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Regulation Of Neutrophil Homeostasis By Chemokines Signaling Through The Cxcr2 And Cxcr4 Receptors, Kyle Eash

All Theses and Dissertations (ETDs)

The number of neutrophils in the blood is tightly regulated to ensure adequate protection against microbial pathogens while minimizing damage to host tissue. Neutrophil homeostasis in the blood is achieved through a balance of neutrophil production, release from the bone marrow, and clearance from the circulation. Accumulating evidence suggests that chemokine signaling in the bone marrow may play a key role in maintaining neutrophil homeostasis. Based on this evidence, we developed a "tug-of-war" model in which opposing chemokine gradients, specifically release-inducing CXCR2 signals and retention-promoting CXCR4 signals, act antagonistically to regulate neutrophil release from the bone marrow. We generated mice …

The Manipulated Mechanism: Towards An Account Of The Experimental Discovery Of Mechanistic Explanations, Donald Goodman-Wilson

All Theses and Dissertations (ETDs)

Recent work in the philosophy of biology has sought after an account of mechanistic explanation. Biologists frequently encounter causal relationships that beg for explanation. For example, genes appear to encode for particular phenotypes. How does gene expression work? Biologists posit mechanisms to explain the link between cause and effect. Thus, gene expression would be explained by an appeal to a complex mechanism linking the gene to the phenotype, as such an appeal will provide answers to broad ranges of "how" and "why" questions about the causal relationship, and predict novel effects. Here, I focus on a recent problem raised for …

Mhc Class I-Dependent Acquisition And Maintenance Of Natural Killer Cell Function, Julie Chase

All Theses and Dissertations (ETDs)

Natural killer: NK) cells are hematopoietically derived immune cells of the lymphoid lineage. Their effector functions, including cytokine secretion and cytotoxicity, are controlled by the integration of signals received from both activating and inhibitory receptors. In a phenomenon known as "missing-self" recognition, NK cells eliminate self-tissues with aberrantly low or absent MHC class I surface expression, as is common in settings of viral infection and transformation, when these cells fail to engage the critical NK cell inhibitory receptors. Interestingly, NK cells that develop in an MHC class I-deficient environment are defective in natural killing and hyporesponsive to stimulation through their …

The Evolution And Reproductive Ecology Of Oenothera (Onagraceae), Kyra Krakos

All Theses and Dissertations (ETDs)

This dissertation describes the role of pollination in the floral diversification of Oenothera with an integration of both ecological and phylogenetic approaches. Oenothera: Onagraceae) is a model system for studying plant reproductive biology. It provides excellent examples of shifts in reproductive traits such as pollination and breeding system, features that have been important in angiosperm diversification. These systems are evolutionarily labile; they easily shift between different states. These different reproductive traits may shift in a concerted fashion; therefore, a more comprehensive approach to understanding the evolution of these plant systems simultaneously addresses shifts in pollination and breeding system. Using 54 …

Effects Of The Aquatic To Terrestrial Habitat Ratio On An Amphibian Predator And Its Prey, Amber Kramer

All Theses and Dissertations (ETDs)

This dissertation explores the effects of varying the composition of aquatic and terrestrial habitats in a landscape: the aquatic to terrestrial ratio) on amphibians that use both the aquatic and terrestrial habitats during their lives. In Chapter 1, I first used meta-analysis and simulations to demonstrate that as the longevity of an amphibian increases, the elasticity of the population growth rate to perturbations in the aquatic: larval) habitat decreases. In Chapter 2, I examined the abundance of larvae of a long-lived amphibian, Ambystoma maculatum, across landscapes that varied in their aquatic to terrestrial ratios and found that larvae of this …

Interactions Between Bmp And Canonical Wnt Signaling Regulate Critical Stages Of The Osteoblast Lifecycle, Valerie Salazar

All Theses and Dissertations (ETDs)

Skeletal development and post-natal bone homeostasis are dependent on the coordinated activity of bone-forming cells called osteoblasts and bone-resorbing cells called osteoclasts. Over 10 million people in the US currently suffer from osteoporosis, which increases the risk of low-trauma fractures and accounts for health care expenditures exceeding $14 billion per year. Osteoporosis is often treated with anti-resorptive compounds, primarily bisphosphonates, which inhibit osteoclast-mediated bone destruction. However, these drugs do not restore bone mass, which can only be accomplished by activation new bone formation, as with intermittent parathyroid hormone therapy. The development of additional bone "anabolic" therapies will require genetic and …

The Role Of The Membrane Proximal Region Of The M2 Cytoplasmic Tail In Virus Replication, Shaun Stewart

All Theses and Dissertations (ETDs)

Influenza A virus encodes M2, a proton channel that has been shown to be important during virus entry and assembly. The primary aim of this thesis was to investigate the role of the membrane proximal region, residues 46-69, of the M2 cytoplasmic tail during virus replication. A cholesterol recognition/interaction amino consensus: CRAC) motif, previously identified in the membrane proximal region of M2 in some influenza A virus strains, was suggested to play a role in virus replication by mediating incorporation of M2 into budding virus particles. Alteration or completion of the M2 CRAC motif in two different recombinant virus strains …

Molecular Genetic Analysis Of Non-Catalytic Pol Iv And V Subunits, Ek Han Tan

All Theses and Dissertations (ETDs)

Among eukaryotes, plants have the distinction of encoding multisubunit RNA polymerases used exclusively for RNA directed DNA Methylation: RdDM) in addition to Pol I, II, and III. In Arabidopsis thaliana, Pol IV is required for the biogenesis of 24nt siRNAs whereas Pol V transcription is needed for cytosine methylation of the DNA sequences corresponding to these siRNAs. The ancestry of Pol IV and V can be traced back to Pol II, and Pol II, IV and V still utilize multiple non-catalytic subunits encoded by the same genes. Genetic analysis of non-catalytic subunits that are highly similar reveals that these subunits …

The Association Between Traumatic Brain Injury And Alzheimer's Disease: Mouse Models And Potential Mechanisms, Hien Tran

All Theses and Dissertations (ETDs)

Alzheimer's disease: AD) is a neurodegenerative disorder characterized pathologically by progressive neuronal loss, extracellular plaques containing the amyloid-β: Aβ) peptides, and neurofibrillary tangles: NFTs) composed of hyperphosphorylated tau proteins. Aβ is thought to act upstream of tau, affecting its phosphorylation and therefore aggregation state. One of the major risk factors for AD is traumatic brain injury: TBI). Acute intra-axonal Aβ and diffuse extracellular plaques occur in approximately 30% of human subjects following severe TBI. Intra-axonal accumulations of total and phospho-tau and less frequently NFTs have also been found in these patients. Due to the lack of an appropriate small animal …

The Gut Microbiome In Healthy And Severely Malnourished Humans, Tanya Yatsunenko

All Theses and Dissertations (ETDs)

Human large intestine is home to tens of trillions of microbes belonging to all three do- mains of life. The functions encoded by the genes in this community: microbiome) include processing and production of macro- and micronutrients. Much remains unknown about the factors that determine the assembly of the gut microbial community starting at birth, and if disruptions in the assembly of this `microbial metabolic organ' early in life result in physiologic and metabolic deficits later in life. The central goal of my thesis was to char- acterize development of the gut microbiome early in life, with a focus on …

Gorwth And Developmental Plasticity Of Chaoborus Americanus Populations, Rachel Moran

Honors Capstones

The larval stage of the phantom midge Chaoborus americanus (Chaoboridae) is an important predator on zooplankton in temperate, fish less ponds. Chaoborus have distinct development stages typical of holometabolous insects: egg, larva (four larval instars), pupa, and adult. Temperature and food levels can significantly affect development rates in insects. The purpose of this study was: (1) to compare developmental patterns of populations of C. americanus from different latitudes (northern Wisconsin, northern Illinois), which experience different annual temperature regimes; and (2) to construct a mathematical model to predict larval development patterns (Developmental Model) and another to predict abundance patterns for C. …

Isolation And Analysis Of Arabidopsis Thaliana Lines Bearing Drg Knock-Out Mutations And Overexpressing Gfp Protein Fusions: Are Wild-Type Drgs Necessary For Heat Stress Granule Formation?, Lindsey Mckinney

Honors Capstones

Purpose and Methodology: The purpose of this study was to determine the role of DRG and GFP in response to heat stress in Arabidopsis by examining whether any DRG mutant combination inhibits the formation of heat stress granules (HSGs) following exposure of plants to heat stress. Methods utilized in the experimentation include the polymerase chain reaction (PCR) and gel electrophoresis to screen for plants containing the desired combination of genes, a root-growth assay to study the relationship between phenotype and genetic composition, and confocal microscopy to observe the formation of HSGs in root tips. Findings: The genetic composition of DRG …

Discovering Conserved Cis-Regulatory Elements That Regulate Expression In Caenorhabditis Elegans, Nnamdi Ihuegbu

All Theses and Dissertations (ETDs)

The aim of this dissertation is two-fold:: 1) To catalog all cis-regulatory elements within the intergenic and intronic regions surrounding every gene in C.elegans: i.e. the regulome) and: 2) to determine which cis-regulatory elements are associated with expression under specific conditions. We initially use PhyloNet to predict conserved motifs with instances in about half of the protein-coding genes. This initial first step was valuable as it recovered some known elements and cis-regulatory modules. Yet the results had a lot of redundant motifs and sites, and the approach was not efficiently scalable to the entire regulome of C. elegans or other …

The Functions Of Human Dna2 In Mitochondrial And Nuclear Dna Maintenance, Julien Duxin

All Theses and Dissertations (ETDs)

Coordination between DNA replication, DNA repair and cell-cycle progression ensures high fidelity DNA replication thus preventing mutations and DNA rearrangements. Interestingly, in addition to nuclear DNA stability, mitochondrial DNA: mtDNA) integrity is also essential for normal development. The current challenge resides in unraveling the different mechanisms that govern nuclear and mtDNA stability and to understand how these two separated genomes have evolved. This work focuses on delineating the biological functions of human Dna2: hDna2). Dna2 is a highly conserved helicase/nuclease that in yeast participates in DNA replication and Okazaki fragment maturation, DNA repair, and telomere maintenance. Immunofluorescence and biochemical fractionation …

Protein-Dna Recognition Models For The Homeodomain And C2h2 Zinc Finger Transcription Factor Families, Ryan Christensen

All Theses and Dissertations (ETDs)

Transcription factors: TFs) play a central role in the gene regulatory network of each cell. They can stimulate or inhibit transcription of their target genes by binding to short, degenerate DNA sequence motifs. The goal of this research is to build improved models of TF binding site recognition. This can facilitate the determination of regulatory networks and also allow for the prediction of binding site motifs based only on the TF protein sequence. Recent technological advances have rapidly expanded the amount of quantitative TF binding data available. PBMs: Protein Binding Microarrays) have recently been implemented in a format that allows …

More Taxa Or More Characters : Which Dataset Is Better?, Stefan Barone

Student Theses and Dissertations

No abstract provided.

Elucidating The Role Of Spy1a During C-Myc Induced Mammary Tumor Development, Evangelia Kirou

Electronic Theses and Dissertations

Speedy (Spy1A) is a novel cell cycle gene whose product binds to cyclin-dependent kinase-2 (CDK2) and activates its kinase activity to promote cell cycle progression through a cyclin independent mechanism. Spy1A is expressed naturally at high levels in the proliferating mammary gland, and aberrant overexpression of Spy1A results in precocious mammary development and eventually tumorigenesis in vivo. Induction of the mammary oncogene c-Myc upregulates Spy1A and I further demonstrate that Spy1A protein levels are elevated in mammary tissue and breast tumors derived from MMTV-Myc transgenic mice. Spy1A knockdown in F5A1-2 cell lines led to downregulation of cyclin-dependent kinase inhibitors (CKI) …

Life History Characteristics Of The Starry Skate, Raja Stellulata, From California Waters, Kelsey James

Master's Theses

The order Rajiformes, or skates, is a morphologically conservative group that exhibits a wide range of life history characteristics. This inter-species variability warrants species-specific research. This study investigates the age, growth, reproduction, and habitat of the Starry Skate, Raja stellulata, which is endemic to the U.S. West Coast. Age and growth parameters were determined using two preparation techniques: gross sectioning and histological sectioning. The assumption that gross sections deposit one band pair a year was indirectly validated with centrum edge analysis and marginal increment ratio. It was not indirectly validated with histological sections. Age estimates from gross sections ranged from …

Discovering Signaling Events In The Actinorhizal Symbiosis, Nicholas J. Beauchemin

Master's Theses and Capstones

Although the symbiosis between Frankia and actinorhizal host plants has been widely studied, very little is known about the initial molecular interactions. To address this issue, Casuarina cunninghamiana root exudates were collected and tested on Frankia Ccl3. Frankia growth yield was enhanced by root exudates but Frankia could not utilize them as a sole carbon and energy source. Exposure to root exudates caused Frankia hyphal curling and surface property changes in fatty acids and carbohydrates. Pre-exposure to root exudates also decreased the time required for nodule initiation. The results show that root exudates and Frankia physiological changes for symbiosis are …

The Effects Of Historic Earthen Barriers On Northern New England Tital Marshes, Jordan W. Mora

Master's Theses and Capstones

Berms, defined as historic earthen barriers, represent one type of hydrological modification introduced by humans in the tidal marshes of northern New England. Three different research approaches were applied to study the impact of berms on various tidal marsh dynamics. The descriptive study shows that restricted flooding from berm interference can result in significantly altered physical gradients in addition to landward subsidence and pool development. The results from the transplant experiment indicate that the altered landward structure affects the relative importance of biological interactions, namely herbivory, in controlling plant species distribution. The predictive GIS analyses illustrate the location of 34 …

Identification And Characterization Of Photorhabdus Temperata Mutants Altered In Cell Surface And Symbiosis, Cintia R. Felix

Master's Theses and Capstones

Photorhabdus temperata forms a mutualistic association with the entomopathogenic nematode Heterorhabditis bacteriophora. Nematode growth and development has an obligate requirement for the bacterial symbiont. The objective of this study was to identify and understand cell surface properties that are required for symbiosis. A previously generated library of 10,000 P. temperata transposon mutants was screened for altered surface properties via a calcofluor dye-binding assay. Seventeen mutants were identified and tested in vitro for symbiosis. Key mutants were tested for symbiosis and insect pathogenesis in vivo with Galleria mellonella larvae. Five mutants showed at least a 10-fold decrease of IJ yield. Four …

Assessing Relationships Of Moose Populations, Winter Ticks, And Forest Regeneration In Northern New Hampshire, Daniel Henry Bergeron

Master's Theses and Capstones

This study examined relationships among winter ticks, weather, and the nutritional and reproductive status of moose, and the impact of moose on regeneration of commercial forests in northern New Hampshire. Three methods were evaluated to assess their usefulness as indices of relative winter tick abundance, and predictors of tick epizootics: tick counts on harvested moose and roadside, spring hair-loss surveys were considered time and cost effective to index winter tick abundance. Physical characteristics of harvested moose (1988--2009) indicated ovulation rates (∼20%), and mean body weight (<200 kg) of yearlings declined since 1988; because adult body weight and ovulation rates remained stable, habitat quality was unlikely related. Winter tick epizootics are likely influenced by abnormal large scale weather events, as evident in the widespread die-off in 2002 associated with warm snowless conditions into mid-December 2001 that extended tick transmission to moose. Spring and fall weather should be monitored for unusual conditions causing high tick abundance and tick loads, particularly warm and snowless conditions in April and December. Mean stocking rate of all age classes of commercial tree species was above the threshold in all regions (49--87%); forest regeneration was not considered a regional problem at any moose density.

Herbage Mass Accumulation In An Intensive Rotational Grazing System At Unh's Organic Dairy Research Facility, Ashley Green

Master's Theses and Capstones

Pasture-based animal management in the Northeast U.S. relies on the ability to efficiently estimate pasture production and animal intake. Accuracy and precision of a rising plate meter, NDVI meter, and height measurements for estimating pasture biomass were compared relative to hand-clipped samples. Pasture measurements were used to describe biomass accumulation, lactating dairy herd intakes, and re-growth patterns for intensively rotated pastures. Pastures were measured from May-September, 2009 at the UNH Organic Dairy Research Facility in Lee, NH. The rising plate meter provided the most robust estimates of biomass (R²=0.58, SEE=2.73). Forty-seven paddocks were measured for 82 total grazing events; grazing …

Genes Differentially Expressed At 1 Day, 6 Weeks, And 6 Months Of Age In Aortas Of Spontaneously Atherosclerotic White Carneau Pigeons, Suzanne Lee Pearlman

Master's Theses and Capstones

Genetics is reported to be the primary causative factor for individuals diagnosed with atherosclerosis, in the absence of known risk factors. The development of atherosclerosis in White Carneau (WC) pigeons is of genetic origin, making it an excellent model to study genetic factors.

Representational Difference Analysis (RDA) was used to determine genes differentially upregulated between three ages, at the celiac bifurcation of the aorta in WC pigeons. Genes responsible for spontaneous initiation of atherosclerosis were hypothesized as being differentially expressed at 1 day, while those differentially expressed at 6 weeks and 6 months were related to progression.

Multiple candidate genes …

Analysis Of Arabidopsis Thaliana Protein Phosphatase 2a C Subunit Expression, Megan M. Thompson

Master's Theses and Capstones

Reversible protein phosphorylation is required for presumably most biological pathways. One of the major enzymes involved in eukaryotic dephosphorylation is Protein Phosphatase 2A (PP2A). PP2A is composed of three subunits: A (scaffolding), B (regulatory), and C (catalytic). Our lab is interested in determining the function of the five C subunits (C1, C2, C3, C4 and C5) in Arabidopsis thaliana. We have identified a Na+-induced altered root growth phenotype in c4 mutant plants. The goal of this project was to determine expression of the five C subunit genes throughout the life cycle of Arabidopsis with emphasis on correlating the location of …

Effect Of Carex Rostrata Removal On Methane Emissions From A Temperate Peatland, Genevieve L. Noyce

Master's Theses and Capstones

Peatlands are a large natural source of atmospheric methane (CH4). Carex rostrata, a sedge species, has a critical role in the production, oxidation, and emission of CH4 from these systems. This study examined the changes in CH4 emissions from a temperate peatland after removing all aboveground C. rostrata biomass. Methane flux, dissolved CH4 concentration at various depths, C. rostrata green leaf area, temperature, and water table depth were measured from June 2008 to November 2010.

There is a strong positive correlation between C. rostrata green area and CH4 flux and the mean summer CH4 flux from the control plots was …

Identification And Characterization Of Photorhabdus Temperata Mutants Altered In Hemolysis And Virulence, Christine A. Chapman

Master's Theses and Capstones

Photorhabdus temperata is an invertebrate pathogen and nematode symbiont that is commonly used as a biological control agent in the management of commercial crop pests. The focus of this study was to investigate the poorly understood molecular elements involved in the expression of hemolysis and virulence in this bacterium. A 10,000 transposant library was screened using a blood agar plate assay to identify mutants altered in hemolytic activity. A total of 74 mutants displaying defective, delayed, or early hemolysis were identified and subsequently tested for altered virulence in the Greater Waxmoth, Galleria mellonella, using an in vitro mortality assay. Ten …

Incidence, Abundance, Post-Harvest Processing And Population Diversity Of Pathogenic Vibrios In Oysters From The Great Bay Estuary, Jong Whan Yu

Master's Theses and Capstones

Shellfish-borne vibrio diseases have increased recently in the US, particularly in cooler, northern areas. Harvest area monitoring and post-harvest processing (PHP) have been implemented to reduce Vibrio disease risks in marketed shellfish, and rapid and reliable detection methods are needed to assess these risks. Both culture based and qPCR detection methods were useful for detecting V. parahaemolyticus (Vp) in oysters. QPCR is more rapid and less subjective, while the culture based method allowed detection of lower Vp concentrations in cold-water oysters where the Vp population diversity was more clonal. Depuration and relaying were assessed as PHP strategies for reducing Vp …