Life Sciences Commons^™

Air- Sea Interactions And Ocean Dynamics In The Southwest Tropical Indian Ocean, Jessica Maureen Burns

Theses and Dissertations

The Southwest Tropical Indian Ocean (SWTIO) features a unique, seasonal upward lift of the thermocline, which is known as the Seychelles-Chagos Thermocline Ridge (SCTR; 55°E-65°E, 5°S-12°S). It is known that a high correlation exists between the depth of the thermocline and sea surface temperature (SST; a key ingredient for tropical cyclogenesis). With a particular focus on 2012/2013, this study reveals the dynamic properties of the SCTR that play an important role in the modulation of tropical cyclones in the SWTIO. Phenomena including Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO) are also well correlated to cyclogenesis through changes …

Mismatch Tolerance During Homologous Recombination In Mammalian Cells, Shen Li

Theses and Dissertations

Homologous recombination (HR) serves critical roles in DNA repair to maintain genome stability, and the malfunction of HR contributes to carcinogenesis and cancer development. Current research focuses on the regulation against deleterious recombination between imperfectly matching sequences, which has been documented in certain myeloid leukemias, hereditary nonpolyposis colorectal cancers and other genetic diseases. Homology dependency of recombination was examined in cultured thymidine kinase-deficient mouse fibroblasts. Cells have chromosomal integration of DNA constructs harboring a herpes tk gene (the “recipient”) and a closely linked truncated “donor” tk sequence. The recipient was rendered non-functional by insertion of the recognition site for endonuclease …

The Influence Of Phytoplankton Size And Community Composition On Carbon Cycling And Planktonic Food Webs In The Sargasso Sea, Bridget Elise Cotti-Rausch

Theses and Dissertations

The Sargasso Sea is a dynamic physical environment located in the western North Atlantic where strong seasonal variability combines with forcing by mesoscale (~100 km) eddies. These drivers determine nutrient, light, and temperature regimes, and ultimate the size, composition and productivity of the phytoplankton community. My general objective was to determine how the structure and function of planktonic communities affected carbon export from the surface ocean in the Sargasso Sea. On four cruises (2011 and 2012; one eddy per cruise), I investigated links between water column structure, plankton community composition, size, and primary production (PP). I then combined PP data …

The Nutrition Assistance Landscape In Afterschool Programs: Understanding The Gap Between Research, Policy, And Practice, Falon Elizabet Tilley

Theses and Dissertations

The Child and Adult Care Food Program (CACFP) aims to increase children’s access to healthful foods in out-of-home care. Approximately half of the 10.2 million children enrolled in afterschool programs (ASPs) are eligible for nutrition assistance through programs like CACFP. Despite awareness of its potential impact on the nutritional status of millions of children, CACFP is underutilized among ASPs and notably understudied in comparison to other federal nutrition assistance programs.

This dissertation addresses key gaps in CACFP research and provides a deeper understanding of the nutrition assistance landscape in afterschool programs by (1) assessing the type of afterschool snacks served …

Molecular Exploration Of Bioavailable Dissolved Organic Matter Across Aquatic Ecosystems, Yuan Shen

Theses and Dissertations

Dissolved organic matter (DOM) in aquatic ecosystems is a large reservoir of reduced carbon that is mostly resistant to degradation. A small fraction of DOM cycles relatively quickly and is biologically utilized on timescales of days to months. This bioavailable DOM (BDOM) supports aquatic food webs, drives major elemental cycles, and is coupled to atmospheric CO2. Despite wide-ranging importance, bioavailability of DOM and its linkages to ecosystem properties (e.g., primary production, nutrients) are poorly characterized, particularly at the ecosystem level. Bioassay experiments are commonly used to determine BDOM, but this approach alters conditions and has limited spatial and temporal coverage. …

The Role Of Exercise Dose On Ghrelin Concentration In Postmenopausal Women, Kimberly Bowyer

Theses and Dissertations

Introduction: As obesity continues to be a major public health concern, exercise is continually at the forefront of combating this epidemic. This thesis aims to examine how two different doses of exercise may affect the “hunger hormone”, ghrelin; in postmenopausal, non-obese women. Methods: 54 non-obese postmenopausal women were randomly assigned to either a higher dose (energy expenditure = 14 kilocalories/per kilogram of body weight/per week) or lower dose (energy expenditure = 8 kcal/kg/week) aerobic exercise training group for 16 weeks. Fasting blood samples were taken at baseline and at post intervention for analysis of ghrelin via multiplex immunoassay. Results: Only …

Do Dynamic Global Vegetation Models Capture The Seasonality Of Carbon Fluxes In The Amazon Basin? A Data-Model Intercomparison, Natalia Restrepo-Coupe, Naomi M. Levine, Bradley O. Christoffersen, Loren P. Albert, Jin Wu, Marcos H. Costa, David Galbraith, Hewlley Imbuzeiro, Giordane Martins, Alessandro C. Da Araujo

School of Integrative Biological & Chemical Sciences Faculty Publications

To predict forest response to long-term climate change with high confidence requires that dynamic global vegetation models (DGVMs) be successfully tested against ecosystem response to short-term variations in environmental drivers, including regular seasonal patterns. Here, we used an integrated dataset from four forests in the Brasil flux network, spanning a range of dry-season intensities and lengths, to determine how well four state-of-the-art models (IBIS, ED2, JULES, and CLM3.5) simulated the seasonality of carbon exchanges in Amazonian tropical forests. We found that most DGVMs poorly represented the annual cycle of gross primary productivity (GPP), of photosynthetic capacity (Pc), and of other …

The Influence Of Genetic And Environmental Factors On Quit Attempt In Adolescent And Young Adult Twins, Gladys Langi

Theses and Dissertations

The purpose of this study was to examine the genetic and environmental influences on lifetime quit attempt in three US adolescent and young adult twin samples (N total = 6,322). The study utilized a common-contingent-causal (CCC) model to estimate these factors for lifetime quit attempts, after accounting for the factors for lifetime cigarette use and cigarettes per day. The study also examined age and sex differences, as well as the degree of relationship between these smoking phenotypes. The results demonstrated significant genetic influences for lifetime quit attempts in adolescents and young adults. No sex differences were observed for the contributions …

Three Dimensional Homology Modeling Of Organic Cation Transporter 3 To Identify Structural Elements Mediating Transporter-Substrate Interactions, Hebing Liu

Theses and Dissertations

Organic cation transporters (OCTs) play a pivotal role in the absorption, tissue distribution, and excretion of a diverse array of substances, and currently the nature of the biochemical interactions between substrate and OCTs are unknown. Therefore, identifying which amino acid residues are critical for OCT-substrate interactions is of central importance to understanding and predicting interactions between drugs and OCTs. A three-dimensional (3-D) homology model of human OCT3 was generated using the crystal structure of a high affinity phosphate transporter from Piriformospora indica (PiPT) as template, and putative binding pocket for the prototypical hOCT3 ligand 1-methyl-4-phenylpyridinium (MPP⁺) was identified …

Ethanol Reversal Of Oxycodone Tolerances, Joanna C. Jacob

Theses and Dissertations

Oxycodone is a semi-synthetic opioid originally developed as a safer alternative to morphine. It is commonly prescribed for its pain-relieving effects, but has recently been implicated as a major underlying cause of the current opioid epidemic due to its clinical limitations that include tolerance, dependence and a high abuse liability. Simultaneous consumption of opioids and ethanol has been shown to increase the risk of overdose and death from opioids in opioid-tolerant individuals. We hypothesized that ethanol reversed opioid tolerance and previous studies showed that ethanol reversed morphine tolerance. This dissertation investigated whether ethanol reversed tolerance to other opioids in mice, …

Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton

Theses and Dissertations

Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response …

Effects Of Prescribed Fire On Cope’S Gray Treefrog (Hyla Chrysoscelis) Across Habitat Scales And Life Stages, Logan Mcdonald

Theses and Dissertations

Fire may alter both aquatic and terrestrial habitat used by all amphibian life stages, yet, our knowledge of its effects on amphibians is primarily limited to adult responses. I present an integrated approach to test the response of Cope’s Gray Treefrog (Hyla chrysoscelis) to fire by examining responses in tadpole performance and survivorship, adult abundance, and oviposition. Tadpoles raised with burned leaf litter had similar survival, but total mass and total length were 440% and 170% greater, respectively, for tadpoles raised in unburned litter. I assessed terrestrial and aquatic oviposition cues by embedding burned and unburned litter treatments within burned …

Novel Role Of The Nociceptin System As A Regulator Of Glutamate Transporter Expression In Developing Astrocytes, Logan Meyer

Theses and Dissertations

Our previous results showed that oligodendrocyte development is regulated by both nociceptin and its G-protein coupled receptor, the nociceptin/orphanin FQ receptor (NOPR). The present in vitro and in vivo findings show that nociceptin plays a crucial conserved role in both human and rodent brain astrocytes, regulating the levels of the glutamate/aspartate transporter GLAST/EAAT1. This nociceptin-mediated response takes place during a critical developmental window that coincides with astrocyte maturation and synapse formation. GLAST/EAAT1 upregulation by nociceptin is mediated by NOPR and the downstream participation of a complex signaling cascade that involves the interaction of several kinase systems, including PI-3K/AKT, mTOR and …

Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith

Theses and Dissertations

Manganese-deficient Streptococcus sanguinis mutants exhibit a dramatic decrease in virulence for infective endocarditis and in aerobic growth in manganese-limited media. Loss of activity of a manganese-dependent, oxygen-dependent ribonucleotide reductase (RNR) could explain the decrease in virulence. When the genes encoding this RNR are deleted, there is no growth of the mutant in aerobic broth culture or in an animal model. Testing the contribution of the aerobic RNR to the phenotype of a manganese transporter mutant, a heterologous class II RNR from Lactobacillus leichmannii called NrdJ that requires B₁₂ rather than manganese as a cofactor was previously introduced into an …

Deletion Of Cardiac Mir-17-92 Cluster Increases Ischemia/ Reperfusion Injury Via Pten Upregulation, Meeta B. Prakash

Theses and Dissertations

The miR-17- 92 cluster is necessary for cell proliferation and development of the cardiovascular system. Deletion of this cluster leads to death in neonatal mice. The role of this cluster still needs to be defined following ischemia and reperfusion. Methods and Results: Adult male mice were injected with Tamoxifen- was to induce inducible cardiac-specific miR-17- 92-deficient (miR-17- 92-def: MCM:TG:miR-17- 92 flox/flox ) and wild type (WT: MCM:NTG:miR-17-92 flox/flox ) mice were subjected to 30 minutes of myocardial ischemia via left anterior descending coronary artery ligation followed by reperfusion for 24 hours. Post I/R survival (48%) and ejection fraction were reduced, …

Role Of Mir-155 And Mir-146a In Mast Cell Function, Amina Abdul Qayum

Theses and Dissertations

Mast cells are resident immune cells abundantly found in the tissue at the host-environment interface, where they play a critical role in inflammatory allergic responses. Mast cell responses may be regulated by the cytokine milieu at the site of inflammation. Recent studies have revealed microRNAs to be important in altering cytokine signaling in immune cells. Here, we demonstrate for the first time that IL-10 and IL-33 induce miR-155 and miR-146a, respectively, to alter mast cell functions. We report that IL-10 enhanced IgE induced activation of mast cells. IL-10 effects are dependent on Stat3 activation, which elicits miR-155 expression, resulting in …

Type 2 Immune Responses In The Context Of Helminth Infection, Asthma, Dendritic Cells, And Myeloid Derived Suppressor Cell Function, Sheela Ruby Damle

Theses and Dissertations

Type 2 (T_H2) immune responses evolved to respond to helminth parasite infections by the production of T_H2 cytokines, which stimulate anti-helminth immunity. Macrophage migration inhibitor factor (MIF) is a pleiotropic cytokine, which is produced by many cell types. We demonstrate that mice deficient in MIF have enhanced clearance of a helminth parasite. MIF deficiency in CD4⁺ T cells was found to be the most important for mediating parasite clearance. We mimicked MIF deficiency by administering an inhibitor of the MIF tautomerase activity, sulforaphane, and this also increased parasite clearance (Section I).

T_H2 immune …

Hub Proteins, Paralogs, And Unknown Proteins In Bacterial Interaction Networks, Neha Sakhawalkar

Theses and Dissertations

Proteins are the functional units of cells. However, a major portion of the proteome does not have a known functional annotation. This dissertation explores protein -protein interactions, involving these uncharacterized or unknown function proteins. Initially, protein – protein interactions were tested and analyzed for paralogous proteins in Escherichia coli. To expand this concept further and to get an overview, protein – protein interactions were analyzed using ‘comparative interactomics’ for four pathogenic bacterial species including Escherichia coli, Yersinia pestis, Vibrio cholerae and Staphylococcus aureus. This approach was used to study unknown function protein pairs as well as to …

Mercury Bioaccumulation In Three Popular Subsistence And Recreational Estuarine Fishes From Southeastern U.S.A., Taylor Cannon

Theses and Dissertations

A rising concern in recent years has occurred over the presence of methylmercury in seafood, particularly fishes, and its impact on human health. However, fish also provide many health benefits, including improved cardiovascular health and neurodevelopment. Because fishes are the main source of methylmercury exposure to humans, and are such an integral part of the human diet, understanding the risks versus the benefits of fish consumption is imperative in allowing the public to make healthy, educated choices. One way that state and federal governments attempt to do this is through issuing fish consumption advisories. Unfortunately, these advisories do not always …

The Addition Of A Concurrent Bimanual Task Influences Postural Sway And Walking Speed Performance And Prioritization Across All Ages, Derek Matthew Liuzzo

Theses and Dissertations

As individuals age, there is an increase in attentional demands, a heavier reliance on vision, reduction in efficiency of both tasks, and longer processing intervals causing greater dual task interference on postural sway and walking speed. While cognitive-motor interference has been investigated, the impact of adding a functional, manual task while balancing or during gait is poorly understood across all ages. The overall purpose was to examine the relationship between age and task automaticity in dual-task conditions with a functional bimanual task, and describe how age influences attentional prioritization strategies. Older adults demonstrated differences in single and dual task performance …

Prenatal Methylmercury Exposure Through Rice Consumption In Rural China, Chuan Hong

Theses and Dissertations

Background: Methylmercury is one of the most toxic forms of mercury, which severely afflicts the developing fetus. Methylmercury exposure occurs not only through fish consumption but also through rice consumption. However, rice does not contain the same beneficial micronutrients that fish/shellfish has. Therefore, prenatal methylmercury exposure through maternal rice consumption may potentially increase adverse health effects on the developing fetus.

Objectives: The purpose of this dissertation was to investigate the magnitude of prenatal methylmercury exposure through rice consumption and the relationship between maternal mercury biomarkers and birth outcomes.

Methods: A total of 398 pregnant women were recruited at parturition in …

Survey Gear Comparisons And Shark Nursery Habitat Use In Southeast Georgia Estuaries, Jeffrey Cohen Carpenter

UNF Graduate Theses and Dissertations

Gill nets and longlines were compared as shark nursery sampling methodologies in inshore waters of Georgia to (1) assess differences in gear selectivity, bias, and stress of capture and (2) determine potential relationships between habitat features and shark distribution and abundance. Gear selectivity varied between gears as a function of both species and life stage resulting in significantly different estimates of species and life stage compositions. Juvenile bonnetheads (Sphyrna tiburo) and young of the year blacktip sharks (Carcharhinus limbatus) experienced significantly higher stress from gill net capture than longline. Major sources of bias are thought to …

The Soundscape Of The St. Johns River And Its Potential Impacts On The Habitat Use Patterns Of Bottlenose Dolphins, Carissa Deeann King

UNF Graduate Theses and Dissertations

The development of effective management plans for animal populations relies on an understanding of how the population is utilizing the habitat as well as the identification of any critical habitat areas. The St. Johns River (SJR), an urban estuary with a high level of anthropogenic disturbance, is home to a resident population of bottlenose dolphins (Tursiops truncatus). In chapter one, SJR dolphin habitat use patterns, the factors that influenced these patterns, and the critical habitat areas were identified. Significant associations were found in most pair-wise comparisons between season, behavioral state, group size, water depth, and location, indicating that …

Characterizing The Role Of The E3 Ligase Itch In Gut Mucosal Homeostasis, Heather L. Mentrup

Theses and Dissertations

The mucosal barrier of the small intestine is highly dynamic, enabling the passage of nutrients that are necessary for the body’s function while simultaneously preventing a breach by harmful microorganisms that are damaging to the host. The effectiveness of the mucosal barrier is dependent on the cohesive relationship established between the luminal mucosal epithelium and the underlying immune compartment in the small intestine. The epithelium provides the first line of defense against pathogens by establishing a physical barrier separating the external environment from the body’s internal milieu, while the immune system secondarily responds to clear bacteria that have breached the …

The Regulation Of Glycoprotein130 Dependent Inflammatory Cytokines One Basal And Mechanical Stimuli Induced Protein Synthesis In Myotubes And Skeletal Muscles, Song Gao

Theses and Dissertations

Maintaining skeletal muscle mass has a well-documented role in health and quality of life. Two members of IL-6 family of cytokines, IL-6 and LIF, and have a paradoxical role in skeletal muscle mass regulation: short term elevation of IL-6 and LIF plays a key role in mechanical stimuli induced muscle growth and muscle hypertrophy, while the long term elevated IL-6 and LIF regulate muscle wasting during cancer cachexia by disrupting muscle protein turnover regulation. The regulation of muscle protein synthesis is an important determinant of mechanical stimuli induced muscle hypertrophy and muscle wasting during cancer cachexia. IL-6 family of cytokines …

Children’S Obesogenic Behaviors During Summer Versus School, Keith Brazendale

Theses and Dissertations

Emerging evidence shows children gain 3-5 times the amount of weight and lose cardiorespiratory fitness (CRF) during summer compared to the 9-months of the school year. Notably, this trend is more pronounced in children who are already overweight or obese going into summer and/or from low-income ethnic minority households. There is little evidence to investigating the underlying mechanisms driving the pronounced occurrence of these negative health outcomes during summer.

The purpose of this dissertation as a whole was to investigate children’s obesogenic behaviors (physical activity, sedentary/ screen time, sleep, and diet) during summer versus school, and compare any differences in …

The Role Of Lipocalin-2 In The Hepatic Microenvironment Of Colorectal Cancer Metastasis, Daniel Titus Hughes

Theses and Dissertations

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States. The major cause of death is metastasis and the frequent target organ is the liver. When diagnosed early at a localized stage, the five year survival rate after resection is 90%. However, after metastasis has occurred, this drops to less than 12%. Metastasis is often asymptomatic and diagnosed at the final stage when therapeutic options are limited. Because of this, the genetic and cellular mechanisms regulating metastasis are still poorly understood. Recent studies have shown that prior to the arrival of cancer cells at the …

Determining The Population Dynamics And Reproductive Life History Of Commercially Important Tunas In The Gulf Of Mexico, Katrina C. Hounchell

Theses and Dissertations

The Gulf of Mexico (GOM) is an important spawning ground for many commercially important fish species including yellowfin, skipjack, and blackfin tunas. In particular, it is an essential spawning habitat for Atlantic bluefin tuna, whose stock status is of great international concern. It is vital to the appropriate conservation management of these species to determine both the location of their spawning grounds and the genetic diversity found within them. Fish eggs are a fisheries-independent source of spawning information that can provide more accurate estimates of spawning sites compared to larvae. This study describes population diversity and reproductive life histories in …

Identifying Associations Between Religious Commitment And Preventive Health Behaviors In A Southeastern Rural County, Nathan A. Peters

Theses and Dissertations

Health disparities within the United States (US) are continuing to impact ethnic minorities living in rural areas nationwide. In response, there is growing interest in using faith-based settings as vehicles to deliver much needed disease prevention interventions. However, few studies have identified the relationship between private and public religious commitment, individually, and the behaviors or risk factors associated with chronic disease. The purpose of this study was to observe the association between religious commitment, both private (i.e., time spent trying to grow in one’s religious understanding) and public (i.e., frequency of attendance, time spent in fellowship with others) individually, and …

The Association Of Changes In Cardiorespiratory Fitness With Changes In Cardiometabolic Risk Factors, Leanna Marie Ross

Theses and Dissertations

Cardiorespiratory fitness (CRF) is well established as having a strong inverse association with numerous cardiovascular disease (CVD) risk factors and mortality. As CVD remains the number one cause of death in America, the detrimental effects of low CRF present a substantial health threat. The studies presented in this dissertation syndicate both epidemiologic and clinical data that will enrich the knowledge base regarding the magnitude of change in CRF in relation to CVD risk factors.

Recently, the American Heart Association established a new construct termed ideal cardiovascular health (CVH), which is characterized by seven metrics known as Life’s Simple 7. The …