Life Sciences Commons^™

Searching For The Soldier Pheromone: Behavioral Effects Of Soldiers And Soldier-Produced Chemicals In The Formosan Subterranean Termite, Coptotermes Formosanus (Blattodea: Rhinotermitidae)), Joseph Mccarthy

LSU Master's Theses

The Formosan subterranean termite, Coptotermes formosanus, is a eusocial insect and an invasive urban pest. Colonies function through a division of labor among castes (i.e., queens and kings, workers, and soldiers). Though soldiers are energetically expensive to maintain, C. formosanus has a relatively large soldier caste (~10% of the colony). Soldiers are physically unable to collect food or build tunnels but are regularly found with foraging workers. In some species, soldiers influence the worker foraging behavior. In C. formosanus, aside from defense, the roles soldiers play remains unknown. In this study, we determined if soldiers influence …

Effect Of Canopy Competition On Tree Growth And Development In Pine Hardwood Mixtures, Jacob Alexander Olichney

LSU Master's Theses

Mixed species forests may benefit from the reduction in intraspecific competition, although the benefit of species mixing has been shown to vary depending on mixture composition and environmental conditions. This study sought to test the effect of species composition in mixed forest stands on canopy development and growth of loblolly pine (Pinus taeda), cherrybark oak (Quercus pagoda), and sweetgum (Liquidambar styraciflua). Even-aged, grid planted monoculture and mixed species forest plots were established with hardwood monoculture plots at a 741 Trees Per Hectare (TPH), and pine monoculture and mixed species plots established at 1482 TPH. …

Assessing Turgor Loss Point In Bottomland Hardwood Trees Using Leaf Spectroscopy, Alexandra M. Eisley

LSU Master's Theses

Climate change is expected to radically alter our planet’s forests, with higher frequencies of drought- and flood-induced mortality events posing a challenge for forest managers and biologists. Research into the factors underlying plant tolerance to environmental stressors is therefore gaining popularity for incorporation into projective and earth system modeling using remote sensing measures. Leaf turgor loss point (TLP) is a key trait associated with drought tolerance among plants and is defined as the water potential at which leaf turgor pressure reaches zero, causing wilting. Here, I investigated patterns of TLP across the landscape and its role as an indicator of …

Esterase Mediated Insecticide Resistance In The Southern House Mosquito, Culex Quinquefasciatus, Vivek Pokhrel

LSU Doctoral Dissertations

Much is known about the development of insecticide resistance associated with targeted application against insect populations. However, off-target selection by applications of insecticides in agricultural and residential sites also impacts development of insecticide resistance and is understudied. Similarly, the impact of selecting one life stage of mosquitoes on the insecticide susceptibility of different life stages is largely unknown. The first part of this study shows that susceptibility to chlorantraniliprole, which is applied in rice and sugarcane fields in LA, decreased (5.7 to12-fold) in populations of Culex quinquefasciatus collected from near these fields compared to a reference field strain. In addition, …

Fish And Invertebrate Community And Trophic Structure In The Gulf Of Mexico Coastal Plains Watersheds Across Varying Hydrologic Connectivity., Erin Elizabeth Thayer

LSU Doctoral Dissertations

Subtropical Northern Gulf of Mexico coastal plains watersheds tend to have mild seasonal temperature, low topography, and fine, mostly homogenous substrate sizes; these watersheds may not follow fish and invertebrate community patterns predicted by established lotic paradigms because those paradigms tend to describe communities in either temperate or tropical regions. However, the bases of most generally accepted lotic paradigms involve evaluation of allochthonous and autochthonous contributions to lotic ecosystems via three hydrologic connectivity dimensions including vertical (hyporheic and shallow groundwater), lateral (floodplain), and longitudinal (upstream and downstream). My dissertation goals were to explore these three dimensions within Louisiana coastal plains …

From Biowaste To Product: The Functionalization Of Biochar For Agricultural And Environmental Applications, Baoyue Zhou

LSU Doctoral Dissertations

Biochar is a porous carbonated substance that is manufactured through pyrolysis of biomass feedstocks in an oxygen-deficiency environment. The production of biochar from agricultural waste materials provides a potential solution for eliminating pollution while improving carbon sequestration. While biochar is shown to provide multiple benefits to soil health and fertility, its use in environmental remediation has been hampered by its low affinity for hazardous anionic species and the difficulty in isolating from water phase. To overcome these obstacles, various efforts have been made to modify biochar surface chemistry and morphology.

Fe/Mg co-doped biochar composites from sugarcane harvest residue were prepared …

Review Of Structural Color In The Genus Chrysochroa Dejean, 1833 (Coleoptera: Buprestidae), Able Chow

LSU Master's Theses

The jewel beetles, (Coleoptera: Buprestidae Leach, 1815), is the eighth most speciose coleopteran family, with the majority of its members possessing diverse bright, saturated structural coloration of multilayer origin. This study focuses on the genus Chrysochroa Dejean, 1833, which includes some of the most brilliantly and charismatically colored buprestid species. While members of Chrysochroa are prised by entomologists amateurs and professional and are well-represented in museum collections, the evolution and ecology of their structural color remain underexplored. Twenty-eight select taxa including exemplars from all 13 subgenera of Chrysochroa were investigated to provide an overview of the objective optical properties and …

Identification Of Quantitative Trait Loci (Qtls) For Resistance To Bacterial Leaf Streak: Xanthomonas Translucens Using Qtl And Association Mapping In Three Populations Of Soft Red Winter Wheat, Benjamin Tyler Meritt

LSU Doctoral Dissertations

Bacterial leaf streak (BLS) and black chaff, caused by Xanthomonas translucens pv. undulosa (Xtu), can be a very destructive disease of wheat, especially in the warmer, wetter areas of the Southeastern U.S. Yield losses of up to 40 percent have been recorded in some cases in southern wheat growing regions. With no effective agronomic or chemical method of disease control, identification of genetic resistance is seen as a promising solution. Three soft red winter wheat populations (GAWN, ARK-SNP, and AGS 2060- AGS 2035 DH) representative of soft red winter wheat germplasm in the southeastern U.S. developed by …

Immunohistochemical Localization Of Kisspeptin And Its Receptor In The Equine Ovary, Bryce M. Gilbert

LSU Master's Theses

Kisspeptin is recognized for its role as the gatekeeper of reproduction in most mammalian species. However, its role in regulation of reproduction at the ovarian level is poorly understood in the horse. In this study, ovaries from follicular phase, luteal phase, anestrous period, and mares treated with ECP-sulpiride were subjected to immunohistochemistry to characterize kisspeptin-10 (Kp10) and its receptor (Kiss1r) protein expression throughout each reproductive stage and follicle type. Kisspeptin and receptor staining was detected in all follicle types (primordial, preantral, and antral) throughout all reproductive stages, as well as oocytes, corpora lutea, and ovulation fossa. The pattern of Kp10 …

A Membrane Transporter Required For Quorum Sensing And Virulence Of The Rice Pathogen Burkholderia Glumae, Asif Iqbal

LSU Doctoral Dissertations

Burkholderia glumae is a Gram-negative bacterium causing bacterial panicle blight (BPB) in rice. BPB can cause severe damage to rice and reduce rice yield up to 75%, while no effective treatment has been developed to control the disease. B. glumae produces and secretes an essential virulence factor, toxoflavin, which is mainly responsible for the symptoms of BPB. Synthesis and transport of toxoflavin are regulated in a quorum-sensing dependent manner. Members of the DedA superfamily are putative membrane transporters and found in nearly all species. Mutation of dedA in Burkholderia species results in sensitivity to colistin, an antibiotic belonging to the …

The Risks Posed By Mosquito Ultra-Low Volume Applications To Procambarus Clarkii Production, Timothy Mcnamara

LSU Doctoral Dissertations

Mosquito abatement has received much scrutiny due to concerns about the impacts of control applications on non-target organisms. In Louisiana, a great deal of this concern has come from crawfish farmers claiming mosquito abatement applications have damaged crawfish production. To determine which mosquito abatement practices and products pose a risk to crawfish production, we conducted a series of studies examining mosquito abatement practices in the vicinity of crawfish production fields and the impacts of common mosquito abatement product exposure on crawfish health and production. We found that mosquito ULV applications are the most likely to result in exposure to crawfish …

Influence Of Hesperidin On The Physico-Chemical, Microbiological, And Sensory Characteristics Of Frozen Yogurt, Roberto Antonio Cedillos Hernández

LSU Master's Theses

Frozen yogurts contain yogurt culture bacteria which might impart health benefits to its consumers. Global frozen yogurt market sales are expected to grow 4.8% by 2028 which represents an important opportunity for the industry, consumers, and researchers. Polyphenols are metabolites found in plants which have antioxidant and anti-inflammatory properties and might prevent chronical diseases such as cancer, diabetes, and cardiovascular diseases. The objective of this study was to elucidate the effect of the polyphenol hesperidin on the physico-chemical, microbiological, and sensory characteristics of frozen yogurts. Hesperidin was incorporated in frozen yogurt at three concentrations (500, 250 and 125 mg/90g of …

Understanding Motivations Among Sustained Cooperative Extension Partners For Obesity Prevention In Rural Louisiana, Catherine R. Losavio

LSU Master's Theses

Louisiana consistently has one of the highest rates of obesity in the nation with higher concentrations of obesity in many rural parishes (i.e., counties). Due to over a century of visibility and engagement in rural communities, Cooperative Extension (Extension) is uniquely poised to reach remote rural communities disproportionately impacted by obesity. As Extension increases its use of community coalitions and implements its new National Framework for Health Equity and Well-Being, understanding motivations and communication preferences among long-term rural coalition partners for obesity prevention and health promotion has become essential for duplicating successful local-level policy, system, and environmental (PSE) changes. This …

Louisiana Agriculture Fall, 2022

Louisiana Agriculture

Livestock industries contribute $2.5 billion to the state’s economy, and beef cattle production is one of the most important sectors of the state’s agricultural enterprise. LSU AgCenter researchers study how to improve cattle production at research stations across the state. AgCenter Extension agents in every parish connect producers with their findings.

In this issue of Louisiana Agriculture magazine, livestock agents and research faculty describe the many programs they have developed to educate cattle producers and help 4-H’ers raise and show animals. Producers discuss what they have learned from Master Cattleman classes, and writer V. Todd Miller details how some cattle …

Effects Of Sensory Cues On Product Acceptability And Consumer Perceptions, Emotions, And Behavior, Cristhiam Gurdian Curran

LSU Doctoral Dissertations

Visual and cognitive cues can affect overall liking (OL) and consumer perceptions, emotions, and behavior. The first study explored the effect of product color difference on the liking, perception, and purchase intent (PI) of cheese-flavored-tortilla chips (CFTC) formulations (A and B) on serving plates (plastic, foam, and paper). Color differences between formulations influenced crunchiness and saltiness liking and perception, which together with overall flavor liking and formulation, mainly determined CFTC OL. Although having similar fracturability (N) and sodium content, formulation A had higher crunchiness and saltiness likings. PI was influenced by crunchiness, saltiness, and OF liking with 37, 49, and …

Role Of Nucleobindin-2/Nesfatin-1 In The Regulation Of Energetic Status And Maternal Mouthbrooding In The Cichlid Fish, Astatotilapia Burtoni, Saachi Chugh

LSU Master's Theses

Feeding and energetics are fundamental processes in all species that must also be balanced with reproductive investment. The peptide hormone nesfatin-1 is encoded by the nucleobindin-2(nucb2) gene and has recently emerged as a key player involved in both feeding and reproduction across vertebrates. How nesfatin-1 might help regulate trade-offs between feeding and reproduction, however, are relatively unexplored. The female cichlid fish Astatotilapia burtoniis an ideal system to examine the role of nesfatin-1 in regulating metabolic and reproductive functions because this species cycles between a gravid feeding state while preparing to mate, followed by a forced starvation …

Understanding Community Assembly Processes Of Foundation Species Within Hyper-Diverse Ecosystems, Carrie Barker

LSU Doctoral Dissertations

Foundation species provide the structure for other species and can significantly affect the composition and overall diversity within a community. Multiple foundation species can coexist within a community, and each can have differential impacts. My dissertation aims to understand the effects different foundation species have on diversity and the community assembly processes responsible for structuring diversity within their respective communities.

First, I quantified the diversity of groundcover plants within the prominent foundation species, bunchgrasses, (dominated by Shizachyrium scoparium) compared to groundcover plant diversity within patches of the alternative foundation species bracken fern (Pteridium aquilinum) and gallberry ( …

Characterizing Habitat Suitability For Gulf Sturgeon (Acipenser Oxyrinchus Desotoi) In Southern Louisiana, Jenna N. Brogdon

LSU Master's Theses

A generalized additive modeling (GAM) framework was used to characterize fish-habitat relationships and develop habitat suitability maps to predict spatiotemporal and ontogenetic shifts in Gulf sturgeon distribution within an impacted estuary in the northern Gulf of Mexico, Lake Pontchartrain. Gulf sturgeon (n = 103) were fitted with acoustic transmitters in the Pearl River during the early summer and fall from 2013 to 2018, and an array of acoustic receivers (n = 81) was used to monitor Gulf sturgeon habitat use and movement in the estuary from 2016 to 2019. Daily presence data from the telemetry array were paired with environmental …

Effects Of Pesticides On Red Rot Of Sugarcane, Kezia Cristina Da Silva Reis

LSU Master's Theses

Red rot disease of sugarcane, caused by Colletotrichum falcatum, can be an important constraint to crop production. In Louisiana, red rot primarily affects seed-cane and is more severe when billets (stalk sections) are planted rather than whole-stalks. At planting application of seed-treatment chemicals, particularly a combination of fungicide and thiamethoxam insecticide, has improved stand establishment and increased yields in billet plantings in Louisiana. However, information has been lacking on the effect of the treatments on disease development. Greenhouse experiments were conducted in 2020 and 2021 to evaluate stalk rot symptom severity and initial plant growth for billets dip-treated with …

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

Application Of Organic Fertilizers For Lawn Establishment And Maintenance In Louisiana, Matthew Lambert

LSU Master's Theses

Landscape contractors are increasingly interested in organic products for Louisiana's residential and commercial turfgrass areas. However, the use, motivations, and barriers to adopting organic practices in the commercial turfgrass and landscape industry are undocumented. A survey with Louisiana Turfgrass Association (LTA) members to gauge their perceptions on current and future use of organic products in Louisiana was performed; and a field trial was conducted to evaluate organic fertilizers during turfgrass establishment. Substantial majorities of turfgrass professionals are currently applying organic fertilizers and believe organic product use will increase due to consumer demands, potential governmental regulation, and the belief that they …

The Effects Of Drought And Shade On Bottomland Hardwood Regeneration, Charles Joseph Pell

LSU Doctoral Dissertations

Floodplain forests support a high diversity of tree species adapted to regenerate under fluctuating water and light availability. Regeneration regulates species composition, and shade and flood tolerance influence the likelihood of regeneration. Regeneration failure of shade-intolerant and flood-tolerant tree species commonly occurs in southcentral and southeastern floodplain forests of the United States, also known as bottomland hardwoods (BLHs). In many BLHs reduced flooding has resulted in a dryer floodplain. These changes in flooding are linked to recent shifts in species composition. The mechanisms controlling regeneration in BLHs and these composition shifts are poorly understood. In a controlled germination experiment, I …

The Association Of Cuzd1 And Stat5 In Adipocytes, Zachary Wigger

LSU Master's Theses

Obesity is a metabolic disorder that has turned into a global epidemic over the past few decades. Adipocyte dysfunction brought on by obesity can lead to increased risk of metabolic diseases such as cardiovascular disease and type 2 diabetes mellitus (T2DM). Knowing how adipocytes function to regulate metabolic homeostasis is critical. CUZD1 (CUB and Zona Pellucida-like Domain-containing protein 1) has not been studied in the context of adipocyte biology but could play a role in several metabolic processes. CUZD1 has been suggested to be a biomarker for several inflammatory diseases and cancers but little functional data has been published. There …

Qualifying Factors That Predict Weight Loss Success Within Diet Interventions, Jordan Losavio

LSU Master's Theses

Evidence-based diet strategies lead to weight loss for some, while for others, the same diet approach could result in trivial weight loss or even in weight gain. This prompts the underlying research question: what factors predict that a given diet strategy will be efficacious for some, but not for others? This research was a secondary analysis of clinical weight loss studies to determine which factors influence an individual’s weight loss success for three diet intervention strategies: low-carbohydrate, low-fat, and low-calorie. A combination of physiological, psychological, behavioral, and dietary factors was evaluated for each diet study. Multiple linear regression and logistic …

Integration Of Remote Sensing Approaches For In-Season Nitrogen Management, Murilo De Santana Martins

LSU Doctoral Dissertations

Nitrogen (N) management is being conducted at flat rate in Louisiana due to practicality and convenience, but the price of N fertilizer and high breakeven costs are forcing producers to find ways to reduce costs and optimize N application. In this scenario, precision agriculture technologies, specifically the use of optical sensors on board of unmanned aerial systems (UAS) to variable rate N application on farm is showing a promising approach to save inputs and reduce environmental impacts. However, the general goal of this research was to develop and evaluate in-season N management approaches for N recommendation in corn (Zea …

Defining Toxicological Endpoints Of Aphis Gossypii Feeding, Flinn O'Hara

LSU Master's Theses

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, due to photosynthate removal and plant virus transmission. This project consisted of two main goals. First, we employed toxicity bioassays and electrical penetration graph (EPG) methodology to quantify changes to feeding behavior and toxicity of A. gossypii after exposure to commercialized aphicides. Commercialized aphicides containing flupyradifurone, sulfoxaflor, thiamethoxam, thiamethoxam + lambda cyhalothrin, and bifenthrin induced > 90% aphid mortality within 4 hours of exposure. This was supported by our EPG results that showed a significant reduction in the proportion of aphids that continued to probe on cotton 4 …

Wetland Soil Development Along Salinity And Hydrogeomorphic Gradients In Active And Inactive Deltaic Basins Of Coastal Louisiana, Amanda Fontenot

LSU Master's Theses

Coastal wetlands provide an abundance of ecosystem services that benefit society, such as essential habitat for commercial species, storm protection, nutrient cycling, and carbon storage. Louisiana faces rapid rates of relative sea level rise (natural subsidence and eustatic sea levels) that threaten wetland survival, which are amplified by a reduction of riverine sediment input. An important determining factor of marsh survival is the formation of wetland platform elevation, known as vertical accretion, which is determined by several processes including sediment deposition & erosion, below ground biomass (BGB) productivity, decomposition of organic matter, shallow & deep subsidence, and soil compaction. Feldspar …

Graph-Based Computational Approach To The Study Of Cancer Pharmacotherapy, Manali Singha

LSU Doctoral Dissertations

Recent advances in the analysis of omics data from various cancer cells pave the way for cancer therapy to predict effective drug responses and drug-target interactions based on cell- specific genetic features such as gene expression profiles, mutations, and copy number variations. Because the phenotype of a complex disease, such as cancer, is determined by several factors, it is difficult to predict the best effective treatment for a certain cell line based just on one sort of data, such as genetic traits and drug molecular features. The overall studies in this thesis proposed a graph-based representation of heterogeneous biological data …

The Link Between Intracellular Calcium Signaling And The Nitric Oxide-Dependent Release Of Chloride In Retinal Amacrine Cells, Li Zhong

LSU Doctoral Dissertations

Regulation of cytosolic Cl^- is an important determinant in synaptic function. Our lab has discovered that cytosolic Cl^- is regulated not only by transport across the plasma membrane but that Cl^- can also be released from internal Cl^- stores (Hoffpauir et al., 2006) in amacrine cells (ACs). Nitric oxide (NO) is a small molecule neurotransmitter that has been demonstrated to be involved in cytosolic Ca²⁺ elevations and Cl^- regulation via activation of the cystic fibrosis transmembrane regulator (CFTR) (Krishnan et al., 2017). Here, I test the hypothesis that intracellular Ca²⁺ signaling mediates the …

Development Of A Non-Dairy Yogurt Alternative Using High Protein Brown And White Rice Flour, Anita Morris

LSU Doctoral Dissertations

There is a great demand for plant-based yogurt alternatives (YAs) due to societal prevalence of milk sensitivities and allergies as well as some consumers abstaining from animal-derived products. Producing YAs from rice flour has considerable potential because (1) rice is not a major food allergen, (2) using rice flour is more economical compared to plant milks, the main ingredient in commercially available YAs, and (3) there are no rice-based yogurt alternatives in today’s marketplace. The overall goals of this study were to develop probiotic YAs from brown and white rice flours, and to evaluate their storage stability, probiotic’s survival in …