Life Sciences Commons^™

Creatures Of Habit? Impact Of Chick Feeder Tray Location On Feed Consumption At 0-7 Days Of Age, Emily Kate Green

Graduate Theses and Dissertations

Early chick nutrition is critical for establishing target growth performance characteristics in broiler chickens. This study evaluated factors within commercial broiler houses that potentially influence feed consumption during the first 7 days. Three trials were conducted in a 12.2 x 122 m commercial broiler house to assess the effects of house sectioning, spatial barriers, and feedline location. In Trial 1, a one-way experimental design was used in which the house was divided into four equal sections using migration fencing every 30.5 m. House sections served as a fixed factor. Feed was provided using chick trays placed beneath the feed line …

Analyzing The Effects Of Message Testing On The Public's Opinion About Gene Editing In Agriculture And Medicine, Luke Sanford Wimpy

Graduate Theses and Dissertations

This paper will present results from the final survey of a multi-stage project examining factors that influence opinions about gene editing in agriculture and medicine. In this final survey, 3,200 U.S. respondents were recruited and randomized to view one of eight videos that communicated the safety of gene editing to determine which factors are most influential in changing opinions. The eight videos were designed based on data collected from focus groups and three previous surveys in this multi-stage project. The eight videos varied by three attributes: messenger, message, and application. The messenger in the videos was either a researcher or …

Consumer Perceptions Of Fda Front-Of-Package Nutrition Labeling, Madison Price

Graduate Theses and Dissertations

The U.S. Food and Drug Administration (FDA) proposed a front-of-package nutrition labeling (FOPL) rule in early 2025 to help consumers more quickly and easily compare the nutritional quality of packaged foods (U.S. Food and Drug Administration, 2025). FOPL is gaining attention as a way to encourage healthier eating habits and consumer choices, but there is still debate over which label format works best. The objective of this study was to examine consumer perceptions, understanding, and trust of FDA FOPL, and to determine how these labels impact purchasing behavior and nutritional decision-making. Data were collected via an online Qualtrics survey distributed …

Dissecting The Complex Genomic Landscape Underlying Oxidative Stress Resistance Using Natural Variation In Yeast, Sonali Lakshika Anne Lenaduwe

Graduate Theses and Dissertations

Stress is experienced across the tree of life. Survival in fluctuating environments depends on a robust genetic architecture. This dissertation examines the genetic and metabolic determinants underlying one such adaptive response: cross-protection. Leveraging natural variation in the stress responses of budding yeast, Saccharomyces cerevisiae, I examine the genetic variation contributing to ethanol-induced cross-protection against oxidative stress. Acquired stress resistance, in which mild pre-exposure improves survival to subsequent stresses, is prevalent across diverse organisms and can involve both same-stress and cross-protection. Using high-throughput bulk segregant analysis (BSA-seq) and advanced intercross mapping populations derived from natural yeast isolates, I identify quantitative trait …

Assessing The Potential Of Taming Chicken Gut Commensal Bacteria Using Random Transposon Mutagenesis, Arjun Chapagain

Graduate Theses and Dissertations

The chicken gut microbiome comprises hundreds of bacterial species whose functional roles remain largely unknown, in part because the tools needed to experimentally manipulate these organisms in their native community context have not been systematically developed or validated. This dissertation addresses the gap through three connected research chapters that progressively build a framework for transposon-based genetic delivery in the chicken cecal microbiome, moving from community-wide accessibility mapping to vector optimization to library preparation refinement. In Chapter 2, we established the community-level insertion landscape in chicken cecal metagenome using Himar transposon delivery via RP4 conjugation and aligned Tn-seq reads to a …

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Resource Allocation Trade-Offs Between Longevity And Reproduction In Daphnia Magna, Amelia Pearson

Electronic Theses and Dissertations

Although trade-offs between longevity and reproduction have been described for a long time, the genetic mechanisms by which organisms modulate allocation of resources between these two essential processes remain poorly understood, due to their complex nature and their modification by existing nutritional states and environmental cues. Daphnia magna represents a valuable model for investigation in this area due to their moderate lifespan and cyclic parthenogenetic mode of reproduction, allowing for the easy study of gene by environment interactions. This dissertation first investigates the change in mortality, reproduction, activity, and gene expression when fully fed Daphnia and calorically restricted Daphnia are …

Microplastic Composition And Exposure Pathways In Freshwater Systems: A Multi-Matrix Comparison Between Streams And Retention Ponds In Hamilton County, In, Mya Whaley

All-Inclusive List of Electronic Theses and Dissertations

Since the early 1900s, the use of plastics has increased exponentially. The breakdown of plastic materials has exposed all ecosystems to microplastics (small particles of plastic < 5 mm), which are now ubiquitous in natural settings. Microplastics have a relatively large surface area, and many chemicals adsorb to these small particles, impacting their fate and transport of pollution. While microplastics have been found in virtually every setting on Earth, research is necessary to understand their impact on freshwater ecosystems and biogeochemical cycles. The focus of this research was to investigate microplastic compositions in crayfish, sediments, and water samples collected in streams and retention ponds. We analyzed trends in microplastic counts across different land-cover classes, waterbody types, and species, and compared concentrations among matrices to improve our understanding of microplastic exposure pathways in freshwater ecosystems. As a secondary objective, lead and arsenic concentrations were analyzed from sediment samples to investigate metal burdens and compare them to microplastic concentrations. Our findings revealed that, in general, urban streams had the highest microplastic concentrations within land cover categories, and retention ponds had higher microplastic counts than streams. Crayfish, such as F. rusticus had higher microplastic concentrations than F. virilis and F. propinquus, although these results may be influenced by study design. The most common microplastic type was fibers, and most common color was transparent. There was no significant correlation between microplastic and metal concentrations in sediments. We found crayfish to be adequate bioindicators of microplastic pollution, because they were less impacted by environmental variability than sediment and water samples. This research presents the first evidence of microplastics in our study species, F. propinquus, F. rusticus, and F. virlis. This work presents new evidence of microplastic accumulation in crayfish, sediments, and water from freshwater systems in the Midwestern United States. Microplastics were found in every sample type—crayfish, water, and sediment—across urban, rural, and forested landscapes, highlighting their pervasive distribution. The findings provide foundational data for assessing emerging ecological and human-health risks and emphasize the importance of sustained monitoring and research on MP contamination in freshwater environments.

Vitaltitration Predicts Fermentation Performance Of Phylogenetically Distinct Saccharomyces Cerevisiae Yeast Strains, Samantha White Ms

All Student Scholarship

Accurate assessment of yeast physiological health is essential for achieving consistent, efficient, and predictable beer fermentations. Although yeast vitality is more predictive of fermentation performance than viability alone, no universally adopted vitality assay currently exists in the brewing industry. This thesis investigates vitaltitration (VT) as a rapid, robust, and brewery-feasible method for quantifying yeast vitality and predicting fermentation performance. We hypothesize that VT provides a reliable measure of metabolic competence that correlates with fermentation kinetics across brewery-relevant yeast strains. To test this hypothesis, VT was evaluated alongside Acidification Power (AP) in structured serial-fermentation experiments in two phylogenetically distinct brewing yeasts: …

Post-Exercise Vitals Recovery Response In Barrel Horses: A Field Study On Cooling Methods Used By Competitors, Lauran E. Hetrick

Electronic Theses and Dissertations

Barrel racing demands peak physical performance from equine athletes, yet limited research evaluates the field-based strategies used to optimize equine recovery at competition. This study assessed recovery management approaches used by competitors to elucidate their influence of physiological recovery by measuring heart rate, respiratory rate, and body temperature during a high-profile barrel race competition. Physiological data were collected at baseline, immediately post-exercise, and during a 15–30-minute cooldown period to characterize recovery under real-world conditions. Significant increases in HR, RR, and BT occurred from baseline to post-run (p < 0.001), followed by reductions during cooldown (p < 0.01), though values remained elevated (p < 0.05). Rinsing reduced HR and RR (p < 0.01), while shade and fans decreased RR and variably influenced HR. Noise, as a confounding variable, decreased HR but increased BT (p < 0.001). Ultimately, these results emphasize multimodal recovery approaches in competitive equine management in the field.

Propagation And Cultivation Of Sarracenia Species, Kathryn M. Huether

Electronic Theses and Dissertations

This study evaluates the effectiveness of seed treatments on Sarracenina species to overcome seed dormancy; as well as evaluating fertilizer concentration and substrate mixture impacts on the growth of Sarracenia × wrigleyana, ‘Scarlet Belle’. The first portion of this study evaluated the effects of cold stratification and chemical treatments (smoke water and gibberellic acid) on the germination rates of Sarracenia alata and leucophylla. The primary objective was to determine whether increasing concentrations of these treatments paired with or without stratification could significantly enhance germination and serve as viable seed treatments for horticultural use. Germination did occur within all the …

Body Size Variation And Floral Associations Of The American Bumble Bee, Bombus Pensylvanicus, In East Texas, Sabekun Nahar

Electronic Theses and Dissertations

The American bumble bee, Bombus pensylvanicus, is an important pollinator species that was once widespread in much of North America but has experienced population declines in recent decades in some regions. As a species of conservation concern, it is important to understand how body size varies in response to environmental conditions and to identify the key floral resources that support this species. I examined body size variation in East Texas and floral resource use of B. pensylvanicus across Texas. In the first chapter, body size variation among queens, workers, and males was quantified using thorax width and size variation …

Disruption Of Energy Homeostasis By Chemical Mixtures Containing Persistent Pollutants In Hepg2 And C2c12 Cells, Morgan Jacobellis

All Theses

The Environmental Influences on Child Health Outcomes Fetal Growth Studies (ECHO-FGS) birth cohort data was used to identify chemical mixtures associated with adverse outcomes. This biomonitoring study associated specific chemical mixtures in maternal serum with low birth weight or childhood obesity (Pearce et al., 2021). Mixture Profiles 1, 3, and 4, comprised of different observed concentrations of DDE, PCB153, BDE47, and PFOS were prioritized. Mixtures were tested to determine whether they perturbed mitochondrial metabolism and energy sensing pathways. The purpose of this study was to elucidate a potential mechanism linking maternal exposure to mixtures containing persistent organic pollutants (POPs) to …

Field Pea (Pisum Sativum L.) Response To Planting Date In South Carolina Organic Cropping Systems, Tristan Lawrence

All Theses

Field peas (Pisum sativum L.) are not widely cultivated in South Carolina, resulting in limited agronomic data to support farmers interested in this crop. However, field peas hold significant promise as a cool season crop for both organic and conventional growers in the region. Most commercially available field pea cultivars are evaluated and bred for the Pacific Northwest, where environmental conditions differ substantially from those in the southeastern United States. Consequently, there is a lack of region-specific recommendations for successful cultivation in South Carolina. To address this gap, a two-year planting date study was conducted during the …

Denisovan Introgression And Selection At Cntnap2 In Ancient And Modern American Populations, Matthew Barker

All Theses

The peopling of the Americas created new opportunities for genetic adaptation as ancient populations encountered novel environments across North and South America. Previous research has shown that segments of Indigenous American ancestry contain elevated proportions of Denisovan alleles. The gene CNTNAP2, which is involved in brain development and neuronal function, contains a Denisovan-derived haplotype that represents a candidate locus for adaptive introgression in admixed American populations. A Denisovan-derived core haplotype approximately 55 kb in length was identified within intron 13 of CNTNAP2. This haplotype is primarily found in admixed American populations and occurs rarely outside the Americas, and …

Forest Overstory Mortality & Recruitment Patterns Eight Years Following Wildfire In The Southern Appalachians, Ruth Cumberland

All Theses

In this study, we investigated patterns of forest overstory mortality and recruitment eight years after wildfire in a large wildfire site the Southern Appalachians, a topic that has not been thoroughly investigated to date. With evidence that pre-fire drought promotes post-fire mortality through impaired physiological function and increased fuel consumption, unknown patterns following wildfire are important to study under shifting climate and land-use conditions. In Chapter 1, three areas of interest were investigated: (a) functional group mortality response to wildfire effects, (b) temporal differences in early (1-3 years) and late (5-8 years) periods of delayed forest overstory mortality patterns following …

Micro-Solar Kiln Design: A Cost-Effective Approach For Small Landowners To Produce Higher Quality Lumber, Bart Swecker

All Theses

Small-scale and hobby sawmill operators increasingly seek low-cost methods for drying lumber to moisture contents suitable for interior use, yet conventional kiln systems are often impractical due to capital cost, power requirements, and operational complexity. While air drying remains common at small scales, many operators require a controlled finishing step to improve dimensional stability and product value. Solar kilns offer an intermediate solution between air drying and conventional kilns; however, most published designs and performance data focus on systems with capacities far larger than those typically used by small-scale operators. Consequently, limited guidance exists for micro-scale solar kilns, particularly under …

Biology, Ecology And Control Of Eye Gnats In An Open Pine Ecosystem, Leela Hospach

All Theses

Eye gnats of the genus Liohippelates are bothersome flies of the family Chloropidae. They breed in moist, disturbed, sandy soils that contain organic matter, and have been implicated as vectors of conjunctivitis, bovine mastitis, and yaws. We conducted research into some basic biological and ecological characteristics. Using wild-caught gnats in a temperature-controlled incubator, we found that their activity peaks between 27°C and 41°C. Trapping at different heights above the forest floor in an open-pine savannah, we captured most gnats at 7.5 m off the ground. This may have to do with the attractiveness of the rotten egg lures we used, …

Characterizing The Molecular Response Of Embryonic Zebra Finch To Acute Sound Playback, Saidat O. Adeniran-Obey Miss

All Theses

Auditory stimuli are important cues that influence developmental plasticity in animals and are important for development and adaptation to an ever-changing environment. In the zebra finch (Taeniopygia guttata), there is evidence of adaptive developmental reprogramming in response to a prenatal ‘heat call’. Embryos exposed to this heat call exhibit changes in growth rate post-hatch, increased heat resistance, and enhanced reproductive success at maturity. However, it has long been assumed that embryonic zebra finches cannot respond to sound due to the immaturity of their auditory system. These findings raise the critical question of whether late-stage zebra finch embryos can, …

Comparative Biomechanics: Blattodea Antennal Morphology And Physiology, Lucas W. Marsh

All Theses

Equipped with muscle-free antennae, many insects can twist and bend their antennae on demand. We hypothesized that hemolymph circulating through the antennae provides pressure that facilitates twisting and bending and provides a feedback control channel for tactile sensing in insects. To test this hypothesis, we conducted a thorough morphological and physiological analysis of antennae in three Clades of Blattodea. We studied morphology by evaluating the distinguishable features of the body and antenna, as well as the internal structure of the antennal lumen. Then, in a series of experiments on live cockroaches, we measured blood pressure along the antenna. This was …

An Investigation Of Entamoeba Histolytica Chitin Synthases And Other Encystation Factors In Early Encystation, John N. Talledo

All Theses

Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.

Currently, there is a lack of understanding of the exact molecular …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …

From Invisible Injury To Measurable Impact: Exploring Associations Between Peripheral Biomarkers Of Neuroinflammation And Mental Health Outcomes After Mtbi, Lauren Leggett Smith

Psychology Theses & Dissertations

Mild traumatic brain injury (mTBI), often referred to as a “silent epidemic,” accounts for the majority of traumatic brain injuries worldwide and is increasingly linked to persistent psychiatric outcomes. Despite its prevalence, mTBI remains understudied due to diagnostic challenges, underreporting, and misperceptions of its clinical significance. The present study examined whether peripheral biomarkers of neuroinflammation and astroglial injury—tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and glial fibrillary acidic protein (GFAP)— mediate associations between mTBI history and psychiatric symptom severity, including depression, anxiety, and posttraumatic stress disorder (PTSD). Participants were 138 traumaexposed adults recruited from an urban university and surrounding community, with …

Changing Dynamics Of Microbial Communities At A Hydrocarbon Contaminated Site And Methanogenic Interactions With Iron Minerals, Jakob Sell

Masters Theses

Microbial life is not only ubiquitous but also plays a critical role in the geochemical makeup of our planet. While researchers have long studied easily culturable aerobic microbes, the influence of anaerobic life on soils and mineral cycling is less understood. Notably, knowledge about interactions between anaerobic microbes and inorganic elements such as iron has progressed with the discovery that magnetite influences how anaerobic archaea carry out methanogenesis. To better understand anaerobic bacterial metabolisms and how they interact with minerals and subsurface hydrocarbons, we extracted 16S rRNA genes from two adjacent subsurface petroleum plumes, sequenced the DNA, and analyzed it …

Historic Patterns Of Growth And Destruction In Nj Seagrass Meadows, Masen Eck

Theses, Dissertations and Culminating Projects

Seagrass meadows are one of the many habitats worldwide under threat from human disturbance and worsening climate conditions. This habitat provides many critical ecosystem services to coastal environments, which is why conserving and restoring seagrass meadows is critical. This study investigates the long-term success and failures from several eelgrass restoration sites in Barnegat Bay, New Jersey. Aerial imagery from multiple years were digitized in ArcGIS to assess restoration trajectories over time. Three of the sites were assessed over a period of twelve years (2012-2023), and one site was assessed twice (2021 and 2023). Results from these time series analyses showed …

Shape Variation In The Mandible Of The Borophagine Canids And Implications For Predatory Behavior, Benjamin Neavear

Theses, Dissertations and Culminating Projects

The borophagines are an extinct lineage of canids that inhabited North America for more than 20 million years. This group included genera such as Aelurodon, Borophagus, and Epicyon. Borophagines are commonly referred to as “bone-crushing dogs” because their skull morphology converged with that of extant hyenas, predators capable of consuming bone. The purpose of this study was to determine whether convergence was present in the mandible, an anatomical structure strongly correlated with feeding behavior, particularly in the genera Aelurodon and Borophagus. It was hypothesized that most borophagine taxa possessed mandibular shapes similar to those of hyenas. Numerous mandibular characters were …

At The Intersection Of Science And Sustainability: A Qualitative Study Of Food Scientists' Personal And Professional Perspectives, Srushti Parikh

Theses, Dissertations and Culminating Projects

Sustainable food systems require not only technological innovation but a more profound understanding of the professionals involved in the field. Even though the topic of sustainability is currently gaining importance throughout the food industry, the real expertise of food scientists is under-researched. PURPOSE: The purpose of this study is to explore food scientists' perspectives on sustainability, how these perceptions influence the way they pursue their careers, and how they view their impact in the larger sustainability agenda of the food industry. METHODS AND MATERIALS: This study captured detailed insights of 22 food scientists’ perspectives through qualitative methods. Food scientists in …

Structural Evidence For Innervation Of A Single Epitheliomuscular Cell By Multiple Sensory Neurons In The Sea Anemone Nematostella Vectensis, Aparajita Das

Graduate Theses and Dissertations

Abstract Here, I report new ultrastructural evidence for multineuronal innervation (many-one) of a single epithelia-muscular cell in sea-anemone cnidarian Nematostella vectensis. Using Serial Block-Face Scanning Electron Microscopy (SBF-SEM) and ImageJ, I found that EMCs are located at the base of ectoderm, with an elongated cell body that includes basal processes, a bilobed nucleus, and myofibrils aligned parallel to the basal surface along with their structural quantification. Notably, I found multiple mechanosensory neurons form synapses with a single EMC. These findings enhance our understanding of cnidarian neuromuscular organization and reveal that coordination between sensory and contractile systems in N. vectensis is …

Searching Harder For The Darter: Evaluating Endangered Yellowcheek Darter (Nothonotus Moorei) Status And Drought Responses, Kearstin Findley

Graduate Theses and Dissertations

Freshwater ecosystems are one of the most imperiled habitats across the world with biodiversity declining rapidly. There are many stressors contributing to freshwater species declines including habitat loss and degradation, land-use changes, anthropogenic water demands, changes in precipitation and weather extremes, and pollution. Current environmental projections predict that these stressors will continue to impact freshwater ecosystems to greater extents moving forward. Stream drying from drought conditions increasing in intensity and frequency is especially concerning in northern Arkansas where seasonal drought is typical in the summer and fall months. With increased drying conditions, the elimination of shallow-water riffle habitats in streams …