Life Sciences Commons^™

Assessing The Effectiveness Of Agricultural Extension Advice On Household Food Consumption And Food Security Outcomes In Malawi, Mphatso Chinsinga

Theses and Dissertations

My study examined the influence of agricultural extension advice on household food consumption and food security outcomes in Malawi. I utilized a pooled cross-sectional dataset from the Malawi Integrated Household Survey (IHS) and Integrated Household Panel Survey (IHPS) conducted in 2010, 2013, 2016, and 2019. To identify the effects, multivariate linear and logistic regression models were employed, considering various factors and incorporating fixed effects for survey wave, district, and data collection month. My findings revealed heterogeneity in the impacts of agricultural extension advice on food consumption and food security outcomes. Specifically, the results showed a positive correlation between agricultural extension …

The Community Ecology Of Ants On The Cumberland Plateau And A Taxonomic Redescription Of The Genus Stenamma Westwood, 1839 (Hymenoptera: Formicidae: Myrmicinae) In A Southeastern Treatment, Zachary Brown

Theses and Dissertations

Grassland communities represent major biodiversity hotspots across the United States. Among these grassland types is the short-leaf pine savanna, a major historical habitat along the Cumberland Plateau. The Cumberland Plateau’s grasslands are under threat due to land use changes such as urbanization and land conversion to pasture and hardwood forests. This study seeks to better understand the community ecology of ants on the Cumberland Plateau using powerlines as a comparison to degraded and historic habitats. Ants have a preference between open sites and forested sites, a separation of 44.5% on a DCA. The Simpson diversity places the short-leaf pine savanna …

Advancing Poultry Nutrition Through Statistical Strategies To Reduce Experimental Variation And Novel Protease Enzyme Research, Caleb Morgan Marshall

Theses and Dissertations

Increasingly, nutritionists are challenged to optimize broiler genetic capacity, while considering varying ingredient qualities and pricing, to meet production goals and profitability. Due to scale and cost, university and private research is often used by nutritionists to help make these decisions; thus, requiring these facilities to detect small, incremental improvements. In Chapters 1 and 2, processing data from several nutrition research trials were utilized to evaluate the impact of processing personnel, sample size, and unit of analysis on the detection of dietary differences. By accounting for potential variability between personnel (as a covariant) and selecting an adequate sample size for …

Identification And Characterization Of Silk Gland Specific Ugt34 Gene In Helicoverpa Zea, Courtney Nicole Wynn

Theses and Dissertations

Uridine diphosphate glycosyltransferase (UGT) is a multigene family of enzymes responsible for catalyzing glycosylation of small hydrophobic molecules. Recently, a genomic analysis of the corn earworm (Helicoverpa zea) identified 45 different UGT genes. We discovered a UGT gene (UGT34) showing high levels of expression exclusively in the silk gland tissue. The expression levels of UGT34 were analyzed in different developmental stages and silk gland sub-segments, revealing that UGT34 is generally expressed at all larval instar stages and largely expressed in the middle and posterior subsegments of the silk glands. The soybean looper (Chrysodeixis includens), another noctuid …

Effects Of Fire Seasonality On Bachman’S Sparrows In The Longleaf Pine Forests Of Southern Mississippi, Michael D. Warren

Theses and Dissertations

The Bachman’s sparrow (Peucaea aestivalis) is a ground-dwelling, pine-obligate species experiencing range-wide population declines due to land development and fire exclusion. We explored the effects of fire seasonality on wintering Bachman’s sparrow abundance in Southern Mississippi from 2021-2022. We used generalized linear mixed models to investigate differences in sparrow abundance and vegetation characteristics following dormant and growing season fire. We explored the effects of growing season fire on breeding territory vegetation characteristics. Our results indicate that burn type (dormant vs. growing season), native grass groundcover, and shrubs over 1m were the most significant predictors for wintering Bachman’s sparrow …

Development Of Hydrophobic Paper And Wood Products Via Metal Ion Modification, Oshani Nayanathara Rathnayaka Mudiyanselage

Theses and Dissertations

Renewable lignocellulosic materials are promising green plastic alternatives to fossil fuel-based plastics. However, the hydrophilic nature and poor water resistance of lignocellulosic materials have hindered their practical applications. This study reports a facile metal-ion-modification (MIM) route, swelling with aqueous metal ion solutions, and drying to convert conventional hydrophilic paper and wood pulp into biodegradable hydrophobic paper and tableware without the addition of hydrophobic sizing chemicals/materials. Metal ions such as Fe3+ and Zr4+ can coordinate with pulp fibers’ polar groups (i.e., O.H., C=O, and COOH) that induce self-assembly of their surface fibrillated “hairy” cellulose nanofibrils to form a more compact structure …

Assessing Drivers Of Overwintering Survival And Annual Range Shifts By The Redbanded Stink Bug, Piezodorus Guildinii (Westwood), Thomas Gustavus Paul

Theses and Dissertations

The redbanded stink bug, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), is a non-native pest of soybeans in the Americas outside of the Carribean. Mortality of overwintering adults due to cold exposure has been implicated as a major driver of interannual fluctuations in the occurrence of P. guildinii in the southeastern United States, but formal investigations of drivers, including factors other than cold temperatures, are rare. We conducted overwintering assays with field-collected P. guildinii to quantify survival and coupled historical occurrence with climatic data to develop a species distribution model. We found that leaf litter provides substantial insulation from lethal temperatures and …

Response Of Lettuce (Lactuca Sativa L.) To Salt Stress, Bikash Adhikari

Theses and Dissertations

Lettuce is a highly nutritional crop that is sensitive to multiple stresses, including salt stress. The decreasing availability of salt-free water is posing a major challenge to growing nutritious lettuce in hydroponic systems. Despite evidence that salt stress affects yield and nutrition, its impacts on economically important growth stages are overlooked. This study addressed the knowledge gaps regarding the salt stress impact on romaine lettuce. Four independent experiments were conducted in controlled environment conditions using 2-38 lettuce genotypes, to assess the effects of salt stress at rosette or head formation. An increase in sodium chloride (NaCl) levels (0 to 150 …

Development Of Preservative-Treated Cross-Laminated Timber And Lignin-Reinforced Polyurethane-Adhesive For Glued Laminated Timber, Samuel Oluwafemi Ayanleye

Theses and Dissertations

Interest in the use of mass timber in building and construction is growing worldwide, this is due to the structural integrity and reduced environmental footprint of timber-based structures. Concerns associated with the biological and environmental degradation of mass timber necessitate the development of adequate protection strategies to ensure the durability of these products. Preservative treatment is a proven technique that increases the durability and performance of wood in-service and can also be applied to large-sized timber panels such as cross-laminated timber (CLT). Therefore, this study focused on investigating the feasibility of treating prefabricated 3- and 5-layer CLT panels with Copper-azole …

Investigating Specialty Crop Farmers’ Preferences For Contract Design And Attitudes Towards Blockchain-Based Smart Contracts, Esther Mmenaa Agyemang-Duah

Theses and Dissertations

This study examines small and medium scale specialty crop growers’ preferences for marketing contract attributes and willingness to adopt blockchain-based smart contracts. The data used were collected using an online survey and discrete choice experiment. Findings indicate that farmers prefer higher average prices, cash, check or electronic bank payment over cryptocurrency, and immediate payment upon product delivery over delayed payment. When choosing a contract, farmers viewed traditional text-based contracts and digital platforms with automated smart contracts equivalently, on average. On average, farmers showed no preference for providing and not providing traceability lot codes to buyers, and between choosing a contract …

Regional Economic Impacts Of Enterococcus-Related Beach Closures In Mississippi, Jessica Lynn Browne

Theses and Dissertations

High levels of Enterococcus are the most frequent reason for beach closures on the Mississippi Gulf Coast and can be made worse by human activities. When beaches close, tourism can decrease, affecting sales. This study aims to 1) analyze the regional economic impact of beach closures at the county level, 2) show empirically how serious the impact of high levels of Enterococcus are compared to other causes of beach closures, and 3) discuss the policy implications for regional economies linked to beach closures. I use a response function approach with beach closure and county-level monthly gross taxable sales data. Results …

A Four-Pronged Approach To Addressing A Wild Pig Invasion In A Bottomland And Upland Forested Landscape, Tyler Scott Evans

Theses and Dissertations

Among exotic species that are capable of invading, establishing, and reaching pest status, few pose the range of impacts to biotic (e.g., competition with native species, predation, herbivory, introduction of other exotics) and abiotic (e.g., soil, hydrology) ecosystem components that can be attributed to the wild pig (Sus scrofa). Despite the presence of wild pigs throughout the southeastern United States for centuries, new invasions continue to occur in previously uninhabited and often under-investigated landscapes, including bottomland and upland forests. The recent invasion of the Sam D. Hamilton Noxubee National Wildlife Refuge (hereafter, NNWR) in east-central Mississippi represents an …

Investigating The Role Of Plant Traits And Interactions In Emergent Wetland Nutrient Removal, Andrew Ryan Sample

Theses and Dissertations

Increasing wetland restoration in the Lower Mississippi Alluvial Valley has been identified as a method to reduce nutrient loading in the Gulf of Mexico. Wetlands have historically been used to treat water through processes facilitated by wetland plants, and relatively few species and plant traits have been identified as important in carrying out these processes. This study focuses on some of those species and traits and aims to identify species differences and plant traits that may be important for wetland nutrient mitigation. Chapter I provides background information on nutrient pollution, wetland biogeochemical mechanisms for nutrient sequestration, and the focal species …

Use Of Comparative Genomics And In Vitro Screening Approach To Identify Vaccine Candidates For The Food-Borne Pathogen Campylobacter Jejuni, Sabin Poudel

Theses and Dissertations

Campylobacteriosis is a leading foodborne illness worldwide, primarily caused by Campylobacter jejuni (C. jejuni) which is associated with poultry consumption. The emergence of antibiotic resistance has emphasized the need for alternative strategies to control C. jejuni colonization in poultry. To assess the prevalence of C. jejuni in poultry, 270 cloacal swab samples were collected from broilers raised under No-Antibiotics Ever system. Among these samples, 16.3% were identified as C. jejuni positive. Notably, these isolates exhibited a diverse range of virulence factors and antimicrobial resistance genes, with 61.36% of isolates showing hyper-motile and 20.45% demonstrating multidrug resistance. Following isolation, whole genome …

Modeling The Effect Of Neighborhood Competition On Tree Diameter Growth In The Pacific Northwest Coast Range, Htet Lin Naing

Theses and Dissertations

Trees compete for various resources such as sunlight, water, and nutrients, which can be expressed as numerical terms, called competition indices (CI). Competition between individual trees is correlated with their growth and mortality. Therefore, CIs are used as independent variables to develop, improve and modify growth and yield models. This study was conducted to test the effect of neighborhood competition on tree diameter growth among Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg) and red alder (Alnus rubra Bong.), in the Pacific Northwest Coast Range, USA. After testing seven distance-independent CIs and three distance-dependent …

A Survey Analysis Of Southeastern U.S. Dairy Producers’ Emotional States And Their Subjective Pain Perception Of Dairy Cows, Michelle M. Schuh

Theses and Dissertations

Dairy producers play a central role in evaluating and seeking treatment or care for animal pain. The primary aim of this study is to examine dairy producers’ emotional states and professional quality of life and analyze the relationship between these variables and their perception of pain in dairy cattle. Dairy farm owners and managers of 65 southeastern U.S. herds participated in a survey that included demographic information, the Depression, Anxiety, and Stress Scale, a modified Professional Quality of Life Scale, and 23 items requiring participants to evaluate various painful conditions in cattle.

Upland Cotton And Nematodes: An Analysis Of Historical Resistance, Upcoming Threats, And Co-Inoculation Effects, Amanda Gaudin

Theses and Dissertations

Upland cotton (Gossypium hirsutum ) is an important fiber crop grown throughout the southern United States. Plant-pathogenic nematodes are worm-like animals that feed on the roots of most agronomic crops, including cotton. The southern root-knot nematode (Meloidogyne incognita, RKN) and the reniform nematode (Rotylenchulus reniformis, RN) cause significant yield losses in cotton every year. Current sources of resistance are effective but limited, therefore historical screenings of cotton accessions were revisited in search for novel resistance sources. None were identified but many of the screened accessions possessed markers of known root-knot nematode and reniform nematode resistance. …

Non-Destructive Evaluation Of White Striping And Microbial Spoilage Of Broiler Breast Meat Using Structured-Illumination Reflectance Imaging, Ebenezer O. Olaniyi

Theses and Dissertations

Manual inspection is a prevailing practice for quality assessment of poultry meat, but it is labor-intensive, tedious, and subjective. This thesis aims to assess the efficacy of an emerging structured illumination reflectance imaging (SIRI) technique with machine learning approaches for assessing WS and microbial spoilage in broiler breast meat. Broiler breast meat samples were imaged by an in house-assembled SIRI platform under sinusoidal illumination. In first experiment, handcrafted texture features were extracted from direct component (DC, corresponding to conventional uniform illumination) and amplitude component (AC, unique to the use of sinusoidal illumination) images retrieved from raw SIRI pattern images build …

Evaluating The Role Of The Bovine Vaginal Microbiome In Neonatal And Maternal Health Outcomes, Riley D. Messman

Theses and Dissertations

The dam vaginal microbiota is the first major microbial inoculating community within the neonate. The composition of the dam vaginal microbiota has implications in calf commensal microbiota development. Alterations of the dam microbial community prior to parturition could alter inoculating communities and immune responses in both the dam and calf. Thus, authors aimed to elucidate the microbial community composition of the bovine dam vaginal and calf nasal microbiota post-partum after utilizing betadine lavages (BL). The dam vaginal and calf nasal microbial communities and immune responses were evaluated at 0-, 15-, 30- and 60-day post-partum. Microbiota composition of the dam haircoat, …

Gene Expression Effects On Productivity And Stress Tolerance In Polyclonal Plantings Of Populus Deltoides, Macy Gosselaar

Theses and Dissertations

Polyclonal plantings of Populus deltoides are expected to display increased site resource use, productivity, and tolerance to stress through plasticity changes leading to niche differentiation (i.e changes to crown/canopy structures). In the present study, P. deltoides Clones S7C8, 110412, and polyclonal plots were tested for differentially expressed genes and enriched biological pathways between planting schemes. Transcriptomic analysis of leaves revealed upregulation of an active growth gene and gene family members that play important roles in plant stress and stress tolerance in polyclonal plantings. A gene associated with oxidative stress was upregulated in polyclonal plantings across all treatments. Secondary metabolic pathways …

Oocytes To Offspring: Optimizing Assisted Reproductive Technologies (Art) To Support Amphibian Conservation, Shaina Shaira Lampert

Theses and Dissertations

The increasing dependence on amphibian captive breeding programs to support at-risk populations has led to growth in the application of assisted reproductive technologies (ART) to aid with the management of decreasing population density and genetic diversity. Already the integration of ART within these programs has led to monumental successes and shows great promise as a means to augment amphibian breeding efforts when natural breeding has low success. The focus of this project was to continue the optimization of ART to aid in making these technologies more widely applicable. Specific objectives include developing a framework that can be used to standardize …

Timing Is Everything: Impacts Of Firing Technique And Season On Plant Communities In The Southeastern United States, Luke Michael Resop

Theses and Dissertations

Prescribed fire is a common land management tool in the southeastern United States. Historical fires occurred primarily in the growing season, but modern day prescribed fire is commonly restricted to the dormant season. Plant community responses to various fire regimes are relatively unknown, and managers require information on how fire regimes impact plant communities. To address these limitations, I studied the impacts of March and June fire on plant communities. Results indicated various woody midstory species respond differently to fire season and community response is driven by species composition. In another study, I examined impacts of February, May-June, and September-October …

Small Area Estimation Of County-Level Forest Attributes Using Forest Inventory Data And Remotely Sensed Auxiliary Information, Okikiola Michael Alegbeleye

Theses and Dissertations

The Forest Inventory and Analysis (FIA) program of the United States Department of Agriculture Forest Service collects forest inventory data that provide estimates with reasonable accuracy at the national scale. However, for smaller domains, these estimates are often not as accurate due to the small sample size. Small area estimation improves the accuracy of the estimates at smaller domains by relying on auxiliary information. This study compared direct (FIA estimates), indirect (multiple linear regression), and composite estimators (Fay-Herriot) using auxiliary information derived from Landsat and Global Ecosystem Dynamics Investigation (GEDI) to obtain county-level estimates of forest attributes namely total and …

Investigating Potential Indicators Of Soil Health Through Microbiome Response To Environmental And Anthropogenic Stressors, Austin Cook

Theses and Dissertations

Traditionally, the analysis of soil health has overlooked the biological component of soil due to poor understanding of connections between the microbiome and empirically measured soil health indicators. The purpose of this study was to assess the effects of environmental and anthropogenic stressors on the soil microbiome, with the aim of identifying measurable soil biological indicators. Chosen soils were examined under distinct conditions to evaluate the effect of selected environmental and anthropogenic stressors on the microbiome. Soil biological responses were analyzed via enzymatic response, microbial functional genes, and microbial community. Environmental factors such as soil moisture and organic matter showed …

Screening And Selection For Resistance To Gray Leaf Spot (Pyricularia Oryzae) In Early Planted Annual Ryegrass, Calyn M. Adams

Theses and Dissertations

Cattlemen in the southeastern United States widely plant annual ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] (ARG). It is often planted earlier than the recommended window. This exposes juvenile stands to increased pressure from gray leaf spot (Pyricularia oryzae Cavara) (GLS), causing stand loss. This study was designed to screen for resistance to P. oryzae in two ARG genotypes, Vertyl and a heat-tolerant germplasm (HTARG5) with the objective of developing a crossbred population to be improved using restricted, recurrent phenotypic selection. Experiments were conducted from 2021 – 2022. Disease severity (DS) was assessed 3wk after inoculation with …

Effects Of Parkinson’S Disease On Motor Asymmetry, Deborah Mazanek Watson

Theses and Dissertations

Introduction: Persons with Parkinson’s disease (PD) experience changes cortically, subcortically and behaviorally. This dissertation examines the asymmetry of motor behavior to explore the role of asymmetry in persons with PD and its connection to clinical symptoms. Purpose: Project 1: To assess the hand asymmetry difference in young adults versus older adults. Project 2: To investigate the difference in hand asymmetry in older adults and persons with PD. Project 3: To explore the correlation between function and clinical symptoms of persons with PD. Methods: 55 right-handed participants [Young Adults (YA) = 20, Female = 10; Older Adults (OA) = 20, Female …

Evaluation Of Occidiofungin Activity On Yeast-Hyphae Morphogenesis And Biofilm Formation By Candida Species, Rabina Kumpakha

Theses and Dissertations

Invasive fungal infections are a significant clinical challenge especially for hospitalized patients as traditional antifungal therapy often fails to resolve these infections. The ability of Candida to undergo yeast-to-hyphae morphological transition is central to this invasive behavior. Morphogenesis is also important for the formation of biofilms which are highly structured communities of microorganisms attached to one another or substratum and embedded within a protective extracellular matrix material. The refractory nature of cells within a biofilm to current antifungal therapies has created a need for alternative antifungal agents for the management of Candida biofilm-related infections. The novel antifungal occidiofungin is a …

Evaluating The Immunogenicity Of Colonization Proteins Of S. Pneumoniae For Identification Of Vaccine Candidates, Isidora Fereday

Theses and Dissertations

Streptococcus pneumoniae is typically an asymptomatic colonizer of the upper respiratory tract but can cause invasive disease in susceptible populations. Pneumococcal vaccines which are currently in use have failed to significantly reduce colonization by S. pneumoniae. To control invasive pneumococcal disease, novel strategies must be utilized. One such strategy is to reduce or eradicate colonization by pneumococcus. Supplementary vaccination with pneumococcal proteins important for colonization could serve to prime the immune system against these targets. This study serves as an initial step towards identification of crucial pneumococcal colonization proteins which may previously have been uncharacterized. Assessing the immune reactivity …

Impacts Of Cover Crop, Soil Steaming, And Plastic Mulch On Field-Grown Tomato Production And Virus-Induced Gene Silencing In Antirrhinum, Penstemon, Petunia, Rosa, And Rudbeckia, Brenton Andrew Earl Breland

Theses and Dissertations

Weeds and soil-borne diseases can cause large yield losses in field-grown tomato (Solanum lycopersicum) production. Techniques have been developed to reduce soil-based problems. In this study, we evaluated the impacts of cover crops, soil steaming, and plastic mulch to reduce weed and disease pressure in field-grown tomatoes. Four cover crop treatments were grown in the fall and winter before spring planting. Soils were steamed to a target temperature of 71.1 °C for 0, 5, or 20 minutes. Plastic mulch was also used on half of the rows. Yield, weed densities, and disease incidence were recorded.

Reduced flowering time …

Integrating Weed-Suppressive Cotton Chromosome Substitution Lines And Cover Crops For Sustainable Weed Management In Cotton Production Systems., Alyssa Lea Miller

Theses and Dissertations

Weeds pose a challenge to cotton production, and herbicides have been the primary means of control. However, there is growing concern over weed resistance to herbicides. To address this issue, we evaluated three cover crop species and six cotton accessions for weed suppression. The study found that hairy vetch, wheat, and B16 cotton CS line effectively suppressed Amaranthus species, while MNTN 4-15, B16, hairy vetch, and wheat were correlated with the highest cotton yield. Cover crops were also analyzed for chlorogenic acid content, with wheat, MNTN 4-15, and hairy vetch producing the highest amounts. The greenhouse tray study showed that …