Life Sciences Commons^™

Population Genetics Among Rhipicephalus Sanguineus Ticks In The Lower Rio Grande Valley, Bianca Liana Guerra

Theses and Dissertations

Rhipicephalus sanguineus is a common tick species in the lower Rio Grande Valley of both human and veterinary concern. Two lineages of R. sanguineus have been described across the United States known as the tropical and temperate lineage. Both lineages can be differentiated morphologically, genetically, biologically, and by vector competence. The species name for both lineages has not been well established therefore this thesis will utilize their widely used identification. Both lineages have been identified in Texas. While the distribution of these lineages has been well-defined in some regions across the world, recent studies have observed sympatric populations in certain …

Estimating The Functional Consequences Of Intra-Specific Trichome Variation Of Tomato, Solanum Lycopersicum On The Specialist Herbivore, Manduca Sexta, Satinderpal Kaur

Theses and Dissertations

Chapter 1: Plants have a wide array of defenses against herbivores and hence they must confer trade-offs between growth and defense related traits. By using Solanum as a model genus, the major plant defense fitness trade-off hypotheses are reviewed in this chapter along with their assumptions and examples.

Chapter 2: This chapter provides an overview of the enormous intra-specific diversity in trichome morphology in tomato, Solanum lycopersicum. Also, the trichome sub-types are analyzed for the variations in density and dimensions in 10 varieties of tomato by using desktop scanning electron microscope.

Chapter 3: This chapter examines the functional consequences …

Road Mitigation Structure And Road Effect Zone Impacts On Rodent Community Composition, Activity, And Predator-Prey Dynamics In South Texas, Adam F. Sanjar

Theses and Dissertations

The effects of road mortality mitigation structures on rodent activity and rodent community composition are not fully understood, both on the regional scale of south Texas and in the broader field of road ecology. This is primarily due to the low conservation priority of most rodent species and the difficulty of noninvasively surveying for rodents effectively. This thesis focused on characterizing how rodents were impacted by both roads and mitigation structures in south Texas, and if rodents are a significant factor to consider when studying the road ecology of rodent predators in south Texas, particularly ocelots, bobcats (Lynx rufus …

Detection Of A Diverse Endophyte Assemblage Within Fungal Communities Associated With The Arundo Leaf Miner, Lasioptera Donacis (Diptera: Cecidomyiidae), Marie-Claude Bon, John A. Goolsby, Guy Mercadier, Fatiha Guermache, Javid Kashef, Massimo Cristofaro, Ann T. Vacek, Alan Kirk

Biology Faculty Publications and Presentations

The larvae of Lasioptera donacis Coutin feed on fungal communities lining galleries within the mesophyll of leaf sheaths of Arundo donax in an aggregative manner. It has been stated that L. donacis could have established a fundamental symbiotic relationship with one fungus, although the fungal composition of these communities remains unsettled. Using a culture-dependent approach and ITS sequencing, the present work characterizes and compares the fungal communities associated with L. donacis in Eurasia with the endophytes of A. donax in Texas where L. donacis is absent. The 65 cultivable isolates obtained from L. donacis fungal communities were sorted into 15 …

Morphological Characterization Of Intraspecific Variation For Trichome Traits In Tomato (Solanum Lycopersicum), Satinderpal Kaur, Neetu Khanal, Robert K. Dearth, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Trichomes, the hairlike protuberances in plants, have been well known to act as the first line of defense against herbivores, and abiotic stresses, along with other structural defenses such as spines, thorns, and waxes. We previously reported the tremendous variation in trichome traits among different wild and cultivated Solanum species and demonstrated that trichomes types and density are traditionally miscalculated and often misnamed. However, intraspecific variation in trichome traits is poorly understood, although this has implications for stress tolerance and resistance breeding programs in economically important crop species and can also mediate ecological interactions at multiple trophic levels in their …

Predicting The Impact Of Climate Change On The Distribution Of Rhipicephalus Sanguineus In The Americas, Marcos Sánchez Pérez, Teresa Patricia Feria-Arroyo, Crystian Sadiel Venegas Barrera, Carolina Sosa-Gutiérrez, Javier Torres, Katherine A. Brown, Guadalupe Gordillo Pérez

Biology Faculty Publications and Presentations

Climate change may influence the incidence of infectious diseases including those transmitted by ticks. Rhipicephalus sanguineus complex has a worldwide distribution and transmits Rickettsial infections that could cause high mortality rates if untreated. We assessed the potential effects of climate change on the distribution of R. sanguineus in the Americas in 2050 and 2070 using the general circulation model CanESM5 and two shared socioeconomic pathways (SSPs), SSP2-4.5 (moderate emissions) and SSP2-8.5 (high emissions). A total of 355 occurrence points of R. sanguineus and eight uncorrelated bioclimatic variables were entered into a maximum entropy algorithm (MaxEnt) to produce 50 replicates per …

Greenbug Feeding-Induced Resistance To Sugarcane Aphids In Sorghum, Heena Puri, Edith Ikuze, Jessica Ayala, Isabella Rodriguez, Rupesh R. Kariyat, Joe Louis, Sajjan Grover

Biology Faculty Publications and Presentations

Plants are attacked by multiple insect pest species and insect herbivory can alter plant defense mechanisms. The plant defense responses to a specific herbivore may also contribute to the herbivore growth/survival on plants. Feeding by one insect species can modulate the plant defenses, which can either facilitate or hamper the colonization of subsequent incoming insects. However, little is known about the effect of sequential herbivory on sorghum plants. In this study, we demonstrate that a specialist aphid, sugarcane aphid (SCA; Melanaphis sacchari) grows faster on sorghum than a generalist aphid species, greenbug (GB; Schizaphis graminum). We also determined …

Effective Farm Management Promotes Native Amf And Benefit Organic Farming Systems, Pushpa Soti, Rupesh R. Kariyat, Alexis Racelis

Biology Faculty Publications and Presentations

Highlights

• Agricultural practices have significant influence on the AMF community dynamics.

• Soil nutrients regulate AMF spore abundance and diversity.

• Using grass cover crops can promote native AMF in farms.

Abstract

Using soil inoculants containing naturally occurring beneficial microorganisms has become a popular practice in sustainable agriculture. However, an understanding of the environmental variables that affect plant-microbe interactions and the benefit of using commercial inoculum is relatively sparse. To address this, we examined the efficiency of three different methods to inoculate AMF (Arbuscular Mycorrhizal Fungi) in organic vegetable farms in south Texas: cover cropping, application of farm-produced (indigenous) AMF inoculum, …

Evidence Of An Established Population Of Cherax Quadricarinatus (Von Martens, 1868) In South Texas, Usa, Adam Sanjar, Drew R. Davis, Richard J. Kline

Biology Faculty Publications and Presentations

Cherax quadricarinatus (von Martens, 1868) is a large parastacid crayfish (Decapoda: Parastacidae) native to Australia and Papua New Guinea. Due to various factors, C. quadricarinatus is an emerging invasive species in an increasing number of regions across the world. Deleterious ecological effects of C. quadricarinatus introduction have been documented in many of these regions, and its spread has been monitored and restricted where possible. Previously, only a small, isolated population of C. quadricarinatus in southern California had been reported within the continental United States. Here, we report the collection of three adult C. quadricarinatus from Brownsville, Cameron County, Texas, the …

The Known And Unknowns Of Aphid Biotypes, And Their Role In Mediating Host Plant Defenses, Neetu Khanal, Christopher Vitek, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Insect species are subjected to disparate selection pressure due to various biotic and abiotic stresses. Management practices including the heavy use of chemical insecticides and introduction of insect-resistant plant cultivars have been found to accelerate these processes. Clearly, natural selection coupled with human intervention have led to insect adaptations that alter phenotypes and genetic structure over time, producing distinct individuals with specialized traits, within the populations, commonly defined as biotypes. Biotypes are commonly found to have better fitness in the new environment and, in the case of aphids, the most commonly studied system for biotypes, have the ability to successfully …

Diel Activity Patterns Of Vector Mosquito Species In The Urban Environment: Implications For Vector Control Strategies, André Barretto B. Wilke, Adequate Mhlanga, Allisandra G. Kummer, Chalmers Vasquez, Maday Moreno, William D. Petrie, Art Rodriguez, Christopher Vitek, Gabriel L. Hamer, John-Paul Mutebi, Marco Ajelli

Biology Faculty Publications and Presentations

Mathematical models have been widely used to study the population dynamics of mosquitoes as well as to test and validate the effectiveness of arbovirus outbreak responses and mosquito control strategies. The objective of this study is to assess the diel activity of mosquitoes in Miami-Dade, Florida, and Brownsville, Texas, the most affected areas during the Zika outbreak in 2016–2017, and to evaluate the effectiveness of simulated adulticide treatments on local mosquito populations. To assess variations in the diel activity patterns, mosquitoes were collected hourly for 96 hours once a month from May through November 2019 in Miami-Dade County, Florida, and …

Revisiting Plant Defense-Fitness Trade-Off Hypotheses Using Solanum As A Model Genus, Sakshi Watts, Satinderpal Kaur, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Plants possess physical and chemical defenses which have been found to deter herbivores that feed and oviposit on them. Despite having wide variety of defenses which can be constitutive or induced, plants are attacked and damaged by insects associated with different mouthparts and feeding habits. Since these defenses are costly, trade-offs for growth and defense traits play an important role in warding off the herbivores, with consequences for plant and herbivore growth, development and fitness. Solanum is a diverse and rich genus comprising of over 1,500 species with economic and ecological importance. Although a large number of studies on Solanum …

The Justice Challenge: Honors Endeavors Innovative Pedagogies Through The Grand Challenge Scholars Program, Jonathan Kotinek, Rebecca C. Bott-Knutson, Leigh E. Fine, Joy L. Hart, William Ziegler, Paul Knox, Timothy Nichols, Susan Sumner, Heidi Appel, Mark C. Andersen

Biology Faculty Publications and Presentations

Honors practitioners from fourteen colleges and programs across the country at land-grant, public, and minority-serving institutions partner with agricultural experts to secure a United States Department of Agriculture (USDA) Higher Education Challenge grant focused on the themes of food justice, climate justice, and sustainable agriculture. Authors describe the program’s origin, objectives, and curricular outgrowths, highlighting its efficacy for empowering students in areas of systems thinking, career readiness, leadership in the service of addressing social needs, and learning through civic engagement.

The Foxo1 Inhibitor As1842856 Triggers Apoptosis In Glioblastoma Multiforme And Basal-Like Breast Cancer Cells, David Flores, Alma Lopez, Shreya Udawant, Bonnie Gunn, Megan Keniry

Biology Faculty Publications and Presentations

Basal-like breast cancer (BBC) and glioblastoma multiforme (GBM) are poor-prognosis cancers that lack effective targeted therapies and harbor embryonic stem gene expression signatures. Recently, our group and others found that forkhead box transcription factor FOXO1 promotes stem gene expression in BBC and GBM cell lines. Given the critical role of cancer stem cells in promoting cancer progression, we examined the impact of FOXO1 inhibition with AS1842856 (a cell-permeable small molecule that directly binds to unphosphorylated FOXO1 protein to block transcriptional regulation) on BBC and GBM cell viability. We treated a set of BBC and GBM cancer cell lines with increasing …

Are Epicuticular Waxes A Surface Defense Comparable To Trichomes? A Test Using Two Solanum Species And A Specialist Herbivore., Sakshi Watts, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Although plants possess a suite of structural defenses, most studies have focused on trichomes. Trichomes can have both pre- and post-ingestive effects and have been consistently found to reduce herbivory. Along with trichomes, a few studies have focused on epicuticular waxes as an important defense; however, manipulated comparisons examining herbivore growth and development is limited. In this study, using two Solanum species (Solanum glaucescens and Solanum macrocarpon) that vary in both defenses, we tested the hypothesis that variation in defenses will affect herbivore feeding, primarily by restricting feeding commencement. We used electron microscopy together with a series of plant- and …

The Photochemical Evolution Of Polycyclic Aromatic Hydrocarbons And Nontronite Clay On Early Earth And Mars, Nina Kopacz, Maria Angela Corazzi, Giovanni Poggiali, Ayla Von Essen, Vincent Kofman, Teresa Fornaro, Hugo Van Ingen, Eloi Camprubi, Helen E. King, John Brucato, Inge Loes Ten Kate

Biology Faculty Publications and Presentations

The photochemical evolution of polycyclic aromatic hydrocarbons (PAHs), an abundant form of meteoritic organic carbon, is of great interest to early Earth and Mars origin-of-life studies and current organic molecule detection efforts on Mars. Fe-rich clay environments were abundant on early Earth and Mars, and may have played a role in prebiotic chemistry, catalyzing the breakdown of PAHs and freeing up carbon for subsequent chemical complexification. Current Mars is abundant in clay-rich environments, which are most promising for harboring organic molecules and have comprised the main studied features by the Curiosity rover in search of them. In this work we …

Nilgai, Boselaphus Tragocamelus And White-Tailed Deer, Odocoileus Virginianus Use Of Water Troughs With And Without Remotely Operated Field Sprayers For Potential Treatment Of Cattle Fever Ticks, John A. Goolsby, Mauricio Cruz, Reyes Garcia Iii, Lauren P. Maestas, Teresa Patricia Feria-Arroyo

Biology Faculty Publications and Presentations

Nilgai antelope, Boselaphus tragocamelus and white-tailed deer (WTD), Odocoileus virginianus are hosts of cattle fever ticks, Rhipicephalus (=Boophilus) microplus, in the Lower Rio Grande Valley of South Texas. Daily use of water troughs and ponds were observed to determine if these locations could be used for field treatment methods for cattle fever ticks using remotely operated field sprayers. Game cameras (n=16) were deployed between June 2020 and September 2022 at two private ranches in Cameron County, TX. Both nilgai and WTD visited water troughs equipped with motion detecting sprayers in similar numbers to ponds, but numbers of animal visits were …

The Molecular Evolution Of Insect Opsin Genes, Maria Jose Cardenas Muedano

Theses and Dissertations

Opsins are part of the superfamily of G-coupled receptor proteins and together with chromophores, are responsible for initiating the signal transduction cascade responsible for animal vision. Since opsins have a critical role on visual perception these genes are crucial for a myriad of adaptive traits and behaviors and should show diverse signs of natural selection at the molecular level. Understanding the evolution of opsins across the wide diversity of insect groups will allow us to better understand the evolutionary pressure on insect opsins and serve as a model for both other gene systems and other taxonomic groups of animals that …

Bobcat Identification, Abundance, And Behavior At Road Mitigation Structures In South Texas, Victoria Hanley

Theses and Dissertations

Highways in South Texas fragment the landscape and result in high road mortality rates for the endangered US ocelot (Leopardus pardalis). In response, the Texas Department of Transportation constructed nine wildlife crossing structures (WCS) on Farm-to-Market (FM) 106 which adjoins Laguna Atascosa National Wildlife Refuge in Cameron County, Texas. With ocelots being rare and elusive, bobcats (Lynx rufus) are often used as a surrogate species to study felid behavior at road mitigation structures in South Texas. Bobcats have unique markings which allow them to be individually identified. Three methods of individual identification of bobcats using camera …

Wildlife Road Mortality Patterns In South Texas And Survey Methodology Improvement, Bradley E. Beer

Theses and Dissertations

Mortalities of wildlife caused by collisions with vehicles along roads are increasing in prevalence, threatening the existence of various species and populations. A better understanding of how mortalities change in response to natural and anthropogenic variables and efficient methods of obtaining mortality data are essential to mitigating such mortalities. This thesis investigates several key elements to improving road mortality surveys in south Texas. First, it was found that road mortality survey counts did not change under a pandemic-related lockdown and that 2 mortality survey observers detect more mortalities than 1. Analysis of brown pelican groundings on Texas State Highway 48 …

Effects Of Disturbance (Mowing) On Florivory And Floral Defenses In Solanum Elaeagnifolium, A Noxious And Worldwide Invasive Weed, Alejandro Rafael Vasquez Marcano

Theses and Dissertations

Chapter 1: Literature Review- In this literature review we have examined weed management as it concerns urban and agricultural ecosystems, as well as the need for mowing assessments as it relates to floral traits and defense against herbivory.

Chapter 2: Experiments- In the experiments we examined the role of mowing on floral growth traits, floral defense traits, and their effect on Manduca sexta specialist herbivores.

Chapter 3: Results- In the results we found SLN flowers to have larger diameters than unmowed flowers; however, flower mass was in line with our predictions as unmowed flowers were heavier in high mowing frequency …

Population Density And Reproductive Seasonality Of Tryonia Cheatumi (Gastropoda: Cochliopidae), The Phantom Tryonia, Kathryn E. Perez, Nina Noreika, Chad Norris, Marty Kelly, Melissa Lopez, Christina Ortega, Salma Ruiz Sandoval, Samantha Gonzalez, Weston Nowlin

Biology Faculty Publications and Presentations

We studied population density, population size, and reproductive seasonality of the Phantom Tryonia, Tryonia cheatumi (Pilsbry, 1935). This endangered freshwater snail is found only in the San Solomon Spring system, a cienega, or karst-based, arid-land freshwater spring system, in western Texas, USA. We sampled populations at seven locations in the system seasonally over a 2-yr period. San Solomon Spring, the system's largest spring and modified into a swimming pool, had the largest population of T. cheatumi, with an estimated 49 million individuals and a mean density as high as 23,626 ± 39,030 (individuals/m2 ± SD). There were seasonal differences …

Soil Nematode Trophic Group Composition And Influence On Growth Of Amaranthus Palmeri And Parthenium Hysterophorus, Orlando Garcia, Dana Garibaldi, Krissa Jhaveri, Jake Lanoue, Pushpa G. Soti

Biology Faculty Publications and Presentations

Weeds have a significant impact on agricultural systems. They not only cause a loss in crop yield by competing with them for resources, but they can also serve hosts for several pests and parasties such as plant parasitic nematodes casusing additional crop loss. The aim of this study was to analyze plant-nematode feedback in two major weeds, Amaranthus palmeri S Watson and Parthenium hysterophorus L. First, a field survey was conducted to determine the rhizosphere nematode trophic groups associated with these two plants in the summer of 2020 and 2021. Then a 6-week greenhouse study was conducted where the two …

Mechanistic Insight Into Functionally Different Human Islet Polypeptide (Hiapp) Amyloid: The Intrinsic Role Of The C-Terminal Structural Motifs, Dibakar Sarkar, Narayan Chandra Maity, Gourav Shome, Kyriakos Gabriel Varnava, Vijayalekshmi Sarojini, Subramanian Vivekanandan, Nirakar Sahoo, Sourav Kumar, Atin Kumar Mandal, Ranjit Biswas, Anirban Bhunia

Biology Faculty Publications and Presentations

Targeting amyloidosis requires high-resolution insight into the underlying mechanisms of amyloid aggregation. The sequence-specific intrinsic properties of a peptide or protein largely govern the amyloidogenic propensity. Thus, it is essential to delineate the structural motifs that define the subsequent downstream amyloidogenic cascade of events. Additionally, it is important to understand the role played by extrinsic factors, such as temperature or sample agitation, in modulating the overall energy barrier that prompts divergent nucleation events. Consequently, these changes can affect the fibrillation kinetics, resulting in structurally and functionally distinct amyloidogenic conformers associated with disease pathogenesis. Here, we have focused on human Islet …

Low Soil Nitrogen And Moisture Limit The Expansion Of The Invasive Grass, Megathyrsus Maximus (Guinea Grass) In Semi-Arid Soils, E. Penelope Holland, Vanessa Thomas, Pushpa G. Soti

Biology Faculty Publications and Presentations

The goal of this study was to predict the range expansion potential of an invasive forage grass, Guinea grass (Megathyrsus maximus). We collected rhizosphere soil samples of M. maximus and coexisting species from 150 different locations and analysed them for soil properties. We estimated the probability of M. maximus presence as a function of soil moisture, organic matter, pH, salinity, total N, and CN ratio using logistic regression. Presence of M. maximus was associated with higher soil moisture, higher organic matter, pH, and nitrogen, but lower salinity and CN ratio. Soil nitrogen and moisture …

Intracellular Hemin Is A Potent Inhibitor Of The Voltage-Gated Potassium Channel Kv10.1, Nirakar Sahoo, Kefan Yang, Alisa Bernert, Sandip M. Swain, Guido Gessner, Reinhard Kappl, Toni Kühl, Diana Imhof, Toshinori Hoshi, Roland Schönherr, Stefan H. Heinemann

Biology Faculty Publications and Presentations

Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC50 of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, …

Analysis Of Sanitizer Rotation On The Susceptibility, Biofilm Forming Ability And Caco-2 Cell Adhesion And Invasion Of Listeria, Md Asfakur Rahman, Nirakar Sahoo, Veerachandra K. Yemmireddy

Biology Faculty Publications and Presentations

The purpose of this study was to determine the effect of sanitizer use conditions on the susceptibility, biofilm forming ability and pathogenicity of Listeria monocytogenes. Two different strains of L. monocytogenes and a non-pathogenic L. innocua were exposed to sodium hypochlorite, benzalkonium chloride and peroxyacetic acid at different concentrations (4 to 512 ppm) and treatment times (30 s to 5 min), respectively. Under the tested conditions, no significant difference (p > 0.05) in reduction was observed among the three tested sanitizers. A reduction of 1 to 8 log CFU/mL was observed depending upon the sanitizer concentration and treatment times. The survived …

Cytochrome C: A Potential Early Biomarker Of Diabetic Retinopathy, Ileana G. Villarreal

Biology Dissertations and Theses

Diabetic retinopathy is an ocular disease which appears in patients who experience progression of diabetes mellitus over a continuous period of time. Oftentimes, patients remain undiagnosed through the first stages of diabetic retinopathy due to the fact that there is not a specific way to determine when a patient develops the disease. Ophthalmologists and other eye specialists diagnose a patient with diabetic retinopathy once the patient begins to show progressed symptoms of the disease. Previous experiments have been performed to increase our knowledge of diabetic retinopathy and early biomarkers of the disease. Several studies have determined the effects of diabetic …

De Novo Transcriptome Analysis Of Orange Jasmine (Murraya Paniculata) Infected With Citrus Greening Disease, Jeffrey Aquino Gomez

Theses and Dissertations

Citrus greening disease, also known as Huanglongbing, is one of the most devastating citrus diseases in the world. Candidatus Liberibacter asiaticus (CLas) is a non-culturable, phloem-limited bacterium that serves as one of two vectors for the transmission of any of the three kinds of greening disease. In cooler climates, the African variant transmitted by the African citrus psyllid (Trioza erytreae) is more prevalent. The Asian form transmitted by the Asian citrus psyllid (Diaphorina citri) where is predominant in warmer conditions and recently discover the American form who is also transmit by Diaphorina citri, was discover in Brazil but has also …

Examination Of Amphibian Community And Environmental Relationships In South Texas Using Environmental Dna (Edna), Sean Michael Collins

Theses and Dissertations

Developing more efficient tools to assess amphibian biodiversity and understanding what environmental variables drive amphibian biodiversity are top priorities, as amphibians are facing extinction events across the globe. Environmental DNA (eDNA) surveys are a promising new tool to asses amphibian biodiversity. Throughout the study eDNA metabarcoding along with a targeted eDNA assay and traditional survey methods were used to provide foundational information on amphibian community assemblages throughout South Texas. Water quality, habitat characteristics and soil composition data were collected and used to examine environmental relationships. eDNA metabarcoding detected significantly more amphibian taxonomic units compared to traditional survey …