Life Sciences Commons^™

Gene Editing Approaches To Improving Grain Amino Acid Profiles In Maize And Sorghum, Joseph Preston Hurst

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

Maize grain is deficient in lysine. While the opaque2 mutation increases grain lysine, o2 is a transcription factor that regulates a wide network of genes beyond zeins, which leads to pleiotropic and often negative effects. Additionally, the drastic reduction in 19kDa and 22kDa alpha-zeins causes a floury kernel, unsuitable for agricultural use. Sorghum, closely related to maize, has a similar lack of lysine that can be corrected with prolamin alteration and also subject to the same deleterious kernel texture. CRISPR/cas9 gives researchers the ability to directly target genes of interest. In this research, gene editing was used to specifically target …

Environmental Effects On Preweaning Calf Health, Lindsay L. Waechter-Mead

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Neonatal calf health is an important factor in the productivity and profitability in the beef cattle industry, influencing preweaning survival, growth, and long-term performance. The overall objective of this thesis is to characterize risk factors that contribute to health issues in young beef calves. The first objective is to review literature exploring the environmental factors affecting preweaning morbidity and mortality, including hypothermia, precipitation, and wind. Management strategies such as the effect of environmental conditions of calving location, body condition score in dams at parturition, and the impacts of dystocia on calf health will also be discussed. Gaps in current research …

Constructing An Attractive Targeted Sugar Bait For Reducing Mosquito Populations, Xi Xian Ng

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

Mosquito-borne pathogen transmission continues to pose a significant burden to global public health, well-being, and economic productivity. In the absence of universally available vaccines and amidst rising insecticide resistance that leads to product failures, there is an urgent need to develop new tools to mitigate mosquito-borne disease risk. Two general strategies exist to reduce transmission risk: personal protective measures and area-wide chemical interventions. Attractive Targeted Sugar Bait (ATSB) systems leverage the sugar-feeding behavior of mosquitoes—critical for sustaining their flight, metabolism, development, and fecundity—by delivering oral toxicants through attractively formulated sugar baits. This study aimed to develop an optimized ATSB formulation …

Movement Ecology Of Sandhills Chub, A Carolina Endemic, Zachary Adam Ramsey

Electronic Theses and Dissertations

Fish movement studies have traditionally focused on species that support commercial and recreational fisheries, but recently more focus has been given to non-game, stream fishes because of their recognized importance in maintaining biodiversity within these ecosystems. Stream fish movement is described as being “restricted” and following a leptokurtic distribution via diffusive spread related to environmental and biological factors. Many studies of stream fish movement ecology in North America have occurred in high-gradient streams with coarse substrate in mountains or in streams of the interior plains. Sandhills streams of the southeastern USA are characterized as warm-water, low gradient, and dominated by …

Flow Field Surrounding Bluegill (Lepomis Macrochirus) During Suction-Feeding, Jensine Caroline Coggin

Electronic Theses and Dissertations

Suction-feeding is a common method for capturing prey by aquatic organisms and contributed to the diversification of fishes by enabling them to consume a wide range of prey. Suction-feeding is a complex fish-fluid interaction governed by various hydrodynamic forces: inertia, unsteady, viscous, and pressure gradients. These forces are described by the coupling between the flow physics equations (Navier-Stokes) and the dynamic behavior of the fish (motion and forces). However, the distribution of the pressure field that drives this process, and the extent to which suction-feeding is three-dimensional, remain underexplored. I estimated the pressure within the flow field surrounding the mouth …

Heterotopias Of Confinement: Zoo Architecture And The Loss Of Elephant Agency, Clayton Gill Beasley

Electronic Theses and Dissertations

Zoos functions as a site where human-animal relationships are structured through built environments that mediate control and representation. This study examines zoos as heterotopias—spaces where power and surveillance are negotiated between human observers and captive nonhuman animals. While zoos are often framed as spaces of conservation and education, their architectural design reinforces hierarchies of observation and confinement, shaping both human perceptions of nature and the lived experiences of nonhuman animals. This research focuses on Asian elephants as a critical species within this framework, exploring how their captivity illuminates tensions between human-imposed structures and nonhuman autonomy. Drawing from theories of heterotopia, …

Kinasefusiondb: An Integrative Knowledge Of Kinase Fusion Proteins In Multi-Scales, Himansu Kumar, Zikang Chen, Abayomi Adegunlehin, Loren Trowbridge, Leonardo Aguilar, Pora Kim

Faculty, Staff and Student Publications

Kinase fusion genes were the most targeted fusion gene group among multiple major cellular gene groups. Kinase inhibitors disrupt aberrant signaling cascades and inhibit tumor progression, yet the specific mechanisms of action of the U.S. Food and Drug Administration (FDA)-approved inhibitors in the context of kinase fusion oncoproteins remain largely unknown. This gap limits our ability to develop personalized therapies and next-generation kinase inhibitors. To address this, we developed a novel in silico pipeline for predicting 3D structures of kinase fusion proteins and performing structure-based virtual screening. This approach enables large-scale structural annotation and drug screening across pan-cancer kinase fusions. …

Bmal1-Hif2a Heterodimer Modulates Circadian Variations Of Myocardial Injury, Wei Ruan, Tao Li, In Hyuk Bang, Jaewoong Lee, Wankun Deng, Xinxin Ma, Cong Luo, Fang Du, Seung-Hee Yoo, Boyun Kim, Jiwen Li, Xiaoyi Yuan, Katherine Figarella, Yu A An, Yin-Ying Wang, Yafen Liang, Matthew Deberge, Dongze Zhang, Zhen Zhou, Yanyu Wang, Joshua M Gorham, Jonathan G Seidman, Christine E Seidman, Sary F Aranki, Ragini Nair, Lei Li, Jagat Narula, Zhongming Zhao, Alemayehu A Gorfe, Jochen D Muehlschlegel, Kuang-Lei Tsai, Holger K Eltzschig

Faculty, Staff and Student Publications

Acute myocardial infarction is a leading cause of morbidity and mortality worldwide1. Clinical studies have shown that the severity of cardiac injury after myocardial infarction exhibits a circadian pattern, with larger infarcts and poorer outcomes in patients experiencing morning-onset events2–7. However, the molecular mechanisms underlying these diurnal variations remain unclear. Here we show that the core circadian transcription factor BMAL17–11 regulates circadian-dependent myocardial injury by forming a transcriptionally active heterodimer with a non-canonical partner—hypoxia-inducible factor 2 alpha (HIF2A)12–16—in a diurnal manner. To substantiate this finding, we determined …

Implications Of Type Iv Pilus Retraction For Dna Uptake By Acinetobacter Baumannii, Yafan Yu

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

Horizontal gene transfer (HGT) via natural competence allows bacteria to incorporate extracellular DNA (eDNA) into their genomes, facilitating genetic diversity and adaptation. In Acinetobacter species, natural competence depends on DNA binding and uptake mediated by type IV pili (T4P). T4P are dynamic extracellular filaments composed primarily of the major pilin subunit PilA, along with a few minor subunits. T4P drive a range of cellular functions including twitching motility, biofilm formation, and DNA uptake, with some functions dependent on pilus retraction and others not. However, how Acinetobacter T4P bind DNA and how T4P/eDNA interactions impact biofilm formation remain unclear. Here, I …

Modifying The Comb, Rethinking The Install: Integrated Approaches To Honey Bee Colony Establishment And Winter Survival, Shelby A. Kittle

Department of Entomology: Dissertations, Theses, and Student Research

The European, or Western honey bee (Apis mellifera L.) plays a vital role in global ecosystems and agriculture, providing essential pollination services and producing valuable hive products. However, honey bee colony losses have escalated worldwide, but particularly across the United States due to various stressors, including biotic and abiotic factors, mismanagement, and environmental challenges. This thesis investigates key challenges in honey bee management and explores solutions aimed at improving colony health and productivity.

Chapter 1 provides an overview of the beekeeping industry, detailing its economic importance, services, and products, as well as the many challenges faced by beekeepers. It …

Mechanisms Of Perennial Sorghum Resistance To Sugarcane Aphid Infestation, Esha Kaler

Department of Entomology: Dissertations, Theses, and Student Research

Sorghum, Sorghum bicolor (L.) Moench, the fifth most-grown cereal crop in the world, is a versatile crop, grown across different agro-ecological regions. Sorghum has numerous uses ranging from food and forage purposes to biofuel production. Sugarcane aphid (SCA; Melanaphis sacchari) is a major threat to sorghum production, accounting for 50% to 100% yield loss under heavy infestations. Perennial sorghum can be a sustainable and climate-resilient alternative to the current cereal farming systems. The development of perennial sorghum offers numerous benefits, such as reduced economic inputs, more carbon sequestration, better soil health, and sustainable yields. We employed host plant resistance …

Epidemiological Inferences Of The Impacts Of Winter Ticks On Moose Health, Krishna S. Woerheide

Department of Entomology: Dissertations, Theses, and Student Research

The North American Moose (mooz in Anishinaabemowin, Ojibwe language, Alces alces), a culturally significant subsistence species for the Anishinaabe people, faces population decline due to calf predation, pathogen transmission, and parasitism by the winter tick (Dermacentor albipictus), all exacerbated by climate change. This study explores the impact of winter tick infestations on moose health, with a focus on natural mineral seeps as potential transmission hotspots in moose habitats within the Grand Portage Indian Reservation (Gichi Onigaming), on Isle Royale National Park (Minong), and within the 1854 Ceded Territory (greater northeastern Minnesota) - ancestral and present homelands of …

The Product Of Property Tax: How Property Tax Affects Agricultural Production In Nebraska, James L. Kriz

Department of Political Science: Dissertations, Theses, and Student Research

The question of what level of property tax is acceptable has become an increasingly prominent question within agriculture, which is shown by the rise of interest groups and bill introduction in Nebraska. As such, this paper examines how property taxes affect Nebraska's agricultural output. The study employs a quantitative analysis of all Nebraska counties over 21 years from 2000 to 2020. This study hypothesizes that as property tax rates increase, farm outputs will decrease. The study offers a new analysis in an understudied subsection of the agriculture policy literature and points towards a new direction in which the field can …

Identification Of Antigens For Food Allergy And Food Allergen Detection, Ellenor Sell

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Antibody-based allergen testing is an essential part of allergen management in the food industry. These methods directly detect one or more molecules of the allergenic foodstuff (target’ molecule(s)) and the presence of the allergenic foodstuff is inferred. The identity of these target molecules is crucial to the performance of the method and the interpretation of results. The goal of this study was to develop protein/antibody capture methodology for the identification of antibody binding partners using mass spectrometry.

This study is broken down into three separate projects: the characterization of the antigen-antibody complexes present in sandwich ELISAs, LFDs, and human sera. …

Assessing Sleep Quality In A Preclinical Model Of Low Back Pain Through Novel Noninvasive Methods, Lydia C. Saltz

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Chronic low back pain (LBP) has widespread negative impacts on quality of life. Current treatments for chronic LBP fail to provide long-term efficacy and motivate the need to understand key drivers of poor patient outcomes. Mounting evidence indicates that sleep disturbances and chronic LBP have a strong reciprocal relationship. Women may be particularly vulnerable to the negative impacts of the sleep-pain axis, exhibiting greater prevalence in both conditions. However, the relationship between sleep, pain, and sex remains understudied. Preclinical models can be used to parse out characteristic sleep features that degrade with pain, which can be further broken out by …

Screening For Chloroplast Inner Envelope-Thylakoid Membrane Contact Site Proteins, Evan W. Labrant

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

Most life on Earth is dependent upon the capture of solar energy and subsequent fixation of carbon. In members of the Archaeplastida lineage these biological processes take place in semi-autonomous organelles called chloroplasts. Chloroplasts are bounded by a double membrane envelope and contain the photosynthetic membrane system, thylakoid membranes, where light capture takes place. While a great deal is known about how thylakoid lipids are synthesized and protein complexes therein are properly maintained, very little is known regarding the processes by which lipids are transported to thylakoids which lack de novo glycerolipid synthesis. We have worked to identify candidate proteins …

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 …

Integrating Genomic And Phenomic Breeding Tools For Wheat Stem Sawfly Resistance In Hard Winter Wheat, Sydney E. Graham

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

The wheat stem sawfly (WSS; Cephus cinctus) is an insect pest that affects wheat (Triticum aestivum) in the Northern Great Plains. This pest causes stem cutting that makes the plants susceptible to lodging and results in up to 30% yield loss. The primary management strategy for producers is utilizing host plant resistance, for which the main trait is stem solidness. This trait increases the pith thickness and provides resistance to the WSS by increasing larval mortality and reducing stem cutting. While stem solidness is largely controlled by a known major gene (SSt1), the phenotypic expression is also …

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 …

Assessing Spatial And Temporal Variation In Photoprotective Responses Of Deciduous And Evergreen Tree Canopies With Leaf Spectroscopy, Alexander Piper

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

Environmental conditions frequently prevent carbon fixation by plants, leading to the absorption of excess light that can damage photosynthetic machinery if not dissipated. To do so, plants utilize several photoprotective mechanisms, some detectable remotely using Photochemical Reflectance Index (PRI). Two components of PRI correspond to the facultative engagement of the xanthophyll cycle (ΔPRI) and constitutive changes in xanthophyll pigment pool sizes (PRI0), representing distinct mechanisms regulating shorter and longer-term photoprotection, respectively. Our understanding of interspecific and intraspecific variation in these mechanisms is limited, primarily because PRI components are often not clearly distinguished. This study aimed to assess the variation in …

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 …

Biological Reduction Of Perchlorate In Martian Regolith Simulant Using Azospira Oryzae, Brianna Bernhardt

Honors Program: Senior Projects (Public)

Establishing a sustainable human presence on Mars will require in-situ resource utilization (ISRU) to reduce costly and inefficient resupply missions. Despite containing many of the requirements for agriculture, Martian regolith is contaminated with toxic levels of perchlorate (ClO₄^-), threatening human health and agricultural success. Biological remediation using perchlorate-reducing bacteria offers a promising approach to address these challenges. This study investigated the perchlorate-reducing ability of Azospira oryzae, a facultative anaerobe capable of converting ClO₄^- to chloride (Cl^-) through dissimilatory respiration. A. oryzae was cultured in Martian regolith simulant (MGS-1) amended with 0.0%, 0.5%, …

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 …

Evolution And Strengths Of School Lunch Programs In The United States And Japan, Sarah Ritterling

Honors Program: Senior Projects (Public)

School lunches around the world perform a vital role in children’s nutritional needs and overall health. These nutritional programs provide a chance for children to learn how to create a balanced meal and about the production and serving of food. However, many countries, including the United States and Japan, have taken different approaches to meet these goals, influenced by the needs of children and communities over time. The United States provides support, funding, and nutritional standards through the National School Lunch Program. Japan promotes the Basic Act of Shokuiku (food and nutrition education) within society and outlines goals for schools …

Developing Custom Fertilizer Strategies Recirculating Hydroponic Systems, Joshua Bryan Tebow

Graduate Theses and Dissertations

Hydroponic systems recirculate nutrient solution to reduce the amount of water used in leafy green production. However, the rootzone of the nutrient solution is complex and influenced by interacting factors such as plant uptake demand, irrigation water quality, supplied fertilizer salts and nutrient concentrations, environmental conditions, and injection of mineral acids/bases to control solution pH. A common strategy for managing nutrients in commercial production is to select a hydroponic solution formulation (i.e. recipe) to supply and maintain a target pH and electrical conductivity (EC) in the recirculating solution over time by automatic injection of mineral acids/bases and concentrated fertilizer stock …