Biology Commons^™

Detecting Snake Fungal Disease (Ophidiomyces Ophiodiicola) In The Lower Rio Grande Valley, Manuel Zavala

Theses and Dissertations

Emerging diseases such as Snake Fungal Disease (SFD) caused by the fungus Ophidiomyces ophiodiicola (Oo) have caused population declines in various snake species in the United States which play a crucial role in the ecosystem as a natural pest control. This fungus targets the scales as a medium to thrive on which can lead to facial disfiguration and respiratory infections. We examined snakes to see if SFD was present in the LRGV and if other fungal species pose a threat to the various snake species population. The data for this study consisted of 14 live snakes captured in …

Discerning Competitive Vs. Facilitative Relationships Of Weeds On Forest Restoration Efforts At La Sal Del Rey, Tx, Mylen A. Arias

Theses and Dissertations

Dryland ecosystems need effective restoration strategies to address severe degradation. It is often assumed that voluntary forb weeds either compete with or have no effect on native seedlings. In contrast, theory and empirical work suggest a potential facilitative role for such forb weeds. We conducted a manipulative weed exclusion experiment at a semi-arid site in South Texas targeted for large scale forest restoration and subsequently dominated by early successional forb weeds to discern the net effect of these weeds on the growth and survival of target thornscrub tree and shrub seedlings. Overall, weed presence did not significantly affect seedling mortality …

Developing Methods To Survey, Collect, Process, And Screen Endemic Entomopathogenic Fungi Against The Asian Citrus Psyllid In The Lower Rio Grande Valley, Jonathan Cisneros

Theses and Dissertations

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vectors “Candidatus Liberibacter spp.”, the causative agent of Citrus Greening Disease. Managing ACP is imperative given the continuous increase in HLB positive trees. An aspect of integrated pest management (IPM) is the use of entomopathogenic fungi for the biological control of D. citri.

In order to identify endemic entomopathogenic fungi actively infecting D. citri, ACP were collected from local residential areas, surface sterilized, and plated on a semi-selective agar medium. Collection of over 9,300 samples from 278 sites throughout the LRGV led to the positive identification of …

Disturbance, Defense And Fitness In Silverleaf Nightshade (Solanum Elaeagnifolium) In Their Native Range In South Texas, Jesus Chavana

Theses and Dissertations

The role of human disturbance in accelerating weed growth is well understood. While most of these studies have focused on soil mediated disturbance, mowing is also a management practice that could impact weed traits. Using silver leaf nightshade (Solanum elaeagnifolium), a noxious and invasive weed, we asked whether continuous mowing affects growth and plant defense traits. We found that mowed plants produced significantly less fruits, had lower total seed fitness, but had higher seed mass, and germinated significantly faster. When three common herbivores were allowed to feed on the seedlings; tobacco hornworm (Manduca sexta), a generalist Solanaceae caterpillar gained more …

Interactive Effects Of Heat Stress And Pesticides Co-Exposure On Swimming Behavior, Oxidative Stress, Antioxidant Expression, And Redox Status In Common Goldfish (Carassius Auratus), Brittney Danielle Lacy

Theses and Dissertations

Aquatic ecosystems are inundated by environmental pesticides. This study, observed the dose-dependent effects of pesticides cocktail (metalachlor, linuron, isoproturon, tebucanazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) and elevated temperature (32 °C for 4-week exposure) on morphology of gills and kidneys, and expression of nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), catalase (CAT), superoxidase dismutase (SOD), Na+/K+-ATPase, renin, and apoptosis in tissues of goldfish. Additionally, the effects on the free-swimming behavior were also observed. Histological analysis showed wide-spread damage in tissues at higher temperature and pesticides co-exposure. Immunohistochemical analysis demonstrated alterations in NTP, DNP, CAT and SOD expressions in tissues at higher temperature …

Role Of Glycolytic Metabolism In Glioblastoma Multiforme, Shreya Udawant

Theses and Dissertations

PI3K/AKT/mTOR signaling pathway is activated in 90% of all Glioblastoma Multiforme (GBM) tumors. We used a dual targeting approach to interfere with the phosphoinositide 3-kinase- mammalian target of rapamycin (PI3K-mTOR) pathway by treating U87MG GBM cells with NVP-BEZ235 (PI3K and mTOR a dual inhibitor) and, their downstream effects on molecular regulation on glycolytic genes were investigated using RNA-sequencing and gene set enrichment analysis (GSEA). RNA-seq identified 7803 differentially regulated genes in response to NVP-BEZ235. GSEA identified two glycolysis-related gene sets had significant differences (P < 0.05) in gene expression between control and NVP-BEZ235 treated samples. The GSEA core enrichment reported 17 and 35 genes were significantly downregulated (P adj < 0.05) in response to NVP-BEZ235 treatment in two different glycolysis related gene sets. We validated the expression of genes using qRT-PCR in U87MG cells as well as other GBM cell lines. Our results suggest novel insights on hallmark metabolic reprogramming associated with the PI3K-mTOR inhibition and provides advances in developing molecular targeted therapies.

Role Of Herbivore Associated Elicitors In Plant Defense Signaling, Akanksha Gandhi

Theses and Dissertations

Chapter 2: In this chapter, I have provided an update on recent developments and advances on early signaling events in plant-herbivore interactions, with a particular emphasis on the membrane potential changes (Vm), calcium (Ca2+), reactive oxygen species (ROS) and plant ion channels involvement in early signaling events initiation and propagation of defense signaling cascade.

Chapter 3: In this chapter, we show that tobacco hornworm (Manduca sexta) caterpillar oral secretion (OS) induces ROS in tomato (Solanum lycopersicum) protoplasts. By using a dye-based ROS imaging approach, our study showed that the application of Plant-Fed (PF) M. sexta OS …

Effects Of Urbanization On Buff-Bellied Hummingbirds In Subtropical South Texas Subtropical South Texas, John S. Brush, Timothy Brush, Alexis Racelis

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Urbanization and its associated processes affect wildlife in a variety of ways. Understanding how this increasing land use type affects biological communities is important for conservation efforts. Hummingbirds (family Trochilidae) are one taxon that has showed positive responses to varying intensities of urban development. We surveyed for Buff-bellied Hummingbird ( Amazilia yucatanensis), a species on its northern range-limits, in urban woodlands, residential, natural, and revegetated habitats. We examined how urbanization is affecting Buff-bellied Hummingbird populations in South Texas with point- count surveys and GIS analysis. We found that Buff-bellied Hummingbirds had greater relative abundances in urban settings when compared with …

Poorly Vetted Conservation Ranks Can Be More Wrong Than Right: Lessons From Texas Land Snails, Kathryn E. Perez, Benjamin T. Hutchins, Jeffrey C. Nekola

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Setting priorities for scarce conservation dollars requires an accurate accounting of the most vulnerable species. For many invertebrates, lack of taxonomic expertise, low detectability, and funding limitations are impediments to this goal, with conservation ranks usually based on expert opinion, the published literature, and museum records. Because of biases and inaccuracies in these data, they may not provide an accurate basis for conservation ranks, especially when compared to de novo field surveys. We assessed this issue by comparative examination of these data sources in re-ranking the conservation status of all 254 land snail taxa reported from Texas, USA. We confirmed …

Using The Rdna Internal Transcribed Spacer 1 To Identify The Invasive Pest Rhagoletis Cerasi (Diptera: Tephritidae) In North America, Norman B. Barr, Daniel Garza, Lisa A. Ledezma, David A. Salinas

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The cherry-infesting fruit fly Rhagoletis cerasi Loew is a significant commercial pest in Europe that has recently invaded North America. To date, it has been trapped only in Canada and northwestern counties of New York. It has the potential to spread further and threaten production and movement of cherry commodities. Timely diagnosis of the pest will facilitate surveys and quick response to new detections. Adult morphology of the pest is distinct from other flies in North America. However, when flies are significantly damaged on traps or the immature life stages are found in fruits, molecular methods of identification are important …

Tobacco Hornworm (Manduca Sexta) Oral Secretion Elicits Reactive Oxygen Species In Isolated Tomato Protoplasts, Akanksha Gandhi, Rupesh R. Kariyat, Cruz Chappa, Mandeep Tayal, Nirakar Sahoo

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Plants are under constant attack by a suite of insect herbivores. Over millions of years of coexistence, plants have evolved the ability to sense insect feeding via herbivore-associated elicitors in oral secretions, which can mobilize defense responses. However, herbivore-associated elicitors and the intrinsic downstream modulator of such interactions remain less understood. In this study, we show that tobacco hornworm caterpillar (Manduca sexta) oral secretion (OS) induces reactive oxygen species (ROS) in tomato (Solanum lycopersicum) protoplasts. By using a dye-based ROS imaging approach, our study shows that application of plant-fed (PF) M. sexta OS generates significantly higher ROS while artificial diet-fed …

Lrrc8 Family Proteins Within Lysosomes Regulate Cellular Osmoregulation And Enhance Cell Survival To Multiple Physiological Stresses, Ping Li, Meiqin Hu, Ce Wang, Xinghua Feng, Zhuangzhuang Zhao, Ying Yang, Nirakar Sahoo, Mingxue Gu, Yexin Yang, Shiyu Xiao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

LRRC8 family proteins on the plasma membrane play a critical role in cellular osmoregulation by forming volume-regulated anion channels (VRACs) necessary to prevent necrotic cell death.We demonstrate that intracellular LRRC8 proteins acting within lysosomes also play an essential role in cellular osmoregulation. LRRC8 proteins on lysosome membranes generate large lysosomal volume-regulated anion channel (Lyso-VRAC) currents in response to low cytoplasmic ionic strength conditions. When a double-leucine L706L707 motif at the C terminus of LRRC8A was mutated to alanines, normal plasma membrane VRAC currents were still observed, but Lyso-VRAC currents were absent. We used this targeting mutant, as well as pharmacological …

Host Plant Defense Produces Species-Specific Alterations To Flight Muscle Protein Structure And Flight-Related Fitness Traits Of Two Armyworms, Scott L. Portman, Gary W. Felton, Rupesh R. Kariyat, James H. Marden

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Insects manifest phenotypic plasticity in their development and behavior in response to plant defenses, via molecular mechanisms that produce tissue-specific changes. Phenotypic changes might vary between species that differ in their preferred hosts and these effects could extend beyond larval stages. To test this,we manipulated the diet of southern armyworm(SAW; Spodoptera eridania) and fall armyworm (FAW; Spodoptera frugiperda) using a tomato mutant for jasmonic acid plant defense pathway (def1), and wild-type plants, and then quantified gene expression of Troponin t (Tnt) and flightmusclemetabolismof the adult insects. Differences in Tnt spliceform ratios in insect flight muscles correlate with changes to flight …

Examining The Efficacy Of Cover Crops As An Integrated Pest Management Tool In Organic Farms In The Lower Rio Grande Valley, Lili M. Martinez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) consists of a mix in subtropical and costal habitats, a combination that provides a favorable environment for the animals and plants that inhabit it. This is a problem for organic farmers as they refrain from using synthetic chemicals and therefore led them to seek other methods of dealing with insect herbivory. Of the many alternative methods available, we looked specifically at integrated pest management methods (IPM) to determine their efficacy in reducing insect herbivory among cash crops. Chapter II discusses an experiment performed in an organic farm in Edinburg, Texas consisting of a two-year …

Identifying Positive Selection In Multiple Subspecies Of Xylella Fastidiosa, Daniel Doroteo Flores

Theses and Dissertations

For this study, we will be looking to identify positive selection in eight genomes of the bacterial plant pathogen Xylella fastidiosa. A previous study used a branching method that identified 2 genes with positive selection along with a site-specific method identifying 34 genes showing positive selection. This current study focused specifically on the site-specific method, resulting in 28 genes (of 1,039 tested) showing positive selection. Of the 28 genes showing positive selection, 12 of them come from the pathogenicity, virulence and cellular structural categories. The remaining genes are found in the biosynthesis, metabolism, macro metabolism, and cellular process categories. …

Genetic Analysis Of Pi3k And Mtor Inhibition In U87mg Glioblastoma Cell Line, Carl G. Litif

Theses and Dissertations

NVP-BEZ235 is a Glioblastoma Multiform chemotherapeutic dual PI3K/mTOR pathway inhibitor created in 2008 and has since been proven experimentally to induce pluripotentcy in oncological cell populations. The inhibition of PI3K and mTOR has shown to coerce phenotypes associated with stem cell markers, most notably OCT4. It is necessary to understand the genetic composure of how PI3K/mTOR inhibited tumor cells are bypassing the canonical pathway for proliferation and growth and utilizing other parallel sources for tumor invasion into other neural regions. Taking a genetic approach with RNA-sequencing allowed us to gain insight into how glioblastoma interact with cytoskeleton factors MAPK4 and …

Optimizing Species Selection For Forest Restoration In The Lower Rio Grande Valley, Faeqa Mohsin

Theses and Dissertations

Over the past four decades, the Lower Rio Grande Valley has been reforested with over 3.3 million native thornscrub plants in old agricultural land through transplanting native species. However, assessments of LRGV forest restoration efforts are scarce, and to address the knowledge gap, this study examined species-specific responses to restoration interventions (RIs) aimed at minimizing seedling mortality for optimizing species selection. A critical period for forest restoration in old croplands is the seedling stage, where high mortality occurs due to the interactive effects of abiotic stress, compromised soil nutrient status from intensive agriculture, and mammalian herbivory. So, we evaluated seedling …

The Long-Term Persistence And Tissue Tropism Of Brazilian Zika Virus In Monodelphis Domestica, Marisol Morales

Theses and Dissertations

Zika virus (ZIKV) rose as a major public health concern due to the congenital abnormalities of infants born to infected mothers during the 2015 Latin American outbreak. While animal models such as transgenic mice and nonhuman primates are used to study ZIKV pathogenesis, they display various limitations. Additionally, the persistence and tissue distribution of long-term ZIKV infection remains unknown. We describe the laboratory opossum, Monodelphis domestica, as a potential new model for ZIKV pathogenesis research to address these issues. We utilized immunohistochemistry, RT-PCR, and ELISA to show that: infant animals inoculated intracerebrally were susceptible to infection, ZIKV infection persisted …

Embryonic Exposure To The Synthetic-Progesterone Levonorgestrel (Lng) Results In Hyperactive Behavior In Zebrafish (Danio Rerio), Austin D. Fuentes

Theses and Dissertations

Exposure to endocrine-disrupting chemicals has been associated with an increased risk of anxiety-like behavior at various life stages. Levonorgestrel (LNG), a synthetic contraceptive, could potentially alter steroidal regulated brain development based on the findings of this thesis. In-silico measurements were used for comparing LNG, which had been found in surface water, to chemical databases to predict the bioavailability, half-life, and estrogen binding potential. Zebrafish (Danio rerio) for illuminating the effects of LNG exposure during early zebrafish embryonic development, similar to fetal development, on behavior was investigated. Our data suggests exposure in a dose-dependent manner of LNG can potentially …

Vertical Transmission And Venereal Transmission Of Zika Virus In A Population Of South Texas Aedes Aegypti, Jeremy Marshall

Theses and Dissertations

Zika virus has become a greater global public health concern from the occurrence of outbreaks in 2007 and its expansion to the Americas in 2015. The presence of Aedes aegypti in the Lower Rio Grande Valley and evidence of local transmission of Zika in Brownsville, Texas provides a need to research transmission dynamics of local populations. In these experiments, a locally acquired, laboratory colony of Aedes aegypti mosquitoes were infected with a blood meal featuring a Mexican isolate of Zika virus to display vector competency, vertical transmission, venereal transmission. Here, we infected 39 females, with 34 of them displaying evidence …

Insect Mediated Species Interactions: Examining Methods To Improve Artificial Buzz Pollination And Testing The Effects Of Plant Based Bioactive Compounds On Herbivore Life-History Traits, Mandeep Tayal

Theses and Dissertations

Pollination and herbivory are two major interactions in insect-plant ecology. Specialized pollination systems such as buzz pollination where pollen grains have to be extracted by bees with special thoracic vibrations and indirect flight muscles, is observed in ~6% of all flowering plants. Breeding and research programs in these species demand artificial pollination, but natural buzz pollinators are unreliable for this purpose. To find an alternative, we tested the pollen extraction efficiency of using inexpensive electric toothbrush over tuning fork (another commonly used device) in two buzz-pollinated species (Tomato and Silverleaf nightshade) at different buzzing frequencies and multiple buzzing time intervals. …

Using Genetic Diversity To Differentiate Mosquito Populations, Rachel Christine Malampy

Theses and Dissertations

Experiment 1: Little is known about Aedes aegypti females sharing oviposition sites. We examined four different oviposition sites in McAllen, TX. A mitochondrial gene was used to analyze the variation within the oviposition site to understand how many egg-laying females are sharing oviposition sites. These results will aid in the understanding of Aedes. aegypti oviposition behavior and contribute to more effective mosquito control techniques.

Experiment 2: Mosquito flight patterns and movement from habitat to habitat can drastically influence the spread of diseases. The anthropophilic Aedes aegypti mosquito has historically been identified as having a very limited flight range. Studies also …

Biological Flora Of The Tropical And Subtropical Intertidal Zone: Literature Review For Rhizophora Mangle L., Hudson R. Deyoe, Robert I. Lonard, Frank W. Judd, Richard Stalter, Ilka Feller

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Rhizophora mangle L. is a tropical and subtropical mangrove species that occurs as a dominant tree species in the intertidal zone of low-energy shorelines. Rhizophora mangle plays an important role in coastal zones as habitat for a wide range of organisms of intertidal food webs, as a natural barrier to coastal erosion, and as carbon sequestration. A review of mangrove literature has been performed, but a review specifically on red mangroves has not. The approach was to cover a broad range of topics with a focus on topics that have seen significant work since the 1970s. This review includes a …

Potential Effects Of Climate Change On The Geographic Distribution Of The Endangered Plant Species Manihot Walkerae, Gisel Garza, Armida Rivera, Crystian Sadel Venegas Barrera, Jose Guadalupe Martinez-Avalos, Jon Dale, Teresa Patricia Feria-Arroyo

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Walker’s Manihot, Manihot walkerae, is an endangered plant that is endemic to the Tamaulipan thornscrub ecoregion of extreme southern Texas and northeastern Mexico. M. walkerae populations are highly fragmented and are found on both protected public lands and private property. Habitat loss and competition by invasive species are the most detrimental threats for M. walkerae; however, the effect of climate change on M. walkerae’s geographic distribution remains unexplored and could result in further range restrictions. Our objectives are to evaluate the potential effects of climate change on the distribution of M. walkerae and assess the usefulness of natural protected areas …

Toxin Transcripts In Crotalus Atrox Venom And In Silico Structures Of Toxins, Ying Jia, Ivan Lopez, Paulina Kowalski

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The western diamondback rattlesnake (Crotalus atrox) is a common and widespread North American pit viper species, and its venom possesses medical applications. In this research, we identified 14 of the most common transcripts encoding 11 major venom toxins including transcripts for a three-finger toxin (3FTx) from the crude venom of C. atrox. In silico three-dimensional (3D) structures of 9 venom toxins were predicted by using deduced toxin amino acid sequences and a computer programme-MODELLER. The accuracy of all predicted toxin structures was evaluated by five stereochemical structure parameters including discrete optimised protein energy (DOPE) score, root mean square deviation (RMSD), …

Conservation Status Of The Recently Described Ecuadorian Amazon Parrot Amazona Lilacina, Rebecca Biddle, Ivette Solis Ponce, Paul Cun, Simon Tollington, Martin Jones, Stuart Marsden, Christian Devenish, Eric Horstman, Karl S. Berg, Mark Pilgrim

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Amazona lilacina is a threatened species endemic to Ecuador, existing across a patchwork of mangroves, lowland coastal forests, agricultural and community owned land. The species was described in 2014 and listed as ‘Endangered’ on the IUCN Red List, however, full assessment of the population was lacking. Using a combination of field observations, roost surveys and community questionnaires, conducted over the last 20 years, we provide up-to-date information on the species’ Extent of Occurrence, estimate its global population size, and evaluate its level of threat. Our results suggest the species occurs across an area of 19,890 km2 in three distinct geographically …

Impact Of Cover Crops On Insect Community Dynamics In Organic Farming, Lili Martinez, Pushpa Soti, Jasleen Kaur, Alexis Racelis, Rupesh R. Kariyat

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Manipulating cover crops as an integrated pest management strategy has recently gained popularity in both traditional and organic agroecosystems. However, little information is available for producers to make informed decisions about cover crop selection, management, and their potential use as a pest management tool. To address this, we conducted a two-year, four-season field experiment on the potential of various cover crops during the summer seasons of both years, followed by monocultures of cash crops during winters. We hypothesized that the cover crop treatments would attract beneficial insects and repel damaging herbivores in a species-specific manner, and the insect community dynamics …

Comparing Novel And Traditional Sampling Methodologies To Analyze The Population Status Of The Rio Grande Cooter (Pseudemys Gorzugi), Amy P. Bogolin

Theses and Dissertations

The Rio Grande Cooter, Pseudemys gorzugi, is an understudied aquatic turtle species of conservation concern in the Rio Grande, Pecos, and Devils river systems. Traditional sampling methodologies for aquatic turtle species face numerous challenges, but novel sampling methodologies, such as drone-based surveys and environmental DNA analysis, may address these issues. This study compared novel sampling methodologies to traditional sampling methodologies in mean detections and identifications of aquatic turtle species, developed and implemented an environmental DNA assay to detect P. gorzugi, and characterized P. gorzugi habitat. Following an introductory chapter, each task is addressed by chapter and formatted to …

Lipid Analysis, Fluorescence Microscopy And Flow Cytometry As Tools To Evaluate Microalgae For Potential Biofuel Production, Giovanina Aimee Hinojosa

Theses and Dissertations

Petroleum-based crude oil is nonrenewable and toxic to the environment, leading to a need for a more efficient and environmentally effective replacement. Microalgae produce lipids which can be converted to recyclable biofuels; therefore, research in lipid production by algae is becoming important for an economic and environmental sustainability. Microalgae can re-absorb atmospheric CO2 and have rapid growth, thereby lowering greenhouse gasses (GHGs) emission, renewability, and simple growth requirements.

Nannochloris sp. is a marine microalga that is amenable for lipid production because there is little research on it so this study will focus on using flow cytometry, fluorescence microscopy and other …

The Effects Of Salvia Hispanica On Biochemical Markers Related To Immune System, Hormone Regulation, And Lumbar Vertebrae In Postmenopausal Rat Model, Daisy M. Mendez

Theses and Dissertations

In women, with age and menopause there is increase in body weight and decreased immunity and bone mass. Due to severe side effects of currently available drugs for obesity and bone loss, new therapies with less side effects are sought after and alternative medications are becoming more popular. Recently, Salvia hispanica (SH), a herbal supplement is implicated in losing body weight. Currently, there is no information on how SH modulates obesity or bone health. In this study, effects of SH seed extract was investigated in a postmenopausal rat model on certain hormones, immune markers, and fourth lumbar vertebrae. The highest …