Investigating the Effects of Peptide Mimics on the Binding Interaction between BRCA1 and PALB2

Type: Undergraduate
Author(s): Madison Adam Biology Casey Patterson-Gardner Chemistry & Biochemistry
Advisor(s): Mikaela Stewart Biology

BRCA1 plays an important role in the DNA damage response pathway by promoting the facilitation of homologous recombination with its binding partner, PALB2. Inherited loss of function BRCA1 variants disrupt this highly conserved and stabilized protein-protein interaction, preventing the complex from repairing double stranded breaks in DNA. Hereditary breast cancers have been treated using well-established methods, such as PARP inhibitors and DNA damaging agents. However, nonhereditary breast cancers that retain BRCA1 function are not susceptible to these treatments because they are able to effectively repair their DNA, leading to a proliferation of the cancer cells.
Here, we investigate whether small peptide-mimicking molecules, such as stapled peptides and macrocycles, have the ability to disrupt the BRCA1 and PALB2 interactions. We designed a short sequence of amino acids that mimicked BRCA1’s coiled coil region, the area that binds to PALB2. This sequence was then “stapled” with a short hydrocarbon to create a stapled peptide. The macrocycles were designed by targeting amino acids necessary to the BRCA1/PALB2 interaction. Binding interactions between the peptide mimics and PALB2 were measured using isothermal titration calorimetry (ITC). This method is incredibly reliable for sensing the heat changes upon binding to predict protein interactions. Our results suggest that macrocycles do not inhibit the BRCA1/PALB2 interaction, while the stapled peptides may be competing with BRCA1 for the binding site of PALB2.
Our findings indicate that due to the high specificity and conservation of the BRCA1/PALB2 interaction, finding a molecule to completely disrupt this interaction would require high throughput screening methods to test multiple compounds at once. These proteins may not be susceptible to rational drug design, so testing a variety of compounds may be the best way to disrupt this interaction. Further refinement of the peptide length, sequence, staple placement, and staple chemistry, as well as different macrocycles, may also be useful to effectively inhibit this interaction. Targeting the BRCA1-PALB2 interaction remains a promising strategy for treatment of non-hereditary breast cancers.

Developing Effective Husbandry Protocols for Larinoides

Type: Undergraduate
Author(s): Sommerlyn Babineau Biology Aidan Duffield Biology
Advisor(s): Matt Chumchal Biology

Developing Effective Husbandry Protocols for Larinoides
Reliable laboratory husbandry is essential for maintaining healthy spider populations used in ecological, physiological, and behavioral research. However, standardized protocols remain limited, particularly in spiderlings. This project focused on developing and refining husbandry techniques to optimize spider survival, health, and rearing of young under lab conditions. This study establishes and evaluates husbandry protocols for Larinoides orb weavers (Family Araneidae), a group of riparian spiders known for constructing vertical orb webs and their ecological role as important predators in aquatic-terrestrial food webs. Six adult spiders were collected from the Trinity river in Fort Worth, TX and mated in the laboratory. Their spider hatchlings were maintained in individually prepared vials containing artificial vegetation designed to support web attachment and movement. Feeding regiments using immobilized fruit flies and hydration strategies using a diluted honey solution were implemented. Observations of survival, activity, and general health were recorded. The husbandry system promoted consistent housing and care routines to promote spider survival in a laboratory setting. The methods used provided a reproducible system that consistently allowed spiders to successfully mate, reproduce, and nurse spiders to adulthood. These findings will contribute to the rapidly expanding field of spider husbandry by providing a reproducible husbandry system.

Exploring the impact of nucleosome ubiquitylation of BRC-1 on meiotic crossover in C.elegans

Type: Undergraduate
Author(s): Nathalie Carlon Biology Coby Gratzer Biology Lucy McCollum Biology Meagan McMann Biology Mikaela Stewart Biology
Advisor(s): Mikaela Stewart Biology

BRCA1, a tumor suppressor protein, when dysregulated, leads to a significant proportion of hereditary breast and ovarian cancers. Better understanding the specific enzymatic functions of BRCA1 and the downstream phenotypic effects is important for advancing cancer research. Because crucial signaling pathways controlled by BRCA1, including nucleosome ubiquitylation, are similarly conserved between humans and Caenohabditis elegans (C.elegans), this organism is a valid model to determine the phenotypic effects of BRC-1, a homolog of BRCA1, when its molecular signaling pathways are altered.
It was previously discovered that wild-type N2 C.elegans, which retains a fully functional BRC-1 protein, mainly display an XX genotype and hermaphrodite phenotype. Conversely, the xoe4 knockout mutant has an absent BRC-1 protein and displays an increased frequency of XO males, presumably due to loss of BRC-1 function in proper meiotic crossover during gamete formation. Yet, it is unknown whether the nucleosome ubiquitylation signaling pathway of BRC-1 directly contributes to successful meiotic crossover and XX hermaphrodites.
We hypothesize that the syb5376 mutant strain, which contains the BRC-1 protein but lacks facilitation of nucleosome ubiquitylation, would exhibit an intermediate phenotype with a male frequency higher than the N2 wild-type strain but lower than the xoe4 knockout strain. To test this hypothesis, we quantified the ratio of male to hermaphrodite progeny and compared male frequencies across all three strains.
Consistent with our hypothesis, the syb mutant illustrated a male frequency that was in between the N2 wild-type and xoe4 knockout strains. This suggests that nucleosome ubiquitylation of BRC-1 mediates successful meiotic crossover, but also contributes to this function either by mediating other protein-protein interactions or ubiquitylation of an alternate substrate.
Ultimately, these findings detail the importance of nucleosome ubiquitylation of BRC-1 in C. elegans, which is useful for determining the importance of nucleosome ubiquitylation of BRCA1 in humans. More broadly, this work advances our understanding of how specific molecular functions of BRCA1 contribute to genomic stability and increase breast and ovarian cancer susceptibility.

Thermal Tolerance and Reproductive Responses of Northern and Southern Dreissena polymorpha Populations

Type: Undergraduate
Author(s): Madeline Comeaux Biology
Advisor(s): Michael Misamore Biology

The Dreissena polymorpha (zebra mussels) and Dreissena bugensis (quagga mussels) are invasive, freshwater species native to Eastern Europe. Since their introduction to the Great Lakes region of the United States in the 1980s, both dreissenid mussels have quickly expanded throughout inland waterways and caused significant economic impacts and ecological changes. Both zebra and quagga mussels have greatly exceeded the expansion range of predicted models, spreading throughout North America and south into warmer waters including Texas. The mechanism facilitating this expansion is a topic of great interest. Understanding differences between cold-water and warm-water adapted mussels may help us to better predict their spread into Texas. In my project, I investigated the differences in temperature tolerance by analyzing survival rates of adult mussels in varying degrees of water. Furthermore, I analyze differences in spawning of egg and sperm and resultant fertilization success between the two groups. Together, these findings provide insight into the temperature-related survival and reproductive strategies that may enable these mussels to continue expanding beyond their predicted range into warmer freshwater environments.

Determination of gamete viability in dreissenid zebra and quagga mussels

Type: Undergraduate
Author(s): Molly Corriere Biology
Advisor(s): Mike Misamore Biology

Zebra mussels are an invasive species known to cause adverse ecological impacts by outcompeting native species, disrupting the food web, and destruction to aquatic habitats. Zebra mussels often aggregate on hard surfaces, clogging pipes, damaging boats and infrastructure, etc., leading to costly economic challenges. As broadcast spawners, they release eggs and sperm into the water column where fertilization and larval development occurs. During this process, the larvae may travel long distances enabling their spread into new locations, including Texas. These early stages of the lifecycle (gametes, larvae) zebra mussels will be most sensitive to external factors and conditions. They may also be the most sensitive to control mechanisms such as copper or bleach treatments. Little is known about exactly how long gametes remain in the water prior to fertilization and how long after spawning are they viable. The objective of this research project is to gain a deeper understanding of Zebra mussel reproduction with a focus on gamete viability. I will assess sperm viability using multiple assays including established procedures such as sperm motility using video analysis, gamete and sperm longevity. We have developed novel a fixed egg assay that allows analysis of sperm binding to eggs without the need for freshly spawned eggs. These assays will allow us to determine how long zebra mussel sperm and eggs are viable after release and to address how environmental factors such as temperature, calcium, or copper affect gamete viability.

Investigating the Role of dUTPase-1 in Iron Acquisition Bacillus anthracis

Type: Undergraduate
Author(s): Sophie Degrand Biology
Advisor(s): Shauna McGillivray Biology

Bacillus anthracis is the bacterial pathogen responsible for the lethal disease anthrax. For the pathogens to cause disease, they must overcome several host defenses including obtaining essential nutrients like iron. Our lab has identified that the dUTPase-1 gene is critical for iron acquisition from hemoglobin in B. anthracis. Normally, dUTPase functions to hydrolyze dUTP into dUMP. This functions to maintain DNA integrity as hydrolysis lowers the concentration of dUTP preventing uracil incorporation. This enzyme has never been linked to iron acquisition before, although in other systems, it has been linked with a secondary role in regulating signaling. Our goal is to determine whether the enzymatic activity, dUTP hydrolysis, is important for iron acquisition from hemoglobin. We hypothesize that dUTPase’s enzymatic activity is not responsible for the iron acquisition phenotype, and that it is through another mechanism. To test this we will introduce amino acid substitutions into two highly conserved residues in the active site using site-directed mutagenesis. This mutation should destroy enzymatic activity which we will confirm using a PCR-based assay. We will then test for iron acquisition ability using our established hemoglobin assay. We are currently working on the construction of our enzymatic mutant and optimizing our hemoglobin to test it once it is completed. This research will help us determine which structural domains are key to the iron acquisition activity of dUTPase and shed light on the secondary function of this enzyme.

"Custom Development of Molecular and Genetic Barcoding Tools for Predator Identification in Texas Horned Lizard (Phrynosoma cornutum) Populations"

Type: Undergraduate
Author(s): Isabelle Galvan Biology Kira Gangbin Biology Dean Williams Biology
Advisor(s): Dean Williams Biology

The Texas Horned Lizard (Phrynosoma cornutum) has undergone dramatic population declines across its native range due to habitat loss, invasive species, and predation. As a result, Texas zoos and the Texas Parks and Wildlife Department have been attempting to reintroduce hatchlings of this species into areas where it has become extinct. To support reintroduction, graduate researchers from TCU’s biology program glued harmonic tags onto the backs of the hatchling THL, making them easier to locate in the wild and to determine the most viable areas for reintroduction. The hatchlings, however, still experience high predation, and we often find their tags in the scat of various predators, such as snakes, birds, and small mammals. Previous tracking studies suggest coachwhip snakes (Masticophis flagellum) are a major predator of these lizards. Identifying the primary predators of reintroduced populations is critical for improving hatchling survival and informing conservation strategies. Tissue samples were collected for coachwhips, other potential Texas snake predators, and a few mammals to create and test a coachwhip-specific primer. We extracted DNA from the scat and used the coachwhip-specific genetic marker and a horned lizard-specific primer to screen over 80+ fecal samples with tracking tags collected across multiple THL release sites from the 2024 fall season. The results of this study will be used to determine how common coachwhip predation is at the reintroduction sites and whether management actions can be implemented to reduce predation during the early hatchling stage.

STEMpower After-School Girls Club

Type: Undergraduate
Author(s): Lilli Gonzales Biology Destiny Gallegos Biology Hermela Leul Nutritional Sciences
Advisor(s): Ashley Titus Physics & Astronomy

A notable occupational gap exists within the STEM (Science, Technology, Engineering, and Mathematics) field between employed women and men. It is likely to occur around the ages of 10-12, as this is when girls typically start to lose interest in STEM-related activities. The purpose of this study is to investigate the views of fourth- and fifth-grade girls on STEM, careers, and post-secondary education as they participate in the STEMpower After-School Club. Additionally, we aim to determine the students’ baseline STEM identities and their interests in STEM careers following their participation in the STEMpower After-School Club. This study is being conducted by following a group of fourth and fifth-grade girls during a year-long academic after-school program. Our methods include a STEM careers survey.

Testing Novel Antioxidant Compounds for Neuroprotective Effects

Type: Undergraduate
Author(s): Gabriel Hernandez Biology
Advisor(s): Giridhar Akkaraju Biology

Alzheimer’s disease is the fastest growing form of dementia in the world. Currently the origin of disease is unknown, however, there are distinct signs seen in patients with Alzheimer’s disease (AD). Chronic neuroinflammation, increased ROS, dyshomeostasis of metal ions, Tau tangles, and mitochondrial dysfunction are well known to the pathogenesis and progression of this disease. Despite the pathogenesis being well documented, most current drugs treat symptoms of the disease, but have no effect on the progression of disease. The aim of this study is to test novel antioxidant compounds (L2 and L3) for their ability to reduce intracellular ROS in mice microglial cells (BV-2) and mice hippocampal cells (HT-22). DCFH-DA assays were used to measure the ROS levels. MTT assays were used to assess cell viability and determine safe concentrations of antioxidant compounds to use. Results of this study show significant reductions of ROS (TBHP) in BV-2 and HT-22 cells by L2, as determined by the DCFH-DA assay. These results are significant because it shows that L2 does not only protect neuronal cells from oxidative stress, but it can also decrease microglial inflammatory response.

The Effect of Media Type on ZnO Cytotoxicity

Type: Undergraduate
Author(s): Louise Hutchison Biology
Advisor(s): Shauna McGillivray Biology Yuri Strzhemechny Physics & Astronomy

The increasing prevalence of antibiotic-resistant bacteria, including Staphylococcus aureus, has intensified the search for alternative antimicrobial strategies. Metal oxides have emerged as promising candidates, with zinc oxide (ZnO) attracting particular interest due to its low cost, thermal and mechanical stability, and minimal generation of harmful by-products. ZnO has potential applications in medical device coatings, food preservation, and topical therapeutics. Previous work in our laboratory demonstrated that growth inhibition of S. aureus correlates with the release of Zn²⁺ ions from ZnO Sigma particles in Mueller–Hinton broth (MHB) (Caron et al., 2024). However, it has been reported that the media can influence Zn2+ dissolution and ZnO toxicity. In support of this, we find that ZnO particles exhibit increased dissolution in saline compared to MHB, resulting in enhanced cytotoxicity toward S. aureus. To further investigate the influence of different media types on ZnO dissolution and bacterial survival, we will investigate HEPES and MOPS buffers as media alternatives to assess ZnO toxicity. By evaluating how different chemical environments affect Zn²⁺ release and antimicrobial activity, this work aims to maximize the potential of ZnO-mediated cytotoxicity.

Hybridization Potential of the Invasive Dreissenid Zebra and Quagga Mussels

Type: Undergraduate
Author(s): Aubryanne Leugers Biology
Advisor(s): Michael Misamore Biology

Zebra and quagga mussels originated in Eastern Europe and were introduced to the United States in the mid-1980s. After spreading from the Great Lakes throughout much of the eastern United States, including Texas, both species have become major ecological and economic pests. The objective of my project is to investigate the hybridization potential between two invasive dreissenid species, Dreissena polymorpha (sebra mussel) and Dreissena rostriformis begensis (quagga mussel). I will analyze fertilization, success, gamete compatibility, larval development, and competitive sperm binding to determine the success and viability of hybridization. Understanding this is important, as hybridization could increase genetic diversity, novel advantageous traits, and the potential for range expansion.

Investigating the Role of Core Gut Symbionts in Defending Bumble Bees Against Opportunistic Pathogens

Type: Undergraduate
Author(s): Dylan Masson Biology
Advisor(s): Annika Nelson Biology

Bumblebees play a central role in pollinating both crops and natural plant populations. Yet, many bumblebee species are declining due to numerous anthropogenic effects, including exposure to pathogens. Bumble bees rely on a specialized community of gut bacteria, termed the “core” gut microbiome, to provide resistance against pathogens. However, the roles of particular bacterial species and strains within the core gut microbiome for defending against opportunistic pathogens remain unclear. This study investigated whether two abundant core gut bacteria – Gilliamella bombi and an unidentified bacterial strain isolated from bumble bee workers (Bombus impatiens) – reduce colonization by the opportunistic bacterial pathogen Serratia marcescens. After experimentally inoculating bumblebees with these two bacterial symbionts across a range of doses, we quantified bee resistance to pathogen infection by counting the number of colony-forming units (CFUs) of S. marcescens that colonized the gut. Contrary to expectations, the symbionts examined did not reduce pathogen colonization rate. These findings suggest that protection may require the full microbial community, specific combinations of taxa, or context-dependent interactions. Understanding when and how microbiomes confer defense is critical for predicting pollinator health under environmental change, and our research suggests that additional work is needed to identify probiotic bacteria that could be deployed to promote pollinator health.

The roles of iron regulatory proteins 1 and 2 in neuronal differentiation and iron-mediated cell death

Type: Undergraduate
Author(s): Kenley Meis Biology
Advisor(s): McKale Montgomery Nutritional Sciences

Iron Regulatory Proteins 1 and 2 (IRP1 and IRP2) are key regulators of cellular iron levels. Iron is essential for proper brain development and function, but can lead to cellular damage if not properly regulated. To investigate the effects of reduced expression of IRP1 and IRP2 on neuronal health and neurodegeneration, we are using mouse neurons that have been transfected with shRNA to specifically knock down IRP1 or IRP2. Mouse neurons are well-studied and share many key cellular pathways with human neurons, making them an appropriate model to study the effects of IRP1 and IRP2 knockdown. We will investigate the effect of the knockdowns on the mouse neurons through proliferation assays and differentiation assays. These experiments will reveal how the knockdown of IRP1 and IRP2 affects neuronal growth, maturation, and development compared to healthy control cells. Understanding these processes is incredibly important for humans, as iron dysregulation can lead to neurodegenerative diseases such as Alzheimer's.

Effect of Novel Drugs on the Expression of Nrf2 Related Genes in Immune Cells in the Nervous System

Type: Undergraduate
Author(s): Ezra Power Biology
Advisor(s): Giridhar Akkaraju Biology

Alzheimer’s Disease (AD) is a neurodegenerative disease that is characterized by progressive neuronal death. AD can be identified by the presence of cytotoxic amyloid-ß plaque on neuronal synapses and misfolded tau tangles in the body of neurons. As the most common form of dementia, AD has become a hot topic for healthcare professionals, and researchers have looked for a better understanding of how to stop the progression of the disease. Recently, studies have looked into the antioxidant pathway as a target for controlling AD. Evidence shows that the presence of Aß-plaques and tau tangles generates oxidative stress in the form of reactive oxygen species (ROS). The persistence of ROS may lead to chronic inflammation and neuronal cell death. Our study looks at the effect of a novel drug, L2, on its ability to activate the antioxidant pathway in mouse cell models. The novel drug is designed to locate ROS and has antioxidant properties, and has been proven to reduce ROS in in vitro studies. If L2 is added into ROS-rich cell culture, then the antioxidant pathway will be activated and express the genes for antioxidant proteins. To test for activation of the antioxidant pathway, mouse microglial cells were treated with L2 and were lysed for messenger RNA (mRNA) extraction. Differentially expressed genes were quantified and analyzed using the RT-qPCR technique and RNA sequencing. Results of the data are still being analyzed.

Evaluating the Effect of Novel Drugs in LPS-induced Neuroinflammation Using Enzyme-Linked Immunosorbent Assay

Type: Undergraduate
Author(s): Maria Revuelta Biology
Advisor(s): Giridhar Akkaraju Biology

Assessment of Penicillin Prodrug Activity Against Gram-positive Bacteria

Type: Undergraduate
Author(s): Katherine Richey Biology Braden Chadwick Biology Aidan Duffield Chemistry & Biochemistry Emma Kulla Chemistry & Biochemistry Emily Rathke Chemistry & Biochemistry
Advisor(s): Shauna McGillivray Biology Jean-Luc Montchamp Chemistry & Biochemistry

Testing The Ability of Novel Drugs to Inhibit TNFɑ-Induced Inflammation via NFκB Activation Pathway Using Luciferase Assay

Type: Undergraduate
Author(s): Isabella Stidham Biology
Advisor(s): Giri Akkaraju Biology

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by memory loss, cognitive decline, and chronic neuroinflammation. Inflammatory signaling pathways such as nuclear factor-κB (NF-κB) play a critical role in the progression of neurodegeneration by regulating the expression of pro-inflammatory cytokines such as TNF-α and IL-1β. Targeting NF-κB signaling therefore represents a promising therapeutic strategy for reducing inflammation associated with AD. This study evaluated the effects of several novel anti-inflammatory compounds provided by P2D Biosciences and Dr. Geen’s research lab on TNF-α–induced NF-κB activation. HEK293 cells were transfected with an NF-κB responsive PRDII luciferase reporter and a CMV luciferase control, followed by treatment with novel compounds and stimulation with TNF-α. Luciferase activity was measured to quantify the effect of our molecules on TNF-a-induced NF-κB transcriptional activation. Results demonstrated dose-dependent reductions in NF-κB activation for several compounds, suggesting potential anti-inflammatory activity. These findings contribute to ongoing efforts to identify novel small molecules capable of modulating NF-κB signaling and may support future therapeutic development targeting neuroinflammation in Alzheimer’s disease.

Investigating the Role of BRCA1 in Regulating Reactive Oxygen Species and Maintaining Genomic Stability

Type: Undergraduate
Author(s): William Stites Biology Shobe Manuel Biology
Advisor(s): Mikaela Stewart Biology

BRCA1 is widely recognized for its role in maintaining genomic stability, particularly through its involvement in several DNA repair pathways and chromatin regulation. While mutations in BRCA1 are strongly associated with increased cancer risk in humans, the broader cellular consequences of BRCA1 mutations under environmental stress remain unclear. The goal of the project was to investigate how loss or alteration of BRC-1, the Caenorhabditis elegans (C. elegans) homolog of BRCA1, affects stress responses at the organismal level, with focus on oxidative stress and reactive oxygen species (ROS) accumulation.

Using C. elegans as a model organism allowed me to study the stress responses within a system where development, reproduction, and genome stability are tightly connected. A key advantage of using C. elegans is that the organism is transparent. This allows for visualization and quantification of fluorescence to measure ROS within the worms, and to see how these values vary depending on BRC-1 status. Three strains were compared: 1) wild-type (N2), 2) a BRC-1 mutant (syb5376) predicted to disrupt nucleosome interaction and H2A monoubiquitylation while retaining other enzymatic functions, and 3) double knockout strain (xoe4) lacking functional BRC-1 entirely. The comparison of these worms with various levels of BRC-1 activity allowed for the investigation of how each of these different strains responded to various oxidative stressors. The broader aim of the project was specifically to look at how altered BRC-1 nucleosome ubiquitylation affects the cell's ability to deal with ROS, and compare this with the wild-type and complete knockout.

Several key questions were used to guide the research: 1) Whether stress responses differed between wild-type, mutant, and knockout strains, 2) How oxidative stressors altered ROS levels in each of the strains, and 3) Whether the syb5376 and xoe4 strains behaved similarly or exhibited distinct patterns compared to wild-type worms. Across multiple experimental conditions, the double knockout strain consistently showed the most elevated fluorescence, indicating increased ROS accumulation and reduced ability to manage oxidative stress due to the lack of BRC-1. The syb5376 mutant displayed an intermediate effect, suggesting partial impairment of regulation when lacking nucleosome interaction. These findings support the idea that BRC-1 plays a protective role under stress conditions and that disruption of nucleosome ubiquitylation may compromise the cellular response to oxidative damage and lead to a higher accumulation of ROS within cells.

Looking at the bigger picture, these results align with the broader understanding that BRCA1 loss does not immediately lead to cancer, but rather increases vulnerability when cells are challenged by environmental or metabolic stressors. Increased ROS levels can lead to DNA damage, and without proper chromatin remodeling and repair coordination, cells may struggle to restore their genomic integrity. The differences observed between the mutant and knockout strains further suggest that mutation type matters in determining the severity of stress sensitivity and the overall impact that this will have on the cell and organism as a whole.

Genetic Analysis of Captive-Bred Texas Horned Lizards (Phrynosoma cornutum)

Type: Undergraduate
Author(s): Alexis Winter Biology
Advisor(s): Dean Williams Biology

The Texas Horned Lizard (Phrynosoma cornutum) has experienced significant habitat loss and population declines across their historic range in the southwestern United States; as such, the species has been listed as threatened by the Texas Parks and Wildlife Department. To mitigate declines, captive breeding programs have reintroduced large numbers of hatchlings into suitable habitat at the Mason Mountain Wildlife Management Area (WMA), which lies within the northern genetic cluster of Texas Horned Lizards. Long-term reintroduction success relies on the management of demographic factors and genetic variance. While demographic viability inherently increases with supplementation from an introduced population, the maintenance of genetic diversity within a reintroduced population must also be accounted for. If genetic management within captive breeding programs is not considered, the reintroduced population risks reduced allelic diversity and lower evolutionary potential, inbreeding depression, adaptation to captivity, or outbreeding depression if management units are mixed. We genotyped all captive-bred Texas Horned Lizards reintroduced in 2023 (N = 456 hatchlings) using 10 microsatellite loci to assess how genetically representative the introduced group is relative to natural populations. Measures of genetic diversity (uHe, He, Ho, AR) were calculated in GenAlEx, and full-sib groupings were constructed in COLONY. Results suggest that the differentiation between the captive and Northern populations is low (average Zoo population pairwise Fst: 0.014), and measures of genetic diversity were very similar (uHe, He, Ho, AR), indicating that the genetic diversity of the reintroduced hatchling population is representative of genetic diversity in North cluster populations. Linkage disequilibrium-based estimates of effective population size, however, reveal a small genetic effective population size (Ne = 37.2 - 44.6 individuals), which will quickly lead to a loss of genetic diversity. The small effective population size of a single reintroduced cohort and high post-release mortality rates underscore the need for continued annual supplementation to buffer against genetic drift, thereby promoting the long-term survival of managed Texas Horned Lizard populations.

Synthesis and Characterization of a Dendrimer to Promote the Formation of Micelles

Type: Undergraduate
Author(s): Diana Avila Chemistry & Biochemistry
Advisor(s): Jean-Luc Montchamp Chemistry & Biochemistry

Alkyl phosphate surfactants were synthesized for the development of a dendricore micelle as a potential drug delivery platform. Conventional surfactant micelles often dissociate under physiological dilution due to their high critical micelle concentrations, limiting their utility. To address this limitation, a dendrimer scaffold templated by surfactants is being constructed through reaction of an amine with succinic anhydride followed by iterative Boc deprotection and carbodiimide coupling. This architecture is expected to enhance micelle stability and support dual-drug delivery.

Europium-doped Cerium Oxide Nanotubes as a Potential Probe for Bioimaging and Optical Sensors

Type: Undergraduate
Author(s): Kayla Brownell Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry

Our project focuses on Europium-doped Cerium Oxide nanotubes and their use as potential probes for bioimaging and optical sensors. Most CeO2 nanomaterials are not intrinsically fluorescent in the visible region, so these materials can be doped with rare earth ions that possess visible fluorescence. Rare earth ions that prefer the +3 oxidation state can be efficiently doped into CeO2 nanomaterials due to their similar ionic radii. Our research utilizes Europium (III) for doping, which is known for its red-orange emission and hypersensitive 5D0→7F2 transition. We choose a one-dimensional architecture for the target nanostructure because of its ideal geometry to interact with cells. A sacrificial template is employed, beginning with the synthesis of Zinc Oxide nanowires on an FTO substrate. After the nanowires are grown, a Europium (III) - Cerium (III) cycling process is performed to construct the nanotube, using the nanowire as a template.
The size and morphology of the nanotubes are measured using a Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The crystalline structure of the Europium-doped CeO2 nanotubes can be characterized using X-ray diffraction (XRD) to determine how varying Eu3+ concentration can change the XRD peaks. Their photoluminescence (PL) spectra are measured as a function of varying the percentage concentration of Eu3+. Light emission is compared as a function of dopant concentration by varying the Eu3+ concentration between 5%-15% to determine the concentration with the optimal fluorescence intensity. Ultimately, the desired characteristic fluorescence of the nanotubes enables their use in bioimaging and as optical sensors.

BOILED-eggs and the Blood-Brain Barrier: How BOILED-egg Modeling Can Predict Permeability of Pyridine Macrocyclic Molecules to Combat Alzheimer's Disease

Type: Undergraduate
Author(s): Luke Chouteau Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry

Every 65 seconds, someone is diagnosed with Alzheimer's disease, which is the seventh leading cause of death in the United States. A major barrier to potential therapeutics is the permeability of these molecules across the blood-brain barrier. We have developed small molecules with strong reactivity to combat the oxidative stress known to cause Alzheimer’s disease. However, the permeability is less than ideal. As a result, my goal is to produce a molecule that has enhanced permeability but retains the reactivity of the parent molecules. To achieve this, the BOILED-Egg model was used to assess different derivatives of our parent molecule, Py2N2. This model showed the differences in lipophilicity among different Py2N2 compounds and how they impact permeability into the blood-brain barrier and gastrointestinal tract. Background information on our parent molecule and its function regarding Alzheimer's development will be outlined to give a scope of what these compounds can target and how they function. Compounds with high lipophilicity reflected in the model will have schemes of synthetic synthesis for future directions.

Characterizing the pH-Dependent Solubility of Protein-Porphyrin Complexes by Spectrophotometry

Type: Undergraduate
Author(s): Ngan Dinh Chemistry & Biochemistry
Advisor(s): Onofrio Annunziata Chemistry & Biochemistry

The binding of the water-soluble porphyrin tetrasodium tetraphenylporphyrintetrasulfonate (TPPS) to bovine serum albumin (BSA) in aqueous media at room temperature can be explored for developing an analytical assay for PFAS (or “forever chemicals”) detection. Indeed, we determined that spectrophotometric detection of PFAS is optimized by exploiting competitive binding of PFAS and TPPS to BSA at pH 4.7. In this poster, we spectrophotometrically investigated BSA-TPPS binding at pH 3.0, 4.7, and 7.2. Specifically, TPPS concentration was maintained constant at 80 M in our experiments and BSA concentration was varied. Interestingly, while BSA-TPPS complexes are soluble at pH 7.2, they form insoluble precipitates in acidic conditions (pH 3.0 and 4.7) at low BSA concentration. Specifically, we find that solubility of TPPS exhibits a minimum as BSA concentration increases. We therefore developed a theoretical model that successfully describes the observed behavior of TPPS solubility. Spectrophotometric calibration curves for the determination of PFAS concentration were constructed using solutions with a sufficiently high BSA:TPPS molar ratio.

Application of the Electrical Double Layer Theory to Diffusion of a Cationic Micelle in Water

Type: Undergraduate
Author(s): Viet Hoang Chemistry & Biochemistry Minh Le Chemistry & Biochemistry Josie Nguyen Chemistry & Biochemistry
Advisor(s): Onofrio Annunziata Chemistry & Biochemistry

Salt-induced diffusiophoresis is the migration of a charged nanoparticle in water, induced by an imposed directional gradient of salt concentration. This transport phenomenon has emerged as a valuable tool for particle manipulation inside porous materials and microfluidics. Micelles are a common example of nanoparticles with the crucial ability of hosting small guest molecules. Thus, micelle diffusiophoresis is important in the manipulation of small molecules. Diffusiophoresis depends on the intrinsic ability of micelles to randomly move (diffuse) in water. In this poster, we report experimental micelle diffusion coefficients for the surfactant hexadecylpyridinium chloride (CPC) in the presence of aqueous NaCl and KCl. The electrical double layer theory was successfully employed to explain the effect of surfactant and salt concentrations on the observed micelle diffusion coefficient. These data were then used to characterize salt-induced diffusiophoresis of charged micelles.

Influence of a NiO Hole Transport Layer on Charge Separation in FTO|WO₃|BiVO₄ Photoanodes for TEMPO-Mediated Oxidation

Type: Undergraduate
Author(s): Favor Igwilo Chemistry & Biochemistry Qamar Hayat Khan Chemistry & Biochemistry Daisy Li Chemistry & Biochemistry
Advisor(s): Benjamin Sherman Chemistry & Biochemistry

Influence of a NiO Hole Transport Layer on Charge Separation in FTO|WO₃|BiVO₄ Photoanodes for TEMPO-Mediated Oxidation

Favor Igwilo, Texas Christian University, Class of 2026
Laboratory of Dr. Benjamin Sherman, PhD;
Department of Chemistry and Biochemistry

Efficient hole transport is critical for driving oxidative transformations in photoelectrochemical systems. In this study, we investigate multilayer FTO|WO₃|BiVO₄|NiO photoanodes for application in TEMPO-mediated oxidation of benzyl alcohol to benzaldehyde, an important chemical reaction used in industrial processes. The stable radical 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) enables selective alcohol oxidation under mild conditions and represents a more sustainable alternative to conventional stoichiometric oxidants that generate hazardous waste. Enhancing interfacial charge transport is essential to improve the viability of this photoelectrosynthetic process.
We hypothesize that nickel oxide (NiO), a p-type semiconductor, can function as an effective hole transport layer due to its favorable valence band alignment, hole mobility, abundance, and low cost relative to traditional materials such as titanium dioxide (TiO₂). A liquid phase deposition protocol was developed to fabricate uniform NiO thin films on fluorine-doped tin oxide substrates, which were subsequently integrated into FTO|WO₃|BiVO₄ substrates. The resulting multilayer photoanodes were evaluated to determine whether NiO enhances charge separation and hole extraction under various conditions.
Electrochemical characterization was performed using cyclic voltammetry to probe redox behavior and assess catalytic onset potentials, chronoamperometry to quantify steady-state photocurrent and operational stability, and electrochemical impedance spectroscopy to evaluate interfacial charge transfer resistance. Measurements were conducted under both dark and illuminated conditions, with and without TEMPO, in Tetrabutylammonium hexafluorophosphate (TBAPF6)in acetonitrile (ACN) solution. We anticipate that incorporation of NiO will reduce interfacial charge transfer resistance, increase photocurrent density in the presence of TEMPO, and improve kinetic parameters associated with benzyl alcohol oxidation.
Photocurrent densities of FTO–WO₃–BiVO₄ and FTO–WO₃–BiVO₄–NiO photoanodes were directly compared to quantify the effect of the NiO interlayer. Additionally, heterogeneous electron transfer rate constants (k₀) were determined under TEMPO-containing conditions to assess how the multilayer structure influences interfacial electron transfer kinetics.
This work establishes a working protocol for NiO liquid phase deposition and clarifies the role of NiO in enhancing TEMPO-mediated photoelectrosynthetic oxidation. These findings can later inform the design of cost-effective photoelectrode architectures for sustainable organic reactions.