Life Sciences Commons^™

Apoptotic And Necrotizing Mechanisms Of Recombinant Panton-Valentine Leukocidin In Thp1 Monocytes., Heriberto Deleon Iii

Theses and Dissertations

The Panton-Valentine Leukocidin (PVL) is a highly specialized bacterial exotoxin produced by Staphylococcus aureus. The increased degree of invasiveness of community associated methicillin resistant Staphylococcus aureus (CAMRSA) has been attributed to the relatively high rates of PVL produced by the pathogen, thus increasing pathogenicity and virulence. The increased rates of PVL encoding CAMRSA infections have been correlated with increased rates of necrotizing fasciitis, invasive osteomyelitis and invasive necrotizing pneumococcal infections. Previous research as revealed that PVL has the ability to induce apoptosis at low concentration (5nM-10nM) and necrosis (50-100nM) at high concentrations, with little detail on the mechanism of initiation. …

Jatropha Curcas Protoplast Isolation And Inhibitory Effects Of Culture, Christopher S. Lukaszewski

Theses and Dissertations

Improvement on the sub-tropical plant Jatropha curcas may increase the use of this drought tolerant oilseed crop for the production of biodiesel. One of the methods for enhancing a species is through genetic manipulation of the protoplast. Isolating protoplasts is challenging and culturing has many obstacles similar to those seen in tissue culture, such as oxidative browning. Successful isolation of J. curcas leaf protoplasts resulted in an average of 3.23 x 106 viable protoplasts/mL. However, protoplasts diminished within 2 days after culturing. A review of the potential solutions used for overcoming the inhibitory effects of culture may reveal further insight …

Is Metabolism Goal-Directed? Investigating The Validity Of Modeling Biological Systems With Cybernetic Control Via Omic Data, Frank T. Devilbiss

Open Access Dissertations

Cybernetic models are uniquely juxtaposed to other metabolic modeling frameworks in that they describe the time-dependent regulation of cellular reactions in terms of dynamic "metabolic goals." This approach contrasts starkly with purely mechanistic descriptions of metabolic regulation which seek to explain metabolic processes in high resolution — a clearly daunting undertaking. Over a span of three decades, cybernetic models have been used to predict metabolic phenomena ranging from resource consumption in mixed-substrate environments to intracellular reaction fluxes of intricate metabolic networks. While the cybernetic approach has been validated in its utility for the prediction of metabolic phenomena, its central feature, …

Influence Of The 3d Microenvironment On Glioblastoma Migration And Drug Response, Ruth Marisol Herrera Perez

Open Access Dissertations

Glioblastoma (GBM) is a highly invasive brain cancer characterized by poor prognosis. Despite significant efforts by the basic and clinical research community our understanding of GBM progression and recurrence has been incremental. Improvements in therapeutic response have been dismal, and GBM continues to be the deadliest tumor of the central nervous system, with patient average survival rate of 12 months. Synergistic relationships that the tumor cells establish with the brain microenvironment have been proven fundamental for successful tumor progression and maintenance. Yet, many in vitro GBM studies are performed in formats that fail to recapitulate the most essential component of …

Microbial Ecology Of Waterborne Pathogens In Sus Scofra And Odocoileus Virginianus In The Jackson Bienville Wildlife Management Area, Jaymes Hunter Collins

Doctoral Dissertations

Previous studies have demonstrated that feral swine (Sus scofra ) are significant reservoirs for a number of pathogens that present a potential threat to wildlife and humans. Despite this, few studies have gone beyond quantifying the incidence of these pathogens to further probe their ecology within a specific habitat or ecosystem.

Overall, the objective of this study was to characterize three potential reservoirs in a feral swine infested habitat; two ungulates, and one aquatic reservoir. Our study area was the Jackson-Bienville Wildlife Management Area (J-B WMA). We chose four waterborne bacteria: Brucella spp., Leptospira interrogans, Salmonella enterica, and Helicobacter …

Clay Nanotube Composites For Antibacterial Nanostructured Coatings, Christen J. Boyer

Doctoral Dissertations

A surging demand for the development of new antimicrobial nanomaterials exists due to the frequency of medical device-associated infections and the transfer of pathogens from highly touched objects. Naturally occurring halloysite clay nanotubes (HNTs) have shown to be ideal particles for polymer reinforcement, time-release drug delivery, nano-reactor synthesis, and as substrate material for nanostructured coatings.

This research demonstrates the feasibility of a novel method for coating HNTs with metals for antibacterial applications. The first ever ability to coat HNTs through electrolysis was developed for customizable and multi-functional antibacterial nanoparticle platforms. HNTs were investigated as substrate for the deposition of copper …

Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr.

Doctoral Dissertations

The National Cancer Institute and the American Cancer Society estimate that 1.6 million new cancer incidences and over half a million cancer related deaths occur annually [1][2]. Cancer the second most common cause of death in the United States [1], [2]. Although the causes of cancer can vary depending on cell type, all or almost all instances of cancer arise from a mutation or from an abnormal activation of the cellular genes that control cell growth and mitosis [3].

Treatment of a given cancer type depends on the subtype, stage and progression of the cancer. Varieties of cancer therapy include …

Alternative Regulation Of Myc In Lung Cancer, Patrick N. Backman

Open Access Theses

Lung cancer is the leading cause of cancer deaths in the United States, accounting for 27% of all cancer induced deaths1. In an attempt to create a effective targeted therapy for the treatment of lung cancer, a strategy used to treat an activated KrasG12D/+;p53 R172H/+ transgenic lung cancer mouse model was to deliver a known tumor suppressive microRNA (miRNA) to stop tumor growth. The tumor suppressive miRNA let-7 was lentivirally delivered in the form of its primary transcript, pri-let-7a-1, and resulted in increased lung size and inflammation compared to lungs exposed to a control lentivirus. It was identified …

An Inventory Of Endemic Leaf Litter Arthropods Of Arkansas With Emphasis On Certain Insect Groups And Diplopoda, Derek Alan Hennen

Graduate Theses and Dissertations

Endemic arthropods of Arkansas were sampled and their nomenclature and distributions were updated. The Arkansas endemic species list is updated to 121 species, including 16 species of millipedes. A study of the millipedes of Arkansas was undertaken, and resulted in the first checklist and key to all millipede species in the state. 68 species are known from Arkansas, including the genera Cylindroiulus and Polydesmus. The first state records for Ophyiulus pilosus, Cylindroiulus sp., and Ptyoiulus coveanus are reported, and new county records are reported for 16 species. This represents the first key to a state's species since 1980, and the …

Validating Side Scan Sonar As A Fish Survey Tool, Michael A. Bollinger

Theses and Dissertations

Hydroacoustic methods can be used to answer a variety of questions regarding fish populations and behavior. In this study, side scan sonar methodology was developed to quantify abundance and biomass and compared to established visual observation methods on SCUBA over artificial reef structures in the western Gulf of Mexico. Side scan sonar methods were equivalent to SCUBA surveys for measuring fish abundance over the same reef areas, however, abundances were significantly higher when the larger area sampled by side scan was utilized. Side scan sonar methods were also more time efficient than SCUBA, ROV and long line fishing methods (66.7%, …

Examination Of The Chagas Disease Vector, Triatoma Gerstackeri, In The Lower Rio Grande Valley, Alfredo Flores

Theses and Dissertations

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, which is carried by an insect vector of the family Reduviidae, and of the subfamily Triatomina. The species Triatoma gerstaeckeri is identified as the primary vector of T. cruzi within the Rio Grande Valley. Species of Triatoma gerstaeckeri were trapped in La Sal del Rey National Refuge in 2012 and 2013.

Data indicates a seasonal dispersal pattern of activity for T. gerstaeckeri. Optimal time of capture was between 1-2 hours after sunset. Different methods were utilized to determine the best combination of lures. Results indicate that the UV-light alone is …

Decomposition And Nitrogen Dynamics Of Turtle Grass (Thalassia Testudinum) In A Subtropical Estuarine System, Monica Delgado

Theses and Dissertations

Seagrass beds are pivotal in the functioning of coastal ecosystems in terms of productivity, organic matter turnover and nutrient cycling. Aiming to document decay and nitrogen (N) dynamics of turtle grass (Thalassia testudinum) in a subtropical estuarine system, decomposition patterns of leaves and rhizomes were characterized and compared. Nitrogen usage during decomposition of tissues, and of live tissues and epiphytes growing on live leaves, was also quantified and compared. Stable isotope ratios allowed tracing N within the seagrass bed, following N incorporation into seagrass tissues from the surrounding media (water, sediment). Leaves had a higher N content and decomposed at …

Activation Of Microglia In The Rotenone Lymnaea Stagnalis Model Of Parkinson's Disease, Xiomara Galvan

Theses and Dissertations

Parkinson’s disease (PD) is the most common irreversible neurodegenerative movement disorder affecting approximately ten million people worldwide. In the central nervous system (CNS), PD is known by the selective loss of Dopamine (DA) cells of the substantia nigra pars compacta. Although the disease has been very widely studied, the underlying mechanisms are not yet understood. Several hypotheses have arisen as result of injury of the mitochondria, some experiments include microglia activation, microtubule damage, and reactive oxidative species, which all result in the death of DA cells. The theory of microglia activation upon inflammation was explored in this study. Using the …

Balanus Eburneus (Crustacea: Cirripedia) As A Potential Indicator Of Estuarine System Recovery In South Texas: A Study Of Recruitment, Growth And Stable Isotopes, Crystal Martinez

Theses and Dissertations

Population characteristics of the barnacle Balanus eburneus were analyzed with the purpose of exploring its potential use as a discriminating indicator among sites exhibiting different disturbances or stages of recovery. The study was conducted from May 2012 to May 2013 at four estuaries in the Lower Laguna Madre, TX including a) Bahia Grande, currently under restoration and divided into Bahia Grande North and Bahia Grande South, b) San Martin Lake, which receives runoff water and c) South Bay, a relatively undisturbed reference estuary. In general, similar barnacle recruitment and growth trends in Bahia Grande South and South Bay were explained …

Effects Of Shrub Encroachment And Removal On South Texas Coastal Prairie Flora, Parker Alex Watson

Theses and Dissertations

Watson, Parker Alex, Effects of shrub encroachment and removal on South Texas coastal prairie flora. Master of Science, December, 2015. 60 pages, 14 tables, 11 figures, 47 references, 5 appendices. Native-invasive honey mesquite (Prosopis glandulosa) and huisache (Acacia farnesiana) are aggressively encroaching onto South Texas coastal prairies, outcompeting Gulf cordgrass (Spartina spartinae) and associated prairie vegetation with potential legacy effects on the landscape. To measure conditions in the presence of shrubs, data loggers were installed for 16 mos in shrub understories and grass cover to monitor light, soil and air temperatures. Vegetation and canopy surveys were also conducted to evaluate …

Comparing Reproductive Capacity Of Nearshore And Offshore Red Snapper, Lutjanus Campechanus, On Artificial Reefs In The Western Gulf Of Mexico, Ricky J. Alexander

Theses and Dissertations

Red snapper collected quarterly from four artificial reefs in south Texas were examined to compare total length, total weight, age, and the proportion of male to female red snapper, calculate gonadosomatic index values, batch fecundity, annual spawning frequency, and annual fecundity, and estimate size and age at maturity. Spawning occurred from April to September, with most active spawning observed in June (58%). Despite larger red snapper producing more eggs, and fish being larger offshore, most active spawning (68%) and egg production (74%) was observed nearshore. Female red snapper reached 50% maturity (L50) between 350-550 mm, and L75 by 600 mm. …

Infection Rates And Distribution Of Trypanosoma Cruzi In Triatomine Insects From Several Public Parks Of Starr, Hidalgo And Cameron Counties, Carlos Guzman Jr.

Theses and Dissertations - UTB/UTPA

Chagas disease is caused by the protozoan Trypanosoma cruzi and is a major public health concern in many areas of the world, including the United States. The disease is transmitted by insect vectors known as kissing bugs from the subfamily Triatominae. While the majority of studies focus on domestic and peri-domestic collections, this study collected insect vectors from state parks in the Lower Rio Grande Valley. PCR analysis was done to obtain infection rates for collected insects, and a morphological examination was done to check insects for gender. In total 18 insects were captured with 12 of the captured insects …

Exploration Of Nickel Tolerance And Hyperaccumulation In Arabidopsis Thaliana Transformed With Streptanthus Polygaloides Metal Tolerance Protein 1 (Spmtp1) Cdna, Madeleine K. Sano

Theses and Dissertations - UTB/UTPA

This study evaluated the role of hyperaccumulator S. polygaloides Metal Tolerance Protein 1 (SpMTP1) in conferring Ni tolerance and accumulation in the non-accumulator Arabidopsis thaliana. Analysis for Ni content in transgenic Arabidopsis transformed with SpMTP1, following a 12-day treatment of 100 µM Ni, showed a significant increase in Ni concentration in comparison to the wild-type Arabidopsis and empty vector transformed plants. Exposure of transgenic Arabidopsis to nickel also resulted in a coordinated increase of antioxidant enzyme (superoxide dismutase, glutathione reductase, and catalase) activities in the transgenic Arabidopsis, suggesting that increased activities of these oxidative stress response (OSR) proteins may be …

Characterization Of Oxidative Stress Response Proteins In Metal-Tolerant And Metal-Sensitive Brassicaceae Plant Species, Luis M. De Santiago

Theses and Dissertations - UTB/UTPA

In this study the expression of oxidative stress response (OSR) proteins in nonaccumulator and hyperaccumulator plant species of the Brassicaceae family were characterized. Oxidative stress was induced via nickel treatment and proteins were characterized through western blotting and image analysis. Statistical analysis indicated that the nonaccumulator species Arabidopsis thaliana significantly decreased catalase (CAT), glutathione reductase (GR), copper/zinc-dependent superoxide dismutase (Cu/ZnSOD), iron-dependent SOD (FeSOD), manganese-dependent SOD (MnSOD) and metal tolerance protein 1 (MPT1) expression in response to Ni-treatment. The hyperaccumulator species Thlaspi montanum variety montanum displayed either no significant change or a significant increase in OSR regulation following Ni-treatment with the …

Ecosystem Services Of Urban Trees And The Impacts Of Urbanization, Jorge E. Cantu

Theses and Dissertations - UTB/UTPA

The University of Texas- Pan American has conducted a complete survey of campus trees in partial fulfillment of the requirements for membership in the International Society of Arboriculture Designation of Tree Campus USA. This tree inventory was accomplished with the help of students whom were trained by faculty and foresters. Other than the completion of the tree inventory, this thesis had two main goals; 1) valuate the ecosystem services provided by campus trees 2) create a unique service learning project that other institutions can model. According to our calculations, the trees on campus have sequestered 568,652 kg of CO2, avoided …

Loss Of Mitochondrial Dna Causes Decreased Cell Viability, Alan M. Herrera

Theses and Dissertations - UTB/UTPA

Mitochondria are an organellar network involved in cellular bioenergetics and apoptosis, and dynamically balance their organization between fusion and fission events. Mitochondrial DNA (mtDNA) and nuclear DNA combine to encode polypeptides for the complexes of oxidative phosphorylation (OXPHOS) in the mitochondrial inner membrane, which generate a transmembrane potential (ΔΨm) to synthesize ATP. Loss of ΔΨm causes mitochondrial fission, which appears to be associated with the progression of apoptosis, a critical cell death mechanism that allows tissue homeostasis, developmental sculpturing, and the removal of unwanted cells. Using cultured human cell models of decreased ΔΨm (both genetic mtDNA-depleted ρ 0 and pharmacological …

Functional Analysis Of The Mms19 Gene In Carica Papaya, Jorge A. Trujillo

Theses and Dissertations - UTB/UTPA

All organisms face DNA-damaging radiation in the form of UV light and must have mechanisms to repair or undo damage. Plants being stationary organisms must cope with damaging UV rays in a molecular fashion and so have developed many forms of resistance. MMS19 is implicated in DNA repair indirectly as a nuclear encoded gene that binds onto protein assembly complexes in the cytosol. A mutant within the SunUp variety of Carica papaya has a large deletion for MMS19 and presents a diminutive phenotype. Deficient DNA repair mechanisms will shunt cells out of the natural cell cycle and reduce cell proliferation …

Dlipin-A Link Between Lipid Metabolism, Glucose Homeostasis And Growth In Drosophila Melanogaster, Sandra Schmitt

Graduate Theses and Dissertations

Lipins are a family of highly conserved proteins found from yeasts to humans. Lipins have dual functions, serving as phosphatidate phosphatase enzymes (PAP) in the synthesis of neutral fats (triacylglycerols, TAG) and as transcriptional co-regulators that affect the expression of genes involved in lipid and fatty acid metabolism. Thus, they play central roles in metabolic control. Disruption of Lipin function has been implicated in lipodystrophy, obesity and insulin resistance. Using dLipin, the Drosophila homolog of Lipin, as a model, I aimed to elucidate the relationship between the two biochemical functions of Lipin and metabolic homeostasis. I discovered there is a …

Management Of A Primordial Problem: Redox-Sensitive Transcriptional Regulation In Methanosarcina Acetivorans, Ryan Christopher Sheehan

Graduate Theses and Dissertations

The primordial Earth which hosted the first forms of life was an environment free of oxygen. Early organisms utilized metabolisms dependent upon anaerobic conditions and incorporated systems to which oxygen is deleterious. As the content of oxygen in Earth's atmosphere increased, anaerobic organisms had to acquire methods to sense and combat oxygen and reactive oxygen species. Several mechanisms were advantageous to such anaerobic organisms which correlated transcriptional processes with the redox state of the cell so that energy may be conserved and oxygen stress recovery genes activated during periods of oxidative stress. Iron sulfur (Fe-S) cluster cofactors incorporated within RNA …

Differential Gene Expression Between Two Developmental Stages Of The Gené'S Organ In The Cattle Fever Tick, Rhipicephalus (Boophilus) Microplus, Jason P. Tidwell

Theses and Dissertations - UTB/UTPA

The southern cattle fever tick (SCFT), Rhipicephalus microplus, is considered the most economically important ectoparasite of livestock worldwide and ranks sixth among the most pesticide resistant arthropods globally. This single-host hard tick is a vector of the infectious agents causing bovine babesiosis and anaplasmosis. The estimated impact of these SCFT-borne diseases on the livestock industry in the world is $7 billion annually. This project focuses on the Gené’s organ and addresses the need to identify novel targets that can serve as the basis for sustainable SCFT control strategies. Wax secreted by the Gené’s organ protects tick eggs from desiccation, bacterial …

The Role Of Oxidative Stress In The Rotenone Model Lymnaea Stagnalis, Homero L. Cantu

Theses and Dissertations - UTB/UTPA

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, characterized by progressive depletion of dopamine (DA). Rotenone, a common pesticide, can induce PD like symptoms in animal models. The goal of this thesis is to quantify the levels and effects of reactive oxygen species (ROS) in brain tissue of the common neurobiological gastropod model, Lymnaea stagnalis, after treatment with Rotenone. The results show that rotenone causes a behavioral deficit and increases ROS production, especially superoxide. Furthermore, glutathione was depleted and protein carbonyl formation increased. These results are consistent with findings in human PD and the high levels of ROS …

Preliminary Transcriptome Analysis And Homeobox Gene Isonlation For Tomocerus Minor (Entomobryomorpha: Tomoceridae), Alejandro Alaniz

Theses and Dissertations - UTB/UTPA

Collembola, or “springtails,” are small, edaphic arthropods classified as Entognatha; a group traditionally included as part of Hexapoda and sister-group to the true insects. However, some genetic studies suggest that they may instead have derived from a separate crustacean lineage rather than from a proto-Insecta lineage. The unique abdominal structures that develop on the collembolan ventral abdomen appear to be appendicular in origin – atypical to the canonical, appendage-less insect abdomen ground plan. I developed culture and embryo fixation protocols for; and sequenced and analyzed a multi-stage embryo transcriptome for Tomocerus minor (Collembola: Entomobryomorpha). This analysis annotated 14,417 distinct genes, …

Expression And Functional Characterization Of Mtp Genes From Arabidopsis Thaliana In Saccharomyces Cerevisiae, Yessica E. Cerino

Theses and Dissertations - UTB/UTPA

In this study the functional characterization and overexpression of Metal Tolerance Protein (MTP) cDNA were evaluated using a transgenic yeast (Saccharomyces cerevisiae) model system as a preliminary means for the characterization of metal tolerance conferred by putative Group III MTP genes from Arabidopsis thaliana. Metal disc assays for nickel, zinc, cobalt and cadmium treatments were performed to measure the tolerance imparted to yeast by the MTP cDNAs. Statistical analysis from zinc and cadmium assays showed AtMTP1 imparted the highest zinc tolerance in yeast, while AtMTPB1 imparted the highest cadmium and cobalt tolerance. However, AtMTPA2 and AtMTPB produced a decrease in …

Management Of Silverleaf Whitefly, Bemisia Argentifolii Bellows And Perring (Hemiptera: Aleyrodidae), Using Non-Crop Companion Plants In Organically-Managed Cantaloupe Systems In South Texas, Ruth Renee Colyer

Theses and Dissertations - UTB/UTPA

Field trials in three separate phases of research were carried out from March, 2010, to August, 2012, to determine the effects of inter-cropping cantaloupe (Cucumis melo var. inodorus) with select non-crop companion plants in an effort to develop organic production strategies for melons in South Texas without the use of pesticides. A research program was designed and initiated to assess the effects of the companion plants and their ability to: 1) attract insect pollinators, and 2) repel or suppress pest species without affecting beneficial natural enemy complexes. The hypotheses were: 1) that organically-managed cantaloupe systems grown with non-crop companion plants …

Isolation And Characterization Of Polychlorinated Biphenyl (Pcb) Degrading Bacteria Isolated From A Pcb Contaminated Reservoir In Donna, Tx, Sergio Cepeda

Theses and Dissertations - UTB/UTPA

The Donna Irrigation System (DIS) located in Donna, Hidalgo County, TX, was confirmed to be contaminated with polychlorinated biphenyls (PCBs) in 1993 and remediation of the site will be attempted in the future. The need to isolate novel PCB degrading bacteria for bioremediation has been an active area of research in recent decades; thus, it was hypothesized that a variety of microorganisms able to degrade PCBs could be isolated from sediments taken from the DIS. Two genes of the PCB degradation pathway, bphA1 and bphC, were detected in 43 bacterial isolates grown from DIS sediments using molecular and culture-based methodology, …