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Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil Dec 2023

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …


The Evolution Of Empathy: Through The Lens Of A Rodent Model., Caroline Driscoll-Braden May 2023

The Evolution Of Empathy: Through The Lens Of A Rodent Model., Caroline Driscoll-Braden

Electronic Theses and Dissertations

Empathy is the capacity to be affected by and share the emotions of others, to discern the circumstances prompting another’s emotional state, and to identify with another by adopting their perspective. Research investigating the empathically motivated behavior of rats can help inform the evolutionary history of empathy and provide additional support of the continuity of empathy in animals and humans. In this dissertation, I examine the helping behavior of rats to explore the complexities of rodent empathy. In Chapter I, I review the multiple layers of empathy and describe both historical and contemporary research examining empathy in non-humans. I explain …


Transmission And The Evolution Of Diseases Caused By Chlamydia Trachomatis, Sars-Cov-2, And Plasmodium Species., Nathan Steffens May 2023

Transmission And The Evolution Of Diseases Caused By Chlamydia Trachomatis, Sars-Cov-2, And Plasmodium Species., Nathan Steffens

Electronic Theses and Dissertations

Principles of natural selection have proven valuable for explaining why pathogens cause the diseases that they do. In theory, the evolved level of host exploitation should reflect how dependent a pathogen is on host health for transmission. This dependency is shaped by transmission mode and transmission opportunity, which should therefore be predictors of disease manifestations. In this dissertation, I apply these principles to investigations of depression in Chlamydia trachomatis and virulence of SARS-COV-2 and Plasmodium species. This dissertation has five chapters. In chapter I, I describe the theoretical foundation of my dissertation research. I also briefly introduce each study system. …


Characterization Of Microbotryum Lychnidis-Dioicae Secreted Effector Proteins That Manipulate Its Host Plant, Silene Latifolia., Ming-Chang Tsai Aug 2022

Characterization Of Microbotryum Lychnidis-Dioicae Secreted Effector Proteins That Manipulate Its Host Plant, Silene Latifolia., Ming-Chang Tsai

Electronic Theses and Dissertations

The smut fungal species Microbotryum lychnidis-dioicae is an obligate phytopathogen colonizing the plant host, Silene latifolia. A significant feature of M. lychnidis-dioicae infection is that the fungus can replace pollen on the anthers of susceptible host plants with fungal teliospores, thus earning the fungus the name: anther smut disease of flowers. The fungus synthesizes and secretes effector proteins into the cells of the plant host during infection, and the protein-protein interactions may interfere with and modify metabolism, plant development, and gene expression of the host to allow fungal colonization. Two potential fungal effector proteins, MVLG_06175 and MVLG_05122, were identified …


Functional Role Of Ppal And Potential For Moss In Industrial Applications., Susana Perez Martinez May 2022

Functional Role Of Ppal And Potential For Moss In Industrial Applications., Susana Perez Martinez

Electronic Theses and Dissertations

This dissertation is an examination and characterization of the functional roles of PPAL. PROTEIN PRENYLTRANSFERASE ALPHA SUBUNIT-LIKE (PPAL) is a recently discovered gene. PPAL homologs are present in all plants and many animals, where its function is largely unknown. It is possible that PPAL could participate in prenylation processes since it shares similarity to the α subunits of known prenylation enzymes. Prenylation is a post-translational modification of proteins that involves the addition of a lipid moiety to proteins to facilitate membrane targeting and association and promote protein-protein interactions. Prenylation has important roles in plant growth and development, including …


Computational And Biochemical Characterizations Of Anhydrobiosis-Related Intrinsically Disordered Proteins., Brett R. Janis Dec 2021

Computational And Biochemical Characterizations Of Anhydrobiosis-Related Intrinsically Disordered Proteins., Brett R. Janis

Electronic Theses and Dissertations

Anhydrobiosis is the remarkable phenomenon of “life without water”. It is a common technique found in plant seeds, and a rare technique utilized by some animals to temporarily stop the clock of life and enter a stasis for up to several millennia by removing all of their cellular water. If this phenomenon can be replicated, then biological and medical materials could be stored at ambient temperatures for centuries, which would address research challenges as well as enhance the availability of medicine in areas of the world where refrigeration, freezing, and cold-chain infrastructure are not developed or infeasible. Furthermore, modifying crop …


Harmful Algal Blooms In The Ohio River: Spatial And Temporal Differences., Bevin Hardy May 2021

Harmful Algal Blooms In The Ohio River: Spatial And Temporal Differences., Bevin Hardy

Electronic Theses and Dissertations

The frequency of harmful algal blooms (HABs) has been increasing across the globe, especially in river ecosystems. Although more common in lakes, more HABs have been reported in rivers in the past decade, particularly in the Ohio River. In 2019, a HAB stretched 200 to 300 miles throughout the Ohio River from September to October. Samples were collected for the duration of the 2019 bloom (August-October) in the McAlpine Pool in Louisville, KY to compare microcystis toxin (microcystin) concentrations on a temporal and spatial scale. Different habitats (bay, creek, river) were sampled throughout the bloom, and two additional sampling days, …


On The Straight And Narrow: How Cultural Beliefs About Sex/Gender Manifest In College Biology Learning Environments., Katherine Ray Kng Dec 2020

On The Straight And Narrow: How Cultural Beliefs About Sex/Gender Manifest In College Biology Learning Environments., Katherine Ray Kng

Electronic Theses and Dissertations

This dissertation focused on the ways that social beliefs about sex/gender and sexuality manifest in biology classrooms. Especially for health science students, classes include topics like sex, sexuality, sexual behaviors, or sex determination that forms the foundation of their understanding of human forms and behaviors. If the information they receive does not include the LGBTQIA+ community, their education will fail to adequately prepare them for the reality of healthcare practice where they will be expected to treat all patients with dignity and respect. There are three chapters in this dissertation. In chapter one, I asked what beliefs about and conceptions …


Undergraduate Students Use Moral Reasoning And Belief In Genetic Determinism In Response To A Crispr/Cas9 Socioscientific Issue., Katie M. Seiter Dec 2020

Undergraduate Students Use Moral Reasoning And Belief In Genetic Determinism In Response To A Crispr/Cas9 Socioscientific Issue., Katie M. Seiter

Electronic Theses and Dissertations

This dissertation explores how students reason about genetic engineering socioscientific issues (SSIs) related to a recently developed, powerful genome editing technology called CRISPR/Cas9. It is divided into three chapters. Chapter One describes an exploratory study that characterized students’ moral reasoning using a sociocultural theoretical framework. I used content analysis and logistic regression to investigate how academic and social factors influenced moral reasoning. Students generally opposed the use of CRISPR/Cas9 technology for non-medical enhancements, and the moral considerations used were influenced by genetics knowledge level and demographic variables such as gender and socio-economic status. Further investigation of moral perspectives for students …


Tobacco Enhances Bacterial-Induced Periodontal Bone Loss In Mice., Mina Iskander May 2020

Tobacco Enhances Bacterial-Induced Periodontal Bone Loss In Mice., Mina Iskander

Electronic Theses and Dissertations

Background: Tobacco smoking is the leading environmental risk factor for periodontal diseases. Delineation of the mechanisms underlying tobacco-induced or exacerbated periodontitis is hampered by the lack of an appropriate and reliable animal model. Hypothesis: We hypothesized that Porphyromonas-gingivalis-infected, cigarette smoke-exposed mice would represent reproducible models of acute (ligature model) and chronic (oral gavage model) tobacco-enhanced periodontitis that reflect multiple aspects of the disease noted in human smokers. Methods: In a chronic oral gavage disease model, Balb/c mice (6-8 weeks, 4 groups of n = 6 per group) were exposed to smoke produced by a Teague-10 smoking machine from 1R6F research …


Aboveground-Belowground Interactions: Roles Of Soil Biotic And Abiotic Factors On Switchgrass's (Panicum Virgatum) Growth, Defense Against Herbivory And Cell Wall Chemistry., Binod Basyal May 2020

Aboveground-Belowground Interactions: Roles Of Soil Biotic And Abiotic Factors On Switchgrass's (Panicum Virgatum) Growth, Defense Against Herbivory And Cell Wall Chemistry., Binod Basyal

Electronic Theses and Dissertations

Plants constantly interact with their biotic and abiotic soil environments. Most terrestrial plants form beneficial associations with soil microbes such as arbuscular mycorrhizal (AM) fungi, which are widely known for their ability to transfer soil phosphorus and nitrogen to the host plants. They help plants tolerate drought stress and improve plant defense against herbivores such as plant-parasitic nematodes (PPNs). This dissertation investigates the role of AM fungi on switchgrass’s (Panicum virgatum) growth, cell wall chemistry, and defense against PPNs using a combination of growth chamber and field studies. Switchgrass is a native warm-season species which is gaining traction as candidate …


Understanding Object Motion Encoding In The Mammalian Retina., Victor Julian Depiero Dec 2019

Understanding Object Motion Encoding In The Mammalian Retina., Victor Julian Depiero

Electronic Theses and Dissertations

Phototransduction, transmission of visual information down the optic nerve incurs delays on the order of 50 – 100ms. This implies that the neuronal representation of a moving object should lag behind the object’s actual position. However, studies have demonstrated that the visual system compensates for neuronal delays using a predictive mechanism called phase advancing, which shifts the population response toward the leading edge of a moving object’s retinal image. To understand how this compensation is achieved in the retina, I investigated cellular and synaptic mechanisms that drive phase advancing. I used three approaches, each testing phase advancing at a …


Transforming Moss P. Patens With Lignin Peroxidase Through Heterologous Protein Expression., Jesse Lee Rozsa Aug 2019

Transforming Moss P. Patens With Lignin Peroxidase Through Heterologous Protein Expression., Jesse Lee Rozsa

Electronic Theses and Dissertations

Lignin peroxidase is an enzyme secreted by white-rot fungi Phanerochaete chrysosporium. Our laboratory is attempting to produce several lignin degrading enzymes in our protein expression system that utilizes the moss, Physcomitrella patens. During our experiments we discovered that this particular species of fungus produces altered splicing variants that are not represented in the previously reported reference sequence. Despite several attempts to produce a positive transformant containing a desired transgene encoding; lignin peroxidase, production of the proper construct eluded our efforts, possibly due to toxic effects associated with lignin peroxidase expression. Our laboratory has created a stepping stone for other laboratories …


Defects In Fetal Mouth Movement And Pharyngeal Patterning Underlie Cleft Palate Caused By Retinoid Deficiency., Regina Friedl May 2019

Defects In Fetal Mouth Movement And Pharyngeal Patterning Underlie Cleft Palate Caused By Retinoid Deficiency., Regina Friedl

Electronic Theses and Dissertations

Cleft palate is a common birth defect. Etiologic mechanisms of palate cleft include defects in palate morphogenesis, mandibular growth, or spontaneous fetal mouth movement. Cleft palate linked to deficient fetal mouth movement has been demonstrated directly only in a single experimental model of loss of neurotransmission. Here, using retinoid deficient mouse embryos, we demonstrate directly for the first time that deficient fetal mouth movement and cleft palate occurs as a result of mis-patterned development of pharyngeal peripheral nerves and cartilages. Retinoid deficient embryos were generated by inactivation of retinol dehydrogenase 10 (Rdh10), which is critical for production of …


Unfolded Protein Response Pathways In Skeletal Muscle Homeostasis., Kyle R. Bohnert Aug 2018

Unfolded Protein Response Pathways In Skeletal Muscle Homeostasis., Kyle R. Bohnert

Electronic Theses and Dissertations

Skeletal muscle mass, contractile properties, and metabolic function are regulated through the coordinated activation of multiple intracellular signaling pathways and genetic reprogramming. The endoplasmic reticulum (ER) plays a pivotal role in protein folding and calcium homeostasis in many cell types, including skeletal muscle. Disruption of calcium levels or accumulation of misfolded proteins in the ER lumen leads to stress, which results in the activation of a signaling network called the unfolded protein response (UPR). Further, recent studies have suggested that in certain conditions, UPR pathways can be activated independent of ER stress. However, the role of ER stress and the …


Regulation Of Haplid Phenotypes In Ustilago Maydis By Ammonium Transporters And Components Of The B Mating Locus., Rena Margaret Wallen Aug 2017

Regulation Of Haplid Phenotypes In Ustilago Maydis By Ammonium Transporters And Components Of The B Mating Locus., Rena Margaret Wallen

Electronic Theses and Dissertations

Fungi that can switch from budding to a filamentous infectious state have evolved mating type loci. Ustilago maydis, the maize pathogen, must mate with compatible partners possessing different alleles at two mating type loci for successful host infection. The a locus encodes pheromones and receptors, while the b locus encodes subunits of a heterodimeric transcription factor that regulates expression of virulence genes. Mating is triggered by environmental signals, including nutrient deprivation. My goal was to determine the fate of nitrogen starved haploid cells without a compatible mating partner. On solid low ammonium media, wild-type U. maydis filaments. I examined …


Social Dynamics, Network Structure, And Information Diffusion In Fish Shoals., Matthew Jerome Hasenjager May 2017

Social Dynamics, Network Structure, And Information Diffusion In Fish Shoals., Matthew Jerome Hasenjager

Electronic Theses and Dissertations

Animal populations are often highly structured, with individuals differing in terms of whom they interact with and how frequently they do so. The resulting pattern of relationships constitutes a population’s social network. In this dissertation, I examine how environmental variation can shape social networks and influence information flow within them. In Chapter I, I review the history of social network analysis in animal behavior research, and discuss recent insights generated by network approaches in behavioral ecology. I focus on the fields of: social learning, collective behavior, animal personalities, and cooperation. Animal network studies are often criticized for a lack of …


Function Of The Enterobactin Operon Of A. Actinomycetemcomitans In The Presence Of Catecholmines And Iron., Taylor Johnson May 2017

Function Of The Enterobactin Operon Of A. Actinomycetemcomitans In The Presence Of Catecholmines And Iron., Taylor Johnson

Electronic Theses and Dissertations

Background: Aggregatibacter actinomycetemcomitans (Aa) possesses a two-component system, QseBC, which is key in biofilm formation/virulence and is activated in the presence of iron-catecholamine complexes. Aa does not synthesize enterobactin, a catechol-based siderophore, yet possesses the machinery for recognition and uptake. We hypothesize that Aa is able to acquire iron by catecholamine mediation through the enterobactin receptor/transporter. Methods: By insertional mutation, we attempted to delete the enterobactin permease from the genome using suicide vector pJT1. A growth curve of truncated mutant ΔfepA was also conducted to observe growth in the presence of iron and catecholamines. Statistical significance was determined by ANOVA …


Transient Receptor Potential Cation Channel, Subfamilies V, Member 1 (Trpv1) And M, Member 1 (Trpm1) Contribute To Neural Signaling In Mouse Retina., Jennifer Noel Dec 2016

Transient Receptor Potential Cation Channel, Subfamilies V, Member 1 (Trpv1) And M, Member 1 (Trpm1) Contribute To Neural Signaling In Mouse Retina., Jennifer Noel

Electronic Theses and Dissertations

The retina processes light information through parallel pathways in order to extract and encode the visual scene. Light information is transmitted to the brain through approximately 30 ganglion cells (GCs), the retinal output neurons. Trp channels modulate the responses of retinal neurons within specific pathways. The study of the expression and function of the majority of Trp channels in the retina is largely in its infancy. My dissertation first investigated the expression and function of the transient receptor potential vanilloid-1 (TRPV1) receptor/channel in the retina. TRPV1, the first cloned and most highly studied Trp channel in the peripheral nervous system, …


Dietary Resource Utilization Patterns And Head Morphology Among Three Sympatric Watersnake Species., Micah Warren Perkins Dec 2016

Dietary Resource Utilization Patterns And Head Morphology Among Three Sympatric Watersnake Species., Micah Warren Perkins

Electronic Theses and Dissertations

The coexistence of similar species may be related to a variety of resource utilization differences. Dietary resource utilization variation may be the most important difference allowing for the coexistence of sympatric snake species. Many watersnakes (Nerodia spp.) live in sympatry and use similar aquatic habitats feeding on similar prey. While these sympatric watersnakes may have different general foraging patterns, snake diet may be affected by a variety of factors. Therefore, I initiated an investigation to understand the coexistence of sympatric plain-bellied (N. erythrogaster), diamondback (N. rhombifer) and northern (N. sipedon) watersnakes by addressing …


Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang Dec 2016

Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang

Electronic Theses and Dissertations

A reaction-diffusion model and a lattice differential equation are introduced to describe the persistence and spread of a species along a shifting habitat gradient. The species is assumed to grow everywhere in space and its growth rate is assumed to be monotone and positive along the habitat region. We show that the persistence and spreading dynamics of a species are dependent on the speed of the shifting edge of the favorable habitat, c, as well as c*(∞) and c*(−∞), which are formulated in terms of the dispersal kernel and species growth rates in both directions. When …


Examination Of The Relevance Of Pi3k And Pten Pathway In Ustilago Maydis., Nathaniel Edward Dalton Dec 2016

Examination Of The Relevance Of Pi3k And Pten Pathway In Ustilago Maydis., Nathaniel Edward Dalton

Electronic Theses and Dissertations

Ustilago maydis is a fungal pathogen that is an obligate parasite on Zea mays (Corn) in order to undergo and complete its sexual life cycle. The cells grow as a haploid form until they meet a compatible partner and undergo a dimorphic switch from a budding yeast-like cell type to a filamentous dikaryon. Infection of the host plant is characterized by leaf chlorosis, anthocyanin content, and formation of large galls that develop on the stem, leaves, cobs, and flowers. Many signaling cascades such as MAPK and PKA are involved in the regulation of the infection lifecycle. The Phosphatidylinosotiol 3 Kinase/ …


Identification And Characterization Of Genes Involved In Metabolism Of N5 Monoene Precursors To N5 Anacardic Acids In The Trichomes Of Pelargonium X Hortorum., Richa A. Singhal Dec 2016

Identification And Characterization Of Genes Involved In Metabolism Of N5 Monoene Precursors To N5 Anacardic Acids In The Trichomes Of Pelargonium X Hortorum., Richa A. Singhal

Electronic Theses and Dissertations

Unusual monoenoic fatty acids (UMFA’s) and specialized metabolites called anacardic acids (AnAc) are produced in glandular trichomes of Pelargonium ´ hortorum (geranium). The UMFA’s, 16:1∆11 and 18:1∆13 are precursors for the synthesis of unsaturated AnAc 22:1n5and 24:1n5 that contribute to pest resistance in geraniums. UMFAs and their derived AnAc metabolites not only provide a useful biological marker that differentiates the biosynthetic pathway for unusual mononenes from the common fatty acids (i.e. stearic, palmitic, oleic, linoleic and linolenic) but also have industrial, medical and agricultural applications. Fatty acid biosynthesis enzymes like acyl carrier proteins (ACPs); thioesterases (TEs) and β-ketoacyl-ACP …


Insights Into The Introduction Histories And Population Genetic Dynamics Of The Nile Monitor (Varanus Niloticus) And Argentine Black And White Tegu (Salvator Merianae) In Florida., Jared Price Wood May 2016

Insights Into The Introduction Histories And Population Genetic Dynamics Of The Nile Monitor (Varanus Niloticus) And Argentine Black And White Tegu (Salvator Merianae) In Florida., Jared Price Wood

Electronic Theses and Dissertations

This dissertation examines the population genetic dynamics of two Florida invasives: the Nile monitor (Varanus niloticus) and Argentine black and white tegu (Salvator merianae). I also provide insights into the introduction histories of both species. This study was developed as part of a collaborative effort with the Florida Wildlife Commission to expand our knowledge of these highly detrimental, invasive lizards. All research activities involving animals and animal tissues were approved by the University of Louisville’s Institutional Animal Care and Use Committee (IACUC Proposal #: 12024). I start with a brief introduction into what makes invasive species …


Effects Of Different Agricultural Management Systems On Arbuscular Mycorrhizal Fungal Diversity, Community Structure, And Ecosystem Services., Charles Bradford Gottshall Aug 2015

Effects Of Different Agricultural Management Systems On Arbuscular Mycorrhizal Fungal Diversity, Community Structure, And Ecosystem Services., Charles Bradford Gottshall

Electronic Theses and Dissertations

Disturbances associated with row-crop agricultural management systems include mechanical (tillage and cultivation) and chemical (fertilizer, pesticides, herbicides, fungicides) inputs and are often co-occurring. Many soil microbes are sensitive to these disturbances, including arbuscular mycorrhizal fungi (AMF), important plant mutualists in agricultural systems. AMF associate with many crop plants and provide direct benefits through root pathogen protection, drought resistance, nutrient acquisition and uptake, as well as contribute to ecosystem services by improving overall soil fertility. Examining how different row-crop management system disturbances affect the AMF community is important for understanding and enhancing benefits provided by these important mutualists, and key to …


Metabolic Profiles Of Household Pseudomonas Species Groups., Ogochukwu S. Onyiri Aug 2015

Metabolic Profiles Of Household Pseudomonas Species Groups., Ogochukwu S. Onyiri

Electronic Theses and Dissertations

Resources influence the distribution, behavior, growth and reproduction of bacterial species. Understanding how closely related species utilize resources will shed light on the ecological traits or principles that shape biogeographic patterns and promote coexistence of species. Twelve Pseudomonas strains isolated from a single human home and PA01, the standard laboratory strain were evaluated in Luria Bertani media to understand whether their growth traits are influenced by their species group and/or their environment of isolation. Total growth, growth rate, early cumulative area under the growth curve (CUC) over 48 hours and viability (viable bacteria count per ml) at 24 and 48 …


The Evolution And Ecology Of Individual Specializations Amongst A Group Of Dietary Generalists., Carl S. Cloyed May 2015

The Evolution And Ecology Of Individual Specializations Amongst A Group Of Dietary Generalists., Carl S. Cloyed

Electronic Theses and Dissertations

This dissertation examines individual diet specializations (IS) in a group of ecologically similar and evolutionarily related frogs and toads. Individual specialization is known to have widespread ecological and evolutionary effects. In an initial literature review (Chapter 2) I build a comprehensive theoretical framework showing how different types of population diversity can help, halt, or hinder sympatric speciation. I argue that IS can be maintained indefinitely in populations yet fail to lead to speciation because it is influenced by ecological conditions that may change. Additionally, IS can potentially aid niche partitioning among similar species, increasing species coexistence and resulting in less …


Next-Gen Transcriptomics Reveals Variable Gene Expression In Stenotrophomonas Maltophilia K279a When Grown In Co-Culture With Pseudomonas Aeruginosa 2192., David Jensen 1984- May 2015

Next-Gen Transcriptomics Reveals Variable Gene Expression In Stenotrophomonas Maltophilia K279a When Grown In Co-Culture With Pseudomonas Aeruginosa 2192., David Jensen 1984-

Electronic Theses and Dissertations

We are constantly surrounded by bacteria, many of which are found in cohabitation with other species in the same niches. These organisms can be particularly problematic when they infect the human body. Cystic fibrosis (CF) is of significant concern because of the frequency that those suffering from this autosomal recessive disease have in colonization by these infectious agents. Affecting more than 30,000 people in the U.S. alone. CF is due to a genetic mutation that causes a thick mucosal buildup in luminal surfaces. This viscous mucus creates a cultivation site for complex respiratory biofilms. Complications of CF include paralysis of …


Do Hydrocarbon And Salinity Disturbance Affect Marine Meiofauna Diversity And Community Structure?, Kyle Edward Anderson May 2015

Do Hydrocarbon And Salinity Disturbance Affect Marine Meiofauna Diversity And Community Structure?, Kyle Edward Anderson

Electronic Theses and Dissertations

Coastal areas around the world are subjected to numerous disturbances, both natural and anthropogenic. Coastal meiofauna are an ecologically important group of organisms that may be sensitive to disturbance and especially useful as indicators of habitat status following anthropogenic disturbances. In this research, I compared the effects of five different intensity levels of hydrocarbon contamination, salinity reduction, and random non-disturbance diversity manipulation on communities of marine meiofauna communities in a microcosm experiment. While I did find the expected negative relationship between intensity and morphogroup diversity in the random treatment, the hydrocarbon and salinity disturbance treatments had no effects on overall …


Earthworm, Microbial Biomass, And Leaf Litter Decay Responses After Invasive Honeysuckle Shrub Removal From Urban Woodlands., Robert Preston Pipal Dec 2014

Earthworm, Microbial Biomass, And Leaf Litter Decay Responses After Invasive Honeysuckle Shrub Removal From Urban Woodlands., Robert Preston Pipal

Electronic Theses and Dissertations

Invasive species are one of the leading causes of biodiversity loss and their presence can significantly impact the structure and function of native ecosystems. In this dissertation, the impacts of the invasive honeysuckle shrub, Lonicera maackii, on exotic earthworm populations, leaf litter decay responses, and inorganic and organic nutrient pools in an urban woodland park are assessed. Chapter 1 provides a brief review of honeysuckle's effects on forest ecosystems. Chapter 2 describes honeysuckle’s effects on exotic earthworm populations and the seasonal importance of macroinvertebrates to leaf litter decomposition in urban woodlands. This study revealed that L. maackii promoted higher exotic …