Life Sciences Commons^™

Effects Of Scarification, Phytohormones, Stratification, Soil Types And Warming On The Germination And/Or Performance Of Three Tamaulipan Thornscrub Species, Paula Luera

Theses and Dissertations

The Tamaulipan thornforests of south Texas and northeast Mexico are an ecologically and economically important conservation hotspot. Thornforest restoration is limited by native tree and shrub seedling availability for planting. Seedling shortages arise from low seed availability and knowledge gaps regarding best practices for germinating and growing the 70+ thornforest species desired for restoration plantings. To fill key knowledge gaps, we investigated three ecologically important thornforest species with low or highly variable germination or seedling survival rates: Ebenopsis ebano, Cordia boissieri, and Zanthoxylum fagara. For each, we quantified the effects of different dosages of chemical seed treatments …

Growth Kinetics Of Salmonella Spp. During Post-Harvest Storage Of Fresh And Fresh-Cut Papaya, Amandeep Singh

Theses and Dissertations

Fresh produce safety is major concern in United States. Fresh produce has been associated with numerous food-borne outbreaks each year. Salmonella has been a recurring issue in the papaya industry. Since 2010, imported papayas have been implicated in 8 multistate outbreaks associated with Salmonella spp. causing 480 illnesses, 113 hospitalization and 3 deaths. The main reason behind this problem is as fresh papaya is grown on fields where they are constantly exposed to preharvest microbial contamination through contaminated irrigation water, agricultural soil, raw manure and/or feces deposited by intruding domestic or wild animals. Moreover, majority fresh papaya is also consumed …

Bullet-Proof Boll Weevil: The History Of Boll Weevil Eradication, Evan A. Berg

Theses and Dissertations

Farmers and entomologists have all experimented with various methods to find the best way to defeat the United States' boll weevil. The techniques themselves, while expansive, can be examined within the scope of the years that they were used. This provides an exciting insight into how cotton pest management became more complex as the decades moved on and revealed how the science of cotton pest management evolved to deal with the boll weevil and other future cotton threats.

Evolutionary Development Study Of Firebrat (Thermobia Domestica), Luis Cantu Jr.

Theses and Dissertations

As most evolutionary development studies regarding wing origin take place using insects taxonomically closer to model organism, Drosophila melanogaster, there is a need of expanding studies to lower clades. While D. melanogaster is higher phylogenetically, basal clades would allow for a historical perspective of what occurs within the gene flow of conservative biomarkers. Further understanding of wings and flight would allow for a clearer understanding of how the migration of insects from sea to land has allowed them to become one of the most speciose taxa. Through the study of Thermobia Domestica, part of the Zygentoma, we expand on comprehension …

Characterization Of Biomarkers For Alzheimer’S Disease And Hiv-1 Associated Neurocognitive Disorders, Armando Garces Iii

Theses and Dissertations

Alzheimer’s disease is a neurodegenerative disorder that is characterized by progressive cognitive decline and the accumulation of amyloid beta and neurofibrillary tangles in regions of the brain. These protein deposits are known to generate multiple effects on the brain that lead to neurodegeneration. It has been established that (Human Immunodeficiency Virus) HIV-1 accelerates the aging process of people living with HIV-1. Moreover, there is significant clinical evidence indicating a potential link between the neurodegeneration developed by those with an HIV-1 infection and AD. HIV-1 viral infection causes cognitive impairment known as …

A Gis-Based Model To Assess On-Site Sewage Facility (Ossf) Contamination Risk To Local Water Resources, Alvaro Garcia

Theses and Dissertations

In a collaborative effort between Texas Water Resources Institute (TWRI), Cameron County Public Health (CCPH), Texas A&M AgriLife Extension (TAMAE), and the University of Texas Rio Grande Valley (UTRGV), a GIS database that includes relevant OSSF information, such as location, system age, lot size, and other important parameters was created.

This OSSF database, along with publicly available GIS data, was used to create an integrative GIS-based risk assessment model where OSSF risk parameters were assigned a risk factor and combined into a spatial contamination risk for surrounding areas and their receiving waterbodies. Parameters were broken down into two categories: environmental …

Early Embryology In Collembola With An Emphasis On Wing Development, Samantha A. Gonzalez

Theses and Dissertations

The primary objective of this study was to further the understanding of the wing origin in insects. Currently there are several theories which are popular such as the tergum theory, the pleural plate theory, and the dual theory of wing origin. Studies for these theories have been done on crustaceans, the ancestors to modern day insects. By utilizing a pre insect hexapod, it may be possible to better understand the transition to insect wings. Members of the Collembola species Hypogastrurid are one of these pre-insect hexapods which may provide a clue into origins of wing development. During this study, the …

Prospecting For And Isolation Of Microalgae In South Texas, Mauricio Alejandro Peña

Theses and Dissertations

Microalgae is a very important microorganism that can be used for beneficial purposes for humans. One way to show the importance of algae in this planet is the contribution of Oxygen it provides to the atmosphere, which many organisms rely on (Medeiros et al., 2015). Carbon footprint has been one of the greatest causes for global warming and it is due to the use of fossils to create diesel. One of the ways to avoid contamination is to replace those fuels that are used on daily basis, such as for transportation. The microalgae are able to produce lipids that can …

Duet Phonology And Syntax Of The Red-Crowned Parrots In South Texas, Abigail Pozulp

Theses and Dissertations

Bird behavioral interaction systems show a preference for temporal precision. This preference is exemplified in the way many species avoid masking of vocal signals. Antiphonal duetting in songbirds suggest that overlapping notes are a sign of poor temporal coordination which can signify a weak pairbond, a possible cue for conspecifics seeking to usurp territories or mates. However, parrots (Psittacidae) are accomplished yet understudied duetters in nature. I recorded antiphonal duets produced by a wild population of red-crowned parrots (Amazona viridigenalis) in Brownsville, Texas. Temporal and acoustic variation of signals was assessed within and across a sample of mated …

Characterization Of Soil Nematode Community As Influenced By Weedy Plants And Edaphic Properties, Orlando Garcia

Theses and Dissertations

Nematodes are one of the most critical species globally as they are part of most nutrient recycling. While nematodes play a vital role in nutrient cycling, little is known about them from an ecological standpoint. The majority of current research has focused on a singular component of the community, being those of herbivore/plant-parasitic nematodes. In this study, the community shifts of the nematode trophic groups were analyzed as influenced by native and invasive grasses species in the Lower Rio Grande Valley (LRGV) with the addition of edaphic soil properties.

In our study, the results indicate changes in the composition of …

Home Range Dynamics And Juvenile Dispersal Of Gray Hawks In The Lower Rio Grande Valley, Michael Stewart

Theses and Dissertations

Using GPS-GSM transmitters I determined when 14 juvenile Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas fledged from their natal areas and how far they traveled once they dispersed. These transmitters also allowed me to calculate home range sizes for 22 adults. Additionally, with the GPS-GSM transmitters and 15 VHF transmitters, I discovered that adult Gray Hawks in the study area remained in their territories year-round. Home range sizes were calculated using the minimum convex polygon estimator, the estimation of kernel home-range, and the estimation of kernel Brownian bridge home-range. The same three methods allowed me …

Morphological Characterization And Functional Assessment Of Trichomes In Solanaceae, Sakshi Watts

Theses and Dissertations

Chapter 1: This chapter provides an overview of various trichome types in plants, and also empirically examines their variation on abaxial and adaxial leaf surface of 14 Solanum species. Detailed nomenclature, density, and dimension measurements of each trichome type has been provided using scanning electron-microscopy.

Chapter 2: Scanning electron microscopy was major component of methodology used in my thesis for scanning leaf samples to estimate trichome traits. In this chapter, a more efficient and cost-effective methodology for scanning electron microscopy has been explored.

Chapter 3: This chapter examines the relationship of trichome density and herbivore feeding behavior using abaxial and …

Exploring The Role Of Stigmatic Exudate In The Water Lily (Nymphaceae) Pollination Mechanism Using N. Ampla (Salisb. Dc.), Luis Uribe

Theses and Dissertations

Water lilies are the only known plant group that uses hyperactive nectar glands to divest pollinators of their pollen. The nectar in Nymphaea ampla is thought to contain secondary metabolites that increase pollen deposition possibly by modifying pollinator behavior. This was explored utilizing visitation and fecundity data from the field coupled with survival and behavioral experiments in the laboratory. Replacing nectar with water reduced seed set in N. ampla which was attributed to reduced visitation in water-bearing flowers and not to effects on pollinator detention time. Exposure to nectar did not reduce survivability in Apis mellifera. Pollen and nectar foragers …

Development Of A Novel Strategy To Improve Checkpoint Immune Response In Pancreatic Cancer, Poornima Devi Shaji

Theses and Dissertations

Pancreatic Cancer is the 3rd lethal causing cancers in United States with a survival rate less than 5-7%. In advanced unresectable pancreatic cancer, treatment options are restrained to surgery because of its extreme aggressiveness. Immunotherapy, one of the current advanced treatments has shown promising response in other cancers. However, this therapy is limited in pancreatic cancer due to desmoplasia and fibrotic tumor microenvironment (TME).

Our superparamagnetic iron oxide nanoparticles (SPIONS) of curcumin (Curcuma longa, principal curcuminoid of turmeric) have potential ability to inhibit desmoplasia and tumor stroma with an increased bioavailability. This would soften up the tumors for …

Uptake Analysis Of As(Iii) And As(V) By Cassia Fistula Seedlings, Valeria Velazquez

Theses and Dissertations

The natural and anthropogenic contamination of water by arsenic has become a major concern to the environment and public health. Phytoremediation is an attractive alternative to ecologically friendly remove contaminants at a potential high efficiency and low cost. Absorption of As(III) and As(V) was evaluated by the measuring the content of arsenic in the roots, leaves and stems Cassia fistula grown under controlled conditions in a hydroponics system. After seeds were germinated, the plants were grown in Hoagland nutrient solution individually supplemented with 1, 2, 5 ppm of As(III) and As(V). After two weeks of exposure, samples of leaves, roots, …

Variation In Trichome Types And Density Mediates Plant-Herbivore Interactions In Two Cucurbitaceae Members, Ishveen Kaur

Theses and Dissertations

Plant structural defenses such as trichomes and spines exert a significant selection pressure on insect herbivores. However, how species variation affects structural defense trait expression in closely related species is less understood. Through our studies, we tried to dissect the role of trichomes in mediating plant-insect interactions, in two non-model cultivated species in Cucurbitaceae: Lageneria siceraria, and Cucumis sativa family, and Trichoplusia ni as our major herbivore of interest. We observed that species differed in their attractiveness to different herbivores and their feeding behavior in common garden experiment. To tease apart structural and chemical defenses and their independent roles …

Effects Of Early Corticosterone Treatment On Vocal Babbling In Wild Green-Rumped Parrotlets (Forpus Passerinus), Celia Rose Mclean

Theses and Dissertations

The stress axis of the endocrine system allows for animals to respond to environmental stressors in contextually appropriate ways. Elevated levels of the stress hormone corticosterone (CORT) in male songbirds can result in compromised song learning ability. Parrots form a sister group to songbirds, but it is unknown whether CORT affects vocal development in parrots. The goal of this study was to assess the effects of CORT supplements in green-rumped parrotlets (Forpus passerinus), a free-ranging parrot species in Venezuela. Bouts of vocal babbling were extracted from nest box videos and analyzed. CORT supplementation resulted in differences in babbling …

Chemical Investigation Of Camu Camu (Myrciaria Dubia) Leaves And Roots, Jorge L. Flores

Theses and Dissertations

Flores, Jorge L., Chemical Investigation of Camu Camu (Myrciaria dubia) Leaves and Roots. Master of Science (MS), December, 2020, 45 pp., 8 Tables, 28 Figures, 21 references, 12 titles.Being the largest on the planet, the Amazon rainforest also has the greatest biodiversity of plant life on earth. In the lowland regions of the Amazon grows the Peruvian camu camu (Myrciaria dubia) plant. A short and shaggy shrub, camu camu produces a tasty but sour fruit. Camu camu’s berry-like fruit is widely consumed by the native people of the Amazon. Its distinguished richness in vitamin C, as …

Biochar Applications To The Remediation Of Lead And Polychlorinated Biphenyl Contaminated Water, Victory Itua Igberase

Theses and Dissertations

This study investigated the performance of biochar materials as adsorbents to remove Pb and polychlorinated biphenyl (PCB) in aqueous solutions. Batch adsorption and column experiment packed with biochar and geomaterials (pumice) in 1:1 volume ratio was evaluated to address the efficacy of biochar in removing Pb while only batch adsorption was employed for PCB removal with biochar materials. Overall, PT biochars performed the best (42–53 mg g−1) followed by BE biochars (10–32 mg g−1) and AB biochars (17–27 mg g−1) while high temperature biochars were favored in terms of maximum Pb adsorption capacity. Column Pb breakthrough showed similar results, with …

Soil Chemistry Modification By Guinea Grass In Semi-Arid Soils: A Litter Mediated Positive Feedback, Vanessa Elizabeth Thomas

Theses and Dissertations

Nutrients are a key component of healthy soils. Their composition plays an important role in plant growth through nutrient cycling and directly influences the functioning of plant communities in both agricultural and natural ecosystems. Shifts in macronutrients such as phosphorus and nitrogen may be initiated by invasive growth as a driver for competition with native plants. The goal of this study is to explore the plant soil feedback in an exotic invasive plant, Guinea grass (Pancium maximum), an invasive bunch grass originally from Africa, across different habitat types in the Lower Rio Grande Valley (LRGV). To determine a positive plant …

Investigation Of Techniques And Their Application For The Cryopreservation Of Algal Species, Jazmine Leija

Theses and Dissertations

An alternative source for petroleum-based crude oils are algae derived biofuels. Fossil fuels are harmful for the environment, expensive and becoming scarce. There has been an increase in research on environmentally sustainable energy, using lipids derived from microalgae, which can be converted into biofuel. The use of microalgae as a source for biofuels has a lot of benefits including decreasing greenhouse gas emissions, rapid fuel production, absorption of carbon dioxide, and production of a renewable source of energy.

Algae cryopreservation aids in the maintenance of the best algae strains selected for producing lipids for biofuels. Cryopreservation will help minimize genetic …

Survival Kinetics And Antimicrobial Interventions To Mitigate Foodborne Pathogen Contamination Of Low-Moisture Foods, Rajat Sharma

Theses and Dissertations

Contamination of low-moisture foods (LMFs) with foodborne pathogens such as Salmonella and Shiga-toxin producing Escherichia coli (STEC) has been rising over the last couple of years. Commodity groups such as peanuts, tree nuts, and their products are frequently recalled when associated with illness outbreaks resulting from these pathogens. In this project, two major challenges related to understanding the survival kinetics of pathogens and the efficacy of novel antimicrobial treatments in mitigating their risk in LMFs were systematically investigated. Studies were conducted for determining the survival kinetics of three Salmonella spp. strains in three different tree nut flours (i.e., almond, chestnut, …

Relationship Between Cognitive Performance, Physical Activity, And Socio-Demographic/ Individual Characteristics Among Aging Americans, Imtiaz Masfique Dowllah

Theses and Dissertations

Despite the attenuation of association following adjustments for covariates, participants who engaged in 3–6 hr/wk of vigorous- and > 1 hr/wk of moderate-intensity PA scored significantly higher in tests that assessed executive function and processing speed domains of cognition compared to inactive peers (η2 = 0.005 & 0.007 respectively, p < 0.05). Also, after adjustment, the effects of 1–3 hr/wk of vigorous-intensity PA became trivial for the delayed recall memory domain test scores (β = 0.33; 95% CI: –0.01, 0.67; η2 = 0.002; p = 0.56). There was no clear dose-response relationship between the cognitive test scores and weekly moderate-intensity PA. Interestingly, higher handgrip strength and higher late-life body-mass-index were associated with a higher performance across all cognitive domains. Observed associations provide evidence linking habitual PA with superior cognition health among older adults. Furthermore, increased muscle strength and higher late-life adiposity may …

Developmental Activation Of Mitochodnrial Opa1 Processing Is Retinoic Acid-Independent, Shaynah St. Vallier

Theses and Dissertations

Mitochondria exist as an organellar network within most eukaryotic organisms, and are critical to biochemical energy production and cellular stress response. Mitochondrial bioenergetic function is directly linked to the complex morphological state of its network, existing in a balance of fusion (interconnected state) or fission (fragmented state). The optic atrophy-1 (OPA1) protein plays a major role in regulating mitochondrial inner membrane fusion, whereas the OMA1 metallopeptidase is highly involved in the degradation of the OPA1 protein, thus contributing to its fragmented state. Cellular stress such as a disruption in mitochondrial membrane potential activates OMA1 cleavage of OPA1. However, our data …

Unravelling The Role Of Pgpr "Pseudomonas Fluorescens" In Semi- Arid Soils Of The Rio Grande Valley, Mandip Tamang

Theses and Dissertations

Chapter 1: In this chapter, we have provided a review on the components of rhizosphere engineering and the potential use of PGPR and its challenges to serve as an efficient component for sustainable agriculture.

Chapter 2: In this chapter, we isolated 35 different strains of a PGPR, Pseudmonas fluorescens and characterized various plant growth promoting traits such as production of ammonia, protease, Indole acitic acid (IAA), 1-aminocyclopropane-1-carboxylate deaminase (ACC) deaminase, ammonia, hydrogen cyanide (HCN), and souliblization of zinc and phosphate.

Chapter 3: In this chapter, we tested the influence of plant beneficial soil microbe, P. fluorescens, on the growth and …

An Assessment On Microplastic Pollution In The Resacas Of The Lower Rio Grande Valley, Texas, Wesley D. Franklin

Theses and Dissertations

Microplastic pollution is a serious issue that impacts most aquatic environments. Microplastics have the potential to cause numerous detriments to the fitness and reproductive capability of many organisms. The resacas of the Lower Rio Grande are an understudied area that could be sinks for large congregations of microplastics. We analyze microplastic pollution in two species of fish as well as the sediment and water of eleven different pools from four resaca systems. We find that microplastics are present in every pool sampled.

Altogether 218 microplastic pieces are found from the water, sediment and fish samples. We find that microplastics are …

Practical Challenges Of Using Sunn Hemp As A Cover Crop In The Lower Rio Grande Valley, Qulina Rai

Theses and Dissertations

Sunn hemp (Crotalaria junceae) is an emerging cover crop with many reported benefits such as nitrogen fixation, carbon sequestration, and suppression of weeds and nematodes. Relatively little is known about appropriate ways to inoculate sunn hemp ensuring nitrogen fixation, and diseases that affect sunn hemp within the Lower Rio Grande Valley of Texas.

Four sticking agents, peanut oil, jaggery, gum arabic, and water used to aid inoculation of Bradyrhizobium japonicum in sunn hemp was checked on nodulation. Water treatment was least effective. Peanut oil and jaggery treatment showed better performance in overall total nodules, and active nodules. Gum …

Exploration Of Antimicrobial And Cell Proliferation Properties Of Nanofibers Incorporating Nopal (O. Cochenillifera) Extract, Cristobal Rodriguez

Theses and Dissertations

This study focused on the fabrication of Forcespinning® nanofibers composed of Opuntia cochenillifera, ‘nopal’, mucilage (N) extract, chitosan (CH), and pullulan (PL) (N/CH/PL) were developed with an optimum fiber average diameter of 406±127 nm, and studied for their ability to sustain adhesion and proliferation of mouse embryonic fibroblast (NIH 3T3) cells. After a 6-day incubation period, N/CH/PL nanofibers displayed robust cell proliferation, while also exhibiting inhibitory properties through an N extract dip-coating process against gram-negative bacteria Escherichia coli in a 24 h bacterial growth study. A demonstration of integrated natural bioactive compounds with combined biodegradable polymers, provide an enhanced …

Understanding An Inflammatory Pathway In Diabetic Retinopathy, Reanna Raye Rodriguez

Theses and Dissertations

Diabetic Retinopathy (DR) is the leading cause of blindness in the U.S. However, not much is known of its molecular pathway and how it attributes to increases in inflammatory response in the eye. One avenue we will investigate is the transforming growth factor beta (TGFB) signaling pathway and its effect of vascular endothelial growth factor (VEGF) secretion and cell viability. VEGF is the hallmark that exacerbates DR progression in prolonged diabetes. Some major concern that have arisen are the underlying effects of oxidants and antioxidants in elevating VEGF secretion in diabetes. In attempt to learn more, we evaluated how an …

Effects Of Plant Secondary Metabolites And Host Specificity On Growth, Development, And Oviposition Of Lepidopteran Herbivores, Sukhman Singh

Theses and Dissertations

Chapter 1: This chapter provides a review of recent and critical literature on the role of polyphenols in mediating plant-insect interactions. I particularly focused on plant defense induction and mode of action of polyphenols, defense fitness trade-offs, and storage of polyphenols for future defense responses.

Chapter 2: This chapter is about the effects of polyphenol rich purple corn pericarp extract on the growth and development of generalist caterpillar i.e., fall armyworm (Spodoptera frugiperda). This study shows that purple corn pericarp extract rich in polyphenols negatively effects the growth and development of S. frugiperda.

Chapter 3: This chapter …