jr.

Doctoral Dissertations

Inflammation and oxidative stress play a significant role in the pathogenesis of age-related macular degeneration (AMD). In AMD, retinal pigment epithelium (RPE) cells are damaged by oxidative stress and die via the process of apoptosis. Anthocyanins from fruits and berries, such as bilberry (Vaccinium myrtillus), possess significant antioxidant activity in vitro and have been used in "traditional medicine" to treat AMD. It is not clear whether intracellular concentrations of anthocyanins are sufficient to quench radical species and mitigate oxidative stress in vivo. In this research project, human RPE cells in vitro were used to establish an oxidative stress model in …