Biology Commons^™

Bugs In The Flux: Links Between Arthropod Diversity And Spatial Variation Of Soil Respiration In A Temperate Forest, Erin-Darby H. Mcclain

Theses and Dissertations

Soil respiration (Rs) is the largest terrestrial flux of carbon (C) to the atmosphere, with heterotrophic contributions to Rs varying spatially and temporally. While microbes are the primary and most thoroughly studied source of soil heterotrophic respiration (Rh), contributions from higher trophic organisms, including arthropods, are rarely quantified and poorly understood. Arthropod abundance and diversity correspond with variation in soil microclimate, which is influenced by site factors including canopy structure, site productivity, and disturbance. However, the extent to which these site factors influence arthropod abundance and diversity, and consequently, spatial variation in Rs is not known. The objective of our …

Investigating Mitochondrial Stress Response Mechanisms In Aging, Aileigh E. Daniel

Theses and Dissertations

Mitochondrial dysfunction is widely recognized as a key contributor to aging and age-related diseases. The concept of mitohormesis suggests that low levels of ROS can activate stress-responsive transcription factors, promoting adaptive mechanisms that enhance longevity. We hypothesized that changes in protein abundance under conditions of mild mitochondrial stress reflect an adaptive response, and that commonly altered proteins across diverse genetic backgrounds of mitochondrial stress can help identify key regulators of stress resilience and aging. Our study identified conserved mitochondrial stress response pathways and highlighted candidate regulators for further investigation. These regulators appear to impair mitochondrial energy production by downregulating ATP …

Climate Change-Induced Shifts In Mediterranean Fungal Fruiting Phenology And Productivity, Rachel Demay

Theses and Dissertations

We used a 29-year dataset of mushroom fruiting from the Pinar Grande forest in northern Spain to investigate the effects of climate change on the phenology, productivity, and diversity of mycorrhizal and saprotrophic mushrooms. We investigated the long-term trends in fruiting season length, yield (by count, total weight, and average weight), and genus richness. Additionally, we identified associations between monthly temperature and monthly precipitation with these fungal responses across functional groups: mycorrhizal, saprotrophic, litter-decaying saprotrophic, and wood-decaying saprotrophic mushrooms, and the economically-important edible genera Boletus and Lactarius. We found that autumnal season length in the Pinar Grande has shortened over …

Molecular Mechanisms Of Kynurenine-Mediated Lifespan Regulation In Yeast, Ryan E. Counterman Jobb

Theses and Dissertations

The kynurenine pathway is a highly conserved pathway that acts as the primary pathway for tryptophan catabolism and has been found to be involved in lifespan regulation across many diverse organisms. Caloric restriction (CR) is the only known dietary intervention to date that both increases the mean lifespan and the health span of multiple organisms, although the molecular mechanisms of these effects are not fully understood. There are known and sometimes contradictory relationships between the kynurenine pathway activity and the life- extending effect of CR but the crosstalk between the two is not well characterized. Understanding these relationships could lead …

Larval Environments Affect The Implementation Of The Sterile Insect Technique On Aedes Mosquitoes, Katherine G. Evans

Theses and Dissertations

Sterile Insect Technique (SIT) is an effective method for controlling pests and has been increasing in popularity to control Aedes mosquitoes. SIT involves inundating an area with sterilized male mosquitoes to reduce egg hatch and ultimately the number of wild adults. Previous research indicates that enacting mortality early in the larval life of Aedes mosquitoes can result in counter-productive effects, due to reduced competition among developing larvae. I hypothesize that the effectiveness of SIT at reducing adult populations is modified by densitydependent mortality and density-dependent growth among larvae. I performed two field-to-lab studies and developed an individual-based model to test …

A Novel Silver-Ruthenium-Based Antimicrobial Kills Gram-Negative Bacteria Through Oxidative Stress-Induced Macromolecular Damage, Patrick O. Tawiah

Theses and Dissertations

The rise in drug-resistant bacteria, together with the decline in antibiotic development, requires new strategies for infectious disease control. Gram-negative pathogens are particularly challenging to combat due to their outer membrane. This study highlights the effectiveness of the silver-containing antimicrobial AGXX® against the Gram-negative bacterium Escherichia coli. AGXX® is a promising silver coating that presumably kills bacteria through the generation of reactive oxygen species (ROS). However, neither AGXX®’s mode of action is fully understood, nor have its effects on Gram-negative bacteria or bacterial response and defense mechanisms towards AGXX® been studied in detail. Here, I report that the bactericidal …

Using Genomics And Transcriptomics As A Tool To Understand Unique Phenotypes Of Hemipteran Insects That Are Relevant To Agriculture And Public Health, Hunter Kelly Walt

Theses and Dissertations

In the past couple of decades, advances in genomic sequencing technology have caused an unprecedented increase in biological data. Because of the quantity and size of these datasets, the need for biologists with computational expertise also increased, and using these large genomic datasets has revolutionized the way we can answer biological questions. In this dissertation, I apply genomic and transcriptomic data to answer questions about insects of the order Hemiptera that are relevant to agriculture and public health. My dissertation mainly focuses on stink bugs (Hemiptera: Pentatomidae), many of which are agricultural pests, and bed bugs (Hemiptera: Cimicidae), which are …

Development Of Novel Nanocarriers With Multi Modal Action Against Lung Cancer, Gayathri K

Theses and Dissertations

Lung cancer ranks among the top causes of cancer-related deaths worldwide. The deteriorating environment and unhealthy lifestyle in the modern era has further contributed to the exponential increase in lung cancer incidence across the globe. Lung cancers fall under two major types based on the location of the tumour in the lung namely, small-cell lung cancer (SCLC) which is more aggressive, and non-small-cell lung cancer (NSCLC) which is more prevalent. Late diagnosis has been a major cause for poor prognosis as the cancer is detected only in an advanced stage.

Conventional therapies like chemotherapy, surgery and radiotherapy against lung cancer …

Survey And Comparative Analysis Of Pollinator Diversity, Abundance, And Foraging Activity Of Diptera And Hymenoptera In Selected Habitats Of South Texas, Melissa Villarreal

Theses and Dissertations

With the declining bee population, non-bee pollinators can serve as an alternative source for pollination. Diptera is a potential source of untapped pollinator resources based on their abundance and visitation rate, but they are understudied in the field of pollination ecology. This study aimed to characterize the pollinator community in selected areas of South Texas. It focused on the Diptera and Hymenoptera families to compare their diversity, relative abundance, foraging behaviors, environmental influences, and vegetation associations. Active sampling and line transect were used in the survey to sample the Hymenoptera and Diptera communities to their family taxonomic rank. Statistical analyses …

How Many Tiny Snails? Circumscription Of Three Species Of Pyrgulopsis (Mollusca: Gastropoda: Hydrobiidae)In Nevada Mountain Springs, Trenton Meadows

Theses and Dissertations

The springsnail genus Pyrgulopsis is one of the most diverse groups of freshwater gastropods in North America (Hershler, 2014), with many species displaying high levels of endemism (Hurt, 2003). This study attempts to circumscribe three putative species of springsnails: Pyrgulopsis serrata, Pyrgulopsis marcida, and a newly identified clade, referred to as Lineage C, from the Ruby Lake National Wildlife Refuge, Nevada, USA and nearby springs. Using an integrative taxonomic approach, we combined morphological, anatomical, and molecular data to examine species boundaries and evolutionary relationships.

Many lines of evidence were considered to determine species boundaries. Phylogenetic analysis of the mitochondrial …

Effects Of Metoprolol And Propranolol Beta-Blockers Mixture On Morphological And Physiological Responses In The American Oyster, Andrew Salinas

Theses and Dissertations

Beta-blockers are extensively used to treat human cardiovascular conditions yet pose significant risks to non-target aquatic organisms. This study aimed to investigate the effects of short-term exposure (one week) to a beta-blocker’s mixture (low-dose: 50 ng/L propranolol and 250 ng/L metoprolol, and high-dose: 250 ng/L propranolol and 650 ng/L metoprolol) in the American oysters. Histopathological assessments revealed structural damage to gills, connective tissues, and digestive glands in both low- and high-dose treatment groups. Additionally, glucose concentration and pH of the extrapallial fluid significantly declined in the high-dose treatment group. Hemocyte density within connective tissues increased proportionally with dosage. The beta-blocker …

Assessing The Influence Of Native And Invasive Grasses On The Behavior Of Aedes Aegypti In South Texas, Emily Medelez

Theses and Dissertations

Invasive grasses in South Texas can have widespread negative effects, displacing native species, reducing biodiversity, and posing risks to public health. These grasses may flourish in moist, shaded environments, which not only support their growth but also creates habitats favorable for mosquito activity. This can increase the population and alter the behavior of mosquitoes, potentially raising the risk of disease transmission. In this thesis, I look at the behavior of mosquito species Aedes aegypti, primary vector of the yellow fever virus. I analyzed the influence of oviposition, flight and resting behaviors. I tested the relative attraction of Aedes mosquitoes …

Plankton Dynamics In A Temperate Estuary:Size Structure And Trophic Implications, Nayan Mallick

Theses and Dissertations

Estuarine ecosystems provide goods and services to around 45% of the entire human population. In recent times, these ecosystems have been severely affected by multiple stressors such as pollution, eutrophication, harmful algal blooms, sea level rise, and, most importantly, climate change. Increasing temperature associated with climate change can have pervasive impacts throughout the ecosystem’s functions and processes. Plankton, a conspicuous member of estuarine food web, are among the first to respond to the changes in temperature due to their high sensitivity to changing environmental conditions.

In this dissertation, I investigated the plankton dynamics in an estuarine ecosystem through a combination …

Impacts Of Ing4-Deficiency On Hematopoietic Stem And Progenitor Cells & Characterizing The Concerns Of Novice Stem Graduate Teaching Assistant, Georgina Alice Anderson

Theses and Dissertations

The hematopoietic compartment is tasked with the establishment and maintenance of the entire blood program in steady-state and in response to stress. Key to this process are hematopoietic stem cells (HSCs), which possess the unique ability to self-renew and differentiate to replenish blood cells throughout an organism’s lifetime. Recent work has illustrated the vast mechanisms involved in regulating stress-induced hematopoiesis, including cytokine-mediated lineage bias, gene signature changes in aged HSCs associated with chronic inflammation, the impact of clonal hematopoiesis and stress tolerance. Inhibitor of Growth 4 (Ing4) has been identified as a critical regulator of HSC homeostasis. We show that …

Illuminating The Twilight Zone: In-Situ Imaging Facilitates Discovery Of Mesopelagic Plankton Dynamics And Community Structure, Alexander Barth

Theses and Dissertations

Ocean ecosystems provide both food and regulation of climate. Much of ocean ecosystem functioning occurs through processes in the pelagic, where plankton are the dominant organisms. While plankton have been researched for several centuries, recent advances in technology are greatly improving the ability to better understand plankton and how their communities are structured. Specifically, in-situ imaging allows oceanographers and plankton ecologists to better sample fragile taxa and record organisms’ true traits at high frequencies. These tools can facilitate investigation into new topics in plankton ecology and better understand critically understudied habitats, like the mesopelagic of open-ocean systems. However, in-situ imaging …

Effects Of Mmp14 Overexpression On Cardiac And Ovarian Connective Tissue And Myocyte Size In Pregnant And Post-Partum Mice, Emily Catherine Walliser

Theses and Dissertations

The main protein component of extracellular matrix is collagen, which fills spaces and supports cells. In the heart, collagen provides the scaffolding for cardiomyocytes and aids in contractile forces. In the ovary, collagen gives follicles their structural support. MMP14 or membrane type 1 matrix metalloproteinase is a membrane bound proteinase that cleaves extracellular matrix proteins, including collagen I and III. Recent studies have shown that overexpression of MMP14 influences collagen content in the heart, and elevated MMP14 has also been linked to ovarian cancer. In the current study, we investigate the effects of overexpression of a human MMP14 (hMMP14) transgene …

Understanding The Role Of Host Derived Interleukin 1 Alpha In Breast Cancer Progression, Manikanda Raja Keerthi Raja

Theses and Dissertations

In breast cancer research, Interleukin-1 alpha (IL1α) remains a lesser-explored frontier, while its counterpart, Interleukin-1 beta, has garnered extensive scrutiny and understanding. To address this knowledge gap, our investigation leveraged the MMTVdriven HER2+ orthotopic model in Wildtype (WT) and IL1α-/- mice. Our approach demonstrated tumor regression in IL1α-/- mice at the 2-week timepoint, while WT tumors grew exponentially. At 2 weeks, IL1α-/- mice exhibited an immune "hot" microenvironment with increased CD45+ immune cells, particularly CD11b+ myeloid, and CD8+ T cells. CD8+ cells in IL1α-/- mice showed enhanced anti-tumor cytokine production and proliferative capability, with …

Estuarine Microbial Community Composition And Efficiency Changes In Response To Vibrio Parahaemolyticus Exposure, Sarah Mulligan

Theses and Dissertations

Vibrio parahaemolyticus is a pathogenic bacterium whose full impact on natural estuarine phytoplankton communities has not been fully resolved. The primary goal of this research was to test how the addition of V. parahaemolyticus to a natural estuarine microbial community would impact the other microbes present. We hypothesized V. parahaemolyticus exposure would reduce phytoplankton biomass and alter the composition of phytoplankton and bacterial communities. Experimental bioassays (60h) were used to assess the effects of the presence of V. parahaemolyticus . Samples for measurements of chemotaxonomic photopigment concentrations, 16S sequencing-based community composition, photosynthetic efficiency, cell density, and V. parahaemolyticus abundance were …

Histories Of Stress: A Life Course Approach To Population Health In Late Medieval And Early Modern Berlin, Emily Brennan

Theses and Dissertations

Given our current climate crisis and urban population increases, researchers are increasingly interested in the health outcomes at the intersection of climate change and urbanization. Since climate change and urbanization affects human health in a variety of ways, more work is needed in diverse cultural contexts to understand temporal and geographic variations of such phenomena more fully. Using skeletal individuals from 13^th – 18^th century Berlin (n = 387), this project analyses demographic and health trends from the founding of the city in the late medieval period (c. 1200 – 1500) to the early modern period, when the …

The Effects Of High Fat Diet On Lipid Deposition In Skeletal Muscle, Alexander Huss

Theses and Dissertations

By the year 2030, almost 50% of adults in the United States are expected to be obese. Obesity has been shown to increase the risk of several chronic metabolic diseases, several cancers, and is associated with impaired skeletal muscle function and metabolism. Despite this, little it is known about the role of altered muscle lipid homeostasis, lipid droplet dynamics, and lipid droplet-mitochondrial interactions in contributing to muscle dysfunction in obesity. Therefore, we sought to investigate the impact of high-fat diet induced obesity on overall skeletal muscle lipid deposition, intramyocellular lipid droplet content and morphology, and lipid droplet-mitochondrial contact. Male C57/BL6 …

Corneal Epithelial Tissue Engineering Approaches To Treat Limbal Stem Cell Deficiency, Sasirekha K

Theses and Dissertations

A clear healthy cornea is essential for visual acuity. As a self-renewing and regenerating tissue, the corneal epithelium has a stem cell pool, the limbus that acts as its proliferative reservoir. When limbal epithelial stem cells are destroyed or become dysfunctional, a pathological state known as limbal stem cell deficiency (LSCD) manifests. Damaged corneas have been successfully reconstructed by transplanting the cultured limbal epithelial stem cells. Limbal stem cell transplantation (LSCT) is one of the applicable and most challenging procedures in clinical ophthalmology for the reconstruction of the stratified ocular surface epithelium in patients with LSCD. Given the above challenge, …

Understanding The Mechanisms Of Bio-Effects Of Carbon-Based Nanomaterials In Planta Using “Omics” Approach, Sajedeh Rezaei Cherati

Theses and Dissertations

Carbon-based nanomaterials (CBNs) are recognized as versatile and promising nanomaterials for various applications across multiple fields, including medicine, genetic engineering, plant biology, and agriculture. Notably, carbon nanotubes have been identified as effective in regulating plant growth, reducing plant diseases, and facilitating the targeted delivery of molecules such as DNA and proteins into plant cells and tissues. Despite these advancements, the comprehensive understanding of CBNs' biological impacts, particularly their role in enhancing plant growth and stress tolerance, remains incomplete. Moreover, the use of CBNs in agriculture raises concerns regarding the safety of consuming contaminated plant products and the implications of CBNs …

The Effects Of People, Time Of Day, And Season On Affiliative And Stereotypic Behaviors In Captive Rhinoptera Bonasus And Other Rays Across Two Human-Interactive Enclosures, Wren C. A. Newman

Theses and Dissertations

Cownose rays (Rhinoptera bonasus) are among the most common species found in aquaria, yet the impact of touch enclosures on their welfare remains largely unknown. While research on animal-visitor interactions has produced mixed results for other species, the lack of studies focusing on fish welfare poses a risk of overlooking potential welfare concerns. Therefore, we aimed to establish a baseline for cownose rays regarding stereotypic behaviors, sociality, and activity in captivity, and to examine the influence of human interaction on these behaviors. We collected over 700 hours of footage from two enclosures at Adventure Aquarium in Camden, NJ …

Sex Differences In The Diets Of Forest-Dwelling Baboons (Papio Anubis), Kara Hartunian

Theses and Dissertations

The ability to eat and switch between many food sources is an adaptative feeding strategy utilized for meeting nutritional needs across different environments, seasons, and physiological conditions. Baboons (genus Papio) excel at both dietary flexibility and foraging selectively, and consequently have one of the most widespread geographic distributions in the Order. To further expand to our understanding of baboon feeding ecology, I analyzed foraging activity and the nutritional characteristics of the diets of the relatively understudied rainforest baboons (Papio anubis) living in Kibale National Park, Uganda. I also investigated if there are differences in food type choice …

An Analysis Of Fish Assemblages And Flow Regimes Upstream And Downstream Of Falcon Reservoir, Christopher J. Austin

Theses and Dissertations

The lower Rio Grande is regulated by Falcon and Amistad dams. Native fish species rely on the natural flow regime for habitat and spawning. I analyzed streamflow discharge and fish assemblages above and below Falcon Reservoir to assess potential impacts of dam impoundment. Fish collections were conducted by seine, and river discharge data was provided by the International Boundaries and Water Commission. I found significant differences in fish assemblages above vs below Falcon Reservoir, and the flow regime was significantly more altered downstream of Falcon Reservoir. I also identified two Species of Greatest Concern for Texas above Falcon Reservoir (Notropis …

Accessory Eyes And Dynamic Color Change In Palaemon Vulgaris, Nicholas Raymond Steichmann

Theses and Dissertations

Eyes are physiologically costly organs to produce and maintain, making the development of secondary eyes intriguing. Caridean shrimp possess reflecting superposition primary eyes, but some species across fourteen families possess an additional pair of eyes called accessory eyes along the dorso-posterior margin of the primary eyes. Secondary eyes are found in lizards, lampreys, and insects, where they often function as illumination detectors. Some shrimps may use accessory eyes to signal endocrine organs in their eyestalks to alter the pigmentation of their carapace providing better camouflage through disruptive coloration. To investigate the role of accessory eyes in dynamic color change we …

Development Of Anti-Fibrotic Agents For Potential Use In Glaucoma Filtration Surgery To Prevent Scar Formation, Nikhala Shree S

Theses and Dissertations

Glaucoma is the second leading cause of blindness with irreversible vision loss. It is marked by the degeneration of retinal ganglion cells, which results in optic nerve head damage. Intraocular pressure (IOP) is a prime risk factor of glaucoma controlled by various treatment regimens i.e., medication, laser, and/ or surgery. It is reported that longterm exposure to anti-glaucoma medications (AGM) may subtle the surgical success rate leading to postoperative fibrosis. Transforming growth factor beta (TGF-β) is a growth factor that plays an important role in the development of glaucoma and promotes fibrosis.

This study is aimed at developing peptides to …

A Careful Examination Of The Parameters Impacting The Study Of Plant/Bacteria Interactions, Caroline Victoria Royals

Theses and Dissertations

Our laboratory has been studying how different Caulobacter strains impact Arabidopsis plant growth. While reading papers published by other laboratories, I noticed inconsistencies in the methods used by different plant/bacteria interaction studies. For example, a variety of different variables have been used for defining a bacterium as Plant Growth Promoting (PGP). To establish a baseline, I conducted longitudinal studies that examined the impact of bacteria on all phases of a plant’s life. I found that individual Caulobacter wild type strains impact different aspects of plant growth. In addition, I continuously encountered problems with within and between pot variation in plant …

Investigating Microbe-Plant Symbioses In Space, David Handy

Theses and Dissertations

As life has evolved on Earth, gravity has been a constant around which biological processes have developed, rather than a pressure that has been adapted to. As humanity ventures into space, we remove this constant and can observe a variety of changes in biological systems, such as bone loss in humans, stunted plant growth, or increased virulence in pathogens. The growing body of data shows that life adapts to spaceflight and microgravity in unique ways that, due to our limited understanding, can be difficult to predict. A particularly under-studied area is that of host-microbe interactions. Despite efforts to limit their …

Characterizing The Quorum Sensing (Qs) System In The Model Eukaryote Chlamydomonas Reinhardtii, Kirstin Donnette Cutshaw

Theses and Dissertations

Group behaviors in microorganisms are often regulated by low-molecular weight molecules that enable them to sense population density, a signaling system known as quorum sensing (QS). QS in prokaryotes has provided insight into the role ‘social’ behaviors play in the bacterial world and refined our models of virulence, bacterial motility, and more. While less common, similar behaviors are observed in certain fungi, primarily yeasts, in which QS controls cell morphology, biofilm production, and other phenotypes. We have recently pursued the potential for QS to be more broadly distributed among unicellular eukaryotes, which could significantly alter our understanding of social behaviors …