Life Sciences Commons^™

Dynamical Modeling In Cell Biology With Ordinary Differential Equations, Renee Marie Dale

LSU Doctoral Dissertations

Dynamical systems have been of interest to biologists and mathematicians alike. Many processes in biology lend themselves to dynamical study. Movement, change, and response to stimuli are dynamical characteristics that define what is 'alive'. A scientific relationship between these two fields is therefore natural. In this thesis, I describe how my PhD research variously related to biological, mathematical, and computational problems in cell biology. In chapter 1 I introduce some of the current problems in the field. In chapter 2, my mathematical model of firefly luciferase in vivo shows the importance of dynamical models to understand systems. Data originally collected …

Evaluation Of Soil Type And Seeding Rate On Winter Cover Crop Species In A Soybean Production System, Donna S. Morgan

LSU Doctoral Dissertations

The integration of winter annual cover crops into a cropping system can potentially improve soil health and crop production, however, the impact of variables such as seeding rates, across two very different soil types, has not been well documented. A two-year study was conducted at the Dean Lee Research Station and Extension Center in Alexandria, Louisiana to evaluate the effects of cover crop seeding rate and soil type on cover crop biomass, weed suppression, soil fertility, and soybean (Glycine max L) growth and yield. Analysis of potential economic impacts was also performed to estimate financial net returns for three …

Transgenic Control Of Aflatoxin Contamination In Maize Through Host-Induced Gene Silencing Targeting Aspergillus Flavus Genes Encoding Polygalacturonase (P2c) And Versicolorin Dehydrogenase (Aflm), Yenjit Raruang

LSU Doctoral Dissertations

Maize (Zea mays L.) is susceptible to Aspergillus flavus infection and subsequent contamination with aflatoxins, the most potent naturally produced carcinogenic secondary metabolites. Here, the A. flavus gene aflM encoding the versicolorin dehydrogenase in aflatoxin biosynthesis and the p2c gene encoding the polygalacturonase that is involved in infection were selected as targets for suppression through host induced gene silencing (HIGS). A HIGS vector targeting these genes was constructed and introduced into immature B104 maize embryos. Thirteen out of fifteen p2c transformation events and six out of seven aflM events were confirmed positive by PCR. Kernels containing the p2c gene …

Habitat Associations And Reproduction Of Fishes On The Northwestern Gulf Of Mexico Shelf Edge, Elizabeth Marie Keller

LSU Doctoral Dissertations

Several of the northwestern Gulf of Mexico (GOM) shelf-edge banks provide critical hard bottom habitat for coral and fish communities, supporting a wide diversity of ecologically and economically important species. These sites may be fish aggregation and spawning sites and provide important habitat for fish growth and reproduction. Already designated as habitat areas of particular concern, many of these banks are also under consideration for inclusion in the expansion of the Flower Garden Banks National Marine Sanctuary. This project aimed to gain a more comprehensive understanding of the communities and fish species on shelf-edge banks by way of gonad histology, …

Effect Of Biosurfactant And Biochar On Ecosystem Functions And Oil Remediation In Crude Oil Contaminated Wetland Soils, Zhuo Wei

LSU Doctoral Dissertations

Decontamination of oil spill from coastal wetland soils requires a delicate approach. Remediation strategies using biochar, biosurfactant, and nutrient additions have been proposed. However, there is little information on application of these with combination for treatment of crude oil-contaminated wetland soil. Therefore, incubation studies were carried out to investigate the impact of biochar and rhamnolipid (RL) biosurfactant along with nitrogen (N) application on petroleum hydrocarbon degradation in a Louisiana coastal saline marsh and their impacts on greenhouse gas (GHG) emission. Additionally, the toxicity of crude oil as well as remediation materials on coastal wetland ecosystem were assessed at three levels: …

Making Decision Adaptive To Price Uncertainty And Risk Preference: A New Decision-Making Model For Forest Management, Fan Zhang

LSU Doctoral Dissertations

While the forest grows, the price of timber fluctuates. Price uncertainty plays a key role in forestry due to the extended rotation length of growing trees. Like double sides of the same coin, risk preference and uncertainties should be considered together. This is because risk preference represents people’s attitude toward that uncertainty when making management decisions. Risk preference is especially an important issue for forest management because forests are exposed to substantial uncertainties during their long growing period. However, most existing relevant studies either simply overlook the risk preference issue or fail to consider it together with a practical forest …

Using Poultry Litter Ash As A Fertilizer Source For Bermudagrass (Cynodon Dactylon) Establishment And Loblolly Pine (Pinus Taeda) Plantation, Crystal L. Vance

LSU Doctoral Dissertations

Lower solubility of P in poultry litter ash (PLA) than conventional phosphorus (P) fertilizers such as triple superphosphate (TSP) may reduce P losses in drainage and runoff; however, lower P solubility may reduce its efficacy as a P source. A laboratory experiment was conducted to examine the effect of acidity on P release and the effect of different combustion temperatures on P solubility as a prerequisite to the following studies. The first research objective was to determine the effect of soil pH on the efficiency of PLA relative to TSP for establishment of common bermudagrass (Cynodon dactylon L.) and …

The Impact Of Anthropogenic Noise On Fish Behavior, Communication, And Development, Julie Butler

LSU Doctoral Dissertations

Noise pollution is pervasive to nearly all aquatic and terrestrial ecosystems and was labeled a pollutant of global concern by the World Health Organization in 2011. In the past few decades, underwater ambient noise levels have risen almost 30 dB SPL re: 1 µPa in the frequency range that most fish produce and detect acoustic stimuli due to rises in shipping, oil exploration, and pile driving. Changes to the natural soundscape can impact almost all aspects of an animal’s life. My dissertation research takes an integrative, whole-animal approach to examining how increased background noise impacts fish behavior, physiology, development, and …

Cellular And Viral Determinants Of Hsv-1 Entry And Transport, Farhana Musarrat

LSU Doctoral Dissertations

Previously, it was shown that the deletion of 38 amino acids from the N terminal end of glycoprotein K (gK) prevents the Herpes Simplex virus Type-1 (HSV-1McKrae ∆gK31-68) from entering into the axons of neurons. Herein, we showed for the first time that this modification in gK disrupts the ability of the virus to carry out a fusion of the viral envelope with the cellular plasma membrane and forces the virus to enter via endocytosis in epithelial cells and neuronal cell bodies. We showed that HSV-1 McKrae infection triggers cellular calcium signaling, Akt activation, and flipping of Akt to the …

Identification Of Quantitative Trait Loci (Qtls) For Resistance To Fusarium Head Blight (Fhb) In Wheat Variety Ags 2060 And Evaluation Of The Effect Of Fhb1 Resistance Gene On Fhb Reaction In A Louisiana Wheat Breeding Population, Alejandro Castro Aviles

LSU Doctoral Dissertations

Fusarium head blight (FHB), caused by the fungus Fusarium spp., is a disease that attacks several grass species, including wheat. Wheat variety AGS 2060 has remained moderately susceptible to FHB and is regularly found in pedigrees of resistant breeding lines. Quantitative trait loci (QTL) mapping was conducted to find sources of resistance to FHB in AGS 2060. A 90K SNP chip was used to genotype a double haploid mapping population produced from a cross between wheat varieties AGS 2060 and AGS 2035. There were highly significant differences between lines in the population for Fusarium damaged kernels (FDK) rating and deoxynivalenol …

The Functional, Ecological, And Evolutionary Morphology Of Sea Lampreys (Petromyzon Marinus), Bradley Morgan Wood

LSU Doctoral Dissertations

Lampreys (Petromyzontiformes) are jawless vertebrates with an evolutionary history lasting at least 360 million years and are often used in comparisons with jawed vertebrates because some of their morphological aspects, such as the segmented trunk musculature with curved myosepta and a non-mineralized skeleton fibrous skeleton, are thought to resemble the condition of early vertebrates before the evolution of jaws. Although earlier authors studied the morphology of the skeleto-muscular system of the trunk of lampreys, their studies are not detailed and complete enough to allow a functional and biomechanical analysis that is needed as a basis for modeling the mechanics of …

Prevalence And Control Of Salmonella Spp. And Sanitary Indicator Microorganisms In Wild Caught And Farm Raised Catfish (Ictalurus Punctatus), Bilan Costley Jessie

LSU Doctoral Dissertations

Catfish inspections have transitioned from the U.S. Food and Drug Administration (FDA) to the United States Department of Agriculture (USDA). The USDA Food Safety and Inspection Service (FSIS) and Food Emergency Response Network (FERN) consider it important to assess the food safety risk associated with consuming catfish in the United States. Surveillance of farm-raised and wild-caught catfish for pathogens is relevant as a public safety protocol. The purpose of this study was to detect the prevalence of Salmonella spp., identify and examine isolates for antibiotic resistance to clinical treatments, evaluate the effectiveness of antimicrobial chemical treatments against Salmonella enterica, and …

Equine Hoof Stratum Internum K14+Cd105+ Progenitor Cells: Culture, Characterization, And Model Of Epithelial To Mesenchymal Transition, Qingqiu Yang

LSU Doctoral Dissertations

For the potential benefit of progenitor cells to be realized in cell-based clinical therapies, it is vital to investigate the mechanism between progenitor cells and abnormal tissue formation. Laminitis is a fatal condition that is often presented by equine hoof inflammation and hoof tissue disarrangement. The persistence of abnormal tissue formation after the resolution of equine laminitis suggests there is progenitor cell compromise. So far, there is limited information about equine hoof progenitor cells and the effects of inflammation on hoof progenitor cells. To pursue a better understanding of both hoof progenitor cell and hoof growth as well as find …

Intrusive Advising And Retention Practices In A College Of Agriculture: A Case Study Of First-Year Student Experiences, Amanda Martin

LSU Doctoral Dissertations

The purpose of this qualitative case study was to explore the perceptions of first-year students who experienced intrusive advising and retention initiatives in the College of Agriculture at Louisiana State University (LSU). Research participants consisted of 20 first-year students enrolled in the college in the fall of 2018. One-on-one, face-to-face interviews with first-year students were conducted to gain insight and understand student experiences with intrusive advising and retention initiatives within the College of Agriculture. College student retention and factors that contribute to understanding retention have been extensively studied (Astin, 1993; Braxton, Hirschy, & McClendon, 2004; Habley, Bloom, & Robbins, 2012; …

Mechanism Of Neutrophil Homeostasis And Immunity In Pneumonia And Sepsis, Sagar Paudel

LSU Doctoral Dissertations

Severe bacterial pneumonia and septicemia are pressing health problems. A better understanding of cellular and molecular players of neutrophil immunity and homeostasis in bacterial pneumonia and sepsis is critical for inspiring novel therapeutics. Chemokine CXCL1 is a widely secreted neutrophil attractant and Nod-like receptor (NLRC4) is commonly expressed cytoplasmic pathogen sensor in hematopoietic compartments. How these innate mediators convert pathogen signals into molecular cues of immune response in context of Gram-positive bacterial pneumonia and septicemia largely remain unknown. Utilizing Cxcl1 gene deficient mice, we demonstrate CXCL1 regulates neutrophil influx, bacterial clearance, and host survival in pneumococcal pneumonia-derived sepsis. Furthermore, Cxcl1 …

Development Of A Tunable Platform For The Study Of Geomacromolecular Matrices Using Controlled Radical Polymerization, Arjun Pandey

LSU Doctoral Dissertations

Soil is an important environmental component, and the study of soil processes have many practical implications such as improvement in agriculture, mitigation of climate change etc. The widespread use of Agricultural Chemicals (ACs) in modern agriculture has resulted in adverse effects in environment and human health mostly through contamination into food and water sources. Study of fate, bioavailability, and transport of ACs involves molecular level understanding of their interactions with soil. This can be challenging due to complex and heterogeneous nature of soil. One common approach used is the correlation of macroscopic properties of soil, (e.g. sorption) with empirical parameters …

Nlrp6 In Gram-Positive Pneumonia And Sepsis, Laxman Ghimire

LSU Doctoral Dissertations

Acute lower respiratory infections (pneumonia) and pneumonia-derived sepsis are among the leading causes of death in the world causing 7.8 million deaths annually. In this regard, Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in the US and implicated for causing high mortality-associated necrotizing pneumonia and aggravating viral pneumonia with superinfection. Additionally, sepsis is the 7^th leading cause of death among newborns in the US and is responsible for more than 750,000 hospitalization cases every year. Although there is a plethora of research in both pneumonia and sepsis, the detailed pathophysiology still remains elusive. Understanding the host defense mechanism will help …

Characterization And Amplification Of Retrotransposable Elements Platy-1 And Alu In The Cebidae Lineage Of Platyrrhine Primates, Jessica Storer

LSU Doctoral Dissertations

Alu mobile elements are much more than “junk DNA”. Inherent properties such as high copy number, small ~300 bp size, and their nearly homoplasy-free nature make these elements particularly useful in resolving primate phylogenies. In addition, shared sequence features and identity with the Alu element allow for discovery of new SINE retrotransposons, such as the Platyrrhine-limited Platy-1 element. Building on previous research of subfamily analysis, the Platy-1 and Alu elements can be used not only to explore the controversial New World monkey (NWM) phylogeny, but also the mode and tempo of their amplification in different primate genera and species.

Chapter …

The Role Of Chromatin State Transitions In Modulating Early Phosphate-Deficiency Response Genes In Plants, Maryam Foroozani

LSU Doctoral Dissertations

Phosphorus (P) is an essential plant macronutrient vital to fundamental metabolic processes. Plant-available P is low in most soils, making it a frequent limiter of growth. Declining P reserves for fertilizer production exasperates this agricultural challenge. Plants modulate complex responses to fluctuating P levels via global transcriptional regulatory networks. Although chromatin structure plays a substantial role in controlling gene expression, the chromatin-level mechanisms involved in regulating P homeostasis have not been determined.

In this work, I used chromatin immunoprecipitation (ChIP) combined with next-generation DNA sequencing (ChIP-seq) to map the distribution of H3K4me3 in rice (Oryza sativa L.) during both …

Silicon Fertilization In Rice And Wheat: Dynamics With Trace Elements And Effect Of Silicate Slag Granular Size On The Release Pattern Of Monosilicic Acid In Soil, Wooiklee S. Paye

LSU Doctoral Dissertations

Studies were conducted to evaluate the impact of silicon (Si) fertilization on the uptake of harmful trace elements in Louisiana rice production system, and document the effect of silicate slag granular size on its ability to supply Si in wheat. The influence of silicate slag and lime on the uptake and translocation of harmful trace elements in rice grain was determined. Results showed that both slag and lime had similar effects on pH at five of the nine sites investigated. Soil Si was significantly (P <0.001) increased with application of silicate slag at all sites. Lime and silicate slag had no effect on the concentration of trace elements in soil. However, increasing Si rates were negatively correlated with arsenic (As) and cadmium (Cd) concentration in rice grain. The release pattern of monosilicic acid (H₄SiO₄) from wollastonite and silicate slag was compared in a wheat greenhouse …

Occurrence Of Aflatoxin And Zearalenone In Concentrate Feeds And Milk Contamination With Aflatoxin M1 And Bacterial Pathogens In Malawi, Chunala Alexico Njombwa

LSU Doctoral Dissertations

Multiple studies were conducted in Malawi to: 1) evaluate knowledge and perception of dairy farmers towards molds, mycotoxins and associated adverse effects; 2) evaluate dairy farmers’ knowledge and perception on milk contamination, proper milk handling practices and adverse health effects associated with raw milk consumption; 3) determine levels of aflatoxins and zearalenone (ZEN) in concentrate feedstuffs; 4) assess prevalence and levels of aflatoxin M₁(AFM₁) in raw milk, dietary exposure and estimate HCC risks to children and adults; 5) assess Salmonella and E. colicontamination in raw and processed milk from selected small scale farms and major …

Quantifying Impacts Of Climate Change On Species Interactions While Fostering Undergraduate Research Experiences Using The Monarch (Danaus Plexippus)- Milkweed (Asclepias Sp.) System, Matthew J. Faldyn

LSU Doctoral Dissertations

Species interactions, specifically plant-insect interactions, are ubiquitous worldwide. Climate change will alter species interactions by affecting abiotic conditions, affecting species phenologies, interaction strengths, and physiological development. However, climate change impacts are often studied using individual species, with limited consideration quantifying the direct and indirect impacts of climate change species interactions. Using lab, field, and greenhouse experiments, I investigated how climate change will directly and indirectly affect species interactions while also fostering undergraduate research experiences using the monarch butterfly (Danaus plexippus)- milkweed (Asclepias sp.) system.

In North America, a widely planted, invasive milkweed species, Asclepias curassavica, negatively …

Electron Transfer Activity Of Mitochondria Neet-Proteins, Yiming Wang

LSU Doctoral Dissertations

Mitochondrial NEET proteins are recently discovered iron-sulfur proteins that are localized within mitochondria. There are three NEET proteins: mitoNEET, a type II diabetes drug pioglitazone binding target, a mitoNEET related protein 1 (Miner1 or NAF-1), and a mitoNEET-related protein 2 (Miner2). While both mitoNEET and Miner1 are mitochondrial outer membrane proteins, Miner2 is a mitochondrial matrix protein. All three NEET proteins bind at least one [2Fe-2S] cluster via CDGSH (Cys-Asp-Gly-Ser-His) motif. In this work, we have investigated the electron transfer activity of mitoNEET, and found that the CDGSH-type [2Fe-2S] clusters of mitoNEET can be reduced by the reduced flavin mononucleotide …

Examining The Evolution Of Urban Multipurpose Facilities: Applying The Ideal-Type To The Facilities Of The National Hockey League And National Basketball Association, Benjamin Downs

LSU Doctoral Dissertations

The standardized versions of ice hockey and basketball emerged during the last quarter of the 19^thcentury. In short order both ice hockey and basketball evolved from amateur, recreational activities to professional sport and entertainment businesses. This study analyzes, contextualizes, and discusses the layout of the urban multipurpose facilities that emerged to house both professional hockey and professional basketball, with particular attention paid to the facilities of the National Hockey League and National Basketball Association. The study uses the lens of modernization and the ideal-type heuristic device to extend Bale’s and Seifried’s facility evolution models. In addition to providing …

Development, Validation, And Testing Of The Eating And Food Literacy Behaviors Questionnaire With Young Adult University Students, Kwadernica Rhea

LSU Doctoral Dissertations

The Eating and Food Literacy Behaviors Questionnaire (EFLBQ) was developed, and its validity, reliability, and ability to measure construct changes was established. Items related to the originally proposed domains of food literacy were included in the initial questionnaire, however five, new components were discovered. The second version of the EFLBQ was tested with 257 young adult university students using exploratory factor analysis, and a five-factor model (R²=57.4%) was returned. Cronbach’s alpha coefficients were calculated (health and nutrition=0.89, taste=0.72, food preparation=0.77, planning /decision-making=0.64, and convenience=0.63). A confirmatory factor analysis, with 923 new responses provided evidence of an adequate fit …

Effects Of Virus Infection And Volatiles On Aphid Virus Vector Behavior On Sweetpotato, John Lawrence Dryburgh

LSU Doctoral Dissertations

Sweetpotato is affected by a wide variety of viruses worldwide, which can cause yield losses of up to 90%. Many of these viruses are transmitted by aphids in a non-persistent manner. Non-persistent viruses are acquired and transmitted within minutes, and thus conventional control, such as insecticides, are ineffective. Altering aphid movement and feeding behavior may affect the rate of virus transmission. One potential method to alter aphid behavior is volatile organic compounds (VOC), including volatiles emitted by virus infected plants, plant hormones, and commercial control agents. Aphid movement near sweetpotato fields was monitored to determine trends throughout the growing season. …

Iron-Sulfur Cluster Biosynthesis In Methanogens, Cuiping Zhao

LSU Doctoral Dissertations

Methanogens live in a syntrophic consortium with bacteria, taking advantage of the metabolic abilities of their syntrophic partners to overcome energetic barriers and break down compounds that they cannot digest by themselves. Interspecies electron transfer, which is a major type of microbial communication in syntrophic processes, improves methanogenesis and anaerobic oxidization of methane (AOM) processes involved in syntrophic consortia. These processes have a significant impact on the global carbon cycle. Most of the essential enzymes involved in methanogenesis are iron-sulfur proteins. Iron-sulfur clusters are one of the oldest and most versatile cofactors present in all domains of life. To date, …

Characterization Of The Integrated Signaling Network Of Burkholderia Glumae For The Regulation Of Virulence-Related Function In The Bacterial Pathogenesis Of Rice Plants, Tiago De Paula Lelis

LSU Doctoral Dissertations

Bacterial panicle blight of rice (BPB) caused by Burkholderia glumaeis a major bacterial disease of rice in many rice-producing areas worldwide. Managing the disease is still very difficult due to the lack of effective methods. B. glumaestrains show phenotypic and genomic variations; however, little variation was detected in the known virulence-related genes. In the present study, the complete genome of B. glumae257sh-1, a natural avirulent strain, was sequenced and analyzed. Several spontaneous mutations in the regulatory genes of these avirulent strains were identified. Presumably, the accumulation of these mutations can have a negative effect on the normal …

Divergent Transcriptional Regulation Of Suppressors Of Cytokine Signaling Genes In Adipocytes, Paula Mota De Sa

LSU Doctoral Dissertations

The Janus Kinase - Signal Transducer and Activator of Transcription (JAK-STAT) signaling pathway transduces several signals crucial for development and homeostasis. Suppressors of cytokine signaling (SOCS) proteins control JAK-STAT signaling via a negative feedback loop. The transcription factor STAT5 is known to play a significant role in fat cell development and function, and several studies suggest that acetylation may affect STAT5 transcriptional activity. To test this hypothesis, we treated 3T3-L1 adipocytes with growth hormone (GH) to activate STAT5 in the presence or absence of histone deacetylase (HDAC) inhibitors. STAT5 acetylation levels were low in adipocytes and mostly unchanged by the …

In Vitro Evaluation Of Ovarian Cancer Tumorigenesis As A Function Of Quinone Oxidoreducatse-1 And Cell Phenotype, Milcah S. Jackson

LSU Doctoral Dissertations

In vitro multicellular spheroids are attractive model systems for assessing genetic and epigenetic changes that occur in diseased tissues. Understanding how such alterations in gene and subsequent protein expression affect disease progression and metastasis, drug resistance, and recurrence is of great interest in cancer research. In this regard, examining expression and activity of proteins, such as those with cytoprotective ability that are overexpressed in cancer cells, in addition to cell phenotype (i.e., stem-like, epithelial, mesenchymal, or mixed), are two ways to evaluate genetic and epigenetic changes. Moreover, determining the impact that cytoprotective proteins and cell phenotype have on tumor formation …