Life Sciences Commons^™

Impacts Of Management Practices And Soil Properties On Free-Living Nitrogen Fixation In Eastern South Dakota, Laura Galvan Nuevo

Electronic Theses and Dissertations

Free-living nitrogen (N) fixation (FLNF) may represent a sustainable pathway to supplement crop N demand in agroecosystems, yet edaphic and management factors regulating this process under field conditions remain poorly understood in the Northern Great Plains. Using 15N2 direct method to quantify potential FLNF (pFLNF) and baseline FLNF (bFLNF), this thesis investigates how crop rotations (2-, 3-, and 4-year systems), tillage management (conventional vs. no-till), cover cropping, and soil properties affect the potential of free-living diazotrophs to supply N via FLNF in a long-term no-till corn-based system in Southeastern South Dakota. A two-year field study evaluated pFLNF across four growing …

Colorectal Cancers With Distinct Metastatic Potential Trigger Divergent Early T Cell Responses, Marwa Ahmed Saad

Student Theses and Dissertations

The intestinal mucosa harbors the largest immune compartment in the mammalianbody, where resident and recruited immune cells must maintain tolerance to commensal and dietary antigens while preserving their ability to mount effective responses against pathogens and malignant transformation. Uncontrolled epithelial proliferation leads to colorectal cancer (CRC), the second leading cause of cancer-related deaths worldwide. More than 85% of human CRC cases arise from accumulating sporadic or hereditary mutations in the tumor suppressor genes Apc, Tp53, Smad4, and the oncogene Kras. Although immune checkpoint blockade has transformed the treatment of certain solid tumors, most CRCs, particularly those with a proficient mismatch …

Investigating Primary Motor Cortex Involvement In Mouse Vocal Communication, Elena N. Duryea Waidmann

Student Theses and Dissertations

Vocal communication is used to transmit a range of information to other individuals. While many vocalizations are innate, some species can learn to change their vocal output. This is termed vocal-learning, and it is a rare trait and a necessary building block for human spoken language and songbird song. Comparative work in humans and songbirds suggests that convergent genetic and neural specializations may drive these learned vocal behaviors. Two key features of these advanced vocal learners are: i) specialized primary motor regions in the forebrain with activity tied to vocalization; and ii) dense monosynaptic projections from the primary motor cortex …

Noncanonical Roles Of Hepatitis B Virus Precore Rna In Reverse, Mengyin Zhang

Student Theses and Dissertations

Hepatitis B virus (HBV) is a partially double-stranded DNA virus that replicates through reverse transcription. Transcription from the HBV core promoter generates two genome-length RNAs: pregenomic RNA (pgRNA) and precore RNA (pcRNA). pcRNA contains the entire pgRNA sequence plus an additional 32 nucleotides at its 5’ end that include the precore start codon, enabling translation of the precore protein, the precursor of the secreted HBV e antigen (HBeAg). Whereas pgRNA is translated to produce core and polymerase and serves as the template for reverse transcription by cis-acting HBV polymerase, pcRNA has long been considered unable to support HBV DNA synthesis. …

Astrocyte Identity And Function Acquisition During Nervous System Development In C. Elegans, Simin Liu

Student Theses and Dissertations

Astrocytes are essential regulators of nervous system development, homeostasis, and function. Beyond their well-established roles in synapse formation, metabolic support, and neural circuit modulation, astrocytes are increasingly recognized as dynamic participants in behavior regulation and neurological disease. Despite their importance, the developmental logic by which astrocytes acquire their identity and functional properties remains incompletely understood. In particular, how distinct developmental programs coordinate to establish astrocyte identity, and how immature glial cells transition into fully functional astrocytes, are central unresolved questions in neurobiology. In this thesis, I investigate the developmental mechanisms that establish astrocyte identity and function using the astrocyte-like Caenorhabditis …

Spatiotemporal Patterns Of Migratory Songbird Habitat Use: An Analysis Of Environmental Drivers At The Net Level, Garrett Kucharski

Dissertations, Master's Theses and Master's Reports

Many eastern North American migratory songbirds are declining at alarming rates, and growing evidence suggests that events occurring away from the breeding grounds, particularly during migration, can be major drivers of these trends. Stopover sites are a key component of migration because they are where birds rest, refuel, and recover before continuing long-distance movements, yet the ecological factors that shape how broadly different species use stopover habitat remain unresolved. From both an applied perspective, identifying habitat attributes associated with use by the greatest diversity of migrants will help land managers prioritize and restore stopover sites, actions that may contribute to …

Fluctuation Of Organochlorine Concentrations In Bull Sharks At Different Life Stages, Mackenzie R. Phillips

Dissertations, Master's Theses and Master's Reports

For Carcharhinid species such as the bull shark (Carcharhinus leucas), the maternal offloading of nutrients is essential for pup development and growth, however, significant amounts of OCs are also transferred. As a top predator in aquatic food webs, bull sharks can potentially bioaccumulate high concentrations of pollutants such as dichloro-diphenyl-trichloroethane (DDT) that biomagnify through aquatic food webs. These pollutants are also hydrophobic and fat soluble and therefore pose toxicity risks to developing young bull sharks. In this study, liver tissues collected from juvenile bull sharks inhabiting Florida’s coastal waters were analyzed for a suite of organochlorine pesticides (OCs) …

Public Perception Of Environmental Contamination And Its Implications For Fish And Community Health In West Bengal, India, Libia Hazra

Dissertations, Master's Theses and Master's Reports

In West Bengal, India, the highest fish-consuming state in the country, fish are woven into everyday life, including ceremonies of birth and marriage, prayers offered during harvesting and the cultural memory of communities whose identities are inseparable from aquatic life. However, the rivers, wetlands, and ponds that sustain these fish-human relationships are increasingly threatened by environmental contamination resulting from industrial discharge, agricultural runoff, and inadequate environmental management. Understanding how communities perceive these environmental changes is essential for developing effective conservation and public health strategies.

In collaboration between the Indian Institute of Technology (ITT) Kharagpur, India, and Michigan Technological University (USA), …

Systematics Of Disk-Winged Bats (Thyroptera), Courtney L. Klumpp

Capstone Showcase

This thesis investigates the evolutionary relationships among disk-winged bats in the genus Thyroptera, a small group of Neotropical bats known for the adhesive suction disks on their wings and feet that allow them to roost inside tightly rolled leaves. The distinctive morphology and behavior of these bats have not been extensively documented, and their phylogenetic relationships remain only partially resolved. The goal of this research is to better understand how these species are related to one another and to determine whether the five recognized species of Thyroptera form a single monophyletic group. To address this question, morphological and genetic …

Mitochondrial Efficiency: Bridging Early-Life Environment And Organismal Performance, Kayla E. Lichtner

Master’s Theses

Mitochondria operate at the forefront of organismal-environmental interactions. Despite remarkable diversity in mitochondrial function both within and among species, all mitochondria serve a universal role in facilitating the flow of energy between organisms and their environment. Energetic efficiency, the way in which organisms assimilate and transform environmental substrate into physiological currency, is a major determinant of organismal performance. Although previous studies have shown that early-life environment can have lasting effects on metabolism, the underlying mechanisms driving the emergence of mitochondrial phenotypic variation remain poorly understood. Leach’s storm-petrels (Hydrobates leucorhous) provide a valuable opportunity to investigate longitudinal hypotheses of …

Rate Response Of Curlyleaf Pondweed And Native Plants To Flumioxazin In Minnesota Lakes, Pearl J. Jensen

All Graduate Theses, Dissertations, and Other Capstone Projects

Curlyleaf pondweed (Potamogeton crispus L.) is an invasive aquatic plant present across the United States that causes significant recreational issues, outcompetes native plant species, and depletes water quality. Before senescing in mid-summer, curlyleaf pondweed forms a large number of turions that can lay dormant in the sediment for several years. Typical herbicide management of this species occurs in early spring to target the plant before turion production occurs and while native plants are dormant. Flumioxazin has shown potential in curlyleaf pondweed management in small scale studies, but its effects have not been assessed in operational management. In this study, treatments …

Ethanol And Iron Absorption Interactions Within Crayfish Invertebrate Models, James Rollman, Andrew Wissmar

Williams Honors College, Honors Research Projects

Analysis of the effects of alcohol consumption (ethyl-alcohol) on iron absorption within crayfish model. The use of tube-feeding provides a novel, more precise output, and less invasive procedure compared to the traditional approach of dissolving the target substance in tank water and measuring hemolymph changes. The project aims to determine the extent to which alcohol influences iron absorption. Ultimately, the choice of iron reflect the future potential to aid in research with genetic hemochromatosis and or Iron overload.

Red Clover Isoflavones And Establishment In The Context Of Tall Fescue Toxicosis Mitigation In The Mid-South, Jonathan L. Stephens

Theses and Dissertations--Plant and Soil Sciences

Low levels of red clover (Trifolium pratense L.) have been shown to mitigate tall fescue (Lolium arundinaceum (Schreb.) toxicosis symptoms. This is because of the presence of plant-produced compounds known as isoflavones. Production of a red clover supplement on a commercial scale would require industrial-level processing of raw plant material into granules or pellets. The first study of this thesis evaluated the impact of drying temperature on bioavailability of isoflavones. Drying temperatures up to 104°C had minimal impact on isoflavone concentrations. Additionally, varietal differences in isoflavone concentrations were documented. The second study of this thesis evaluated optimal establishment …

Characterizing The Role Off The Sp1/Klf Transcription Factor Huckebein In The Drosophila Melanogaster Ventral Nerve Cord, Benjamin Almond

Distinguished Undergraduate Researcher Program

Over the course of embryonic development, the ectodermal cell layer gives rise to a vast array of neurons and glia patterned across the central nervous system (CNS). Neurulation and specification is achieved in the ectoderm through temporospatial patterns of transcription factor (TF) expression, many of which are conserved across evolutionary history. These conserved regulatory motifs allow the use of Drosophila melanogaster to study the mechanisms of neurodevelopment across the animal kingdom. The huckebein (hkb) gene encodes a conserved SP1/KLF TF known to play important roles in cell cycle regulation, tissue morphogenesis during tubular organ development, and gut specification in Drosophila. …

Measuring The Rise And Fall Of Plasma 25-Hydroxyvitamin D Concentrations In Blue-Tongued Skinks (Tiliqua Scincoides) Following Ultraviolet B Exposure And Withdrawal, Ashleigh Godke, Haerin Rhim, M. Graciela Aguilar, Keishla Marrero-Acosta, Mark Mitchell

Distinguished Undergraduate Researcher Program

Species-specific husbandry guidelines remain limited for blue-tongued skinks (Tiliqua scincoides), especially in relation to ultraviolet B (UVB) lighting and vitamin D requirements. This study aimed to determine whether UVB exposure is necessary for these skinks and how long 25-hydroxyvitamin D (25-OHD) concentrations persist after UVB withdrawal. Eleven adult skinks who had been fed with wet cat food were exposed to 12 or 2 h of UVB per day for four weeks. Plasma 25-OHD concentrations were very low at the baseline, and significantly increased post-UVB in both groups (p < 0.01), with the 12-hour group increasing from baseline concentrations of 18.5 [12.8–20.5] nmol/L to 820 [730–1251.3] nmol/L and the 2-hour group increasing from baseline concentrations of 22 [15.5–22] nmol/L to 635 [401–892.5] nmol/L. Following the discontinuation of UVB exposure, 25-OHD gradually declined and was not significantly different from baseline concentrations at 7 and 4 months for the 12-hour and 2-hour groups, respectively. Dietary vitamin D3 (2.5 IU/g as dry matter basis), provided through wet cat food alone, appeared insufficient to support sustained plasma 25-OHD concentrations. These findings strongly suggest that blue-tongued skinks rely on UVB exposure to increase their 25-OHD concentrations. Moreover, the shorter 2-hour exposure provided a significant rise in 25-OHD concentrations and remained above baseline for 4 months, suggesting the shorter exposure can benefit these animals, while potentially reducing secondary risks associated with UVB exposure.

Structural Determination And Regulatory Mechanisms Of Rice Lipoxygenase-1, Lillie Ballanco, Nathaniel Gilbert, Adam Offenbacher

Distinguished Undergraduate Researcher Program

Lipoxygenases (LOXs) are non-heme iron containing enzymes that catalyze the oxygenation of polyunsaturated fatty acids (PUFAs) such as linoleic acid (LA). These lipoxygenase enzymes are found in both plants and animals. In humans, LOXs have been linked to inflammatory diseases such as asthma, atheroscelerosis, and allergic rhinitis. Plant LOXs have been primarily linked to the growth, development, and stress response of the plant. This paper focuses on Oryza sativa lipoxygenase-1 (OsLOX1), an enzyme found in rice (Oryza sativa). OsLOX1 has been associated with enhanced drought tolerance in rice and may play a role in regulating growth under water-limited conditions. Understanding …

Analysis Of The Pervasiveness Of Per- And Polyfluoroalkyl Substances (Pfas) And Their Relationship With The Incidence Of Neurological Health Disorders, Emma Waters

2026 Research Poster Competition

Per- and polyfluoroalkyl substances (PFAS) are a contaminant of emerging concern due to their chemical structure that afford a plethora of issues with regards to degradation on environmental and metabolic fronts. PFAS are amphiphilic and contain a carbon-fluorine bond, which complicates their movement through the environment and ensures their longevity in biological systems. Their persistence in biological systems has led them to be marked as “forever chemicals” and have emphasized them as a priority area for research in recent years. Current work on PFAS relationships to human health have pointed to some causes for concern. Much of the research on …

Satisfaction With Physician Communication, Joyce Ho

2026 Research Poster Competition

Problem. Provider-patient communication can be sorted into two approaches: patient-centered communication (PCC) and doctor-centered communication (DCC). PCC is characterized by a patient focus, in which patients are encouraged to participate in decisions regarding their care, while DCC is characterized by a doctor focus, in which the physician acts as an informational source for patients (Bientzle et al. 2017). Physician communication style is known to be influenced by gender. Female physicians are more likely to utilize PCC than their male counterparts (Roter 2004). Female patients are more likely to have higher measures of PCC in interactions with their physicians (Bertakis et …

Bmal1 Mediates Sex-Specific Circadian Regulation Of Cardiac Ion Channels And Temporal Arrhythmia Vulnerability, Brian P. Delisle, Ezekiel Rozmus, Abhilash Prabhat, Spencer B. Procopio, Xiping Zhang, Emilia Entcheva, Karyn A. Esser, Elizabeth Schroder

Physiology Faculty Publications

No abstract provided.

C/Ebpα Is Essential For Gonadal But Not Inguinal White Adipose Tissue Formation In Mice, Krista Y. Hu, Yu-Lin Ma, Esme A. Dodge, Olivia A. B. Maguire, Caio V. Matias, Ryan K. Barney, Hector S. Himede, Juliana Gomez Pardo, Miriam Cepeda, Scott M. Gordon, Robert C. Bauer

Physiology Faculty Publications

Objective: The distribution of excess white adipose tissue (WAT) in obesity correlates with risk for comorbidities. Thus, understanding depot-specific WAT developmental mechanisms is translationally relevant. SNPs near the gene CEBPA associate with waist to hip ratio, and while C/EBPα is a recognized regulator of adipogenesis, there is no previously known role for C/EBPα in regulating adipose distribution.

Methods: We crossed Cebpa floxed mice to the AdipoQ-Cre transgenic mouse strain, generating mice with adipocyte-specific knockout of Cebpa (Cebpa_ASKO). Mice were phenotyped on a chow diet and after prolonged high-fat diet (HFD) feeding.

Results: Cebpa_ASKO mice almost entirely lack gonadal …

Dim Light At Night Worsens Cardiac Autonomic Dysregulation In Female Diabetic Mice, Abhilash Prabhat, Shrishti Naidu, Isabel G. Stumpf, Tanya S. Seward, Elizabeth A. Schroder, Brian P. Delisle

Physiology Faculty Publications

Cardiovascular autonomic neuropathy (CAN) is a common complication of diabetes mellitus. CAN is characterized by impaired cardiovascular autonomic control and is associated with increased mortality, especially among women with type 2 diabetes. Identifying environmental factors that exacerbate the CAN-associated phenotype may reveal modifiable strategies to reduce cardiovascular risk.

Nighttime light exposure is a novel cardiovascular risk factor. Among ∼90,000 individuals, greater nighttime light exposure correlated with increased atrial fibrillation and heart failure risk. Light at night disrupts sympathovagal balance and elevates nocturnal heart rate in humans. Dim light at night similarly disrupts autonomic regulation of heart rate in mice. We …

Early Microglial Response To Amyloid Plaques Drives Sleep Loss In Alzheimer’S Disease, Nicholas J. Constantino, Riley E. Irmen, Matthew J. Lanning, Sierra M. Turner, Clair C. Ashley, Caitlin M. Carroll, Evan M. Neary, Dave Rubinow, J. Andy Snipes, Shannon L. Macauley

Physiology Faculty Publications

Introduction: Sleep disruption is an early feature of Alzheimer's disease (AD), but the cellular mechanisms linking amyloid pathology to sleep loss remain unclear.

Methods: Electroencephalography/electromyography (EEG/EMG) recordings, quantitative EEG analysis, and sleep deprivation were performed in APPswe/PSEN1dE9 (APP/PS1) mice at different stages of pathology relative to normal aging. Amyloid burden and microglial density were quantified with whole-brain light-sheet microscopy. CSF1R-mediated microglial depletion explored effects of microglia on sleep loss.

Results: Amyloid plaques caused non–rapid eye movement (NREM) sleep loss that did not worsen with increased plaque burden. Aging reduced REM sleep and eliminated sleep rebound. Amyloid pathology was associated with …

Agricultural Evidence Synthesis At A Critical Juncture: Quality Gaps And Implications For Evidence-Based Agriculture, Chao Cai, Jane Yatcilla, Justyna Czader, Sylvie Brouder, Jeffrey Volenec

Libraries Faculty and Staff Scholarship and Research

Systematic reviews and meta-analyses have become essential tools for synthesizing evidence to guide agricultural policy and practice, yet whether these syntheses are themselves conducted with sufficient rigor has rarely been systematically assessed. This study provides a field-wide assessment of reporting quality in agricultural evidence synthesis, examining whether existing reviews are conducted with sufficient transparency and rigor to support the policy and practice decisions they are meant to inform. We drew a random sample of 244 systematic reviews and meta-analyses from a bibliometric dataset of 1,709 articles published between 1997 and 2023, evaluating reporting quality using a 12-indicator rubric across four …

Labor Savings From Mechanical Rice Transplanting In Bangladesh, India, Nepal, And The Philippines: A Systematic Review And Meta-Analysis, Rodrigo S. David

ASEAN Journal on Science and Technology for Development

Rice production in South and Southeast Asia faces serious challenges, including acute labor shortages and rising wages, which threaten regional food security. Mechanical rice transplanting offers a promising solution; however, evidence on labor savings, especially region-specific data, remains inconsistent. This systematic review and meta-analysis aimed to quantify labor savings from mechanical versus manual transplanting across Bangladesh, India, Nepal, and the Philippines.

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search was conducted across four major scientific databases (2000–2026) using Boolean search terms for mechanical transplanting and labor outcomes. Of 284 initial records, 52 met eligibility …

Climate And Seasonal Influences On Indo-Pacific Sea Level: Insights From 30 Years Of Satellite And Tide Gauge Data, Karlina Triana

ASEAN Journal on Science and Technology for Development

We analyze Indo-Pacific sea-level variability using monthly satellite altimetry (1993–2025) validated against records from 16 tide-gauge stations. Cross-comparisons show strong agreement, especially in the western Pacific, confirming the reliability of altimetry for regional assessments. Seasonal SLA variability is largest in the Bay of Bengal and South China Sea and reflects monsoonal forcing, whereas interannual fluctuations in the eastern Indian and western Pacific oceans are dominated by ENSO and modulated by PDO. Harmonic decomposition isolates annual and semi-annual cycles, and an EOF/PCA framework identifies the leading modes: EOF1 (30.8%) captures basin-scale interannual variability and EOF2 (20.9%) reflects the seasonal cycle. Spectral …

Long Biogeographic Separation Limits Arthropod Associations On Eastern Asian Plants Introduced To Eastern North America, Robert J. Warren

Biology Faculty Datasets

No abstract provided.

Bees Carry More Exposed Pollen Than Flies And On Body Regions Well Placed For Floral Contact, Robert Warren

Biology Faculty Datasets

Pollination studies generally emphasize bees, although flies are abundant flower visitors and may remain active under conditions in which bees do not forage. Pollination success depends not only on how much pollen is carried but also if the pollen is carried on body surfaces likely to contact flower stigmas. We compared exposed pollen load and its body placement on 527 bee (Hymenoptera) and fly (Diptera) specimens collected in a commercial apple orchard. Pollen was quantified by direct microscope counts for 376 specimens and hemocytometer wash counts for an additional 151 specimens. Pollen concentrated within scopae and corbiculae, which is less …

A Simple Statistical Tool To Correct The Daily Temperature Effect On Dielectric Soil Matric Potential Sensor Readings, Sebastián Bravo Peña, Meindert Commelin, Ole O. Wendroth

Plant and Soil Sciences Faculty Publications

High-resolution time series recorded by soil water dielectric sensors are often affected by other processes. Dielectric soil matric potential sensors, such as the TEROS 21, exhibit temperature sensitivity, resulting in deviations of readings from the true value due to soil temperature fluctuations. However, methods for correcting this effect remain limited. The objective of this study was to create a straightforward, scale-based statistical approach to mitigate the influence of daily temperature oscillations on matric potential dielectric readings. The temperature sensitivity correction function (TSCF) identifies, quantifies, and smooths diurnal fluctuations caused by soil temperature dynamics. We provide a detailed description of the …

Characterization Of The Human Thnatomicrobiome By Decomposition Stage Through Bioinformatic And Meta Data Analysis, Ashton C. Laughlin

Biology Theses

Estimating the postmortem interval (PMI) is one of the most crucial factors in forensic death investigations. Recent advances in forensic microbiology have led to increased interest in using the study of the human postmortem microbiome, or “thanatomicrobiome,” to improve PMI estimates. In addition to current PMI estimation techniques, microbial community succession could serve as a valuable tool in estimating PMI. Further research is needed to develop a comprehensive understanding of the human postmortem microbiome. The purpose of this study is to contribute to the expansion of this tool by reviewing the current literature and analyzing previously published data using the …

Adversarial Robustness In Biomedical Time-Series Models, Rohan Tiwari

Bioengineering Theses

This study investigates adversarial vulnerabilities in deep learning models for biomedical time-series classification across two clinically important modalities: electrocardiography (ECG) and electroencephalography (EEG). Using the MIT-BIH Arrhythmia and CHB-MIT seizure datasets, I evaluate time-domain attacks (FGSM, PGD), Fourier-domain constrained attacks, and learned spectral perturbations designed to reveal modality-specific sensitivity patterns. Across both tasks, a consistent trend emerges low-frequency components (0–5 Hz) constitute a dominant axis of adversarial vulnerability, with perturbations in this range producing the steepest degradation in classification performance. In ECG models, protecting the physiologically relevant QRS band (5–20 Hz) significantly improves robustness, whereas EEG models remain highly sensitive …