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Ediacaran Paleocommunity Structure, Body Size Evolution, And The Rise Of Complex Animals, Matthew Philip Craffey

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The Ediacaran period (635-538ma) is a key interval in the evolution of life as it records the first macroscopic animal communities. Major extinction pulses appear to have altered the composition of the global marine biosphere between each sub-interval of the Ediacaran Period: the Avalon, White Sea, and Nama assemblage Zones. While considerable attention has been paid to the causes of these extinction pulses, less has been afforded to the consequences of Ediacaran biotic turnover for community organization and function. Moreover, it is unclear how body size - the defining trait of macrofauna - affected the transition between animal groups across …

Influence Of Biotic And Abiotic Factors On Decomposition And The Determination Of Time Since Death: Applications Of Forensic Entomology And Taphonomy, John Oladapo Obafunwa

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The determination of the postmortem interval (PMI) is essential for the investigation and successful prosecution of suspected cases of homicide. While the forensic pathologist might be able to draw fairly accurate conclusions during the initial 24–36 hours, beyond this period, the assistance of other experts like forensic entomologists and taphonomists would be required. The present study was designed to observe the postmortem changes in Sus scrofa placed in a cage in Nebraska, located in the American Central Great Plains. The setting is in an open grassland in late spring to early summer. The observed variables with respect to biotic and …

Spatial Ecology And Predator–Prey Interactions Of Mountain Lions In California's San Francisco North Bay, Jacob A. Harvey

School of Natural Resources: Dissertations, Theses, and Student Research

Understanding spatial ecology and predator-prey interactions are central to wildlife ecology and conservation. We tracked mountain lions with GPS telemetry to evaluate space use, predator-prey interactions, and resource selection in California’s San Francisco North Bay, USA. In Chapter 1, we evaluated the influence of human disturbance on home range size, prey composition, and kill rates on black-tailed deer (Odocoileus hemionus columbianus) across an urban-rural gradient. Both males and females increased home range size with increasing development at low to moderate levels of development, but female home range size stabilized across greater proportions of development while male home range …

Maggot Mass Effect On The Development And Survival Of Forensic Blow Flies, Akomavo Fabrice Gbenonsi

School of Natural Resources: Dissertations, Theses, and Student Research

Forensic entomology scientists use blow flies' developing patterns to estimate the postmortem interval (PMI). However, larval aggregations produce metabolic heat, resulting in complex microclimates that may change growth timetables. This study investigates how larval density and associated temperature changes affect the development and survival of two forensically essential blow fly species, Lucilia sericata and Calliphora vicina.

This study examined how larval density and associated thermal profiles affect the development of both blow fly species. Using a split-plot design, we tested four larval densities at 25°C and 30°C, with temperature gradients measured via thermocouple at four mass positions three times …

Assessment Of Sampling Gears For Bigheaded Carp In Mid-Order Prairie Rivers In Nebraska, Brett M. Anderson

School of Natural Resources: Dissertations, Theses, and Student Research

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis (collectively bigheaded carp) have invaded tributaries to the Missouri River and Platte River in Nebraska, USA. Information pertaining to efficient sampling protocols for assessing bigheaded carp populations as well as benefiting removal efforts is needed. Herding is a method used to increase the capture efficiency and detection probability of adult bigheaded carp by simultaneously using active and passive sampling gears. During June-July 2023, four herding techniques were assessed regarding their ability to elicit directional movement past an enclosure gate. The combination of sound and electrofishing resulted in the highest mean …

Leveraging Historical Data For Estimating Genetic Gain And Implementing Genomic Selection In A Student Led Barley Breeding Program, Sydney Graham

Department of Statistics: Dissertations, Theses, and Student Research

In Nebraska, winter feed barley presents an emerging market for producers and an opportunity to diversify cropping systems. The University of Nebraska Barley Breeding Program aims to develop high-yielding, winter-hardy varieties. A unique aspect of this program is that doctoral students serve as barley breeders and are responsible for crossing, data collection, and advancement decisions. While this provides hands-on experience for the students, the impact of student leadership has not been examined.

This study used a historical data set to evaluate the realized genetic gain of the breeding program, and as a training population for genomic selection. The dataset consisted …

Treating The Black Fever: Evaluating Combination Chemotherapy For Leishmania Donovani, Robert Frank Mickatavage

Biochemistry and Molecular Biology

Visceral leishmaniasis (VL) is a neglected tropical disease (NTD) endemic to Africa, Asia, and the Americas, caused by the parasite L. donovani and spread by the Phlebotomine sandfly. If left untreated, VL is almost always fatal, bearing a mortality rate of over 95%. Many individuals within endemic regions are often too poor to afford treatment, and the financial burden of current treatments may only exacerbate their poverty. Antimonials and more modern treatments display varying effectiveness, but are nonetheless toxic to the host, commonly inducing hepatotoxicity, nephrotoxicity, and renal failure. The development of more effective and safer treatments is crucial, particularly …

Sodium And Potassium In Health And Cellular Function, Jordyn Branz

Honors Program: Senior Projects (Public)

Sodium (Na⁺) and potassium (K⁺) are essential electrolytes that regulate numerous physiological processes. These include cell function, nerve transmission, and muscle contraction. The Na+/K+-ATPase plays a critical role in maintaining the balance of these ions by actively transporting three sodium ions out of the cell and two potassium ions into the cell against their concentration gradients. This process is vital for maintaining the resting membrane potential and supporting the function of excitable cells. The Na+/K+-ATPase consists of two main subunits, with the alpha-subunit being primarily responsible for ion transport activity. Isoforms alpha1, alpha2, and alpha3 are tissue-specific and contribute to …

Advancing Mitochondrial Dna Visualization And Dynamics In Plants: Application Of The Mt-Hi-Ness Fluorescent Marker, Madeleine H. Faber

Honors Program: Senior Projects (Public)

Mitochondrial DNA (mtDNA) plays a crucial role in cellular energy production and inheritance, yet its dynamics and exchange remain poorly understood in plant systems due to limitations in visualization techniques. Traditional visualization methods such as exogenous DNA stains and fluorescent protein markers present challenges in specificity and live-cell imaging. To address this challenge, we adapted the MT-HI-NESS fluorescent marker, originally developed for mammalian cells, for use in plant mitochondrial studies. Using Arabidopsis thaliana as a model system, we employed mitochondrial targeting sequences (IVD and AOX) to ensure accurate localization and to confirm mtDNA binding specificity. The validation process included fluorescence-based …

Evaluation Of Fecal Egg Counts (Fec) As A Viable Means To Estimate Ascaridia Galli, Heterakis Gallinarum And Capillaria Obsignata Burdens In Laying Hens, Alexander H. Moss

Animal Science Undergraduate Honors Theses

The control of gastrointestinal helminths, specifically Ascaridia galli, Heterakis gallinarum, and Capillaria obsignata, is a critical component of poultry health management, particularly in free-range and organic farming systems. Methods of estimating parasite burdens, such as post-mortem examinations, are not feasible for large-scale commercial operations due to their invasiveness and time requirements. This study aimed to evaluate the use of fecal egg counts (FEC) as a non-invasive and efficient method for estimating the worm burdens of these parasites in laying hens. A flock of 12 brown egg laying, spent, hens were individually penned on concrete. Fecal samples (both cecal and intestinal) …

Acetylcholine Release In The Dorsal Lateral Straitum During Social Approach Task, Taylor Good, Oyku Dinckol, Noah Wenger, Jake Caselli, Munir Gunes Kutlu

Rowan-Virtua Research Day

Nicotine Decreases ACh Release in the DS leading to a Serenic Effect during Social Approach Task

Acetylcholine (ACh) regulates attention, learning, and stress responses (Benarroch E. E., 2012). The dorsal striatum (DS), essential for stimulus-response learning, is also linked to anxiety and compulsivity (Casado-Sainz et al., 2021). We used behavioral pharmacology and in vivo fiber photometry to study ACh responses during social approach tasks in the dorsal striatum. Male and female C57BL/6J mice underwent stereotaxic surgeries to inject a fluorescent ACh sensor (ACh.Sn.Fr) and implant fiber optic cannulas in the DS. Using in vivo fiber photometry, we tracked ACh release …

Hypoxia Induced Ribosomal Rna Fragmentation Mediated By Rnase L, Vanessa Kristina Pizutelli, Dimitri G Pestov

Rowan-Virtua Research Day

Ischemic injury contributes to a range of global pathologies. Ischemia/Reperfusion Injury (IRI) is a paradoxical phenomenon that involves an initial restriction of blood flow followed by a sudden restoration of perfusion. This type of injury takes place in conditions such as myocardial infarction, acute kidney disease, and ischemic stroke and often leads to cellular death. Additionally, IRI exacerbates post-surgical outcomes and plays a role in graft dysfunction and transplant rejection. Despite efforts to develop therapies targeting known IRI pathways, clinical trials have largely been unsuccessful, underscoring the need for alternative mechanisms and biomarkers associated with IRI-induced apoptosis. Reactive oxygen species …

Modulation Of Opioid Receptor Expression In The Ventral Tegmental Area Following Stress Exposure In Rats, Maya Patel, John Tkaczynski, Jordan Riser, Nicole Shellenbarger, Jin Park, Daniel Manvich, Daniel J. Chandler

Rowan-Virtua Research Day

Background: The ventral tegmental area (VTA) contains dopamine-producing neurons projecting to various brain regions. VTA dysfunction is linked to addiction and depression. Delta opioid receptor upregulation relates to chronic pain, inflammation, cancer, and early adversity. Kappa receptors in the VTA influence stress, drug-seeking, mood, and reward. Notably, chronic substance abuse upregulates the κ-receptor/dynorphin system, and the opioid system regulates social interaction needs.

Hypothesis: Stress will upregulate opioid receptors.

Methods: We compared group-housed and individually-housed rats using stress tests, analyzing behavior and quantifying VTA opioid receptor expression.

Results: Social isolation upregulated delta and kappa opioid receptors in …

Investigating The Effects Of Prenatal E-Cigarette Exposure On Postnatal Liver Histology, Emma Mcclellan

College of Arts & Sciences Senior Theses

The electronic cigarette (e-cigarette) entered the American market in the mid-2000s and quickly became popular. This product poses a significant threat to youth with 1.63 million students reporting use in 2024. Adverse health effects to different organs are well known. The liver is less studied, and despite its role in detoxification of e-cigarette chemicals, is a target of injury. Unlike the known effects of cigarettes and nicotine on the liver from adult or prenatal exposure, effects of prenatal exposure to e-cigarettes on liver remain to be defined. The current study investigated the effects of prenatal exposure of e-cigarettes on liver …

Effects Of Cadmium And Diet On Metal Accumulation And Kidney Cell Death Pathways., Justin Xu

College of Arts & Sciences Senior Theses

Cadmium (Cd) is a non-biodegradable environmental toxin and accumulates in the body with an estimated half-life of 30-45 years. Humans can be exposed to Cd through diet, drinking water, tobacco smoking, and industrial pollution. Cd can especially accumulate in the kidney due to the release of Cd from protein-metal complexes when filtering blood in the tubules causing oxidative stress and inducing kidney injury. Obesity is another risk factor for kidney disease therefore we examined the dual effects of Cd and obesity on the accumulation of essential metals in mouse kidneys. Starting in utero and continuing until 24 weeks postweaning, male/female …

Understanding The Properties Of Repair Protein P26 For Dry-State Preservation Of Biological Materials., Hannah Skaggs

College of Arts & Sciences Senior Theses

The preservation of complex biological materials in the frozen state has been well established and plays a critical role in the advancement of clinical applications and the pharmaceutical industry. Cryopreservation of complex biological materials has several clinical applications, including vaccine preservation, bone marrow transplants, cell therapeutics, and increasing the shelf life of red blood cells (RBCs) for transfusion. However, many challenges are present, including the use of toxic protective agents and the financial burden of maintaining extremely low temperatures between 193.15 and – 77.6 K (Parihar, Kumar et al. 2023). Lyophilization, or freeze-drying, presents an opportunity to mitigate such challenges. …

Behavior Change: Actions To Restore Piedmont Prairie And Adopt Sustainable Behavior, Kacey Marie Kaibery

All Theses

Restoration of an ecosystem or adoption of sustainable behavior could benefit the environment. Valuable ecosystem services, like water filtration and habitat for pollinators, inspire investigation into the restoration of grasslands, like Piedmont prairies. This research endeavors to determine the impact of disturbance type (tilling, herbicide, mowing, fire, control with seed or no seed). The second-year aboveground biomass was harvested, identified, counted, and weighed to understand plant species’ response after the application of the disturbance. Target species and plant community diversity did not significantly vary between disturbance types. Planting methods (hand dispersal, drill, one-month and six-month transplanting) on Asclepias tuberosa establishment …

Characterization Of 3d Printed Microdialysis Probes For Solute Recovery And Non-Specific Adsorption, Bailey N. Scoggins

Chemistry & Biochemistry Undergraduate Honors Theses

Microdialysis is an important sampling technique that has uses in a wide range of disciplines, such as neuroscience and pharmacokinetics. 3D printing aims to address adaptability and customization issues that are present in standard “off-the-shelf” microdialysis probes. This work aims to lay the groundwork for characterizing a 3D printed microdialysis probe designed at the University of Arkansas. One experiment involved measuring solute recovery of caffeine as a function of flow rate of a standard CMA 11 probe to assess its membrane performance. The other goal was to learn about non-specific adsorption tendencies of enzymes (i.e., to what degree proteins stick …

Maximizing Crop Production And Profitability Through Double Cropping Corn And Soybean Systems In South Carolina, Bennett Harrelson

All Dissertations

Profitability is critical for farm sustainability, efficiency, and longevity. Over the last decade, corn and soybean commodity prices have fluctuated considerably, and more recently, extreme increases in input prices have narrowed profit margins. Non-traditional cropping systems that can boost profit are becoming of interest to farmers in South Carolina, specifically double cropping soybean behind corn. In this scenario, corn is harvested at high moisture contents and followed by ultra-late planted soybean. However, prior research related to the agronomic production practices of double cropping corn and soybean is minimal. To develop best management practices for growers interested in double cropping corn …

Natural Killer T Cell-Mediated Control Of Francisella Tularensis-Induced Cytokine Storm Syndrome, Cameron M. Torres

Open Access Theses & Dissertations

Inflammation is critical for the effective clearance of viral and bacterial challenges, while simultaneously a mechanism utilized by many highly infectious pathogens to cause disease. The bacterium Francisella tularensis, the causative agent of human tularemia, elicits a cytokine storm, wherein the immune system over-responds to the presence of the bacterium causing a dysregulated release of proinflammatory and regulatory cytokines. Without treatment, tularemia mortality can be as high as 30%, with inhalation of as few as 10 CFUs inducing respiratory tularemia. Natural Killer T (NKT) cells are innate-like T lymphocytes with a diverse array of regulatory functions. Unlike conventional T cells, …

Morphology Of Smallmouth Bass (Micropterus Dolomieu) In Arkansas, Robert Laroche

Biological Sciences Undergraduate Honors Theses

The Smallmouth Bass, Micropterus dolomieu, is one of the most important game fishes in Arkansas. Three distinct lineages are recognized from different river basins: the Northern, Neosho, and Ouachita Smallmouth Bass. Understanding the biodiversity within this species complex inhabiting different water bodies in Arkansas is important for effective management of the fisheries resource and to guide conservation efforts. But current data on distribution of distinct forms are insufficient to guide management. The primary goals of the study presented here was to quantify morphological characteristics to identify distinct lineages of Smallmouth Bass, and to determine their specific locations within Arkansas streams …

The Prevalence Of Cytauxzoon Felis In Southern United States, Anna Haynes

Biological Sciences Undergraduate Honors Theses

Cytauxzoonosis, caused by transmission from a tick infected with the pathogen Cytauxzoon felis, is considered an emerging tick-borne disease in domestic felines. While not as fatal in other vertebrates such as the reservoir host Lynx rufus (bobcat), in domestic cats, infection is fatal nearly 100% of the time. This study sought to screen ticks pulled from felines for the pathogen across three states in an area identified as a hotspot. Out of 80 ticks screened, 12 tested positive for the pathogen. The positive population of ticks came from 3 neighboring counties in Southern Missouri: Jasper, McDonald, and Newton. McDonald …

The Expression Of Intestinal Tight Junction Proteins Induced By 1,25-Dihydroxyvitamin D3-Glycosides Supplementation To Reduce Bacterial Chondronecrosis With Osteomyelitis Lameness In Broilers, Kennedy M. Hicks

Biological Sciences Undergraduate Honors Theses

Bacterial Chondronecrosis with Osteomyelitis (BCO) is a leading cause of lameness in broiler chickens, impacting animal welfare and commercial poultry production. Supplementation using organic trace minerals, vitamin D, probiotics, and prebiotics has been studied to mitigate BCO lameness incidences in broiler chickens. Our previous study demonstrated that feeding Panbonis®-G-1,25(OH)₂D₃ from Solanum glaucophyllum, containing 1 µg/kg G-1,25(OH)₂D₃, to broilers for the first 28 days of their production cycle reduced BCO lameness by approximately 50%. In this study, we investigated the impact of 1,25-dihydroxy vitamin D₃ supplementation on the expression of tight junction …

Immune Function Modulation By Temperature On Isolated Rainbow Trout Macrophages, Abby Hunter

Biological Sciences Undergraduate Honors Theses

Fever is an evolutionary mechanism that enhances immune function, yet the molecular and metabolic responses to fever temperatures in ectothermic species remain poorly understood. In this study, we investigated how fever temperatures (19° C) influence macrophage function and metabolic activity in rainbow trout (Oncorhynchus mykiss), rather than normal temperatures (16° C). Using a rainbow trout monocytic cell line, RTS11, and primary head kidney-derived macrophages (HKCs), we examined the effects of fever temperatures on nitric oxide (NO) production, gene expression, protein synthesis, and energy metabolism. We found that fever temperatures increased NO production in both cell types, with further …

Speed Breeding And Fungal Blight Testing Of The Darling 54 American Chestnut (Castanea Dentata), Virginia G. May

All Theses And Dissertations

The American chestnut (Castanea dentata) was a dominant, foundational forest canopy species in eastern North America until an imported chestnut blight (caused by Cryphonectria parasitica) rendered it functionally extinct across its native range. Biotechnological approaches, like the Darling 54 transgenic line, have potential for future restoration, but need both lab and field evaluations of their breeding and blight tolerance. This thesis adds to the body of knowledge on the Darling 54 American chestnut. This research reports three novel advancements made through indoor breeding and the first systematic field test for blight tolerance of transgenic American chestnuts.

Historically, …

The Effects Of Pfos Exposure On Zebrafish Dopaminergic Neurodevelopment, Allison G. Fletcher

Departmental Honors & Graduate Capstone Projects

Per- and polyfluoroalkyl substances (PFAS) are a group of environmental contaminants that cause disruptions to the nervous and endocrine systems. Perfluorooctanesulfonate (PFOS) is considered one of the most disruptive PFAS to the nervous system, and may disrupt neurodevelopment of the dopaminergic system, which has been linked to neurodevelopmental disorders like Attention Deficit/Hyperactivity Disorder (ADHD) in humans. I hypothesized that early life PFOS exposure disrupts the development of the dopaminergic system. To test this hypothesis, I exposed zebrafish to 0.05, 0.5, and 5.0 mg/L PFOS through 5 days of embryonic and larval development. To assess acute effects of PFOS on the …

The Regulatory Role Of Collagen Α1(Xi) Amino-Terminal Domain Isoforms In Collagen Fibrillogenesis, Abu Sayeed Chowdhury

Boise State University Theses and Dissertations

Collagen α1(XI) is a minor fibrillar collagen involved in the critical regulation of collagen fibrils, such as nucleation, assembly, and regulation of fibril diameter. The amino-terminal domain consists of an amino-propeptide (Npp) domain and a variable region, which is the result of alternative splicing from exon 6A, 6B, 7, and 9. The spliced variants involving Npp, with the combinations of exon 6A, 6B, 7, and 9 gives rise to different isoforms with very distinctive chemical nature. The Npp of collagen α1(XI) chain is retained on the surface of the collagen fibril for an extended period of time and may play …

Regulation Of The Hypothalamic-Pituitary-Adrenal Axis Through Corticotropin-Releasing Factor Receptor 2 Activation And Androgens Acting On Androgen Receptors In Mice Exposed To Repeat Stress Conditions, David Reilly

Biological Sciences

The hypothalamic-pituitary adrenal (HPA)-axis is the body’s main neuroendocrine mechanism for regulating stress. It has been shown in both animal and human models that anxiety and depression like behavior is more prevalent in females compared to males. Studies have shown evidence that suggests there are sex differences in the HPA-axis that likely contribute to the observed sex difference. It has been shown that anxiety related behavior and HPA-axis responsiveness is correlated with androgens acting on androgen receptors (AR). The role of androgens acting on AR has a more unclear role in stress behavior and HPA-axis regulation when subjected to chronic …

Implications Of Acetylation And Phosphorylation On Metabolic Enzymes, Nour Fatema

Graduate Theses and Dissertations

All living things depend on glycolysis and the TCA cycle for energy production and metabolic control. Post-translational modifications (PTMs) such as acetylation and phosphorylation, which can change enzyme activity, substrate binding, and overall metabolic balance, tightly regulate these pathways. Diseases like cancer and metabolic problems are associated with disruptions in these alterations.

Serine phosphorylation and lysine acetylation are two of the many PTMs that are evolutionarily conserved processes that alter protein function. Previously thought to be a static histone alteration, acetylation is now understood to be a dynamic regulator of metabolic enzymes that modifies contacts, charge, and conformation. In response …

Sustainable Agriculture Through Data-Driven Land And Soil Management For Rural Farming Communities, Peggy Clareece Discenza

Open Access Theses & Dissertations

This thesis aims to investigate sustainable farming practices by utilizing a database containing soil, weather, and water data. Additionally, it evaluates cropping strategies using a system that incorporates nutrient dynamics and environmental values. The objective is to monitor, develop predictive models, and assess the impact of both controlled and uncontrolled nutrient variables. This is achieved through the development of an algorithm that provides information on soil health based on datasets and land use, with a particular focus on residual values after harvesting for deeper analytical insights and interpretation. This study focuses on key nutrients, including pH levels, water availability, and …