Life Sciences Commons^™

Small Noncoding Rna Expression During Extreme Anoxia Tolerance Of Annual Killifish (Austrofundulus Limnaeus) Embryos, Claire L. Riggs, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Small noncoding RNAs (sncRNA) have recently emerged as specific and rapid regulators of gene expression, involved in a myriad of cellular and organismal processes. MicroRNAs, a class of sncRNAs, are differentially expressed in diverse taxa in response to environmental stress, including anoxia. In most vertebrates, a brief period of oxygen deprivation results in severe tissue damage or death. Studies on sncRNA and anoxia have focused on these anoxia-sensitive species. Studying sncRNAs in anoxia-tolerant organisms may provide insight into adaptive mechanisms supporting anoxia tolerance. Embryos of the annual killifish Austrofundulus limnaeus are the most anoxia-tolerant vertebrates known, surviving over 100 days …

Embryonic Development Of The Annual Killifish Austrofundulus Limnaeus: An Emerging Model For Ecological And Evolutionary Developmental Biology Research And Instruction, Jason E. Podrabsky, Claire L. Riggs, Amie L. Romney, S. Cody Woll, Josiah T. Wagner, Kristin M. Culpepper, Timothy Grant Cleaver

Biology Faculty Publications and Presentations

Background: Austrofundulus limnaeus is an annual killifish from the Maracaibo basin of Venezuela. Annual killifishes are unique among vertebrates in their ability to enter into a state of dormancy at up to three distinct developmental stages termed diapause I, II, and III. These embryos are tolerant of a wide variety of environmental stresses and develop relatively slowly compared with nonannual fishes.

Results: These traits make them an excellent model for research on interactions between the genome and the environment during development, and an excellent choice for developmental biology laboratories. Furthermore, A. limnaeus is relatively easy to maintain in a laboratory …

Impact Of Staff Education On Geriatric Polypharmacy, Valerie Ikemefuna

Walden Dissertations and Doctoral Studies

Polypharmacy, the simultaneous use of multiple drugs to treat a single ailment or condition, is a

major health problem among the elderly population that contributes to adverse drug side events,

health risks, hospital readmissions, morbidity, and mortality. Therefore, a staff education

program geared toward reduction of such adverse drug events was implemented at a single site.

The purpose of the project was to determine if the staff education program would increase

knowledge of adverse drug events due to geriatric polypharmacy. The Orem theory provided the

theoretical support for the project, and the Iowa model guided the evidence-based practice

change process. …

Development Of An Educational Program To Obtain And Maintain Healthy Weights Among 4th And 5th Grade Students, Stephanie Dean Black

Walden Dissertations and Doctoral Studies

Development of an Educational Program to Obtain and Maintain Healthy Weights Among 4th and 5th Grade Students

By

Stephanie D. Black

MSN, University of Phoenix, 2008

BSN, Southwest Baptist University, 2006

ASN, Southwest Baptist University, 2003

Capstone Project Submitted in Partial Fulfillment

of the Requirements for the Degree of

Doctor of Nursing Practice

Walden University

October 2017

Obesity is prevalent in schoolchildren and increases risk of chronic diseases throughout the lifespan. Strategies are needed to address this growing health problem. Education in elementary schools targeting the topics of nutritional choices and prevention of obesity, particularly in 4th-5th grade population, is …

Using Multi-Theory Model To Predict Low Salt Intake - Nigerian Adults With Hypertension, Christine Adekemi Dokun-Mowete

Walden Dissertations and Doctoral Studies

Hypertension is a chronic non-communicable disease and a major risk factor for cardiovascular diseases, renal malfunction, disability, and premature death. One of the public health recommendations for the management of hypertension is the reduction of sodium/salt intake. There is need to develop and implement new evidence-based theoretical interventions to initiate and sustain behavior change in health education and promotion. Therefore, the quantitative cross-sectional method and design was used to investigate the adequacy of multi-theory model (MTM) constructs for the initiation and the sustenance of low sodium/salt intake behavior in hypertensive Nigerian adults. In addition, the impact of the MTM (initiation) …

Strategies For Preventing And Mitigating The Effects Of Agro-Food Supply Chain Disruptions, Everjoyce Muzvondiwa

Walden Dissertations and Doctoral Studies

Supply chain disruptions are detrimental to the performance of companies due to the associated loss of profitability and reduced sustainability. In 2016, organizations lost at least $1.2 million in a single supply chain disruption. Guided by the contingency theory of fit, the purpose of this exploratory multiple case study was to explore the strategies agribusiness managers use to prevent and mitigate the effects of disruptions in the agro-food supply chains. A total of 5 purposefully-selected agribusiness managers from Harare, Zimbabwe participated in semistructured interviews. Participants were senior agribusiness managers who implemented successful strategies for preventing and mitigating the effects of …

Evaluation Of The Brazilian Agrarian Reform Objective: Agricultural Production Yield Change, Tiffany Kwader Harbour

Walden Dissertations and Doctoral Studies

Brazil has an active agrarian reform policy program, publicly organized by the federal government and publicly administered at the state level by the National Institute for Colonization and Agrarian Reform. The objective of the agrarian reform policy program is to retitle unproductive and underproductive rural lands to increase agricultural production and land use. Previous agrarian reform researchers have examined quantities of land redistributed, rural technology developments, and the impact of social movements on land redistribution, but a knowledge gap remains regarding the correlation of agricultural production yields in rural municipalities before and after policy program participation. The State of Ceará …

Subsistence Farmers' Perceptions Of Pluralistic Agriculture Extension In Northern Ghana, Amos Kwame Egyir Baah

Walden Dissertations and Doctoral Studies

In 2013, the Ministry of Food and Agriculture of the Republic of Ghana implemented a reformed food and agriculture sector development policy (FASDEP II) to reduce poverty among the poorest subsistence farmers in the nation. These extension efforts have been unsuccessful. The purpose of this ethnographic case study was to understand the perceptions of subsistence farmers in the Savelugu-Nanton District (SND) who participated in FASDEP II on how the program had affected their ability to meet their subsistence needs. The theoretical framework of collaborative advantage was used to analyze farmers' opinions of how the decentralized, pluralistic extension policy did or …

Nutrition Services, Viral Suppression, Cd4, And Retention In Ryan White Program Participants, Theresa Jumento

Walden Dissertations and Doctoral Studies

The Ryan White HIV/AIDS Program (RWHAP) provides HIV-related medical and support services for uninsured and underinsured people living with HIV (PLWH) in the United States. In addition to HIV-related medical care, the program provides medical nutrition therapy and food assistance. The role of nutrition in the health of PLWH is well-documented, especially in resource poor areas; however, the role of medical nutrition therapy and food assistance provided through the RWHAP in resource rich areas is not well documented. This study addressed the association between the nutrition services of food assistance and medical nutrition therapy and the HIV-related health outcomes of …

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 …

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 …

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 …

Using Rainbow Trout Cell Lines As A Model For Understanding The Innate Anti-Fv3 Immune Response, Graeme Robert Jones Lisser

Theses and Dissertations (Comprehensive)

Ranavirus infections are on the rise and have been implicated in numerous species die-offs across the globe. Frog virus 3 (FV3) is the type-species of the genus, yet the immune mechanisms governing susceptibility remain poorly understood. Arguably the most important immune response to infection is the type I interferon (IFN) response. Type I IFNs trigger an “antiviral state” in host cells via the production of numerous interferon-stimulated genes (ISGs) that act to inhibit virus replication in various way, including the induction of apoptosis. Apoptosis is an important antiviral defense mechanism to limit virus replication within infected cells. This study employed …

Dsrna Sensing In Fish Cells: Using Chse-214 As A Model For The Study Of Class A Scavenger Receptors, Andrea Monjo

Theses and Dissertations (Comprehensive)

When infecting cells, most viruses produce dsRNA molecules at some point in their replicative cycle. When an infection results in cell lysis, these molecules are released into the extracellular space. Class A scavenger receptors (SR-As) on the surface of animal cells bind extracellular dsRNA and bring it into the cell where dsRNA triggers an innate immune response, enabling the cell to protect itself from an impending virus infection. Very few cells are unable to bind and respond to extracellular dsRNA, thus cell-based assays for studying extracellular dsRNA sensing via SR-As have been limited. CHSE-214 cells are a promising model for …

The Effect Of Acute Thermal Stress On Gene Expression Levels Of Hsp70 In The Antarctic Notothenioid, Notothenia Coriiceps, Eudiah Ochieng

Honors College Theses

The waters of the West Antarctic Peninsula are known as one of the most cold, stable environments on earth and organisms living within, such as the fish Notothenia coriiceps, have become highly specialized over evolutionary time. However, water temperatures in this environment have been steadily warming over the past two decades due to global climate change. In addition to the challenges created by increasing temperatures N. coriiceps will also be faced with difficulty meeting oxygen demands to carry out metabolic processes due to the decrease solubility of oxygen in warmer environments. Heat stress proteins (Hsps) are critical molecules that …

The Effects Of Elevated Co2 Levels On Broad Bean, Vicia Faba, Growth/Defense Tradeoffs, Harley B. Kitching

Honors College Theses

Atmospheric changes, associated with global climate change, are increasing at an unprecedented rate. Plants generally display higher rates of growth in response to elevated CO₂ levels, but this response varies among species. In addition, very little is known about how plant growth/defense tradeoffs will be altered by increasing CO₂ levels. By raising Broad bean, Vicia faba L., plants under ambient (400 ppm) and elevated (900 ppm) levels of CO₂, it was shown that atmospheric composition directly altered plant growth/defense tradeoffs. Plants grown under elevated CO₂ had lighter stem weights but greater numbers of extrafloral nectaries …

The Biological Stress Response In Bluegill Sunfish (Lepomis Macrochirus) To Variations In Environmental Temperature And Dissolved Oxygen Content., Monique Kellman

Honors College Theses

With the predicted increase in global water temperature and acute hypoxic episodes, knowledge of the effects these stressors can have on local aquatic life is extremely valuable. This study thereby quantified the change in metabolic rate in Bluegill sunfish, in response to increased temperature and low dissolved oxygen concentration, by utilizing intermittent flow respirometry. Both maximum metabolic rate (MMR) and resting metabolic rate (RMR) were determined in response to variations in dissolved oxygen content, specifically > 95% O₂ and 40% O₂. Additionally, three temperature treatment groups were established, with temperatures of 20, 25 and 30°C in order to …

An Analysis Of White-Tailed Deer, Odocoileus Virginianus, Killed In Deer Vehicle Accidents On Bulloch County, Ga Roadways, Mackenzie P. Payne 4003933

Honors College Theses

White-tailed deer, Odocoileus virginianus, are native to Georgia. With over 1.2 million individuals in the state, White-tailed deer have been implicated in a large number of motor vehicle collisions (ca. 1 million) each year. It is unknown, however, if deer are more likely to be killed: 1) if they are of particular ages (or classes), and 2) in areas with specific road characteristics. We addressed these two questions by collecting the remains of 20 White-tailed deer killed in deer vehicle collisions (“deer vehicle accidents” - DVAs) in Bulloch County, GA. When a deer was located, the road characteristics were …

An Examination Of Spasticity Of The Lower Extremity Among Young People With Cerebral Palsy, Jordan Nourse

Honors College Theses

Background: Spasticity is the most common symptom among individuals with Cerebral Palsy (CP). Spasticity is often presented as stiff limbs often resulting in pain. Currently, clinicians are limited in diagnosing spasticity using observational tools. The purpose of this study was compare spasticity at various functional levels using dynamometry. Methods: Participants included nine adolescents (12-19) with CP and nine adolescents (age-matched) without CP. The participants participated in passive stretches delivered by the Biodex System 4 Pro Dynamometer at four different speeds (90, 120, 150, and 180 deg/s), Measurements of the quadriceps will be collected before and during passive knee extension stretches …

Comparative Floristic Studies Of Georgian Sandhill Ecosystems Reveals A Dynamic Composition Of Endemics And Generalists, James M. Long, John Schenk

Honors College Theses

Sandhill habitats are characterized by sandy, xeric soils that contain a unique assemblage of plants and animals. Similar to the broader long-leaf pine (Pinus palustris) and wire grass (Aristida stricta) ecosystem that sandhills are a subset of, agriculture, development, and habitat modifications have caused sandhill ecosystems to become degraded, putting many species at risk of extinction. Previous studies have focused on diversity within individual sandhills, leaving us with an incomplete understanding of how these communities form, what species are endemic, whether endemics are widespread across sandhills, and how species have adapted to these communities. To gain a more comprehensive understanding …

Inbreeding Depression In The Introduced Spider Latrodectus Geometricus, Margaret A. Howard

Honors College Theses

The brown widow spider (Latrodectus geometricus) is thought to be native to South America or Southern Africa, but its distribution has expanded to most continents by human introduction. In the continental USA, L. geometricus was first documented in south Florida in the 1930’s. In the early 2000’s a population expansion occurred, and this species is now found in Florida, Georgia, South Carolina, Alabama, Mississippi, Louisiana, Texas, and southern California. Introduced species may face many obstacles when establishing a new population. One common obstacle might be severe inbreeding following founder events or genetic bottlenecks. The purpose of this study was …

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 …

Disease Models With Immigration, Reem Almarashi

Theses and Dissertations (Comprehensive)

In this thesis we focus first on studying the susceptible, exposed, and infected ($SEI$) disease model without immigration. We determine the basic reproduction number $\mathcal{R}_0$, which can be interpreted as the expected number of new cases that can be produced by a single infection in a completely susceptible population. Further, by using the Jacobian matrix, we determine the local stability of the disease model. Then we have the result that when $\mathcal{R}_0<1$ the DFE point is locally asymptotically stable(L.A.S). In contrast, when $\mathcal{R}_0>1$ we find that the endemic equilibrium is L.A.S. After that, we analyze the $SEI$ model with immigration of infected individuals.

Furthermore, we investigate the direction that the …

Quantifying Relationships Between Phosphorus Availability And Mycorrhizal Associations In Wetland Plants, Daniel Marshall

Theses and Dissertations (Comprehensive)

Increasing evidence indicates that plant community structure and therefore ecosystem function are mediated by below-ground fungal communities that form intracellular associations with plant roots called mycorrhizal associations. Arbuscular mycorrhizal fungi (AMF) are a type of mycorrhiza that colonize the plant host intracellularly but maintain hyphae outside the root cell for resource acquisition. The importance and function of AMF associations are well-documented in terrestrial ecosystems, but are less understood in aquatic or semi-aquatic systems. Phosphorus availability is the primary factor influencing mycorrhizal colonization and growth in terrestrial soils, with phosphorus-abundant soils leading to a decrease in mycorrhizal growth. However, the relationship …

The Complexity Of Electron Transport: A Study Of Variegation Through Chemical Inhibition Of Plastoquinol Terminal Oxidase (Ptox) In Tobacco (Nicotiana Tabacaum), Hillary Peon

Theses and Dissertations (Comprehensive)

The photosynthetic electron transport (PET) chain relies on the chlorophyll and carotenoid biosynthetic pathways for pigments that harness light, and protect the photosynthetic apparatus from damage by light. The pigment pathways also connect to the PET chain through electron transfer where the plastoquinol (PQ) pool accepts electrons from phytoene desaturase (PDS) of the carotenoid pathway and the aerobic cyclase (ACS) of the chlorophyll biosynthetic pathway. Genetic studies have shown a plastoquinol terminal oxidase (PTOX) protein functions to regulate the redox state of the PQ pool. Without PTOX to maintain balance between the two redox states of the PQ pool it …

An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll

Theses and Dissertations (Comprehensive)

Giant Mine is an inactive gold mine located nine kilometers north of Yellowknife, Northwest Territories. Giant Mine has been the source of arsenic trioxide for the Baker Creek watershed since it opened over 60 years ago. Although arsenic levels in the creek are above the limits considered to be biologically relevant, there is no concrete evidence that plants and mycorrhizae have actually been affected. This study provides an initial assessment of the impacts mining activity at Giant Mine has had on plants and mycorrhizae in the Baker Creek watershed. Nine sites were sampled around Giant Mine: five sites downstream from …

An Examination Of Imagined Contexts: The Unreliability Of Context-Dependent Memory Effects In Recall, Caitlin J. I. Tozios

Theses and Dissertations (Comprehensive)

It is generally accepted that the environmental context present during memory encoding serves as an effective cue for recall if reinstated during retrieval. Participants who perform a free recall test in the same context as that during which they learned a set of words, often remember more words than participants who experience a context mismatch from encoding to retrieval. This is referred to as the context-dependent memory effect and forgetting due to a change in context is referred to as context-dependent forgetting. Recent evidence suggests that contexts need not always be physical but can be mentally generated or imagined and …

An Investigation Of The Relationship Between Intervertebral Disc Puncture, Inflammation, And Tissue Mechanics Using A Rat-Tail Model., Brigitte Laird

Theses and Dissertations (Comprehensive)

Introduction: The intervertebral disc (IVD) is composed of the annulus fibrosus (AF), which surrounds and contains the nucleus pulposus (NP). It is hypothesized that when the IVD becomes injured, in the case of IVD herniation, a localized innate immune response is initiated. Although the presence of pro-inflammatory cytokines in injured IVDs has been well documented, the extent to which inflammation affects the mechanical properties of the IVD remains poorly understood. The purpose of this study was to determine the effect of IVD damage (via puncture) and inflammation (via lipopolysaccharide (LPS) exposure) on the mechanical and structural properties of the IVD. …

Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho

Theses and Dissertations (Comprehensive)

Cuscuta (dodder) is a genus of roughly 200 species of obligate stem parasites with sub-cosmopolitan distribution. The fruit, generally regarded as a capsule, has a thin pericarp containing one to four seeds and opening at the base (circumscissile dehiscence; DE), or remaining closed (indehiscent; IN). IN has evolved multiple times in Cuscuta from DE, and is most common in the North American clades of subgenus Grammica. In addition, some species produce fruits that open irregularly. Characteristics pertaining to the fruits of Cuscuta are important as their seeds contribute most to their distribution and prevalence across the globe, and their reduced …

Behavioral Ecology Of An Invasive Species: Habitat And Mate Preference(S) In Drosophila Suzukii, Yvonne Young, Natasha Buckiewicz, Tristan Af Long Dr.

Theses and Dissertations (Comprehensive)

The invasive Spotted-Wing fruit fly, Drosophila suzukii, has inflicted substantial economic losses to the soft-fruit agriculture industry worldwide due to the ability of females in this species to use a large, serrated ovipositor to cut the fruit’s skin and lay eggs directly into the mesocarp of ripening fruit. Once the eggs hatch, larvae consume the fruit flesh, ultimately leaving the fruit unmarketable. This species parasitizes numerous commercial fruit types (including blueberries, blackberries, strawberries, raspberries and occasionally grapes) as well as fruits from a variety of wild plant species. Since fruit types vary in their nutritional composition, as well as their …