Biology Commons^™

Assessing The Level Of Perception Of Knowledge About Ticks And Tick-Borne Diseases Among The Residents Of Several Cities In The Transboundary Region Of U.S.-Mexico, Consuelo Aguilar

Theses and Dissertations

The transboundary region of U.S.-Mexico possesses similar weather conditions and habitats favoring insects (vectors) like ticks. Several tick species found in the transboundary region of U.S.-Mexico can transmit pathogens. In the last three years, a total of 40 cases of Rickettsial infections, 28 in Tamaulipas and 12 in the Lower Rio Grande Valley, have been reported. A low level of knowledge about diseases that ticks can transmit along with a lack of appropriate protection practices can severely affect human health. Limited surveys on ticks and tick-borne disease are available. Our goal was to (1) assess the perception of knowledge of …

Understanding An Inflammatory Pathway In Diabetic Retinopathy, Reanna Raye Rodriguez

Theses and Dissertations

Diabetic Retinopathy (DR) is the leading cause of blindness in the U.S. However, not much is known of its molecular pathway and how it attributes to increases in inflammatory response in the eye. One avenue we will investigate is the transforming growth factor beta (TGFB) signaling pathway and its effect of vascular endothelial growth factor (VEGF) secretion and cell viability. VEGF is the hallmark that exacerbates DR progression in prolonged diabetes. Some major concern that have arisen are the underlying effects of oxidants and antioxidants in elevating VEGF secretion in diabetes. In attempt to learn more, we evaluated how an …

Winners And Losers In Reforestation Efforts In The Lower Rio Grande Valley Of Texas, And The Predictive Power Of Xylem Anatomy On Long-Term Growth And Survival, Clifton F. Albrecht

Theses and Dissertations

Reforestation has been ongoing in the Lower Rio Grande Valley annually since the 1980s, and to date over 6400 ha of land has been reforested in this area. However, there has been little subsequent study of the change and development of those forests as they mature. This thesis consists of two, interrelated, studies: (1) surveys of a five-site chronosequence of restored forests and (2) quantification of xylem anatomical traits of a subset of species present at the reforestation sites. Surveys showed a consistent reduction in species diversity and stem number density on the landscape, and identified a suite of species …

Opa1 Modulation Of Mitochondrial Dynamics In Ac16 Cardiomyocytes, Patrick De La Torre Schutz

Theses and Dissertations

This thesis explores mitochondrial dynamics in the AC16 cardiomyocytes. Mitochondria are capable of fission and fusion, controlled by specific proteins that respond to cell stress. The transmembrane potential(∆ψm) of the mitochondria is responsible for both bioenergetic functions and regulating the activation of the OMA-1 protein, which regulates the cutting of OPA-1. OPA- 1 has two isoforms: a long (active) and short (inactive) isoforms. Our research is exploring the impact of the levels of OPA1 expression on the observed ∆ψm threshold of mitochondrial fusion. Our laboratory has demonstrated that 143B cells lose L-OPA1 isoforms at [CCCP]> 4.75 µM and …

Understanding The Ecological Role, Population Dynamics, And Geographic Distribution Of Manihot Walkerae, Gisel Garza

Theses and Dissertations

Walker’s Manihot, Manihot walkerae Croizat (Euphorbiaceae), is an endangered plant that is endemic to the Tamaulipan thornscrub ecoregion. Understanding M. walkerae’s geographic distribution, populations, and species interactions can provide essential information for the development of sound conservation strategies. To this aim, I asked the following questions: 1) What is the potential geographic distribution for M. walkerae? and, will it be affected by climate change? 2) Using global and regional extinction risk assessments, what is the extinction risk category for M. walkerae after incorporating species distribution models? 3) What do natural history observations reveal about M. walkerae’s population …

Physical And Chemical Defense Mechanisms In Aloe Barbadensis Against Insect Herbivores, Zachary Johnson

Theses and Dissertations

Chapter 1: This chapter provides an overview of insect herbivore impacts on plants and plant defense mechanisms to combat them. I particularly focused on physical and chemical defenses in the broader sense.

Chapter 2: This chapter describes the experiments that showed the effects of extracts from Aloe barbadensis on the growth and development of tobacco hornworm (Manduca sexta) and fall armyworm (Spodoptera frugiperda), model herbivores used to understand herbivore growth and plant defenses. This study shows that extracts from the Aloe differentially affected the growth and development of M. sexta and S. frugiperda. This chapter …

Roles Of Holocene Climate And Pastoralism In Shaping Andean Landscapes, Courtney Renee Shadik

Theses and Dissertations

The Holocene (c. 11,700years ago –present) was a time rich in Andean climatic, environmental, and cultural changes. Assemblages were reforming after the last ice age, millennial scale wet and dry events caused the largest changes in lake level of the last 100,000 years, and humans came to dominate the landscape. Against the backdrop of ecological change, this study asks the following questions-Was the onset of camelid domestication associated with mid-Holocene aridity? Are modern, high-elevation vegetation assemblages a product of manufactured landscapes? What are the long-term effects of intense agropastoralism on paleoecological reconstructions of Andean landscapes? Did Holocene agropastoral domesticates coevolve? …

Exploration Of Antimicrobial And Cell Proliferation Properties Of Nanofibers Incorporating Nopal (O. Cochenillifera) Extract, Cristobal Rodriguez

Theses and Dissertations

This study focused on the fabrication of Forcespinning® nanofibers composed of Opuntia cochenillifera, ‘nopal’, mucilage (N) extract, chitosan (CH), and pullulan (PL) (N/CH/PL) were developed with an optimum fiber average diameter of 406±127 nm, and studied for their ability to sustain adhesion and proliferation of mouse embryonic fibroblast (NIH 3T3) cells. After a 6-day incubation period, N/CH/PL nanofibers displayed robust cell proliferation, while also exhibiting inhibitory properties through an N extract dip-coating process against gram-negative bacteria Escherichia coli in a 24 h bacterial growth study. A demonstration of integrated natural bioactive compounds with combined biodegradable polymers, provide an enhanced …

Investigating Bmp7 Expression In Glioblastoma Multiforme, Yajaira Janett Macias

Theses and Dissertations

The PI3K/AKT/mTOR pathway regulates important cell processes such as growth, survival, motility, inflammation, proliferation, and apoptosis. In Glioblastoma multiforme (GBM) the PI3K/AKT/mTOR pathway is aberrant as it is almost always active. This results in the deregulation of downstream molecules and ultimately leads to cancer progression and maintenance in GBM tumors. In this study, we used RNA-sequencing to identify differentially expressed genes (DEGs) in U87MG GBM cells treated with NVP-BEZ235, a dual inhibitory drug targeting PI3K and mTOR. A total of 7,803 differentially expressed genes were identified via RNA-seq. GEPIA2 online tool was used to assess differential gene expression …

Effects Of Plant Secondary Metabolites And Host Specificity On Growth, Development, And Oviposition Of Lepidopteran Herbivores, Sukhman Singh

Theses and Dissertations

Chapter 1: This chapter provides a review of recent and critical literature on the role of polyphenols in mediating plant-insect interactions. I particularly focused on plant defense induction and mode of action of polyphenols, defense fitness trade-offs, and storage of polyphenols for future defense responses.

Chapter 2: This chapter is about the effects of polyphenol rich purple corn pericarp extract on the growth and development of generalist caterpillar i.e., fall armyworm (Spodoptera frugiperda). This study shows that purple corn pericarp extract rich in polyphenols negatively effects the growth and development of S. frugiperda.

Chapter 3: This chapter …

An Assessment On Microplastic Pollution In The Resacas Of The Lower Rio Grande Valley, Texas, Wesley D. Franklin

Theses and Dissertations

Microplastic pollution is a serious issue that impacts most aquatic environments. Microplastics have the potential to cause numerous detriments to the fitness and reproductive capability of many organisms. The resacas of the Lower Rio Grande are an understudied area that could be sinks for large congregations of microplastics. We analyze microplastic pollution in two species of fish as well as the sediment and water of eleven different pools from four resaca systems. We find that microplastics are present in every pool sampled.

Altogether 218 microplastic pieces are found from the water, sediment and fish samples. We find that microplastics are …

Exploring Effects Of Sample Storage, Preparation, And Tissue Type On Fourier Transform-Near Infrared Spectroscopy (Ft-Nirs) Ageing Across Fish Taxa, Keith Fuller

Theses and Dissertations

The accurate determination of age for fish is a vital part of both populationmanagement and ichthyological research. However, the methods which are primarily employed to age fish can be difficult, time consuming, inaccurate, or some combination thereof. Most ageing is currently done via hard parts (such as otoliths, vertebrae, or scales) which are read in a manner similar to tree rings with markings corresponding to known or presumed periods of time. Recently, Fourier transform-near infrared spectroscopy (FT-NIRS) has been investigated as a novel tool to age fish more quickly and objectively. This method works by recording the vibrational frequencies of …

Investigating The Dynamic Interactions Of Rapidly Growing Precocial Shorebird Chicks, Luke R. Wilde

Theses and Dissertations

Organisms in dynamic environments must continually reassess the cost-benefit trade-offs of their interactions and adjust their behaviors accordingly. Nevertheless, ecological research often takes a ‘snapshot’ approach to studying interactions across sample locations and timepoints. Investigating ecological interactions in this way can miss important information about the influence spatiotemporal context has on the scale and direction of their effects. Longitudinal studies that follow individuals can elucidate how changing contexts affect an individual’s ecology while deepening our understanding of adaptive behavior. However, determining how context influences the effect of an interaction requires it be measured across a range of spatiotemporal conditions. Studying …

Effect Of Oxidative Stress On Lifespan And Cellular Survival, Benedicth Onyeka Ukhueduan

Theses and Dissertations

When cells experience oxidative stress, the integrated stress response (ISR) signaling pathway is activated. One of the first outcomes of such ISR-activated response is to temporarily halt protein synthesis, which aids in cellular recovery. However, if cells cannot recover from the stress, they activate the cell death pathways which kills the affected cells, usually by apoptosis, which can then lead to either acquisition or prevention of diseases depending on the situation. In physiological aging, a compromised stress response is observed as an organism ages, which leads to disrupted homeostasis and elevated risk of disease. Thus, longevity of an organism is …

Applications And Mechanisms Of Near Infrared Spectroscopy For Age Estimation In Otoliths Of Red Snapper Lutjanus Campechanus, Michelle S. Passerotti

Theses and Dissertations

Near infrared spectroscopy (NIRS) is a light spectroscopy method useful for non-invasively discriminating and quantifying chemical composition of a wide variety of substances. Recently-developed applications of NIRS to fish age estimation across a range of taxa have sparked intense interest in exploring the feasibility of its use for rapid age estimation in fisheries population management. In this pursuit, development of species-specific calibration models relating traditionally-derived age estimates (i.e., those estimated from growth band counts) to NIR spectral signatures from ageing structures is required to derive predictive models that can then estimate age from rapid scans of whole ageing structures alone. …

Plasmids Bring Novel Functions To Caulobacter Genomes, Taylor Howell Carter

Theses and Dissertations

Caulobacter is a well-studied bacterial genus, but little is known about the plasmids that are found in some wild Caulobacter isolates. I identified nine plasmids from seven different Caulobacter strains and grouped them based on their size and the similarity of their repABC, parAB, and mobAB genes. Protein pathway analysis of the genes on the K31p1, and K31p2 plasmids showed many metabolic pathways that would enhance the metabolic versatility of the host strain. In contrast, the CB4 plasmid contained 21 heavy metal resistance genes organized into 9 operons. The majority of the CB4 heavy metal resistance genes code for …

Resrouce Allocation And Visual Communication In Lepidoptera, Linda Nicole Fipps

Theses and Dissertations

Visual signals in the form of wing color, size, shape, pattern, and UV reflectance play an important role in the mating and reproductive strategies of diurnal butterflies. Wing-based visual signals are linked to different functions and can be acted on by a variety of selective pressures. In a comprehensive look at the literature on the visual communication strategies of lepidopteran species, I look at how visual signals, most notably color, are used, generated, and perceived. I discuss the costs and benefits of those strategies for the fitness of butterflies and moths and look at lepidopteran visual communication through the lens …

A Computational Investigation Of The Biophysical Mechanisms Underlying Thermotaxis In The Afd Neurons Of Caenorhabditis Elegans, Zachary Mobille

Theses and Dissertations

Thermotaxis in the nematode Caenorhabditis elegans (C. elegans) is studied at the cellular scale of the amphid finger-like ciliated (AFD) neurons, which have previously been shown to be essential for thermoreception. The voltage and calcium signals of AFD during temperature stimuli are described with ordinary differential equations. The primary calcium model is a modified version of that published by Kuramochi and Doi in 2017 to explain the calcium responses of the chemosensitive amphid single-ciliated right (ASER) neuron to fluctuations in extracellular salt concentration. To account for the effects of temperature, changes to the stimuli conditions under which inactivation takes place …

The Reemergence Of Eradicated Disease Due To Ecological Impact Of Climate Change, Claudia Kolakowski

Theses and Dissertations

Global warming is radically changing aspects of the Earth. As scientists continue to research the effects, the ramifications of melting permafrost is coming to light. We build off of a previously existing Anthrax model in the hopes to include climate change as a factor in Anthrax spread. Chapter II develops a simplified version of an Anthrax model. Parameters for the model are found by using previous research and eigenvalues are analyzed in order to find thresholds and equilibria. Chapter III consider the general solutions of the model through eigenvalues and eigenvectors. This model is then extended to include a parameter …

Physiological Consequences Of Neuromodulation And The Cellular Properties That Underlie Them, Margaret Louise Demaegd

Theses and Dissertations

Neuronal activity is a product of more than the underlying neuronal connections. Modulatory influences like changes in the animal’s environment, the animals physiological state, or the release of neuromodulators can dramatically alter neuronal activity. Modulatory influences can be beneficial for the animal because they are a source of neuronal and behavioral plasticity, and they can provide neuronal circuits with the robustness needed to continue to function in new conditions, states, or tasks.However, malfunctions of the modulatory system can disrupt neuronal activity and lead to pathologies. Predicting how modulatory influences will alter neuronal activity is challenging because the underlying cellular and …

Mechanism Of Dna Damage Checkpoint (Ddc)- Mediated Repression Of Histone Mrnas And Role Of Acetyl-Coa In Histone Transcription, Madhura Bhagwat

Theses and Dissertations

My dissertation contains two projects. The first project is focused on the mechanism of DNA damage checkpoint (DDC)- mediated repression of histone mRNAs. The second project deals with the role of acetyl-CoA in histone transcription. Proliferating cells coordinate histone and DNA synthesis to maintain correct stoichiometric amounts for chromatin assembly. Histone mRNA levels must be repressed when DNA replication is inhibited to prevent toxicity and genome instability due to free non-chromatinized histone proteins. In the first project we show that, unlike in mammalian cells, DNA replication stress does not trigger decay of histone mRNAs in the yeast Saccharomyces cerevisiae. However, …

Rna Splicing In Neuron Physiology And Neurodegenerative Diseases, Md Faruk Hossain

Theses and Dissertations

Gene expression is regulated at multiple levels, including transcription, RNA editing, pre-mRNA splicing, mRNA export, translation, and posttranslational modifications. Alternative splicing is a process by which exons can be included or excluded, giving rise to multiple mRNA isoforms from the same transcript. Alternative splicing is an important mechanism in developmental, tissue- and cell-specific control of gene expression, and it is key for expanding proteomic diversity and complexity from a limited number of genes. Moreover, more than 95% of multiexon genes undergo alternative splicing in humans, and about half of all disease-causing point mutations in humans affect pre-mRNA splicing, including neurological …

Characterizing Ferroptosis Pathways In In Vitro Motor Neuron Models, Alejandra Martinez

Theses and Dissertations

Ferroptosis is a non-apoptotic regulated form of cell death driven by the toxic accumulation of lipid peroxides and the presence of iron. The mechanism by which ferroptosis operates requires further investigation; here I will discuss the findings regarding the role of ferroptosis in different cellular models as well as the genes that may be involved with either promoting or hindering the ferroptotic pathway. NSC-34 is a hybrid cell line of neuroblastoma and primary spinal cord cells that can be differentiated into a motor neuron-like state allowing the characterization of ferroptosis in two distinct cellular conditions. Additionally, iNIL cells are a …

The Ion Channel Trpm7 Regulates Zinc Depletion-Induced Mdmx Degradation, Herui Wang

Theses and Dissertations

Zinc deficiency has been linked to human diseases including cancer. p53, a zinc-containing transcription factor, is the most frequently mutated tumor suppressor protein in human cancer. MDM2 and MDMX are zinc- containing proteins and crucial negative regulators of p53, which have been found to be amplified or overexpressed in various cancers. To investigate the effects of zinc depletion on the p53 signaling pathway, we have used ion chelators TPEN and bispicen as well as zinc-deficient medium to treat cells. We report here that zinc depletion results in MDMX degradation in a ubiquitination-independent and 20S proteasome-dependent manner. Restoration of zinc recovers …

Alpha-Synuclein Multimerization Is Dependent On Structural Characteristics Of Repeated Ktkegv Regions, Benjamin Ira Rosen

Theses and Dissertations

Parkinson’s disease (PD) is the most common movement disorder and is characterized by neuronal loss and the presence of Lewy bodies in dopaminergic neurons of the substantia nigra pars compacta. PD is a chronic, progressive, and irreversible neurodegenerative disorder associated with the selective loss of dopaminergic neurons. Initially described in an Ayurvedic medical treatise and Galen’s writings, and later by James Parkinson in 1817, the most common symptoms of PD are resting tremors, abnormal posture and gait, and muscle rigidity. Approximately 1 million people are living with PD in the United States and worldwide estimates are between 7 and 10 …

Microrna Regulation And Cellular Proteostasis In Parkinson's Disease, Alberim Kurtishi

Theses and Dissertations

Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disorder predominately affecting the aging population. It is the second most common neurodegenerative disorder after Alzheimer’s disease (AD) affecting over 1 million individuals in the US alone. Recent studies have tried to understand the exact nature in which healthy neurons transition to a degenerative state in PD. There are a multitude of combinatory factors that can lead to the development of PD including environmental factors, genetic factors, and aging. The majority of PD cases are sporadic in nature, however familial cases account for 5-10% of total PD cases world-wide. The hallmark …

Evolution And Flower Shape From The Hawaiian Lobelioids To The Campanulaceae, Jingjing Tong

Theses and Dissertations

Campanulaceae, with roughly 2,400 species, is divided into five subfamilies, in part, by differences in their floral orientation and symmetry, with broad transitions between radial and bilateral floral symmetry. The Hawaiian lobelioids in the Campanulaceae is the largest endemic clade of Hawaiian angiosperms, and they have long been viewed as one of the most spectacular examples of an adaptive radiation in plants. In the first part of our study, we focus on Clermontia, which is one of the largest genera of Hawaiian lobelioids, employing variable low-copy nuclear gene sequences to determine their phylogenetic relationships. We use intron regions from four …

Assembly And Function Of The Polycystin Receptor-Ion Channel Complexes And The Otop1 Proton Channel, Bin Li

Theses and Dissertations

Polycystin complexes, or TRPP/PKD complexes, made of transient receptor potential channel polycystin subfamily proteins (TRPP) and polycystic kidney disease (PKD) proteins, play key roles in coupling extracellular stimuli with intracellular Ca2+ signals. For example, the TRPP2/PKD1 complex has a crucial function in renal physiology, with mutations in either protein causing autosomal dominant polycystic kidney disease (ADPKD). In contrast, the TRPP3/PKD1L3 complex responds to low pH and plays a potential role in sour taste. It has been previously shown that the protein partners interact via association of the C-terminal or transmembrane segments, with consequences for the assembly, surface expression, and function …

Comparison Of Antibiotic Resistance In Biofilm, Sediment, And Planktonic Communities Of The James River, Mary Bernadette Coughter

Theses and Dissertations

Antibiotic resistance spread within aquatic bacterial communities, particularly ones in urban areas, is in part driven by wastewater inflows that may contain both elevated concentrations of antibiotics and increased abundance of antibiotic resistant bacteria. These can be transmitted into the environment via release of treated wastewater, since removal of these compounds by most wastewater treatment facilities is inadequate, or by release of untreated waste from leaking wastewater treatment networks and overflow of combined sewer systems. This study used the James River and the City of Richmond wastewater network as a model urban waterway to study both types of impacts. Shotgun …

Chloroplast Genome Evolution In The Klebsormidiophyceae And Streptofilum, Sarah Glass

Theses and Dissertations

The Klebsormidiophyceae are a class of green microalgae found globally in both freshwater and terrestrial habitats. Morphology-based classification schemes of this class have been shown to be insufficient, particularly due to the simple morphology of these algae, the tendency of morphology to vary in culture versus in field conditions, and rampant morphological homoplasy. Molecular studies revealing cryptic diversity have renewed interest in this group. We sequenced the complete chloroplast genomes of taxa in the Klebsormidiophyceae representing the known taxonomic breadth of this class, as well as the chloroplast genomes of three strains of Streptofilum, a recently discovered algal lineage …