Life and Environmental Sciences Undergraduate Theses


Recent Submissions

Now showing 1 - 5 of 627
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    Identifying Metabolic Differences in The Synovial Fluid of Males and Females Affected by Osteoarthritis
    (2024) Kiki, Bourekis; Hahn, Alyssa; Beck, Ashley; Sheafor, Brandon; Otto-Hitt, Stefanie
    Osteoarthritis (OA) is the most common joint disease in the body, characterized by limited mobility due to the degradation of cartilage. Age, weight, and genetic profiles have been identified as clear risk factors for OA; women are also more likely to suffer from OA compared to men. While previous research indicates that postmenopausal women have an increased likelihood of developing OA due to decreasing estrogen, few studies have investigated metabolic differences between diseased males and females. This study seeks to understand the differences between global metabolic profiles of males and females with OA. In order to investigate metabolic discrepancies, metabolites were extracted from joint-effusion-related OA synovial fluid. Global metabolomic profiling by liquid chromatography-mass spectrometry (LC-MS) was then employed to identify significant metabolic differences between sexes. The results of this study suggested a distinct metabolic response to OA in males and females, most notably a significant difference between fatty acid and amino acid metabolism. This study provides a greater understanding of metabolism in OA pathogenesis and suggests opportunities for more individualized, therapeutic interventions that target sex differences. In the future, researchers should replicate this experiment with a larger sample size and employ targeted metabolomics to further elucidate the role of fatty acid and amino acid metabolism in OA responses.
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    Time Course of Metabolic Shifts in Cartilage Explants Exposed to Short-Term Simulated Microgravity
    (2023) Houske, Eden; Hahn, Alyssa; Sheafor, Brandon; Beck, Ashley
    Abnormal mechanical joint loading leads to an imbalance in chondrocyte metabolism that results in cartilage degeneration – a hallmark of osteoarthritis (OA). Microgravity exposure in space significantly reduces mechanical loads applied to the joints, leading to increased catabolic activity of chondrocytes and thus increasing the risk of OA. This study assesses how chondrocyte metabolism is altered in response to simulated microgravity (SM) exposure to gain insight into the mechanisms responsible for cartilage degeneration in reduced-loading environments. Healthy post-mortem human cartilage explants were exposed to SM for one or four days using a Rotating Wall Vessel (RWV) bioreactor and compared with the control explants exposed to normal gravitational forces. A subset of the control and SM explants were analyzed for cell viability by staining and measuring relative fluorescence. Metabolites were extracted from explants and surrounding media, and data were generated by liquid chromatography-mass spectrometry. Pathways upregulated in response to SM include the metabolism of pyrimidine, amino acids, and sugars, which may be suggestive of extracellular matrix remodeling. Changes in metabolites secreted from explants into the surrounding media mapped to lysine and vitamin E metabolism. These pathway changes have been previously detected in human synovial fluid from osteoarthritic donors, suggesting that even short-term SM exposure may induce metabolic shifts similar to that of early OA. Notably, this study is the first to map global metabolic changes in cartilage in response to short-term SM exposure to gain insight into the risk of developing OA post-spaceflight.
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    The Insects of Sevenmile Creek: A Pictorial Guide to Their Diversity and Ecology
    (2022) Sater, Shane; Hokit, Grant; Heiser, Patricia; Graham, Loren
    Insects play an incredible variety of essential roles in all ecosystems; insect diversity is intimately linked with the diversity of other organisms, including plants and birds. In this fully illustrated report I present a guide to 277 insect species (212 identified to species plus an additional 65 identified to genus) on the Sevenmile Creek restoration site near Helena, Montana, USA, along with observations of their seasonal occurrence. I summarize information from the literature about the ecology and life history of each insect and relate this information to field observations at Sevenmile Creek. In order to facilitate a thorough understanding of ecological relationships, I also present an annotated checklist of 232 species of vascular plants I have documented on the site and review the insect-feeding habits of the 164 species of birds recorded there. This guide will prove useful not only for biologists but also for all those in the Helena area with an interest in understanding the landscape around them.
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    Spatial-temporal analysis on distribution and abundance of Missouri River fish from 2001-2021 seining data
    (2022) Hagengruber, Joseph; Hokit, Grant; Heiser, Patricia; Cline, Kelly
    Montana Fish Wildlife and Parks and Northwestern Energy have conducted seining fisheries surveys on the Missouri River from 2001 to 2021, to determine the abundance and distribution of fishes that reside between five sampling transects along the river. These locations include Morony Dam, Fort Benton, Coal Banks, Judith Landing, and Fred Robinson Bridge. There haven’t been significant efforts to examine and interpret the large dataset. My project aims to establish a spatial and temporal analysis of relationships between the diversity and abundance of species, and environmental factors such as water temperature, discharge, and Secchi depth readings. The intent of the project is to provide an analysis that demonstrates an association between biological and environmental variables. The project is not a controlled experiment, so the results displayed do not indicate causation. Through this study, I found that species’ relative abundance and diversity fluctuate between years, but not significantly between the five study reaches. The results of the study also demonstrated associations between discharge rates and biological relationships which influenced relative abundance among fish species. I hope to provide ideas for future management of non-game and prairie fish and establish a baseline analysis of the long-term dataset, especially for species that are listed as species of concern.
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    Global Metabolomic Profiles and Viability of Encapsulated Chondrocytes Exposed to Short-Term Simulated Microgravity
    (2022) Bergstrom, Annika; Hahn, Alyssa; Carpenter, Chrissie; Almquist, Travis
    Shifts from physiological loading conditions, such as overloading or reduced loading, can lead to an imbalance that increases catabolic pathways resulting in cartilage degeneration consistent with that of osteoarthritis (OA). The risk of developing OA and the mechanism by which chondrocytes respond to reduced mechanical loading remains unclear. This is of particular concern in space, where reduced mechanical forces during prolonged microgravity (10-6 g) exposure could lead to OA, compromising flight crew mobility and leading to reduced quality of life post-spaceflight. We encapsulated human chondrocytes in an agarose gel of similar stiffness to the pericellular matrix to mimic the cartilage microenvironment and exposed encapsulated chondrocyte constructs to SM using a rotating wall vessel (RWV) bioreactor to better assess the cartilage health risks associated with spaceflight. Global metabolomic profiling detected a total of 1205 metabolite features across all samples, with 497 significant metabolite features by ANOVA (FDR-corrected p-value < 0.05). Unsupervised statistical analyses did not show clear separation between SM and control cohorts, suggesting that short-term (< 4 days) exposure to microgravity does not induce large-scale shifts in chondrocyte metabolism. However, we detected specific metabolic shifts in response to simulated microgravity (SM) exposure by identifying clusters of co-regulated metabolites in a HCA clustergram and by ranking metabolites by OPLS-DA VIP scores. Microgravity-induced metabolic shifts mapped to histidine, amino sugars, fatty acid, butanoate, phosphatidyl phosphate, methionine, and cysteine metabolism, valine, leucine, and isoleucine degradation; glycine, serine, threonine, methionine, cysteine, glutathione, arginine, proline, and glutamate metabolism. The specific metabolic shifts that occurred in response to microgravity exposure were consistent with early osteoarthritic metabolomic profiles in human synovial fluid, which suggests that even short-term exposure to microgravity (or other reduced mechanical loading environments) may lead to the development of OA.