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Hiv-1 Envelope-Induced Signaling Mediates Actin Cytoskeleton Rearrangements Necessary For Fusion And Entry, Brooke Harmon

All Theses and Dissertations (ETDs)

Human immunodeficiency virus type-1: HIV-1) initiates infection by direct fusion of the virus membrane with the plasma membrane of the target cell. This fusion event is a multi-step process mediated by the envelope: Env) surface subunit gp120 and the transmembrane subunit gp41 which anchors gp120 into the viral membrane. First the surface subunit gp120 binds to the primary receptor CD4. This interaction promotes actin cytoskeletal rearrangements in the target membrane that bring the chemokine coreceptor, CCR5 or CXCR4, into close proximity for binding and induces conformational changes in gp120 that allow it to couple to the coreceptor. Formation of the …

Functional Significance Of Glycoprotein Clearance By The Asialoglycoprotein Receptor And The Mannose/Galnac-4-So4 Receptor, Lindsay Steirer Taylor

All Theses and Dissertations (ETDs)

Glycosylation plays an important role in many biological functions. Two highly abundant, carbohydrate-specific, endocytic receptors reside in parenchymal and endothelial cells of the liver. Our lab has shown that the asialoglycoprotein receptor: ASGR) is capable of clearing glycoproteins bearing terminal Siaalpha2,6GalNAc as well as ones bearing terminal Gal/ GalNAc and that the Mannose/GalNAc-4-SO4 receptor: MR) is capable of clearing glycoproteins bearing terminal GalNAc-4-SO4. I am taking a genetic approach identifying endogenous ligands for the ASGR and the MR in vivo and establishing the biologic significance of clearing these glycoproteins from the blood. A number of glycosylated hormones such as luteinizing …

Calling Cards For Dna-Binding Proteins, Haoyi Wang

All Theses and Dissertations (ETDs)

Organisms respond to their environment by altering patterns of gene expression. This process is orchestrated by transcription factors, which bind to specific DNA sequences near genes. In order to understand the regulatory networks that control transcription, the genomic targets of all transcription factors under various conditions and in different cell types must be identified. This remains a distant goal, mainly due to the lack of a high-throughput, in vivo method to study protein-DNA interactions. To fill this gap, I developed transposon "Calling Cards" for DNA-binding proteins. I endowed DNA binding proteins with the ability to direct the insertion of a …

Gamebird 2006: Quail Vi And Perdix Xii, Sandra B. Cederbaum, Brant C. Faircloth, Theron M. Terhune, Jeffrey J. Thompson, John P. Carroll

School of Natural Resources: Faculty Publications

Foreword v

Acknowledgements vi

Editorial Panel vii

Sponsors x

Invited Manuscripts 2

Integrating Management, Research, and Monitoring: Balancing the 3-Legged Stool. Michael J. Conroy & James T. Peterson . 2

Management of Southern African Gamebirds: Opportunities and Threats. Tim Crowe . 11

Taking the Northern Bobwhite Conservation Initiative to the Next Level. Donald F. McKenzie . 16

Restoring a Gray Partridge (Perdix perdix) Population and the Future of Predation Control. G.R. Potts . 24

Abundance Estimation 27

The GWCT Partridge Count Scheme: A Volunteer-Based Monitoring and Conservation Promotion Scheme. Julie Ewald, Nevile Kingdon, & Hugues Santin-Janin . 27

Refining the …

Identification And Characterization Of Novel Astroviruses, Stacy Finkbeiner

All Theses and Dissertations (ETDs)

Approximately 1.8 million children die from diarrhea annually, and millions more suffer multiple episodes of nonfatal diarrhea. Despite the availability of improved molecular diagnostics to detect the known viral agents, the etiology of a large proportion of diarrheal cases is unknown. In fact, it is estimated that no causative agent can be identified in up to 40% of sporadic cases or in gastroenteritis outbreaks. Detection of novel or unexpected viruses is the first step in identifying agents that could potentially close the diagnostic gap and pave the way for the development of more comprehensive preventative measures and better treatments. This …

Systemic Levels Of G-Csf And Il-6 Determine The Angiogenic Potential Of Bone Marrow Resident Monocytes, Alyssa Gregory

All Theses and Dissertations (ETDs)

Recent studies have demonstrated the efficacy of hematopoietic cell-based therapies in promoting therapeutic angiogenesis for a wide variety of vascular syndromes, however the cell populations responsible and the mechanisms involved are poorly understood. Using a mouse model of hindlimb ischemia, we previously showed that an adoptive transfer of donor monocytes significantly enhanced revascularization. Monocytes are a widely heterogeneous cell population and differences in the ability of various monocyte subsets to mediate revascularization have not been previously investigated. Using the hindlimb ischemia model we demonstrate that an adoptive transfer of inflammatory: CX3CR loGr-1+), but not resident: CX3CR1hiGr-1-) monocytes, significantly enhances revascularization …

A Role For The Ecdysone Response Gene E93 In Imaginaling Patterning During Metamorphosis, Xiaochun Mou

All Theses and Dissertations (ETDs)

Drosophila melanogaster E93 is an early ecdysone response gene that encodes a pipsqueak domain transcription factor. E93 is induced by ecdysone at the end of larval development, and directs the death and elimination of several larval tissues during metamorphosis. Although E93 has been considered a dedicated regulator of larval cell death, I have found that E93 is also widely expressed in imaginal tissues during metamorphosis, where it is required for the proper patterning of many adult structures. Our working hypothesis is that E93 functions in imaginal tissues as a metamorphosis-specific cofactor that determines the pupa-specific action of numerous other transcription …

Aggregation & Localization Of A Disease-Associated Prion Protein (Prp) Mutant, Andrea Rhonda Medrano

All Theses and Dissertations (ETDs)

ABSTRACT OF THE DISSERTATION Aggregation & Localization of a Disease-Associated Prion Protein: PrP) Mutant by Andrea Rhonda Zaragoza Medrano Doctor of Philosophy in Biology and Biomedical Sciences: Genetics) Washington University in St. Louis, 2009 Professor David A. Harris, Chairperson Prion protein: PrP) is a GPI-anchored sialoglycoprotein involved in the pathogenesis of infectious and inherited forms of transmissible spongiform encephalopathies: TSEs). A nine-octapeptide insertional mutation in the prion protein: PrP) causes a fatal neurodegenerative disorder in both humans and transgenic mice. To determine the precise cellular localization of this mutant PrP: designated PG14), we have generated transgenic mice expressing PG14-EGFP, a …

Evolution Of Endosperm Starch Synthesis Pathway Genes In The Context Of Rice: Oryza Sativa) Domestication, Guoqin Yu

All Theses and Dissertations (ETDs)

The evolution of metabolic pathways is a fundamental but poorly understood aspect of evolutionary change. The rice endosperm starch biosynthetic pathway is one of the most thoroughly characterized biosynthesis pathways in plants, and starch is a trait that has evolved in response to strong selection during rice domestication and subsequent crop improvement. In this study, I have examined six key genes in the rice endosperm starch biosynthesis pathway to investigate the evolution of this pathway before rice domestication and during rice domestication. Oryza rufipogon is the wild ancestor of cultivated rice: Oryza sativa). Oryza sativa has five variety groups: aus, …

Identification And Characterization Of A Xylosylphosphotransferase Of Cryptococcus Neoformans, Morgann Reilly

All Theses and Dissertations (ETDs)

Cryptococcus neoformans is an environmental yeast and an opportunistic pathogen capable of causing a meningoencephalitis in human hosts. The organism produces an extensive polysaccharide capsule that is unique among pathogenic fungi and absolutely required for its virulence. Work in the Doering laboratory on the capsule and other glycoconjugates of C. neoformans has focused on the identification of glycosyltransferases, enzymes that catalyze the transfer of a sugar moiety from an active donor to a specific acceptor, creating a particular linkage. Previous work demonstrated that xylose residues, derived from the nucleotide sugar UDP-xylose, are necessary for cryptococcal virulence. An assay to detect …

Medial Temporal Lobe Structure And Function, Meghana Karnik

All Theses and Dissertations (ETDs)

Medial Temporal Lobe Structure and Function by Meghana Sunil Karnik Doctor of Philosophy in Biology and Biomedical Sciences: Neuroscience) Washington University in St. Louis, 2009 Professor John G. Csernansky, Chairperson My main goal was to examine the relationship between brain structure and function, specifically medial temporal lobe structure and episodic memory, in various groups of subjects who had schizophrenia, were at risk for schizophrenia because of genetic and disease influences, or who were healthy, in order to explore the influence of genetic and disease influences on brain structure-function relationships. Most of what is known about the neural structures thought to …

Flap Endonuclease 1 Ensures Telomere Replication And Stability, Abhishek Saharia

All Theses and Dissertations (ETDs)

Telomeres, protein-DNA structures that distinguish the end of a chromosome from a bona fide DNA double strand break, are integral to genomic stability. High fidelity replication of telomeres is indispensable for their stability. Telomere replication is a challenging task that is completed through the coordinated actions of telomere binding proteins and DNA replication and repair proteins in ways that are not well understood. This work focuses on delineating the function of one DNA replication and repair protein, Flap Endonulcease 1: FEN1), in telomere replication and maintenance. I demonstrate that FEN1 is essential for the efficient replication of telomeres through its …

The Mechanisms And Roles Of Feedback Loops For Visual Processing, Jing Shao

All Theses and Dissertations (ETDs)

Signal flow in the brain is not unidirectional; feedback represents a key element in neural signal processing. To address the question on how do neural feedback loops work in terms of synapses, microcircuitry, and systems dynamics, we developed a chick midbrain slice preparation to study and characterize one important feedback loop within the avian visual system: isthmotectal feedbackloop. The isthmotectal feedback loop consists of the optic tectum: OT) and three nucleus isthmi: Imc, Ipc and SLu. The tectal layer 10 neurons project to ipsilateral Imc, Ipc and SLu in a topographic way. In turn Ipc and SLu send back topographical: …

Tracking Bacterial Pollution In The Cains Brook/Mill Creek Watershed: Implications For Policy And Management, Aaron Kornbluth

Master's Theses and Capstones

Pathogenic fecal bacteria present a management challenge when they contaminate surface waters used by humans. This study examined the extent to which the ongoing Cains Brook/Mill Creek watershed restoration in Seabrook, NH has successfully characterized the problem of bacterial pollution and implemented mitigation practices. Guided by the policy sciences analytical framework, this study employed a policy implementation audit reviewing relevant bacteria source tracking data, interviews and online surveys as a means to triangulate multiple data sources. Results indicate that bacteria arise from multiple sources and impairments still exist, although bacteria levels were not generally high. Management activities have likely reduced …

Morphological Variation In Codium Fragile In The Northwest Atlantic, Lucy Elizabeth Pleticha

Master's Theses and Capstones

Codium fragile (Suringar) Hariot, an invasive Asiatic green alga, has colonized areas of the NW Atlantic within the past fifty years. The plant has a dichotomously branched cylindrical thallus made of tangled filaments surrounded by a dense covering of swollen filament tips, or utricles, terminating in pointed mucrons. This study's goal was to investigate morphological differences in NW Atlantic C. fragile populations to determine which subspecies are present. In the summer of 2008, I surveyed 24 sites from the Canadian Maritimes to Long Island Sound and evaluated size variation in utricles. Morphological investigations revealed a two-fold difference in utricle and …

Karyotyping And Localization Of Genes On The Chromosomes Of The Sea Urchins, Strongylocentrotus Drobachiensis And Strongylocentrotus Purpuratus, Celeste Chloe Eno

Master's Theses and Capstones

The purple sea urchin, Strongylocentrotus purpuratus , is an important model for probing gene interactions during animal development and is the only non-chordate deuterostome for which a complete genome sequence is available. None of the genes cloned in this project have been localized on chromosomes, and maps of gene loci for S. purpuratus and for all sea urchin species do not exist. Here I provide a description of the first successful methods for karyotyping and localizing of specific gene loci on chromosomes of the purple sea urchin, Strongylocentrotus purpuratus and also of the related green sea urchin, Strongylocentrotus droebachiensis.

Both …

Temporal Expression Of Progesterone And Proteins Associated With Prostaglandin F2alpha-Induced Luteolysis In The Sheep, Darren E. Ferguson

Master's Theses and Capstones

To better understand the events associated with the functional and structural regression of the corpus luteum (CL), the temporal expression of steroidogenic acute regulatory (StAR) protein, progesterone (P4), matrix metalloproteinase (MMP)-2 and -9, tissue inhibitor of metalloproteinase (TIMP)-1 and -2, cyclooxygenase (COX)-1 and -2 was determined following three systemic infusions of PGF2alpha, in sheep. Luteectomies were performed at 0 hour (controls) or at -1, 1, 8, 16, and 24 hours relative to the third infusion of PGF2alpha. Plasma samples were also collected. StAR decreased 60 and 45% at the 16 and 24 hour time points, respectively, while P4 reached a …

Effects Of Forested Buffers And Wetland Characteristics On Vernal Pool Macroinvertebrate Assemblages, Joanne Evelyn Theriault

Master's Theses and Capstones

From 2005-2007, I sampled macroinvertebrates at 10 vernal pools to determine the effects of forested buffer treatments (30-m or 100-m). I grouped taxa into three subgroups: taxa enumerated and identified to genus (Trichopterans, Anisopterans, Coleopterans, and Hemipterans); taxa identified to family and documented as present or absent; and predatory taxa (enumerated and identified to genus). I measured hydroperiod, surface area, pH, conductivity, substrate cover, canopy cover, and annual and seasonal variability and used Non-Metric Multidimensional Scaling (NMS) to examine effects on composition. Finally, I analyzed NMS scores using Linear Mixed Models. Buffer treatments explained a significant amount of variation in …

An Assessment Of Stress In Acer Saccharum As A Possible Response To Climate Change, Martha Carlson

Master's Theses and Capstones

Climate change is projected to extirpate Acer saccharum throughout its range in the United States. The current investigation evaluates the potential of spectral indices of foliar reflectance, measures of leaf area and bud quality, and historic trends in sap sugar and wood increments for detecting stress in sugar maple.

Thirty trees were examined in 10 plots on 5 sugar bushes in or near the Bearcamp Valley, New Hampshire, over the course of the 2008 growing season. The study found water stress in 100% of trees; reduced chlorophyll content in 60%; early abscission of leaves in 80%; reduced growing season in …

Extrapolating Hyperspectral Anthocyanin Indices To Multispectral Satellite Sensors---Applications To Fall Foliage In New England, Erica Lindgren

Master's Theses and Capstones

Anthocyanin, thought to be a universal indicator of plant stress, is a red pigment found in many plant species and can seen in New England autumns. Detecting its presence is useful for ecosystem analysis and monitoring changes during autumn senescence. Currently fall foliage is subjectively measured; creation of a satellite-based anthocyanin index will provide an objective measurement and enhance understanding of the distribution of plant stress and senescence over large areas. Anthocyanin indices were tested hyperspectrally in a laboratory setting, then indices were simulated for Hyperion, MERIS, MODIS, and Landsat TM/ETM+ to see which most accurately represents changes in anthocyanin …

Contributions Of Groundwater Seepage To The Water And Nutrient Budget Of Mendums Pond Barrington, New Hampshire, Susan E. Wilderman

Master's Theses and Capstones

An understanding of the rates of groundwater seepage into and out of a pond or lake is important in assessing the flux of contaminants in a given system. Many studies have assessed the contribution of overland runoff and precipitation to freshwater pollution, but few have focused on direct measurement of groundwater inputs of nutrients and water to lakes. Spatial variation and natural heterogeneity of groundwater seepage around a large pond or lake can vary and make it an ambiguous and challenging parameter to quantify. The amount of groundwater seepage is thought to be related to the physical characteristics of a …

Assessing Spatial Distributions Of Cyanobacteria And Microcystins In Nh Lakes With Implications For Lake Monitoring, Amanda Lee Murby

Master's Theses and Capstones

Cyanobacteria pose a threat to the health of humans and wildlife when concentrations are high and the species present are toxic. However, routine monitoring of toxic cyanobacteria in lakes is not typical in the United States and, currently, there are no standards on the allowable limit of cyanotoxins in N.H. water bodies. Phycocyanin (PC) fluorescence was evaluated as an indicator for cyanobacteria densities, with implications for monitoring cyanobacteria and microcystins in lakes. PC fluorescence predicted cultured cyanobacteria, ranging from 0--900,000 cells ml-1 (Adj R 2 0.99, p<0.001). PC fluorescence was also useful for estimating microcystin (MC) concentrations among lakes of varying trophic status (p<0.001) and was more significant than net cyanobacteria counts were for predicting microcystin concentrations (p=0.049). Synoptic, horizontal sampling revealed the significant variability in the spatial distributions of cyanobacteria and microcystins in N.H. lakes.

Insect Responses To Invasive Shrubs In Early-Successional Habitats, Johanna L. Fickenscher

Master's Theses and Capstones

Early-successional habitats are valuable to wildlife species and susceptible to invasive shrubs, possibly negatively affecting biodiversity of whole communities. Insects provide energy links between plants and wildlife, thus, change in insect communities due to invasive shrubs may have detrimental impacts on wildlife---especially nesting songbirds. I gauged how invasive shrubs affect insect abundance, richness, and phenology using flight-intercept trapping and beat/sweeping methods. Lepidopteran larvae were provided a choice to consume native or invasive shrub foliage. Invasive shrubs negatively affected communities with reduced insect abundance and richness on individual shrubs as well as the entire habitat. Lepidopteran larvae preferred native shrub foliage …

Regulation Of Polyamine Metabolism In Transgenic Poplar Cell Cultures, Smita Cherry

Master's Theses and Capstones

Polyamines (PA) are naturally occurring low molecular weight aliphatic amines found in all living organisms and essential for their growth and development. The present study uses the tool of transgenic manipulation to elucidate the regulation of PA pathway in poplar cells. This study was divided into two segments; the first segment provides insight into biochemistry of a putrescine overproducing cell line (HP) that overexpresses a mouse ornithine decarboxylase (mODC) under 35S-CaMV promoter, with respect to different treatments. The second segment focused on creation and biochemical characterization of a cell line (SOS1) that overexpresses ODC/SAMDC from Plasmodium falciparum controlled by the …

Effect Of Cholinergic Deafferentation Of Prefrontal Cortex On Working Memory For Familiar And Novel Odors, Emily Carter

Master's Theses and Capstones

The role of acetylcholine in the medial prefrontal cortex (mPFC) in working memory was investigated in aged rats. Subjects with cholinergic lesions of the prelimbic portion of the mPFC (pACh-lx) or a sham lesion of the same region were trained on an odor delayed non-match to sample paradigm. The effects of prefrontal cholinergic depletion and aging were assessed in task variations that manipulated mnemonic demand and stimulus novelty.

pACh-lx animals were impaired relative to sham-lx animals at memory for familiar stimuli over delays. This global impairment was not dependent on the length of the delay, suggesting that aged pACh-lx animals …

Eeg During Pedaling: Brain Activity During A Locomotion-Like Task In Humans, Sanket G. Jain

Master's Theses (2009 -)

This study characterized the brain electrical activity during pedaling, a locomotor-like task, in humans. We postulated that phasic brain activity would be associated with active pedaling, consistent with a cortical role in locomotor tasks. 64 channels of electroencephalogram (EEG) and 10 channels of electromyogram (EMG) data were recorded from 10 neurologically-intact volunteers while they performed active and passive (no effort) pedaling on a custom-designed stationary bicycle. Ensemble average waveforms, two dimensional topographic maps and amplitude of the beta (13-35 Hz) frequency band were analyzed and compared between active and passive trials. The absolute amplitude (peak positive-peak negative) of the EEG …

Genetic Over-Expression Of Cytokeratin 18 In Bovine Luteal Cells: Effects On Intermediate Filament Formation And Fas Ligand-Induced Apoptosis, Jennifer J. Forcina

Master's Theses and Capstones

The receptor Fas and its ligand, FasL, are implicated in apoptosis of luteal cells during regression of the corpus luteum (CL). In some cell types, cytokeratin (CK) 8/18 filaments impair FasL-induced apoptosis. Here, we determined if genetic over-expression of CK18 filaments in luteal cells similarly prevents FasL-induced apoptosis. Luteal cell cultures were prepared from early and late stage bovine CL (day 5 and days 16-18 post-ovulation, respectively). The cells were transduced with media, mock vector containing GFP, or a CK18-containing vector, and then exposed to a cytokine cocktail containing FasL for 24 hours. Transduction of luteal cells with CK18 vector …

Feature Topography And Sound Intensity Level Encoding In Primary Auditory Cortex, Paul Watkins

All Theses and Dissertations (ETDs)

The primary auditory cortex: A1) in mammals is one of the first areas in the neocortex that receives auditory related spiking activity from the thalamus. Because the neocortex is implicated in regulating high-level brain phenomena, such as attention and perception, it is therefore important in regards to these high-level behaviors to understand how sounds are represented and transformed by neuronal circuits in this area. The topographic organization of neuronal responses to auditory features in A1 provides evidence for potential mechanisms and functional roles of this neural circuitry. This dissertation presents results from models of topographic organization supporting the notion that …

Characterization Of Ligand-Induced Conformational Changes In The Egf Receptor, Katherine Yang

All Theses and Dissertations (ETDs)

ABSTRACT OF DISSERTATION Characterization of ligand-induced conformational changes in the EGF receptor by Katherine S. Yang Doctor of Philosophy in Biochemistry Washington University in St. Louis, 2009 Professor Linda Pike, Chairperson The epidermal growth factor: EGF) receptor is a classical receptor tyrosine kinase that mediates cellular processes such as proliferation, migration, and differentiation in response to growth factor stimulation. Crystal structures of the EGF receptor suggest that its activation is associated with extensive conformational changes in both the extracellular and intracellular domains. However, evidence of these structural dynamics in intact cells has been lacking. This thesis describes the characterization of …

Effects Of Sedimentation And Periphyton Communities On Embryonic Rainbow Smelt, Osmerus Mordax, Lauren Helena Wyatt

Master's Theses and Capstones

The decline of anadromous rainbow smelt (Osmerus mordax) populations has been suspected to be linked to anthropogenic causes. Increased runoff from agriculture and urbanization has led to additional sediment inputs and eutrophying compounds in rivers. The aim of this study was to assess the survival of embryonic rainbow smelt from fertilization through hatching under varying levels of sedimentation (0.00, 0.25, 1.00, and 6.00 g per 45.6 cm 2) and with periphyton communities of different biomass and algal composition. Additionally, embryo survival was assessed when cultured on periphyton in combination with sterilized sediment or eutrophying compounds (nitrates and phosphates). Oxygen consumption …