Life Sciences Commons^™

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 …

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. …

Recombinant Expression And Purification Of Porphyromonas Gingivalis Tyrosine Kinase 1 In Escherichia Coli., Laura K. Hanna

College of Arts & Sciences Senior Theses

The goal of this study was to optimize the expression and purification of Porphyromonas gingivalis Tyrosine Kinase 1 (Ptk1) in recombinant Escherichia coli containing the plasmids Gro_ESL and Ptk1, with a His₆ tag_, to obtain a highly pure protein sample. Various experimental conditions were tested to determine the most effective parameters for protein expression and purification, including adjustments in induction timing, buffer composition, and purification techniques.

Optimal protein expression was achieved when cells were induced at an optical density (OD) of 0.3 to 0.4. β-D-1-thiogalactopyranoside (IPTG), which activates the lac operon, was used to induce Ptk1 expression. A …

Dual-Task Cost Of Gait Measures In Individuals With And Without Parkinson's Disease, Addison G. Miller

Health, Human Performance and Recreation Undergraduate Honors Theses

Parkinson’s disease (PD), estimated to affect over one million people by 2030, is a neurodegenerative disease that damages the dopaminergic neurons located in the brain. Losing these neurons cause individuals with PD to experience impairments in basic motor and cognitive functions. Symptoms of PD often include bodily shaking, muscle stiffness, and abnormalities in gait and posture. Individuals with PD can also experience impairment when walking and performing secondary tasks, such as walking while talking, known as dual tasking. Dual tasking can lead to increased risk of falling or losing balance, as well as the inability to move freely while carrying …

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 …

Evaluation Of Escherichia Coli Lithium Binding Properties, David Andrew Gonzalez

Theses (2016-Present)

Lithium is a commonly used element in everyday items such as batteries, electronics and industrial applications. With the common use of lithium comes the problem of what to do with lithium waste. This problem calls for the need of an efficient environmentally friendly recovery process. This study investigates the potential of Escherichia coli for lithium biosorption in aqueous solutions. Although the roles of copper and Bacillus coagulans were initially explored for comparative biosorption potential, they were not used in experimental trials. This study explores the potential of E. coli and its potential for lithium biosorption in water solutions. Lithium chloride …

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 …

Growth Of Methanogens Using Pyrite As An Energy Source: Implications For Life On Mars, Mckenzie K. Ragan

Biological Sciences Undergraduate Honors Theses

The search for life beyond Earth has been the motivating factor for many scientist’s research in the past and currently. Specifically, the efforts have largely been focused on Mars. Mars exhibits qualities that are similar to the life-harboring characteristics of Earth, creating the possibility for life to exist on Mars. Mars’ subsurface conditions may be ideal for specific microorganisms to thrive, providing a haven away from the harsh surface conditions (Mancinelli, 2000). It is known that one of the most important elements to support life, H₂O is found in the subsurface of Mars, along with an atmosphere lacking …

Protein Intake And The Wellbeing Of Postmenopausal Women: Investigating Sleep, Mood, And Quality Of Life, Aleesha Imran

Biological Sciences Undergraduate Honors Theses

Postmenopausal women commonly experience declines in sleep quality, mood, and overall wellbeing, with limited non-pharmacological options available to address these concerns. This randomized controlled trial investigated whether daily beef consumption as part of a higher-protein diet could improve sleep, mood, and quality of life over four weeks. Participants were randomized to either a standard protein intake control group or a treatment group consuming a high-protein diet with daily lean beef.

The treatment group showed modest improvements in subjective sleep quality and perceived health compared to controls, although these changes were not statistically significant. Fatigue, however, significantly decreased in the treatment …

Metabolic Responses Of Adipose-Derived Stem Cells In Collagen I Hydrogels, Caroline R. King

Biological Sciences Undergraduate Honors Theses

Peripheral nerve injury affects approximately 44 in 1 million people in the United States every year and can lead to incomplete nerve recovery and loss of motor and sensory function. A significant amount of energy is required for nerve injury repair. A lack of energy allocation to the injury site hinders repair. Current treatments include hollow nerve guidance conduits, decellularized nerve grafts, and autografts. However, they are limited by factors such as donor site morbidity and sustained immunosuppressive treatments. Using three-dimensional collagen I hydrogels laden with adipose-derived stem cells (ASCs) can assist in neural regeneration. Three-dimensional collagen scaffolds aim to …

The Relationship Between Oxidative Stress And Partner Opposition In Conflict Resolution, Jenna Thomas

Biological Sciences Undergraduate Honors Theses

Given the inevitability of conflict in romantic relationships, understanding its biological impact is crucial for developing conflict resolution strategies that promote physical health. While many studies highlight relationship conflict’s negative effects on bodily systems, few examine how specific facets of conflict, such as opposition, impact the body. Partner opposition may contribute to oxidative stress, a biological marker associated with poor physical health, by activating the amygdala. This study investigated the association between partner opposition and oxidative stress in 126 couples expecting their first child. Participants attended a lab session where problem-solving discussions were recorded to assess oppositional behavior and urine …