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Clonal Plants' Traits And Responses Following Fire Disturbance In Ponderosa Pine Ecosystems In The Colorado Front Range, Raymond Erskine

Master's Theses

Mountain ecosystems are currently experiencing increasing impacts of disturbances (e.g., wildfire) due to global changes in climate and land use, leading to significant changes in vegetation composition and landscape dynamics. Clonal plants, characterized by their vegetative reproduction strategies, offer a range of ecologically important traits to cope with disturbances. However, clonality is often excluded in studies of post-fire vegetation dynamics in mountain ecosystems, and our knowledge of the ability of clonal plants to respond to differing disturbance regimes is limited. Therefore, I examined the response of understory vegetation following fire disturbance in burned and unburned ponderosa pine stands of the …

Role Of Atp-Binding Cassette (Abc) Transporters As A Protector Of Testis Stem Cell Niche From Chemotherapy Drugs In Drosophila Melanogaster, Swagata Maity

Master's Theses

In chemotherapy treatments most tumor cells are destroyed by drugs, but some tumor cells are drug resistant, and these are known as cancer stem cells (CSCs). Normal adult stem cells are also chemo resistant. Therefore, investigation of normal stem cells can be useful to provide further knowledge of CSCs. One of the primary ways that CSCs achieve drug resistance is by drug efflux through transmembrane pumps called ATP-binding cassette (ABC) transporters. Many studies on ABC transporters have been performed in vitro using cultured cell lines, but very few studies have been performed on normal stem cell populations in vivo. Drosophila …

The Role Of B Cell Activation State And Sex In Aryl Hydrocarbon Receptor Mediated Induction Of Chemokine Receptor 9 And Alpha4beta7 Expression In Vitro, Logan Bauerle

Master's Theses

Defense of mucosal tissues from microbial infection and allergy is reliant on continual production of antibodies. The aryl hydrocarbon receptor (AhR) is known to regulate B cell development and is associated with suppression of systemic humoral immunity. Recent attention has been paid to the role of the AhR in altering expression of cell adhesion molecules (CAMs). B cells express CAMs and chemokine receptors to migrate around the body for localized secretion of antibodies. AhR agonists promote B cell migration to the small intestine through upregulation of chemokine receptor 9 (CCR9) and integrin α₄β₇. Both the AhR …

Clonal Growth And Trait Variation In The Colorado Front Range: The Influence Of Elevation And Ecosystem, Jordan Conley

Master's Theses

Amid global climate change, exploring adaptive strategies among alpine flora, particularly through clonal growth, becomes critical for biodiversity conservation. This study aims to explore the patterns of dominance and distributions among clonal species across environmental gradients in the Colorado Front Range, employing a trait-based comparative analysis to understand the adaptive strategies of alpine flora and their implications for conservation amid rapid climate change. We focused on two species, studying traits like lateral spread, bud count, and bulbil numbers. Advanced statistical methods such as Permutational Multivariate Analysis of Variance (PerMANOVA) and Multi-Response Permutation Procedures (MRPP) were used to evaluate community compositions …

Potential Bioprospecting Within Vemons Of Rear-Fanged Snakes, Tanner Milbank Harvey

Master's Theses

Philodryas baroni (Baron’s Green Racer) and Trimorphodon lambda (Sonoran Lyre Snake) each belong to extensively studied genera of rear-fanged venomous snakes. Investigating the bioactivities and structural composition through methods not typically included in venomic workflows, which use homologous sequences and describe venoms by their constituent peptides, provides valuable insights into both the degree and extent to which venom diversity and complexity can be overlooked by many venomic workflows. This study explores the venom compositions of P. baroni and T. lambda and compares them to published toxins observed in opisthoglyphous snakes, specifically taxon-selective three-finger toxins and metalloprotease-dominated venoms.

This study underscores …

Investigating The Therapeutic Potential Of Cannabigerol (Cbg) In Female Nonalcoholic Steatohepatitis (Nash) Mouse Model, Raznin A. Joly

Master's Theses

Nonalcoholic Steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD) characterized by inflammation, fibrosis, steatosis, and oxidative stress, in addition to excessive fat accumulation in the liver. Cannabigerol (CBG), a precursor molecule of Cannabidiol (CBD), has demonstrated anti-inflammatory and anti-oxidative effects in various studies. Our previous data showed that a low dosage of CBG reduced inflammation and fibrosis in male NASH mice. However, the impact of CBG on female mice remains unknown. Recent studies have identified changes in immune cell populations in NAFLD patients. The goal of this project was to test the impact of CBG treatment …

Auto-Resistance Toward Snake Venom Metalloproteases In United States Pitvipers, Kaleb Hill

Master's Theses

Analysis of natural snake venom inhibitors in snake blood began in the 18th century with the pioneering work of Fontana on European vipers (Hawgood, 1995). Serum resistance to conspecific and heterospecific venoms has subsequently been identified in many snakes, but results vary. Many of these snakes demonstrating resistance are either allopatric or distantly related, making the ecological explanation of this resistance unclear. Auto-resistance to one’s own venom for protection against self-envenomation has been suggested to be provided by endogenous serum-based protective molecules that bind to the venom components. Toxin resistance could develop in venomous organisms resulting from the physiological production …

Analyzing Grassland Bird Song And Success: The Impact Of Landscape Characteristics On Western Meadowlarks (Sturnella Neglecta), Leah Crenshaw

Master's Theses

Grassland birds across both North America and globally are in rapid decline, and these population losses are primarily due to agricultural practices driving land-conversion and habitat degradation. While the effects of landscape characteristics like land cover, fragmentation, anthropogenic features, and land use on bird abundance and diversity are well-studied, the mechanisms behind those effects are poorly understood for many species. In our studies, we considered how individual condition and behavior may be underpinning some population losses in Western Meadowlarks (Sturnella neglecta). First, we investigated what natural, anthropogenic, and climatic landscape characteristics best predicted Western Meadowlark song structure. We used 421 …

Student Reasonings And Cognitive Biases In Climate Change Predictions, Kaela Clabaugh Howell

Master's Theses

Undergraduate biology educators strive to understand how to best teach students the concepts of climate change. The root of this understanding is the establishment of what students know about climate change. This research aims to describe undergraduate biology students’ conceptions of climate change and their argument practices and associated cognitive biases in how they think about the topic. We used a basic qualitative research design to explore interview data from 26 American biology undergraduate students who predicted how climate change would affect a forested ecosystem after an average of one degree increase in Fahrenheit over 25 years. Overall, the majority …

Mechanisms Behind The Luteoprotective Effects Of Fish Meal Supplementation In Bovine: Cytokine Sensitivity And Luteal Blood Flow, Anika Shelrud

Master's Theses

Early pregnancy loss continues to be problematic in the cattle industry. A large proportion of the pregnancy loss occurs during the maternal recognition of pregnancy (MRP) phase of gestation. During the MRP, a developing conceptus must secrete sufficient interferon tau to inhibit release of the uterine- derived and luteolytic mediator, prostaglandin F2 alpha (PGF2��). If successful, the progesterone- secreting corpus luteum (CL) will be maintained, which is necessary for establishment and maintenance of pregnancy. Pregnancy loss at the point of MRP may be due to a slow developing conceptus that does not effectively block PGF2��. Therefore, reducing the influence of …

Conservation Genomics: Utilizing Genetic And Transcriptomic Sequencing For Effective Conservation Management Of Astragalus Osterhoutii, Christine Mowad

Master's Theses

Astragalus osterhoutii M.E. Jones (Fabaceae) is a federally listed, rare, endemic species restricted to seleniferous soils in Grand County, CO (Anderson, 1989). This research utilized both RADseq and RNAseq to generate neutral and adaptive genomic datasets. Neutral data analysis aimed to determine i) the genetic diversity of A. osterhoutii and each of its populations level, ii) how genetic structure is partitioned across the species range, and iii) the closest relative to A. osterhoutii. Analysis of adaptive, RNAseq data aimed to identify i) differentially expressed genes, ii) if patterns of expression are similar to neutral data, and iii) differences in Se …

Immunological Effects Of Berberine And Physical Activity In A Murine Breast Cancer Model, Janae Mudge

Master's Theses

Berberine (BBR) is a plant-derived alkaloid popularly used in a complementary context to treat splenomegaly and chronic disease states such as rheumatoid arthritis, diabetes, and cancer. Recent research has examined BBR as a regulator of lipid and glucose metabolism in association with the AMPK pathway; but little is known concerning its immunological impacts. It is also known that exercise is a potent AMPK activator exhibiting immunological benefits, but nothing is known about the combination of these complementary approaches for treating breast cancer. The purpose of this study is to determine if oral consumption of BBR when paired with physical activity …

Understanding Species Boundaries Between Penstemon Acaulis And Penstemon Yampaensis: Implications For Conservation And Management, Juliet Simpson

Master's Theses

Effective conservation management relies upon accurate taxonomic information and an understanding of the genetic health and population structure for each species. Penstemon acaulis and P. yampaensis are endemic species to Colorado, Utah, and Wyoming, and have been considered for listing under the Endangered Species Act (ESA). There is little biological data published about either and there remains taxonomic uncertainty surrounding the two. Phylogenetic analyses showed P. acaulis and P. yampaensis to be distinct, monophyletic lineages and morphological data further supported taxonomic recognition of both species, however these results did not support the previous species boundaries. Eastern populations of P. acaulis …

Topo-Climatic Effects Of Fuel Loading In Ponderosa Pine (Pinus Ponderosa) Forests Of The Colorado Rocky Mountains, Justin Yow

Master's Theses

A key restoration focus is the mitigation and prevention of intense wildfires. This is done using a regularly prescribed fire regime and forest thinning practices to reduce surface fuel loads. Prediction of fuel loads at the forest floor is pivotal when assessing the hazard level a forest fire may present. Scientists already have much data correlating fuel characteristics to fire effects and behavior. However, links between montane climate variability and relative effects on fuel load characteristics have not been extensively explored in the Front Range and southwestern Colorado. This study system was uniquely located along a North-South monsoonal gradient and …

Genetic Analysis Of The Rare, Colorado Endemic Rocky Mountain Monkeyflower, Mimulus Gemmiparus, Branson Wetzstein

Master's Theses

Mimulus gemmiparus is a rare, Colorado endemic plant which possesses a limited range, strict habitat requirement, and unique life history. Most peculiarly, Mimulus gemmiparus seemingly relies entirely on clonal spread using vegetative propagules known as brood bulbils to persist year to year. This inconspicuous annual is only found within a narrow range of Colorado’s Rocky Mountains, possessing a total known range of about 2500 km2. There are currently 11 known natural populations of Mimulus gemmiparus spread across three general regions: North (Larimer, Boulder, and Grand Counties), Central (Clear Creek and Jefferson Counties), and South (Jefferson County). Lack of sexual reproduction, …

The Role Of Aryl Hydrocarbon Receptor Activation On Immunoglobulin A-Secreting B Cell Gut Homing, Linda Ortiz

Master's Theses

Within the United States, foodborne diseases are estimated to result in more than 100,000 hospitalizations each year with 3,000 fatalities. Acute gastroenteritis impacts more than 1.5 million children each year in the United States. Worldwide, childhood morbidity and mortality are largely attributed to infectious diarrheal diseases. To combat infection at mucosal surfaces, immunoglobulin (Ig) A is produced by antibody-secreting B cells to inhibit and neutralize pathogens and their toxins. B cells are influenced by various extrinsic signals through activation of the aryl hydrocarbon receptor (AhR). The AhR is a ligand-activated transcription factor that links diet and environmental factors to intestinal …

Long Term Recovery From Cattle Grazing Disturbance And Climate Impacts At Capitol Reef National Park, Utah, Erin Tessens

Master's Theses

Cattle grazing has influenced the environment in the western United States since European settlement in the 1800’s. Continuous and heavy grazing on arid and semi-arid rangelands has resulted in decreased biodiversity, changes in vegetation structure, and vulnerability to exotic plant invasion. Heavy grazing has also been linked to decreased cryptobiotic soil due to trampling and susceptibility to erosion. With a lack of effective means of successful habitat restoration, there is a rising concern among land managers to maintain these intricate systems, notably under the threat of climate change. Consequently, there is a critical need to understand these system’s response to …

Resistance To Rattlesnake Venoms In An Eastern Colorado Rodent Community, Neil Balchan

Master's Theses

The grasslands of eastern Colorado are inhabited by two species of rattlesnakes, the Prairie Rattlesnake (Crotalus viridis) and the Desert Massasauga Rattlesnake (Sistrurus tergeminus edwardsii). An array of rodent species, both native and introduced, also occupy these grasslands, and serve as a varied prey base for the previously listed rattlesnakes. Predator-prey interactions in this system gain an additional level of complexity due to the presence of venoms, a chemical arsenal possessed by both rattlesnakes to incapacitate their prey. Rodents in other systems have demonstrated resistance to snake venoms, and there is potential for a similar dynamic to be present in …

Investigating The Role Of Atp-Binding Cassette Transporters In Drosophila Melanogaster Testis Stem Cells, Israel J. Wipf

Master's Theses

Multidrug resistance is among the most pressing obstacles in cancer treatment today. Resistance is thought to arise from the ability of cancer stem cells to efflux therapeutic molecules using a collection of membrane proteins called ATP-binding cassette (ABC) transporters. There is strong interest in targeting ABC transporters to preserve and improve drug efficacy and reduce cancer recurrence. Many studies have been performed in vitro using cultured cell lines, but currently there is a lack of simple models in which to study ABC transporters in vivo. As a solution, I propose to use the fruit fly Drosophila melanogaster for the study …

Indirect Impact Of Soil Microbial Communities On Plant-Aphid Interactions, Zachary Tiemann

Master's Theses

The community dynamics of soil micro-environments are influenced by root, fungal, and bacterial exudates that can preferentially select for functional classes of microbes. Arbuscular mycorrhizal fungi (AM) fungi and plant growth promoting rhizobacteria (PGPR) are members of this community form symbiotic relationships with plants and play an important role in triggering induced systemic resistance (ISR), resulting in defensive “priming.’ Consequently, ‘primed’ plants can activate stronger and faster defense responses to future attacks by pathogens and insects. The biological system in this study involved four genotypes of barrel medic plants (Medicago truncatula), pea aphids (Acyrthosiphon pisum), and microbial communities present in …

Cannabigerol Attenuate Methionine/Choline Deficient Diet- Induced Non-Alcoholic Steatohepatitis Symptoms In C57bl/6 Male Mice Via Modulating The Expression Of Cannabinoid Receptors, Nouf Aljobaily

Master's Theses

Non-Alcoholic Steatohepatitis (NASH) is the advanced and more aggressive form of Non-Alcoholic Fatty Liver Disease (NAFLD). NASH is associated with severe hepatic fibrosis and inflammation. Methionine/choline deficient (MCD) high fat diet is known to induce NASH in a short period of time without showing signs of metabolic syndrome. Cannabigerol (CBG) is a plant-derived, non-psychotropic cannabinoid that has a potential anti-inflammatory effect. Other hemp extracts reduce the progression of NAFLD to NASH, whereas the impact of CBG on NASH is still unknown. Therefore, these studies aim to 1. Evaluate the therapeutic potential of CBG on reducing hepatic steatosis and fibrosis. 2. …

Assessing The Effects Of Habitat On Bird Song Propagation, Braelei Hardt

Master's Theses

The Acoustic Adaptation Hypothesis (AAH) posits that animal acoustic signals meant for long-range communication should be adapted to transmit well within the habitats in which they evolved. However, comparative studies investigating predictions of the AAH relating to signal form indicate that support for the hypothesis is not universal. Several studies have employed experimental playback approaches to testing signal transmission which can provide complimentary analyses to comparative studies of signal form in the field. Here, I first summarize these experimental playback tests of the AAH in birds, mammals, insects, and anurans, describing the methodologies used in these tests, and assessing the …

The Role Of Gibberellic Acid In Aphid-Plant-Arbuscular Mycorrhizal Fungus Interactions, Drew Olson

Master's Theses

Arbuscular mycorrhizal (AM) fungi form beneficial associations with the roots of most terrestrial plants, which is mostly characterized by increased plant nutrient acquisition (phosphate and nitrogen) by the fungi in exchange for carbon and lipids from the plants. These associations can also enhance plant coping mechanisms to abiotic and biotic stresses. However, insect herbivores, such as aphids, can benefit from AM fungi-plant symbioses by altering plant defenses that are driven mainly by the phytohormones jasmonic acid (JA) and salicylic acid (SA). Nevertheless, other phytohormones can modulate plant defenses by altering the balance of the JA and SA signaling pathways, such …

Effects Of Omega-3 Fatty Acids And Hypoxia On Progesterone Biosynthesis And Mitochondrial Morphology In The Corpus Luteum, Brian Krum

Master's Theses

The corpus luteum is a transient steroidogenic endocrine gland that forms from the remnants of the ovulatory follicle. This gland is responsible for the synthesis and secretion of the hormone progesterone, which is critical for the establishment and maintenance of pregnancy. In a non-pregnant cow, PGF2a is released from the uterus to regress the corpus luteum. However, in the case of pregnancy, the embryo must mitigate PGF2a synthesis to prevent corpus luteum regression. If the embryonic signal is either too late or too weak, uterine PGF2a secretion may result in corpus luteum regression and termination of pregnancy. Omega-3 fatty acids …

Zebrafish Eye Development: Rac And The Creepy Crawlers Of The Eye, Zvi Murry

Master's Theses

During vertebrate eye development the optic vesicles protrude from either side of the brain and form the optic cups. As an optic cup starts to surround the lens a groove on the ventral side of the eye forms, known as the choroid fissure (CF). Normally, the CF will close around the optic nerve and hyaloid vasculature. If this process does not occur properly it results in a keyhole opening in the eye known as coloboma. This results in blindness and affects nearly 1 in 4-5,000 births. Zebrafish were utilized as a model for eye development to study CF closure (CFC) …

Does Population Density Affect The Singing Behavior Of Female Canyon Wrens (Catherpes Mexicanus)?, Lorraine Dargis

Master's Theses

Bird song has historically been considered from the perspective of temperate males despite females in many bird species being prolific singers. In this study, I investigated one species with female song, the canyon wren (Catherpes mexicanus). Canyon wrens do not duet like many other species with female song or other wrens. Instead, males and females sing sex-specific songs. The resource defense function of male canyon wren song is well-described, and males sing often during the breeding season. Females have only been observed to sing sporadically during the breeding season but sing reliably and often when exposed to playback of other …

Type 3 T Helper Cell And Myeloid Derived Suppressor Cell Population Dynamics In A Mammary Carcinoma Model, Viva Rase

Master's Theses

Immunotherapies that augment Type I immunity show robust responses in diffuse blood cancers yet remain relatively ineffective in breast and other solid tumor malignancies. Breast tumor resistance to immunotherapies is associated with polarization towards pro-tumor Type 2 immunity, as well as the expansion of a myeloid derived suppressor cell (MDSC) population that inhibits Type 1 T helper (Th) and CD8+ cytotoxic T cells. Does polarization toward Type 3 immunity play a role in mammary tumor formation? This question had not been investigated prior to these studies despite established relationships between MDSCs and Type 3 Th cells in other inflammatory pathologies. …

The Examination Of The Function Of The Cofactor Schnurri In The Cyst Stem Cells Of The Drosophila Melanogaster Testis Niche, Jade Koretko

Master's Theses

The study of adult stem cells in modern day research provides pertinent information about the development of organisms, how they grow, and how tissue is maintained. Drosophila melanogaster provide an ideal model for in vivo stem cell research, with one of the best-characterized niches in the testis. The testis stem cell niche consists of a hub that provides signals to the local stem cells, germline stem cells (GSCs), and cyst stem cells (CySCs). The CySCs produce cyst cell lineage that will provide support for the GSC daughter cells, which differentiate into sperm. Previously, Matunis, et al. determined the function of …

Characterizing The Role Of Tumor Suppressors Merlin And Expanded In The Stem Cell Niche Of Drosophila Testes, Bryan Johnson

Master's Theses

The ability of adult organisms to maintain tissue homeostasis and repair tissue in response to injury is mediated by small groups of partially differentiated cells called adult stem cells that support the tissue they reside in. Adult stem cell maintenance is highly regulated by signals from the surrounding microenvironment referred to as the stem cell niche. A better understanding of this process will have important implications for the fields of both regenerative medicine and cancer biology. Due to the complexity of most niche environments in mammals, we turned to the less complex model organism Drosophila and the well-characterized niche in …

A Description Of Lichen Community Structure And The Impacts Of Spruce Beetle Disturbance In Northwestern Colorado, Anna Freundlich

Master's Theses

Spruce beetle disturbance has affected millions of acres of forest throughout North America and Europe, but thus far little research has investigated how this disturbance influences lichen communities. To address this problem, we studied lichen communities and habitat characteristics within 44 plots across a chronosequence of spruce beetle damage spanning 1996–2017 in northwestern Colorado. We found 82 species of lichens, few habitat differences among spruce beetle disturbance classes, and only the most recently affected plots (2012–2017) had significantly different lichen community structure relative to remaining areas. Two primary gradients explained the majority of variation of lichen community structure within our …