Life Sciences Commons^™

Transcriptome And Gene Expression Profiling Of Sweetpotato Responses To Nitrogen And Phosphorus Deficiency During Storage Root Formation, Lisa I. Arce

LSU Doctoral Dissertations

Nitrogen (N) and phosphorus (P) are essential macronutrients required by plants for normal growth and development. In sweetpotato [Ipomoea batatas (L.) Lam.], these nutrients are the most limiting factors affecting both yield quality and quantity. While most research focuses on agronomic responses and genomic analyses, limited research has examined transcriptomic responses to nutrient stress in sweetpotato. Here, we employed next-generation sequencing to investigate the molecular mechanisms underlying N and P deficiency responses in cultivar 'Bayou Belle' (BB). We utilized root tip tissue and investigated responses during the critical stage of root development and storage root formation at 5, 10, …

Functional Cellulose Nanomaterials In Value-Added Applications, Mohammad Shayan

LSU Doctoral Dissertations

Cellulose nanomaterials (CNMs), including cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs), offer potential value-added applications. This dissertation explores their versatility through three applications. In the first application, CNCs and CNFs were combined to create a pH-sensitive film by immobilizing anthocyanins from red cabbage extract (RCE). The addition of RCE altered the suspension's rheological, optical, and mechanical properties, with films containing 30 wt.% RCE exhibiting optimal performance and rapid pH responsiveness for seafood packaging. The second application addressed zinc dendrite growth and short circuits in aqueous zinc-ion batteries (ZIBs) by fabricating a hybrid NFC/Al(OH)₃ /PTFE protective layer for zinc anodes. …

Evaluation Of Host Resistance To Rotylenchulus Reniformis In Sweetpotato Germplasm, Timothy S. Miller

LSU Master's Theses

The reniform nematode (Rotylenchulus reniformis) is an emerging plant-parasitic threat to sweetpotato production. Dissimilar from the galling caused by root-knot nematode infections, infections from the reniform nematode occur without visible damage to the root system. In the southern United States, heavily infested sweetpotato fields can lose up to 40% of their total yield. Growers rely heavily on fumigants and nematicides which provide inconsistent control and are not sustainable in the long-term. Past research has been more focused on the efficacy of chemicals than in the identification of host resistance or tolerance in sweetpotato germplasm. This study evaluated past …

Binding Of A [2fe-2s] Cluster Drives Dimerization Of Ferric Uptake Regulator (Fur) In Escherichia Coli, Fatemeh Najafi, Aidan G. Purcell, Finbar H. Homes, Huangen Ding

Faculty Publications

The ferric uptake regulator (Fur) is a global transcription factor that reversibly binds an iron-sulfur [2Fe-2S] cluster via the cysteine residues (site 3) in response to elevation of intracellular free Fe content in Escherichia coli. Here, we report that when E. coli Fur is expressed in E. coli cells grown in M9 medium supplemented with Fe or zinc (Zn), purified Fur binds a [2Fe-2S] cluster or Zn(II), respectively. While apo-form Fur is a monomer and has no DNA-binding activity, both the [2Fe-2S] cluster-bound Fur and the Zn(II)-bound Fur are homodimers and have a similar binding activity for the DNA sequence …

Effects Of Cryoprotective And Mitochondrial Stabilizing Agents On Vitrified Bovine Oocytes, Allison Hoang

LSU Master's Theses

Oocyte vitrification success is highly dependent on cryoprotectant agent (CPA) choice as well as possible additives that could help preserve mitochondrial membrane potential (mMP), reactive oxygen species (ROS) production, and calcium homeostasis within the cell. It is a delicate balance between levels needed for proper oocyte function and activation and levels needed to induce apoptotic pathways. The results of oocyte cryopreservation determine the eventual oocyte viability and subsequent fertilization and embryo development.

In this study potential permeating cryoprotectant combinations were explored such as ethylene glycol (EG) and propylene glycol (PG) or EG in combination with dimethyl sulfoxide (DMSO). Also, the …

Characterization Of The Role Of Rsd-6, A Tudor Domain Protein, In Antiviral Rnai Pathway In Caenorhabditis Elegans, Krishna Prasad Dahal

LSU Doctoral Dissertations

RNA interference (RNAi) triggered by virus produced dsRNA intermediate offers robust innate immunity against invading viruses in plants, insects and animals. Caenorhabditis elegans has been extensively used as a model organism to study host virus interaction. Recently, a forward genetic screen identified RNAi spreading deficient-6 (RSD-6), a Tudor domain protein, as a key component in antiviral RNAi pathway against Orsay virus in C. elegans but its contribution in the pathway remained unclear. Here, we generated a rsd-6 null allele using CRISPR-Cas9 genome editing, crossed it with other known RNAi mutants and analyzed Orsay virus replication in them and in combination …

Patterns And Processes Behind Secretive Marshbird Movement, Abundance, And Distribution Across Southeastern Louisiana, Leah Moran

LSU Doctoral Dissertations

Restoration and conservation of coastal Louisiana hinges on understanding the patterns and processes underlying habitat heterogeneity on the landscape and therefore the species that inhabits this region, including secretive marshbirds. Elusive in nature, this guild of birds has evolved under dynamic hydroperiods, and myriad plant communities present within wetlands. Only recently, however, has research focused on the role of hydrologic dynamics and vegetative structure and distribution on abundance, movement and detection of marshbirds, specifically within southeastern Louisiana. This study aimed to quantify the ecological patterns and processes, particularly hydrologic processes and landscape structure, driving breeding secretive marshbird movement, abundance and …

Environmental, Social, And Molecular Regulation Of Foraging Behavior In The Formosan Subterranean Termite, Arjun Khadka

LSU Doctoral Dissertations

Foraging is a critical activity in social insects, essential for resource acquisition and colony sustenance. In termites, this behavior is shaped by environmental, social, and genetic factors, yet the underlying regulatory mechanisms remain poorly understood. In this study, we examined how environmental food and moisture availability, and the age of termites affected foraging activities, along with the molecular regulation of foraging in the Formosan subterranean termite, Coptotermes formosanus, using a combination of behavioral assays, transcriptomics, and molecular biology approaches. First, we demonstrate that food and moisture deprivation (FMD) significantly affects foraging, with termites under deprivation conditions exhibiting increased foraging …

Novel Tools And Datamining Techniques To Visualize And Interpret Historical Sugarcane Datasets, Zachary A. Taylor

LSU Master's Theses

Heritable genetic variation is an essential raw ingredient of variety development programs. This variation is acted upon via selection by identifying elite progeny that can be utilized agronomically or exploited as parents. Sugarcane breeders are tasked with creating optimal genetic variation through crossing. Prior knowledge of pedigree and parental performance allows breeders to discern which crosses to prioritize, since the time to make crossing decisions and the space to evaluate tens and thousands of progenies are both limited resources in sugarcane variety development programs. In this project, we have updated and validated the U.S. sugarcane pedigree …

Maternal Hyperleptinemia Alters Placental Transcriptome And Progesterone Regulation Without Affecting Early Equine Fetal Growth, Lucinda L. Thorburn

LSU Master's Theses

While consequences of equine obesity are well defined, the extent to which persistent hyperleptinemia and accompanying leptin (Lep) resistance affect the fetal-maternal environment warrants further exploration. This study compared endocrine, fetal, placental, and uterine parameters during early pregnancy (through day 70) in mares with elevated leptin versus normal leptin (NL) concentrations. Fourteen mares were classified as either NL (n = 6; Lep 0.9 ± 0.3 ng/mL), moderate leptin (ML; n = 4; Lep 3.0 ± 0.3 ng/mL), or high leptin (HL; n = 4; Lep 5.8 ± 0.7 ng/mL) based on annual plasma leptin. Mares were artificially inseminated and induced …

Evaluation Of Diy Pest Management Strategies For The German Cockroach (Blattella Germanica) In The Presence Of Vitamin K Precursors And Synthetic Amorphous Silica, Mohamed S. Shaik

LSU Master's Theses

The German cockroach, Blattella germanica (Linnaeus) is a globally distributed indoor dwelling pest of medical concern. Insecticides are the preferred method of cockroach management due to their low cost, quick action, and availability. However, after continuous use, the development of insecticide resistance has emerged as a challenge for the pest management industry to effectively eliminate German cockroaches. Integrated pest management (IPM) is a sustainable framework which includes the use of glue board traps, vacuuming, in combination with different insecticide formulations such as sprays, gel or dust baits, and insecticide rotation has been successful for the management of German cockroaches. This …

Role And Electrophysiological Properties Of Sexually Dimorphic Oxytocin Receptor Expressing Neurons In The Anteroventral Periventricular Nucleus Of The Female Mice, Armita Abdollahi Govar

LSU Doctoral Dissertations

Oxytocin is a neurohypophyseal hormone that plays a crucial role in regulating mother-infant bonding and maternal behavior. Oxytocin modulates sex-specific parental behaviors by binding to the oxytocin receptor (OXTR)-expressing neurons in the brain. This study investigates the sexually dimorphic OXTR neurons in the anteroventral periventricular nucleus (AVPV) to understand how oxytocin modulates behavior in females. Specifically, we explored the behavioral roles, neural projections, and intrinsic electrophysiological characteristics of these neurons in the female mice. Using immunohistochemistry revealed that the number of OXTR-expressing neurons was enhanced in postpartum females compared with virgin females, suggesting that these neurons are involved in female-specific …

Effects Of Staphylococcal Superantigen-Like Protein 11 (Ssl11) On The Host Immune Response During Lung Infection, Sajani Ghaju

LSU Master's Theses

Staphylococcus aureus (S. aureus) is an opportunistic pathogen that produces numerous immune evasion molecules that target various components of the host immune defense to cause infection. One of these is a family of virulence factors, Staphylococcal superantigen-like proteins (SSLs) with 14 members that exhibit host immune-evasion functions. SSL11 has been reported to inhibit neutrophil migration, preventing its recruitment to sites of infection. However, its role in vivo and effect on neutrophil phagocytosis have not been known. This thesis focuses on studying the effect of recombinant SSL11 protein in an in vivo S. aureus-induced pneumonia model and in vitro …

Assessing Natural Resources Conservation Service (Nrcs) Impacts On Rice And Soybean Efficiency In The Mid-South, Ayodeji Samuel Ayiti

LSU Master's Theses

The study investigates how the Mid-South region of the U.S. rice and irrigated soybean production efficiency is influenced by (NRCS) incentives. To evaluate the effect of crop insurance, subsidies, and conservation incentives on lowering inefficiency, this study used a stochastic frontier model (SFA). The dataset covered the years 2010 – 2023, which allowed for a thorough evaluation of efficiency trends over time. While crop insurance programs reduce inefficiency in rice production, it shockingly increases inefficiency in soybean production, according to the study, which highlights the disparate effects of net support (insurance-subsidy).

The results show that while external factors like changes …

Ergonomic And Biomechanical Assessment Of Vertical Ladder Climbing For Exoskeleton Integration In Construction Tasks, Ehsan Shourangiz

LSU Master's Theses

Active exoskeletons are increasingly utilized in physically demanding industries such as construction and manufacturing to reduce strain and lower the risk of work-related musculoskeletal disorders, supporting worker safety and long-term health. However, most existing systems are designed for repetitive tasks like lifting or prolonged standing, with limited consideration for dynamic activities such as vertical ladder climbing. Ladder climbing is common and physically demanding in industrial environments, often required to access elevated areas like scaffolding, tanks, or rooftops. Since exoskeletons are intended to remain worn throughout multiple tasks, requiring workers to remove and re-don the device during ladder climbing would reduce …

Hemp Cultivation Under Off-Season High Tunnel Growth Chamber Environments In South Louisiana, Gabriel Lococo

LSU Master's Theses

Industrial hemp (Cannabis sativa) production in Louisiana began in 2020 with 932 acres cultivated for fiber and cannabidiol (CBD) extraction. By 2024, production had declined to just 58.4 acres (Louisiana Department of Agriculture and Forestry, personal communication). During the 2020–2021 season, over 40% of field-grown hemp was lost due to tropical storms, insect pressure, and diseases associated with warm, wet conditions. To mitigate these challenges, hemp was planted and harvested between November and January, a cooler period with reduced environmental stress.

‘Sour Citron’, a day-neutral cultivar, was selected for its insensitivity to photoperiod, enabling flowering during shorter days. …

Elucidation Of A Role In Biofilm Production For The Tyrosine Catabolism Pathway In Vibrio Cholerae And Analysis Of Reversible Phase Variation In Vibrio Vulnificus, Aheli S. Mukerji

LSU Doctoral Dissertations

Biofilms produced by the cholera pathogen Vibrio cholerae not only enhance its ability to survive in the environment but also allow pathogenic success of the bacterium. This organism also undergoes phase variation, switching between smooth and rugose colonial phenotypes, the latter forming much more vibrio polysaccharide (VPS) resulting in more robust biofilms and subsequently having an increased level of persistence. In a previous study, many genes were found to be upregulated in the transition from the smooth to the rugose phenotype. Here, several of these upregulated genes were investigated for their potential role in biofilm production, and an additional gene, …

Stream Fish Assemblage Dynamics And Barriers To Aquatic Connectivity In The Ichawaynochaway Creek Watershed, Georgia, Usa, Jake R. Duhé

LSU Master's Theses

Stream fishes in the southeastern United States are adapted to hydrological disturbances such as droughts. However, this region is projected to experience increasingly frequent and severe disturbances that will elevate water demands given increasing agricultural and urban development. Further, road-stream crossings (RSCs) are abundant features in these streams that can exacerbate drought-mediated stream fragmentation and impede movements by many aquatic organisms, including fishes, when poorly constructed. These compounding effects may adversely affect the diversity and abundances of resident stream fishes, but their interactions remain poorly understood, warranting rigorous testing of how droughts and RSCs influence stream fish dynamics. I assessed …

Metabolic And Physiological Regulation In C. Elegans: Insights Into Sperm Activation And Peroxisome-Mediated Longevity, Yash Flora

LSU Doctoral Dissertations

Organelle dynamics lie at the heart of cellular signaling and metabolic regulation, orchestrating physiological processes such as reproduction and aging across the lifespan. In this dissertation, I investigate how organelle-based signaling coordinates sperm activation and modulates organismal aging in the nematode Caenorhabditis elegans. I identify SPIN-4, a previously uncharacterized Spinster family transporter, as a key regulator of spermiogenesis. SPIN-4 is strongly expressed in developing sperm, localizes to the plasma membrane, and promotes sperm activation by facilitating the export of sphingosine-1-phosphate (S1P). Loss of spin-4 results in defective pseudopod formation, reduced motility, and compromised fertility, phenotypes that can be rescued …

Weather Impacts On Specialty Fruit Wholesale Prices, Oladayo Daniel Oluleye

LSU Master's Theses

This article investigates the relationship between temperature and precipitation variability and wholesale specialty fruit prices in the United States. Using fixed-effects panel regression and a comprehensive dataset of monthly price observations across ten major U.S. wholesale markets (Atlanta, Baltimore, Boston, Chicago, Detroit, Los Angeles, Miami, New York, Philadelphia and San Francisco) from 2000 to 2019, we examine how weather fluctuations affect wholesale market prices for five fruits including apples, avocados, grapes, oranges, and strawberries. Our analysis categorizes temperature into discrete bins representing the number of days per month within specific temperature ranges. The results show that extreme temperatures, particularly above …

Assessing Niche Differences Across The Dwarf Salamander Species Complex Of The Southeast Us, Sarah Roy

LSU Master's Theses

Characterizing niche differences in closely related species can provide valuable insights into the extent of ecological divergence between species, and the potential evolutionary processes behind speciation. This study builds the first ecological niche models for the Eurycea dwarf salamander species complex, which includes five species with varying distributions across the southeastern United States. Ecological niche models (ENMs) were built for each species using the machine-learning algorithm, MaxEnt. We used pairwise niche overlap analyses and statistical validation techniques to investigate potential ecological drivers behind species divergence and the degree of niche overlap among the five Eurycea species. We found an overall …

Mate Choice And Movement Ecology Of Plegadis Ibis In Louisiana, Ryan T. Klutts

LSU Master's Theses

In 1817, George Ord documented the first North American records of Glossy Ibis (Plegadis falcinellus), a species native to the Old World. Over the next 200 years, Glossy Ibis expanded its breeding range to include the Atlantic coast to southernmost Florida and thence up the Gulf coast to eastern Texas. Forty-five to 75 years ago, its range expansion brought it into secondary contact with White-faced Ibis (P. chihi) in Louisiana, a native species whose breeding range includes freshwater wetlands in Louisiana and eastern Texas. Hybridization between the two species resulted in a large hybrid zone in southern Louisiana, providing an …

A Phylogenomic Investigation Of The Historical Biogeography Of Livebearers (Cyprinodontiformes: Poeciliidae), Sheila Rodríguez Machado

LSU Doctoral Dissertations

The Neotropics contain several biodiversity hotspots and harbor the highest diversity of freshwater fishes globally. Yet, recognizing the patterns and processes driving this richness remains a challenge. Similarly, all groups and subregions have not received the same attention, especially in the genomics era. Addressing these knowledge gaps will help us to better understand the region’s evolutionary and biogeographic complexity. The goal of this dissertation is to examine phylogenetic and biogeographic patterns of Neotropical freshwater fishes, with emphasis on the Greater Antilles, across multiple taxonomic and geographic scales. To achieve this goal, I generated a genomic dataset of hundreds of ultraconserved …

Functional And Comparative Genomics Of The C.Sojina- Soybean Interaction, Alejandra Maria Vargas Oyuela

LSU Master's Theses

Frogeye leaf spot (FLS), caused by Cercospora sojina, is a significant foliar disease of soybean (Glycine max) and is responsible for substantial yield losses worldwide. While management strategies rely on host resistance and fungicide applications, the emergence of new virulent races and fungicide-resistant isolates necessitates a deeper understanding of C. sojina host interactions and genomic variability. Here, we employed comparative and functional genomic approaches to decipher the molecular mechanisms underlying the C. sojina-soybean interaction. A dual RNA sequencing approach was used to identify transcriptomic changes in G. max cultivars Blackhawk (susceptible) and Davis (resistant) across multiple …

A Natural Short Sleep Mutation Promotes Longevity Through Mitochondrial Respiration In Drosophila, Pritika Pandey

LSU Doctoral Dissertations

Aging is an irreversible process characterized by progressive physiological decline and an increased risk of metabolic disorders, cognitive impairment, cardiovascular diseases, and neurodegeneration. Disruptions to the circadian clock—whether due to genetic mutations or behavioral factors—accelerate aging and age-related pathologies, highlighting a strong link between circadian regulation and longevity. However, certain individuals harbor a dec2^P384R mutation, which enables natural short sleep without the detrimental effects of chronic sleep deprivation. This suggests that these individuals have evolved adaptations that activate pro-health pathways, allowing them to function optimally with reduced sleep. To investigate the genetic mechanisms underlying these changes, we developed a …

Impacts Of Climate Change On Cannibalism And Disease Transmission In The Fall Armyworm, Kale Rougeau

LSU Master's Theses

Climate change may alter host-pathogen dynamics in terrestrial ecosystems due to rising global temperatures and carbon dioxide levels. Here, we examined cannibalism and disease transmission using the fall armyworm (Spodoptera frugiperda), an invasive agricultural pest, and its species-specific lethal baculovirus, Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), under various potential challenges of climate change. We used three temperature treatments (cooler, optimal, warmer) based on the fall armyworm’s thermal performance curve to simulate a changing climate and four artificial diets with various protein-to-carbohydrate ratios (low, equal, high, standard) to manipulate resource quality from altered carbon dioxide levels. We found that higher …

Neuronal Cftr: A Study Of Subcellular Localization And Interactions With Implications For A Role In Synaptic Transmission, Brandon J. Leviskas

LSU Doctoral Dissertations

Protein-protein interactions vary among cell types and the localization of these interactions help to define protein function. The function of cystic fibrosis transmembrane conductance regulator (CFTR) is well established in the context of epithelial tissue due to the debilitating effects of its mutations that cause the disease cystic fibrosis. While in neurons a role has been established in our lab for CFTR in the regulation of cytosolic Cl- in retinal amacrine cells (ACs). This research sets out to learn if CFTR has a synaptic role. Exploring this potential role, localization of CFTR was examined using fluorescent and immunogold labeled transmission …

Intraspecific Variation In Morphological And Biochemical Responses To Salinity And Flooding In Phragmites Australis, Olivia Hurley

LSU Master's Theses

Phragmites australis is a widespread wetland plant species with numerous haplotypes, several of which are highly invasive. In low-lying coastal marshes of Louisiana, the Delta-type (haplotype M1) dominates across a wide range of salinity and flooding environments. This suggests that Phragmites may be highly adaptable to diverse environmental conditions and that there may be a genetic component, as seen in other coastal wetland plant species. While non-native Phragmites haplotypes are targeted for control and removal in many areas, they are considered beneficial for marsh stabilization and contributing to elevation gain in coastal Louisiana, where several areas experience rapid land loss. …

Metabolic Transitions In Embryos Of Artemia Franciscana: Regulation And Consequences For Oxidative Stress, Daniel Anthony Arabie

LSU Doctoral Dissertations

Embryos of Artemia franciscana survive harsh conditions in diapause and anoxia-induced quiescence for years by undergoing deep metabolic transitions. I investigated the relationship between phosphorylation of pyruvate dehydrogenase (PDH) and carbon flux to the tricarboxylic acid (TCA) cycle during metabolic depression. The difference in catalytic activity of the PDH complex (PDC) in maximally phosphorylated and dephosphorylated samples was 16.5-fold. Western blot analysis confirmed the changes in phosphorylation of PDH. Analysis of PDH expression in diapause and post-diapause embryos via phospho-PDH showed no significant differences. Investigation of post-diapause embryos under anoxia showed that phosphorylation of PDH decreased and activated the enzyme. …

Louisiana Agricultural Magazine, Spring 2025

Louisiana Agriculture

Growing fruits and pecans is a part of Louisiana’s agricultural heritage. Citrus trees have been planted here for three centuries, and the state is famous for strawberries. Pecans and mayhaws are native to the state, and they are beloved by Louisianans. Some of these fruits have become industries worth millions of dollars, while others have become popular for home production.

This issue of Louisiana Agriculture focuses on the efforts of LSU AgCenter Extension experts working to foster home fruit production and support the fruit and pecan industry in Louisiana. Through their research and extension programs, they provide homeowners and commercial …