Life Sciences Commons^™

The Functional Implications Of Anuran Metamorphosis For Survival, Locomotor Performance, And Limb Bone Mechanical Properties, Chase Kinsey

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Many organisms must contend with navigating their environments from birth. An organism could be classified as – and is often studied – in the context of locomotion through a single habitat type. However, many organisms must contend with a wide variety of environmental obstacles and substrates. What’s more, a large group of animals, Lissamphibia, do so while undergoing drastic transformation of their morphology and locomotor appendages. This transformation, term metamorphosis, typically coincides with a movement from water as a tadpole, to land as a frog or salamander. Many studies have associated this transitionary period with decreased locomotor performance and worse …

Revision, Description, And Diagnosis Of Adult And Larval Pycnopsyche Spp. (Trichoptera: Limnephilidae) Using Morphological And Molecular Methods, Matthew Green

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The genus Pycnopsyche Banks, 1905 (Trichoptera: Limnephilidae) is the 2nd most species-rich genus of Nearctic Limnephilidae. Larvae and adults are ecologically diverse and widespread throughout eastern North America. Larvae construct cases from mineral or plant material and are frequently used by biomonitoring professionals at the species level to monitor trends in water quality. However, only two species of Pycnopsyche are currently separable as larvae, with diagnosis limited by the number of unknown larvae associated with known adults. Using morphological and molecular data, the phylogenetic relationships among Pycnopsyche species and species groups were inferred with Bayesian and Maximum Likelihood analyses to …

Functional Characterization Of The Toxoplasma Gondii Endolysosomal System, Leah Brock Thornton

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Toxoplasma gondii is an obligate intracellular parasite that can infect a wide range of mammalian hosts. T. gondii can cause severe disease in immunocompromised individuals as well as pregnant women, in which congenital toxoplasmosis can lead to spontaneous abortion and fetal blindness. T. gondii infects up to roughly one-third of the global human population and is the causative agent of toxoplasmosis. Given this health burden of toxoplasmosis and that antibiotics currently used for the treatment of infection lead to strong side effects, identification of parasite-specific targets are necessary for novel therapeutic strategies.

T. gondii parasites contain a dynamic and active …

Supertertiary Structural Dynamics Modulate Function In Postsynaptic Density Protein 95, George L. Hamilton Iii

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Proteins, RNA, and DNA serve as the primary sub-cellular machinery that give rise to the necessary functions of life. The long-standing paradigm has been that the structures of biomolecules, or the arrangement of the subunits that make up a biomolecule, determine biological function. However, biomolecules are not static objects. Instead, they often undergo structural rearrangements that are crucial to enabling and regulating their functions. In my thesis I present several studies of the interplay between the structures, dynamics, and functions of biomolecules that combine experimental fluorescence spectroscopy and computational methods to probe these systems at the single-molecule level. In particular, …

Killer Cell Activation By A Novel Multifunctional Protein: An Immuno/Gene Therapy For Cancer, Ashlee Tietje

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One of the characteristics of advanced tumors is the evasion of the immune system. There are multiple methods that tumor cells employ to achieve this including reducing the expression of activating ligands on the cell surface and a shift in the tumor microenvironment toward pro-tumor cytokines. The purpose of this research is to develop a novel bifunctional fusion protein that will target these two deficiencies in the tumor microenvironment and activate killer cells that are already present. The proposed protein combines the extracellular domain of a ligand for the killer cell activating receptor NKG2D and Interleukin-12 (IL-12). It is hypothesized …

Life History And Natural Enemies Of Parthenolecanium Spp. In Four Southeastern States, Ernesto Robayo Camacho

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Soft scales (Hemiptera: Coccidae) are some of the most prevalent and difficult to control arthropod pests in urban landscapes of the southern United States. European fruit lecanium, Parthenolecanium corni (Bouche), and oak lecanium, Parthenolecanium quercifex (Fitch), are commonly found in mixed populations as pests of oak trees (Quercus spp.) in the region. The phenology and natural enemies of the two species are poorly understood, which in turn hinders pest managers' ability to develop an integrated management program against these species. This research project aims to fill the information gaps concerning the life history and natural enemies of P. corni and …

Phylogenomics And Historical Biogeography Of The Gooseneck Barnacle Pollicipes Elegans, Sergio Andres Marchant Rojas

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This dissertation explores the systematics, biogeography, and genomics of the gooseneck barnacle Pollicipes elegans, a marine crustacean of the tropical Eastern Pacific. In Chapter 1, I provide a broad framework for my research by introducing and focusing on the long-­‐standing debate of the mechanisms behind the latitudinal gradient in species diversity, which provided the initial motivation for using Pollicipes elegans as a model system to study the mechanisms leading to genetic differentiation and speciation in tropical regions. In Chapter 2, I examine the genetic structure, infer patterns of connectivity across the warm tropical waters of the eastern Pacific, and reconstruct …

The Avian Thrombocyte Is A Specialized Immune Cell, Farzana Ferdous

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Thrombocytes are the most abundant circulating cells next to red blood cells in avian blood. Avian thrombocytes are homologous in function to mammalian platelets. Avian thrombocytes and the mammalian platelet are widely recognized contributors to inflammatory responses upon stimulation with various microbial stimulants. However, some observed responses of the avian thrombocyte depart from a standardized model ascribed to innate cells. To help unravel the role of thrombocytes in innate immunity, and possibly adaptive immunity, first we examined the surface features of chicken thrombocytes. Chicken thrombocytes constitutively express transcripts for different Toll-like receptors (TLRs) that are crucial for the innate immune …

Influence Of Periostin On Bone Marrow-Derived Cell Contribution To Dermal Wound Repair, Suzanne Parks

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Originally thought to function only as a scaffold, the extracellular matrix (ECM) is now understood to provide signals that regulate all aspects of cellular phenotype. Matricellular proteins are a subset of ECM-related molecules defined by their ability to modulate interactions between cells and the ECM. Periostin was recently classified as a matricellular protein based on its expression and function during development and wound repair. Periostin has been shown to influence cell behavior and collagen fibrillogenesis in several tissue types. In this study, we examined how periostin expression influences fibrocyte behavior after dermal injury using periostin null (Pstn -/-) and wild-type …

Range Collapse, Genetic Differentiation, And Climate Change: An Ecological History Of The Diana Fritillary, Speyeria Diana And Projections For Its Future, Carrie Wells

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The geographic ranges of most plant and animal species are tied closely to climatic factors, including temperature, precipitation, and soil moisture. For this reason, recent changes in the global climate due to human activities are predicted to have profound effects on natural populations, communities and ecosystems over a relatively short period of time. Combined effects from global warming and other anthropogenic activities such as land-use changes, pollution, and habitat loss/fragmentation, are altering species' distributions faster than they can be documented. Recent climate change has also been shown to alter species' breeding behaviors and alter the synchrony and timing of species' …

Range Limits, Range Shifts, And Lower Thermal Tolerance In The Tropical Barnacle Megabalanus Coccopoma, Samuel Crickenberger

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Climate change and species introductions are leading to shifts in marine species' geographic distributions. However, few studies have examined range limits and range shifts in tropical marine species. The barnacle Megabalanus coccopoma is native to shorelines from Baja California to Peru and has been introduced to a number of locations worldwide including the Atlantic US SE coast, where its current introduced range extends from Ft. Pierce, FL to Cape Hatteras, NC with seasonal populations as far north as Kitty Hawk, NC. In order to understand the potential poleward range limit of M. coccopoma in the US SE under modern day …

Gap Junctions: Regulators Of Cellular Immunity And Parasite Manipulation In The Remarkable Tripartite Relationship Involving Insects And Genome-Integrated Polydnaviruses, Daniel Hasegawa

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Communication means everything. From vocalization to the firing of a neuron, coordination through the exchange of signals is essential to the survival of all living things. At the cellular level, communication is accomplished through the use of gap junction channels. Gap junctions are found in virtually all multicellular animals, where they play critical roles in developmental, physiological, metabolic, and even structural processes. From the maintenance of heart rhythms in humans, to the coordination of tissue regeneration in flatworms, and to the processing of visual stimuli in flies, the roles for gap junctions are diverse. However, how this diversity is accomplished …

The Effects Of Temperature On Energy Utilization By Marine Invertebrate Larvae, Elizabeth Whitehill

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Most ectothermic organisms are larger when reared at lower temperatures and temperature can greatly affect an organism's physiological state, so understanding how temperature affects larval size and quality can provide insight into how the larval thermal environment affects post-metamorphic success. Because quality is often defined in terms of size and energy content, I focused on how temperature affects energy utilization by larvae and how differences in energy accumulation and utilization may carry over into the juvenile stage. Marine invertebrate larvae are often classified into two groups: larvae from smaller eggs that must obtain food from the environment in order to …

Lipid Metabolism In Trypanosoma Brucei: Molecular Characterization Of Fatty Acid Synthesis And Uptake, Patrick Vigueira

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My doctoral studies focused on the fatty acid metabolism of the deadly protozoan parasite, Trypanosoma brucei. Fatty acid metabolism in T. brucei can be broadly divided into two pathways, synthesis and uptake. In Chapters 2-4 I describe experiments investigating the parasite's fatty acid synthesis pathway. Chapter 2 contains the initial characterization of acetyl-CoA carboxylase (ACC) in T. brucei. Knockdown of TbACC by RNA interference (RNAi) reduced parasite virulence in a mouse model, suggesting that TbACC has the potential to be utilized as a drug target. Chapters 3 and 4 explore the effects of two known ACC inhibitors, the …

The Effects Of Indirubin Derivitives On Gene Expression And Cellular Functions In The Murine Macrophage, Abigail Babcock

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Indirubin is the active ingredient in the ancient herbal remedy, Danggui Longhui Wan, which is used as an anti-leukemic, anti-inflammatory, and detoxification treatment. Indirubin-3'-monoxime (IO) is the most widely studied of the indirubin derivatives. Most have been shown to inhibit cyclin-dependent kinases and glycogen synthase kinases, triggering cell cycle arrest and apoptosis with different levels of activity depending on the particular structure. These kinases inhibited by indirubin(s) play key roles in cellular proliferation and immune functions, therefore synthetic indirubins may have significant applications as therapeutic agents for cancer, inflammation, and neurological diseases.
Indirubin is also a potent aryl hydrocarbon receptor …

Histologic Examination Of Host-Parasite Interactions In The Gulf Killifish, Fundulus Grandis, Marlee Marsh

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Little is known about the immunobiology of fish responses to parasitic infections. The aim of this study was to describe a model for the examination of fish-nematode interactions on the immunological front, and to develop new reagents for the study of this model. Gulf killifish, Fundulus grandis, were collected over two seasons from Simmon's Bayou, Jackson County, MS, USA, pre Hurricane Katrina, and examined for endoparasites, particularly the larval nematode Eustrongylides ignotus. A baseline study was preformed to determine the prevalence, intensity, and histologic features of E. ignotus infection in F. grandis, and this study serves as the first description …

Biochemical Study Of Endonuclease V And Its Application In Mutation Scanning, Honghai Gao

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The integrity of the genetic information encoded by DNA is essential to all living organisms, yet the reactive bases of DNA are constantly attacked by endogenous and exogenous agents resulting in as many as one million individual molecular lesions per cell per day. Excessive DNA damage or deficiency in DNA repair enzymes may cause cancer, premature aging, and neurodegenerative diseases.
Endonuclease V (Endo V) is a DNA repair enzyme which can recognize all four types of DNA deamination products, specifically, uracil, hypoxanthine, xanthine and oxanine. It was also shown that endo V can recognize mismatches. We screened about 60 mutants …