Life Sciences Commons^™

Co-Infection Of Zika And Dengue Virus In Aedes Aegypti And Aedes Albopictus Mosquitoes, Felicia Vazquez

Theses and Dissertations

The term co-infection describes an event when multiple pathogens infect a single host. For vector-borne diseases, a vector may become co-infected by feeding either on a single host that has multiple pathogens or feeding multiple hosts, each of which may be infected. Co-infection in non-vector hosts has been shown to influence immune response and eventual outcome of disease, and is likely to have a similar impact on vector species. With multiple vector-borne diseases circulating in South Texas, the potential for co-infection exists. We examined when mosquitoes are infected with one virus and subsequently infected with another. We hypothesized that the …

Effects Of Invasive Nilgai Antelope (Boselaphus Tragocamelus ) Browsing On Black Mangrove (Avicennia Germinans) In South Texas: A Study On Microenvironmental, Physiological, Structural, And Reproductive Parameters, Tianna Picquet

Theses and Dissertations

Mangroves are important for coastal systems because they provide habitat for fish and bird species, mitigate erosion, and create an area for carbon sequestration. Along the Gulf of Mexico, at the southern tip of Texas, recent observations have shown that A. germinans stands (the dominant species in Texas) are being browsed on by invasive nilgai antelope (Boselaphus tragocamelus). The antelope were introduce to the south Texas region via King Ranch in the 1930’s and have since significantly increased in population and distribution. Previously thought to be grazers, B. tragocamelus were captured on camera utilizing A. germinans as a …

Local Delivery Of Mesenchymal Stem Cells Expressing Osteogenesis-Inducing Microrna For Bone Tissue Engineering Applications, Marco Antonio Arriaga

Theses and Dissertations

Bone is capable of regenerating autonomously when the injury is small (< 2.5 cm), however, large (> 2.5 cm) or insufficiently vascularized defects require intervention to repair. The overall goal of this project is to contribute towards the development of novel strategies to aid bone tissue regeneration by delivering mesenchymal stem cells expressing microRNAs that induce expression of the runt-related transcription factor 2 (RUNX2). It was determined that porous polycaprolactone (PCL) scaffolds fabricated to have a higher surface area to volume ratio (SVR) (> 80) compared to lower SVR (< 80) were hydrolyzed at a higher rate. Scaffolds fabricated with 80 vol. %/300–500 µm porogen were optimal for cell colonization as higher absorbance of metabolized MTT was detected compared to other scaffold types. From the subset of 5 miRNAs tested, miRNA-26a, miRNA-196 and miRNA-218 demonstrated higher upregulation of RUNX2 gene expression and calcium mineralization and thus, are promising candidates for bone tissue regeneration.

A Phylogenetic Analysis Of Leptogorgia Virgulata And Leptogorgia Hebes In The Northwestern Gulf Of Mexico, Samantha Silvestri

Theses and Dissertations

The use of genetics in recent years has brought to light the need to reevaluate the classification of many gorgonian octocorals. In 2017, Poliseno et al. conducted a comprehensive, phylogenetic study of the genus Leptogorgia and found that it, too, was in need of taxonomic revision. To expand on their study, 25 samples representing two Leptogorgia species—L virgulata and L. hebes —from the northwestern Gulf of Mexico (GOM) were examined. Ten novel, complete mitochondrial genomes were sequenced using Next Generation sequencing and 24 novel mtMutS sequences were obtained from both species. The phylogenies reconstructed from these sequences indicate the …

Arabidopsis Thaliana Transformed With Streptanthus Farnsworthianus Metal Tolerance Protein 1 (Sfmtp1) Or The Native A. Thaliana Metal Tolerance Protein 1 ( Atmtp1) Cdna And The Effects On Sod Enzyme Activity Upon Nickel Treatment, Selina Urbina Fernandez

Theses and Dissertations

Superoxide Dismutase enzyme activity was analyzed in transgenic Arabidopsis thaliana, a non-accumulator weed plant species of the Brassicaceae family, that was transformed with Streptanthus farnsworthianus Metal Tolerance Protein1 (SfMTP1) or A. thaliana Metal Tolerance Protein 1 (AtMTP1 ). The transgenic A. thaliana was exposed to a 12 day treatment of 100 ?M Nickel Acetate in 1/10 X Hoaglands solution in hydroponics. Analysis of Super Oxide Dismutase activity determined that transgenic A. thaliana transformed with the AtMTP1 cDNA and treated with 100 µM Nickel showed a significant increase in Super Oxide Dismutase activity compared to A. thaliana …

Embryology And Wing Development In A Dragonfly (Tramea Onusta), Valeria M. Casas

Theses and Dissertations

Most phylogenetic research within the insect phylogeny is focused on higher order taxons. Therefore, to better understand insect wing and flight origin, genetic studies on more primitive insect orders is necessary. Odonata, the order including dragonflies, is one of the earliest insect taxa to develop wings. Hox genes are highly conserved regulatory genes involved in embryonic development of organisms. Hox gene expression studies in insects allow improved insight of body plan development including wings. Embryonic development of dragonfly, Tramea onusta, was analyzed at various developmental stages. Developmental genes Antennapedia, Distal-less, Ultrabithorax, abdominal-A, Abdominal-B, engrailed, Cadual, engrailed 2, Wingless, nubbin, …

Questing Activity Of Cattle Fever Tick Larvae, Rhipicephalus (Boophilus) Microplus (Acari: Ixodidae): Environmental Influences And Implications For Control In South Texas, Brenda Leal

Theses and Dissertations

Questing ticks ascend stems, leaves, or rocks, extend their front legs, and wait poised for attachment to a passing host. Ixodid ticks have four developmental stages. Because ticks detach and molt between stages most ticks require three separate hosts to complete their lifecycle. Three-host ticks quest for a new host between each stage, whereas a few specialist tick species remain on and thus require only a single host. These one-host ticks only quest for hosts as larvae. As much as 90% of the life cycle may consist of questing when hosts are scarce. Most of the literature on questing relates …

Nannochloris Sp. And Oocystis Sp. Algae Exposed To Osmotic Stress For Increased Lipid Production For Use In Biofuels, Laura M. Chavez

Theses and Dissertations

Algal biofuel research is important due to the potential need for replacement of non-renewable fossil fuels and a changing global climate. Under stress, algal cells tend to increase neutral lipid production, which are a suitable source for biofuels. The goal of this study was to subject Nannochloris sp.. and Oocystis sp. algal cells to osmotic stress by modifying sucrose and salinity levels in different treatment medias.

The treatment containing the lowest salinity (15 ppt) and no sucrose yielded the highest lipid fluorescence/cell in Nannochloris sp.. cells (0.00142 ± 0.00044) on day 2 while the treatment containing highest salinity (35ppt) …

Environmental Conditions In San Martin Lake: Effects Of Eutrophication In An Estuary Associated With The Laguna Madre, Wendy L. Rogers

Theses and Dissertations

San Martin Lake is a shallow water Estuary in the lower Laguna Madre off the Port of Brownsville Shipping channel. It is influenced both by incoming tides and waste water runoff both from local farms and the Brownsville water treatment plants. The resulting mixture of eutrophic water and incoming sea water creates the perfect mix for a potential algal bloom. This study looks at the nutrient levels and environmental conditions in the main basin of the estuary to establish baseline levels and to observe the rate of nutrient clearing being accomplished in this environment. As sport recreation in the area …

Survey Assessment Of Community Knowledge And Prevention Of Chagas Disease And Its Vector In Hidalgo And Cameron Counties, Adam Dennis Wiejaczka

Theses and Dissertations

Chagas disease, caused by the parasite Trypanosoma cruzi, kills thousands of people annually and is the dominant cause of infectious myocarditis worldwide. Kissing bugs are vectors that carry T. cruzi . and are found in the Lower Rio Grande Valley (LRGV). There is no vaccination nor cure for Chagas. The best mechanism of prevention is to control vector infestations. Little research is available regarding the level of understanding local communities have about Chagas.

Our goal was to test the knowledge of several communities in the LRGV on Chagas disease. Our hypothesis states that local communities do not have sufficient …

Trichomonas Vaginalis Cytoadherence Is Modulated By Oxidative Stress, Magali Ayala

Theses and Dissertations

The adherence of Trichomonas vaginalis to the human urogenital tract is a prerequisite for the pathogenesis of the infection. This multifactorial process is modulated by environmental factors such as iron, estrogen, temperature and pH and specific receptor/ligand interactions. During natural infections, the anaerobe T. vaginalis is exposed to oxygen resulting in oxidative stress. This environmental change may alter trichomonad cytoadherence to the ectocervical tissue. Therefore, it was hypothesized that changes in the redox status of T. vaginalis may modulate cytoadherence levels. Results showed that oxidative stress reduces levels of trichomonad cytoadherence to HeLa cells by > 50% when exposed to 150 …

Characterization Of Urban Wetland Vegetation And Management Practices, Megan Anne Larson

Graduate Dissertations and Theses

Urban wetlands are important ecosystems that moderate flooding risks and improve water quality. Vegetation is a key component of urban wetlands; plants promote sedimentation, play critical roles in biogeochemical cycling, and provide food and habitats for other organisms. My research focuses on the standing vegetation and seed banks of urban wetland plant communities. Urban wetlands in south-central New York had a higher percent cover of invasive species in the standing vegetation and significantly lower species richness; however, native species were also common in urban flora. These sites had a high percentage of obligate wetland species, and most closely resembled emergent …

Investigating The Role Of Nuclear Foxo3 In Pten-Null Glioblastomas, Lilia Sanchez

Theses and Dissertations

The PI3K pathway activates AKT, leading to inactivation of FOXO transcription factors. Loss of PTEN results in constitutive inactivation of tumor suppressor FOXO. There is increasing evidence that FOXO resides and promotes transcriptional activity in the nucleus despite high PI3K output within certain advanced cancers and embryonic stem cells. Here, we investigate the regulation and roles of FOXO transcription factors in glioblastoma and basal breast cancer. First, we built and published genetic models to investigate the roles of FOXO transcription factors in cancer cell lines for glioblastoma (U87MG). We examined the function of FOXO transcription factors using these genetic models …

Regional Distribution, Non-Invasive Detection, And Genetic Diversity Of The Black-Spotted Newt (Notophthalmus Meridionalis), Evan A. Bare

Theses and Dissertations

The Black-spotted Newt (Notophthalmus meridionalis ) is one of three a salamander species native to Gulf Coast prairies of Texas and Mexico, with respective state and federal protections. This species has been neglected by the scientific community despite concerns of dramatic population declines and a globally endangered status, with the most recent work being conducted in the early 1990’s going unpublished. This study presents the most recent examination of the species providing probabilistic distribution maps, descriptions of three novel populations, assessments of surveying techniques, and the first known examination of intrapopulation genetics including the first documented genetic examination of …

Metabolic Dysregulation: An Investigation Of The Role Of Foxo3 In Gluconeogensis In Pten-Null Glioblastomas, Victor Fanniel

Theses and Dissertations

Many processes are regulated by the Phosphatidylinositol 3 kinase (PI3K) pathway in the cell including cell survival, metabolism, and apoptosis. Increased activation of the PI3K pathway is a hallmark of many cancers which can be oftentimes attributed to the mutation of PTEN, which encodes an enzyme that performs the reverse reaction of PI3K. When PTEN is null-mutated, this creates a constitutively active PI3K pathway and constitutively active AKT. Since AKT phosphorylates conserved residues on FOXO transcription factors to mark them for nuclear export, this renders FOXO inactive. However, new research has provided evidence that FOXO is still present in …

Monitoring Wildlife Guards And Crossing Structures On A Divided Highway In South Texas, Tiffany C. Cogan

Theses and Dissertations

To mitigate ocelot (Leopardus pardalis albescens ) road mortality, Texas Department of Transportation installed fencing, wildlife road crossing structures (WRCS, n = 5), and wildlife guards (WG, n = 18) on divided State Highway 100 in Cameron County, Texas. During construction, active infrared (AIR, n = 24) and passive infrared (PIR, n = 24) cameras were side-by-side at WRCS (n = 6) and WG (n = 6). Community composition was significantly different (p = 0.0001) between camera types with AIR cameras detecting a more diverse and abundant community. Wildlife community was significantly different (p = 0.0002) between three WRCS …

Progress And Potential Of Two Biological Control Agents Of The Invasive Giant Reed (Arundo Donax L.), Madeline Marshall

Theses and Dissertations

Biological control, or the use of natural enemies for pest management, may the best long-term option for managing the invasive Arundo donax , a noxious weed dominating riparian habitats globally and along the Rio Grande River. This work reports on the progress and potential of two arundo biological control agents permitted for release in Texas and Mexico. The arundo wasp, Tetramesa romana, released in 2009, is having significant impacts as reported from various field locations around the world, described here using standard exit hole counts. The highest density levels were found in Texas (introduced range) compared to relatively low …

Species Delimitation Among Southeastern Us Oxyloma (Gastropoda: Succineidae), Marco A. Martinez Cruz

Theses and Dissertations

The Succineid genus Oxyloma found throughout Canada and United States contains approximately 15 described species whose criterion for differentiation is considered unreliable. As a first step towards understanding the evolutionary history and revising the taxonomy of North American Oxyloma, we have sampled four species found in eastern North America (O. salleana, O. subeffusa, O. effusa, and O. retusa) from their type localities. We used mitochondrial COI, and nuclear LSU sequences with samples found across their range and members of the family to produce a phylogenetic hypothesis of evolutionary relationships and test species boundaries. Molecular phylogeny and species …

A Phylogeographic Analysis Of Black Coral (Antipatharia) On Artificial And Natural Reefs In The Northwestern Gulf Of Mexico, Heather Otte

Theses and Dissertations

NOAA's Islands in the Stream concept (IitS) of designating networks of marine protected areas as refugia in the Gulf of Mexico depends on genetic connectivity. Isolated habitats like those proposed by the IitS occur naturally off the Texas coast where hard-bottom structures protrude from mudflats, offering a small-scale study of the IitS feasibility. Two sequences, mitochondrial 16S ribosomal RNA and nuclear internal transcribed spacer, were used to build haplotype networks of Antipatharians (Anthozoa: Hexacorallia), corals with planktonic larvae that can act as a proxy for connectivity of other organisms. Two species showed no significant genetic differentiation or pattern of genetic …

Functional Variation In The Mitochondrial Genome Of The Yeast Saccharomyces Cerevisiae, John F. Wolters

Graduate Dissertations and Theses

Mitochondrial haplotypes contribute to functional diversity in natural populations. Uniparental inheritance makes it difficult to characterize the genetic architecture of mitochondrially driven phenotypes. In this work I explored the natural diversity of mitochondrial genomes in the yeast Saccharomyces cerevisiae. Few complete mitochondrial genomes were available for S. cerevisiae owing to challenges in high-throughput sequencing. I developed sequencing strategies using new technologies to generate complete high quality yeast mitochondrial genomes. Comparisons of 100 complete yeast mitochondrial genomes demonstrated extensive variation between populations in coding sequences and variable introns.

I demonstrated that these mitochondrial variants directly caused growth differences in strains with …