Biology Commons^™

Sphingolipids In Cancer Health Disparities And As Prospective Targets For Cancer Therapy, April E. Boyd

Theses and Dissertations

Lung cancer is the deadliest cancer both in the United States and worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. However, lung cancer disparities are not shared equally across racial groups, with large differences between African American and Caucasian populations. Advances in research have revealed roles of lipid mediators in cancer biology and disease progression, but sphingolipid alterations in tissues should be explored further. To address this, using mass spectrometry (MS), extensive sphingolipidomic characterization of NSCLC tumors and adjacent uninvolved tissues from African American and Caucasian patients were performed. This study revealed that NSCLC …

The Heat Is On: Comparison Of Thermoregulatory Behavior In Parasitised Versus Unparasitized Caterpillars Of The Tobacco Hornworm, Manduca Sexta (L.) [Lepidoptera: Sphingidae], Jessica M. Johnston

Theses and Dissertations

Insect thermoregulatory research has demonstrated evidence of variation occurring within and among species with respect to infection, pathogens, and parasitism, but few studies have examined differences in thermoregulatory behavior in a host-parasite system with a coevolved symbiotic virus. I investigated the role of parasitism by Cotesia congregata (Say) (Hymenoptera: Braconidae) on the thermoregulatory behavior of Manduca sexta (L.) (Lepidoptera: Sphingidae) using an experimental design in a thermal gradient chamber and a complementary observational field study on wild M. sexta collected from tobacco farms. Parasitism and larval age were not found to have a significant effect on the preferred body temperature …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

Characterizing The Transport Of Parasitoid Wasp Genaspis Hookeri Venom Serca Into Host Drosophila Hemocytes, Christopher Lark

Theses and Dissertations

The female endoparasitoid wasps introduce venom accompanied by an egg into the larval hosts’ body cavity during oviposition. The venom contains a mixture of proteins that exploit the host’s biological processes, such as, regulating gene expression, disrupting immune signaling pathways, or inducing immune cell death to give a decided advantage to the incipient wasp to develop unchallenged. Drosophila possesses a highly conserved innate immune response that recognizes and neutralizes foreign microbes and macroparasites. The venom of Ganaspis hookeri (strain G1) endoparasitoid wasp has co-evolved to suppresses the humoral phase Drosophila’s innate immune response by inhibiting Ca2+ bursts needed to induce …

Overcompensation In Aedes Mosquitoes Populations: Field Tests On Likelihood And An Agent-Based Model To Investigate The Influence Of Cohort Structure, Katherine G. Evans

Theses and Dissertations

The number of individuals in a competitive environment can affect the growth rate, survival, size, and fecundity of those individuals, which is known as density-dependent effects. Overcompensation may occur if few juveniles survive to adulthood in a high-density environment. Overcompensation arises when density dependent survival interacts with extrinsic sources of mortality, such that more juveniles survive to adulthood than if no extrinsic mortality had occurred.

I tested the hypothesis that density dependent effects are common and strong in the field for three mosquito species: Aedes aegypti, Aedes albopictus, and Aedes triseriatus. I surveyed naturally occurring densities in novel and established …

A Male-Female Genotype-By-Genotype Interaction Mediates The Effect Of Mating On Female Immunity In Decorated Crickets, Kylie J. Hampton

Theses and Dissertations

Sexually antagonistic coevolution should lead to the rapid divergence of male and female genotypes related to the effects of ejaculatory substances on female physiology. Hence, the outcome of mating should depend on an interaction between male and female genotypes. Although mating has been shown to influence female immune responses in diverse insect taxa, a male-female genotype-by-genotype effect on female immunity post-mating remains largely unexplored. Here, we investigate both the effects of mating on female immunity and the potential for a male-by-female genotype interaction on the form and magnitude of this response in decorated crickets. Females from three distinct genotypic backgrounds …

The Relationship Between Biofilm Production And Human Respiratory Cell Attachment And Invasion By Acinetobacter Baumannii, Rachel A. Pearson

Theses and Dissertations

Acinetobacter baumannii is an opportunistic gram-negative bacterial pathogen that causes many nosocomial infections in immunocompromised individuals. Common infections include catheter-associated urinary tract infections, ventilator-associated pneumonia, skin and soft tissue infections, and bloodstream infections that often lead to septicemia. Increasing multidrug resistance (MDR) in A. baumannii warrants new approaches to understanding its virulence mechanisms and pathogenicity. As a first step in infection, A. baumannii can attach to host cells, providing a surface for the bacteria to grow and perhaps facilitating biofilm formation and subsequent tissue invasion. In this study, we evaluated antibiotic resistance and characterized biofilm formation, attachment, invasion, and surface …

Non-Native Leaf Litter Modifies Algal Resources With Effects On Tadpole Growth, Spencer L. Cruz

Theses and Dissertations

Leaf litter species play a key role in determining the quality and quantity of algal resources in aquatic ecosystems as a cross-boundary subsidy. The invasion of non-native plant species into forests can alter aquatic resources. I investigated the effects of non-native leaf litter species on algal resources and green frog, Lithobates clamitans, development using a randomized complete block experiment that lasted 288 days. In experimental ponds, I added two non-native and two native leaf litter species in the presence and absence of tadpoles. Early in the experiment, Japanese honeysuckle and Chinese privet decreased periphyton N:P ratios and stimulated tadpole …

Characterization Of Plasmids Harbored By Vibrio Cholerae Isolates Endemic To The Rio Grande Delta, Viviana Trevino

Theses and Dissertations

Cholera is a diarrheal disease responsible for considerable morbidity and mortality globally. Epidemics along the Rio Grande Delta were reported during the 1850s, and the etiological agent Vibrio cholerae, remains endemic, thus presenting a unique opportunity for a study of historical and biological relevance. V. cholerae strains were isolated from two locations: the Rio Grande River under a bridge linking Brownsville to Matamoros (site 21) and where the river empties into the Gulf of Mexico (site 42). Two strains from site 21, and one from site 42 were selected to isolate, subclone, sequence, assemble and annotate extra-chromosomal elements. Results …

Genetic Determinants Of Variation In The Gh/Igf-1 Axis And Their Relationship To Cardiometabolic Health, Rafael Luis Aguirre Guillen

Theses and Dissertations

Background: In a study of Mexican Americans, we performed analyses of GEI and pleiotropy in the axis in relation to MS. GH/IGF-1 axis components were studied. Model parameters and likelihoods were estimated by maximum likelihood.

Results: Pleiotropy was observed for IGFBP3 (p

Conclusions: IGF-I and IGFBP3 are genetically correlated with MS whereas MS influences the additive genetic variance in IGFBP1 variables mainly but also in IGF-I somewhat by virtue of the VH exhibited by IGF-I/IGFBP1.

Genetics And Morphology Of Invasive Tubastraea Species Within The Gulf Of Mexico: A Case Study Of Species Misidentification And Distribution, Amelia E. Mcclure

Theses and Dissertations

The invasive corals, Tubastraea coccinea and Tubastraea micrathus, are known to thrive in reefs within the Gulf of Mexico (GOM). Many studies have indicated that species within this genus are spreading throughout the western Atlantic due to their successful invasion on degraded and artificial reef systems. In the Northern GOM, artificial reefs have been created from decommissioned oil rigs and sunken vessels to provide a hard substrate for coral growth. Although, this method is demonstrating success, it is also facilitating, the dispersal of undesired species. The species, T. coccinea and T. micranthus, were thought to be the only …

Assessing The Rehabilitation Status Of The Reflooded Bahia Grande, Texas Based On Trace Gas Fluxes, Benthic Macroinvertebrates, And Fish Community Data Along Salinity And Seagrass Gradients, Catherine M. Eckert

Theses and Dissertations

The Bahia Grande is a 6,500-acre tidal basin located at the southernmost tip of Texas. Tidal flow into this coastal estuary was cut off by construction projects in the 1930s, causing the basin to dry up for ~70 years. In 2005, a pilot channel was built to reconnect the estuary to tidal waters, allowing the basin to refill. However, the pilot channel, in addition to other barriers within the basin, do not allow for adequate tidal exchange, leading to intermittent, extreme hypersalinity. Presumably because of the extreme hypersalinity in parts of the Bahia Grande, seagrass beds, which play vital roles …

Determining The Role Of Human Plasma In Amyloid Fiber Synthesis, Carlee Renee Confer

Theses and Dissertations

The presence of plaques and tangles in the human brain is a major feature observed in several neuropathological diseases including Parkinson’s and Alzheimer’s. Due to the high morbidity and mortality rates of such diseases, research on the characteristics and functions of these highly ordered structures aims to expand the understanding of how the presence of these plaques lead to cognitive decline. Many studies have led to the development of models that suggest that the presence of amyloid plaques and tangles within the brain induce a cytotoxic cycle that results in the suffocation and death of neurons within the brain. A …

Intraspecific And Interspecific Interactions Between Two Species Of North American Vulture At Feeding Sites., Dixie Claire Grammer

Theses and Dissertations

Vultures are a necessity to the natural world. These elite scavengers have the ability to eliminate disease, bacteria, and other harmful pathogens from the environment by simply eating infected carcasses. There are several species of vulture that are threatened with extinction due to a number of reasons, human connotation being one of them. These birds are often persecuted because of their appearance and also because of damage that they have caused. Although at times they may be considered nuisance animals, their need in their environment greatly outweighs the problems they sometimes cause. Research is a way to educate the public …

Regulation Of The Microtubule Cytoskeleton And Cell Wall Development In Arabidopsis Thaliana, Christy J. Fornero

Theses and Dissertations

Regulation of the cortical microtubule cytoskeleton is critical for organized plant cell division. Arabidopsis ton1 and ton2 mutants display random cell division plane placement and lack the plant-specific cortical microtubule array that encircles the nucleus prior to mitosis. In wild type plants, this preprophase band (PPB) of cortical microtubules precisely marks the future division plane. The specific roles of TON1 and TON2 in PPB formation are not yet known. It is suspected that TON1 Recruiting Motif (TRM) proteins may be involved in TON1 and TON2 recruitment to the PPB. Here we describe results for the targeted disruption of a group …

Distribution And Abundance Of Vibrio Parahaemolyticus In Surficial Estuarine Sediment From North Inlet, Sc, Usa, India Briana Gartmon

Theses and Dissertations

Vibrio parahaemolyticus is a ubiquitous coastal organism that causes gastroenteritis (vibriosis) after ingestion of mishandled or undercooked seafood. Cases of vibriosis have increased rapidly in the past decade. V. parahaemolyticus densities have historically been associated with an increase in sea surface water temperatures, but recent shellfish bed closures in fall and winter months in cooler regions (the Baltic Sea, the Pacific NW, and New England) suggest that there may be additional environmental parameters that affect densities of V. parahaemolyticus. The vertical distribution of V. parahaemolyticus was assessed in the pristine North Inlet Estuary (SC, USA). The goal of this …

Evidence For P53-Mediated Induction Of Wrap53a In Response To Dna Damage, Anne Shelton Hucks

Theses and Dissertations

p53 is a powerful tumor suppressor mutated in approximately half of all cancers. Its mRNA is stabilized post-transcriptionally via complementary base pairing with the transcript of its antisense gene, WRAP53α; without this interaction, p53 protein cannot accumulate enough to carry out its many functions related to apoptosis, cell cycle arrest, and DNA damage repair. Previous studies have shown that WRAP53α is induced in response to DNA damage. The purpose of this study was to determine which transcription factors might be responsible for this induction. After identifying three putative p53 binding sites on the WRAP53α promoter, we used chromatin immunoprecipitation …

Assessing The Competitive Advantage Of Carbonic Anhydrase In Estuarine Microalgae Through Removed Enzymatic Activity, Eilea R. Knotts

Theses and Dissertations

Carbon concentrating mechanisms (CCMs) are used by photoautotrophs to overcome possible limitations in carbon acquisition but the competitive strategies and efficiencies of these mechanisms among photosynthesizers can be variable. The diversity in carbon acquisition abilities establishes the potential for alterations in community structure with shifting carbon concentrations. Given the role of phytoplankton and benthic microalgae (BMA) in the trophodynamics of estuaries, understanding the mechanisms of carbon acquisition in these systems is important in predicting how primary productivity and nutrient cycling might change in response to increasing concentrations of atmospheric CO2. Our approach to investigate whether induced carbon limitation would show …

Distribution And Dispersal Potential Of The Endemic Tree Loblolly Bay (Gordonia Lasianthus) In The Southeastern United States Coastal Plain And Implications For Conservation In The Context Of Forecast Climate Scenarios., Herrick Hermann Klaus Brown

Theses and Dissertations

Plant communities in the Southeastern United States Coastal Plain constitute a rich assemblage of species from neighboring floristic provinces and include over 1,000 species endemic to the region. Conservation of these unique landscapes requires a better understanding of potential impacts from human activity and a changing climate. As a model species, the endemic tree Loblolly Bay (Gordonia lasianthus) is representative of Carolina Bays, pocosins, and isolated wetland habitats that accentuate Longleaf Pine ecosystems which dominate the focus area. Seed-dispersal events in Loblolly Bay are limited to periods of relatively low humidity primarily during the months of October to December, and …

Population And Kin Structure Of Hawksbill Turtles: Insights On Natal Homing Precision, Time To Maturity And The Male Component Of The Breeding Population, Kathryn Erin Levasseur

Theses and Dissertations

Marine turtles have long endured population declines and face a growing number of contemporary threats, highlighting the need for population assessments and conservation action. Research on these species, however, remains a challenge due to complex and extensive oceanic life cycles that hinder direct observation. The pelagic, post-hatchling life stage is particularly difficult to track, preventing empirical research of fundamental behavior and life history traits such as natal homing precision and time to sexual maturity. Also, much of our current knowledge of marine turtles comes from nesting females and hatchlings, stages of the life cycle that are easy to observe. Far …

Transformation Of The Dental Faculty To Promote Changes In Dental Educaiton, Clark A. Dana

Theses and Dissertations

This work introduces a series of papers developed to explore the case for change in dental education. Three issues facing dental education are (a) the challenging financial environment of higher education, making dental schools very expensive and tuition-intensive for universities to operate and producing high debt levels for students, which limits access to education and restricts career choices; (b) the profession's apparent loss of vision for taking care of the oral health needs of all components of society and the resultant potential for marginalization of dentistry as a specialized health care service available only to the affluent; and (c) the …

Temperature Influence On Insecticide Resistance In Aedes Aegypti And Aedes Albopictus Mosquitoes From South Texas, Wendy Soledad Salinas

Theses and Dissertations

Aedes aegypti and Aedes albopictus are vectors for several emerging arboviruses including Zika, chikungunya and dengue. Both mosquitoes are found along the Rio Grande River in South Texas, along the border between Mexico and the United States of America. These mosquito species typically reside near human settlements. A preventative measure public health official use to help halt the spread of diseases is by controlling vector population with the use of insecticides, but as temperature vary, and with the constant exposure to commonly used insecticides, mosquitoes from South Texas may be developing a resistance to the insecticides. Resistance to insecticides may …

Comparison Of Eight Remnant Tamaulipan Biotic Province Plant Communities In The Lower Rio Grande Valley Using Multivariate Analyses [Comparación De Ocho Comunidades Vegetales Remanentes De La Provincia Biótica Tamaulipeca El Valle Del Río Grande Usando Análisis Multivariada], Raziel I. Flores

Theses and Dissertations

The Tamaulipan Biotic Province falls within a biogeographic ecotone between temperate North America, the neotropics and the Chihuahuan Desert, and has consequently been defined as “Tamaulipan brushlands.” No quantitative, comparative study has ever been undertaken on the many and varied plant communities that occur in the region. This study compares eight remnant, primary plant communities to test the null hypothesis that the province comprises a single definable vegetation type. Four 50 x 10 m belt-transects were established at each site and woody plants taller than 1 m were recorded to determine species frequency, density, stratification and dominance. Community diversity was …

Connecting The Dots: Exploring The Relationship Between Avian Eggshell Pigmentation And Paternal Provisioning Effort, Kara E. Hodges

Theses and Dissertations

In a number of bird species, eggs laid by females breeding in the same population can vary extensively in the extent of their eggshell pigmentation, but the adaptive significance of this intraspecific variation remains unknown. One hypothesis posits that shell pigmentation is an honest signal of female quality that reflects her level of oxidative stress, one that is used by males to inform their subsequent paternal investment. We employed a reciprocal clutch cross-fostering design to test whether provisioning by male house wrens (Troglodytes aedon) responds to the clutch pigmentation of their mates. In experimental replicates, dark clutches were swapped with …

Mechanism Of Positive, Non-Additive Litter Decomposition, Na Yin

Theses and Dissertations

Litter decomposition is a fundamental ecosystem process. It is responsible for nutrient cycling and influences carbon (C) sequestration, and soil physical and chemical properties. In nature, litter is usually heterogeneous and may not decompose the way homogeneous litter does. For example, heterogeneous litter decomposition is frequently non-additive. This makes the rate of nutrient cycling as well as fluxes of C into and out of soil C pools impossible to predict. The most frequently proposed mechanisms for positive, non-additive decomposition include the supply of limiting mineral nutrients, the supply of available C (priming), and the improvement of micro-environmental conditions. However, all …

The Role Of The Gut Microbiome In Tumor Development And Response To 5-Fluorouracil In The Apc^Min/+ Mouse, Kristen Michele Hogan

Theses and Dissertations

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer related deaths. While CRC is initiated by mutations in critical tumor suppressor genes, its development and progression to malignancy is aided by host derived cells that are recruited to the tumor microenvironment (TME) and by cancer-associated microbiota that constitute the gut microbiome. Components of the gut microbiota have been shown to alter immune cell infiltration into tumors and influence response to therapy, disease stage, and patient survival. In previous studies, we found that ApcMin/+ mice, a model of early colon carcinogenesis, had reduced tumor …

Proteomic And Genomic Evolution Of Phicbkviruses, Kiesha Wilson

Theses and Dissertations

It is estimated that there are 10³¹ phages in the global population. They continue to maintain their populations by undergoing 10²⁴ infections per second. Every time these phages replicate, there is potential for genetic exchange and mutations. Because of this potential, it has been assumed that phage evolution is heavily influenced by mosaicism. However, it is now clear that phage evolution varies by host type and phage type. Here, we use genomic and proteomic analyses to study the evolution of phages that infect Caulobacter crescentus. The study began by comparing six bacteriophage genomes that were larger than …

Regulation Of Arabidopsis Floral Organ Development By The Transcription Factor Aintegumenta-Like6, Jorman Heflin

Theses and Dissertations

Flowers, and the fruits and seeds they produce, are of great agricultural and economic importance. Understanding the molecular mechanisms that mediate the identity, size and arrangement of floral organs within the flower may allow us to tune these elements for increased crop productivity. I examine several potential regulatory targets of the Arabidopsis AINTEGUMENTA-LIKE6 (AIL6) transcription factor that is involved in these processes and I identify protein-protein interactions that may mediate its activity in flowers. As described by the ABCE model, unique floral organ identities are specified in each whorl of the flower by different combinations of homeotic gene activities. Two …

The Persistent Maladaptation Of Pieris Macdunnoughii: Constraints On Adaptation To An Evolutionary Trap, Rachel A. Steward

Theses and Dissertations

Evolutionary traps arise when organisms use novel, low-quality or even lethal resources based on previously reliable cues. Persistence of such maladaptive interactions depends not only on how individuals locate important resources, such as host plants, but also the mechanisms underlying poor performance. Pieris macdunnoughii (Remington) (Lepidoptera: Pieridae) lays eggs on a non-native mustard, Thlaspi arvense (L.) (Brassicaceae), which is lethal to its larvae. However, in the 150 years since T. arvense invaded this butterfly continues to recognize and oviposit on the invasive mustard.

I evaluated two possible constraints on the evolution of decreased preference within an invaded population. First, an …

Adversarial Deep Neural Networks Effectively Remove Nonlinear Batch Effects From Gene-Expression Data, Jonathan Bryan Dayton

Theses and Dissertations

Gene-expression profiling enables researchers to quantify transcription levels in cells, thus providing insight into functional mechanisms of diseases and other biological processes. However, because of the high dimensionality of these data and the sensitivity of measuring equipment, expression data often contains unwanted confounding effects that can skew analysis. For example, collecting data in multiple runs causes nontrivial differences in the data (known as batch effects), known covariates that are not of interest to the study may have strong effects, and there may be large systemic effects when integrating multiple expression datasets. Additionally, many of these confounding effects represent higher-order interactions …