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.

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.

Prolonged Intake of a Typical American Diet Triggers the Expression of Genes Related to Hepatic Inflammation and Oxidative Stress

Type: Graduate
Author(s): Lacey Eddleman Biology
Advisor(s): Michael Chumley Biology

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that affects behavior, memory, and overall health and well-being. Although it is the sixth leading cause of death in the United States among people aged 65 and older, there is currently no cure or effective preventive treatment. Multiple risk factors contribute to the development of AD, including aging, genetics, chronic stress, and diet. Increasing evidence suggests that diet is a major modifiable factor influencing disease risk through mechanisms involving systemic inflammation and oxidative stress. Diets high in saturated fats, refined carbs, and sugars typical of the American diet promote lipid buildup, especially in the liver. Excess hepatic lipids can cause fatty liver, metabolic issues, inflammation, and oxidative damage, potentially contributing to AD pathology. To better understand how diet influences these biological pathways, our lab developed two macronutrient and calorie-matched rodent diets: one that models a Mediterranean-style diet (MD) and another representing the typical American diet (TAD). Previous studies in our lab using male and female C57BL/6J wild-type mice examined the effects of these diets over shorter periods. In a three-month dietary exposure study, mice fed the TAD exhibited notably greater hepatic lipid accumulation compared to those fed MD, suggesting early metabolic stress. However, gene expression analyses did not show significant evidence of inflammation or oxidative stress. This suggests the duration might not have been sufficient to detect molecular changes. This study prolonged diet exposure to six months to determine whether extended TAD intake leads to alterations in liver gene expression associated with inflammation and oxidative stress. We examined several inflammatory genes (e.g., TNF-α, Il-1β, and IL-6) and oxidative stress-related genes (e.g.,NRF2, HO-1, and SOD) and found that mice on the TAD showed higher expression of inflammatory and oxidative stress markers than MD-fed mice. Our lab has also previously demonstrated that six-month consumption of the TAD diet leads to AD-related markers such as elevated amyloid-β levels in the brain and the associated decrease in cognitive function. Combined, these results suggest that prolonged exposure to poor dietary conditions encourages inflammatory and oxidative stress signals from the liver, which may help drive AD pathology.

"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.

Novel Drivers of Nest-site Selection in Texas Horned Lizards

Type: Graduate
Author(s): Kira Gangbin Biology Julianne Li Interdisciplinary Madison Upton Interdisciplinary Dean Williams Biology Brian Wright Interdisciplinary
Advisor(s): Dean Williams Biology

Reproductive success in oviparous reptiles is shaped by both nest environment and post-emergence resource availability. While the abiotic conditions of a reptile’s nest can greatly influence hatching success, post-emergence resource availability affects hatchling survival and growth. Many studies evaluate whether females favor particular nesting sites based on abiotic conditions; however no studies have linked nest site choice with post-emergence resource availability. Understanding this relationship could improve habitat management and enhance survival in Texas horned lizard (Phrynosoma cornutum) reintroduction programs. The species’ strong dietary specialization, particularly the reliance of hatchlings on small native ants (Crematogaster, Dorymyrmex, Pheidole, and Tetramorium spp.), makes it possible to test whether females select nest sites that maximize post-emergence prey availability. During the summers of 2023 and 2024, we located 21 nests of Texas horned lizards at a reintroduction site at Mason Mountain WMA and at a natural population (~42 km away) in central Texas. We compared nest and random sites to assess a female’s ability to select a nest site based on fire ant abundance, native ant abundance, soil moisture, soil compaction, and vegetation structure. Using stepwise model selection, results suggest that horned lizards select nest sites that have low soil compaction, reduced grass cover, and high amounts of hatchling prey. This information will be used to determine if there are suitable nesting areas at reintroduction sites and how to best manage land for optimum horned lizard survival. Release sites with softer soil, less grass, and higher abundance of native ants should be prioritized.

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.

What in the worm!? Investigating nucleosome ubiquitylation by BRCA1 in C. elegans

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

BRCA1 protects genomic stability by signaling for the homologous recombination pathway, DNA repair, and transcriptional regulation. A pathogenic mutation in BRCA1 causes a higher predisposition to the development of breast and ovarian cancer. BRCA1 acts as a scaffold for many dynamic protein complexes, as well as functions as an E3 ligase towards various substrates. We do not know which if these interactions and substrates are tied to the many phenotypes associated with BRCA1 dysfunction. Our lab is exploring the importance of BRCA1 E3 ligase activity toward the substrate histone H2A. Using structural and biochemical assays we designed a BRCA1 mutant that maintains other critical BRCA1 interactions and substrates but specifically eliminates nucleosome ubiquitylation. This mutant allows us to connect this specific BRCA1 function to downstream phenotypes at an organismal level. A homolog of BRCA1 is conserved in C. elegans as BRC-1. We propose that nucleosome monoubiquitylation is a key mechanism contributing to some cellular functions of BRC-1, including DNA damage accumulation and transcriptional regulation of cytochrome p450 genes. We have generated a C. elegans mutant strain with these two specific point mutations that alter the ability of BRC-1 protein to interact with the nucleosome and ubiquitylate histone H2A while retaining all other functions. We hypothesize this mutation increases DNA damage accumulation and disrupts transcriptional regulation to establish nucleosome ubiquitylation as a necessary precursor for these, but likely not all, BRC-1 functions. We compare three strains of C. elegans (wildtype, brc-1 knockout, and our nucleosome monoubiquitylation-deficient mutant) in different conditions designed to induce cellular stress or DNA damage accumulation. We find that BRC-1 nucleosome ubiquitylation contributes to embryonic survival under standard conditions as well as DNA damage-inducing conditions. Preliminary results also indicate an intermediate response regarding the role of nucleosome ubiquitylation in transcription regulation of cytochrome p450 genes. These findings help us better connect specific BRCA1 activity with downstream functions in the organism. We hope this project can be used as a blueprint for how protein structure to function relationships can be explored with the powerful C. elegans.

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.

Dietary Contributions of Aquatic and Terrestrial Insects to Methylmercury Exposure in the Arctic Wolf Spider

Type: Graduate
Author(s): Cami Middlebrooks Biology Keira Braun Biology Charlie Duethman Biology Omid Ghuman Biology Ramsey Jennings Biology Chidi Mbagwu Biology Denice Rodriguez Biology Kyle Trevor Biology Lance Viscioni-Wilson Biology Tristan Williams Biology David Wright Biology
Advisor(s): Matt Chumchal Biology

The Arctic is contaminated with mercury (Hg) higher than historic baselines because of emissions from temperate and subtropical areas. The nonbioavailable form, inorganic Hg, is deposited on the landscape and is thought to have limited impacts on terrestrial organisms. In aquatic systems, inorganic Hg is converted to methylmercury (MeHg), a contaminant that biomagnifies through food webs and poses reproductive and neurological risks to wildlife and humans. The Arctic wolf spider (Pardosa glacialis), is one of the most abundant terrestrial predators in western Greenland, and prior research has linked MeHg concentrations in wolf spiders to emergent aquatic insects, indicating cross-ecosystem contaminant transfer. While freshwater ecosystems are recognized as important sources of MeHg to terrestrial consumers, recent observations suggest that Arctic terrestrial insects may also exhibit elevated Hg concentrations comparable to aquatic insects, potentially providing an additional pathway of contamination for terrestrial predators. However, the relative contribution of aquatic versus terrestrial prey to P. glacialis diets across Arctic ponds remains unclear. We investigated how aquatic and terrestrial prey contribute to the diet of P. glacialis and how this dietary composition may influence contaminant exposure in Arctic terrestrial food webs. We hypothesize that wolf spiders consume a mixture of both aquatic and terrestrial insects, broadening the source of P. glacialis’s contamination. To test this, we captured and analyzed wolf spiders, terrestrial insects, and emergent aquatic insects at six Arctic pond sites. Across all ponds, spider populations exhibited a dietary mixture of aquatic and terrestrial insects. These results indicate that both aquatic and terrestrial insects influence P. glacialis MeHg contamination. This suggests that all artic food webs, not just those connected to aquatic systems, may be contaminated with MeHg, suggesting that the Arctic is more contaminated than previously thought.

Targeting ferroptosis in Alzheimer’s disease: investigating glutamate-induced oxidative stress in HT-22 hippocampal neurons

Type: Graduate
Author(s): Maddie Perkins Biology Ella Dammen Biology Keller Williamson Psychology
Advisor(s): Michael Chumley Biology Gary Boehm Psychology

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline and neuronal loss. Although amyloid-ß plaques and tau neurofibrillary tangles are well-established pathological hallmarks of AD, growing evidence suggests that additional mechanisms, including oxidative stress, iron dysregulation, and ferroptosis contribute significantly to the progression of the disease. Ferroptosis is an iron-mediated form of regulated cell death driven by lipid peroxidation and impaired antioxidant defenses. Neurons are particularly susceptible to ferroptotic damage due to their high metabolic demand, lipid-rich membranes, and reliance on highly regulated redox homeostasis. Disruption of the cystine/glutamate antiporter (system xc-) can deplete intracellular glutathione (GSH), impair glutathione peroxidase 4 (GPX4) activity, and promote the accumulation of toxic lipid peroxides, ultimately triggering ferroptotic cell death.

This study investigates the role of ferroptosis in oxidative neuronal injury using the immortalized HT-22 mouse hippocampal neuronal cell line, a well-established model of glutamate-induced oxytosis. Oxidative stress is induced through glutamate exposure, which inhibits cystine uptake via system xc- and depletes intracellular glutathione levels. Cell viability is assessed using MTT assays, and quantitative PCR is used to evaluate transcriptional changes in key genes involved in ferroptosis and antioxidant defense, including Nrf2, Slc7a11, Acsl4, Ptgs2, Sod2, and Catalase. Lipid peroxidation is quantified through MDA measurement.

By characterizing both functional and transcriptional responses to oxidative stress, this research aims to better define the underlying molecular mechanisms by which glutamate toxicity leads to ferroptotic neuronal death. Understanding how ferroptosis contributes to neuronal vulnerability may reveal novel therapeutic targets aimed at strengthening antioxidant defenses and mitigating neurodegeneration in Alzheimer’s disease.

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.

Using genomics to determine origins and dispersal patterns of invasive northern pike (Esox lucius) in southcentral Alaska

Type: Graduate
Author(s): Mikay Reuter Biology
Advisor(s): Matthew Hale Biology

Invasive species harm local ecosystems, economies, and cultures. There has been a substantial effort to research the recent increase in the number and frequency of successful invaders; however, relatively little information regarding if and to what extent genetics influences a species ability to become a successful invader exists. Whole genome sequencing provides a mechanism that could illuminate the importance of genetics for successful invasion and uncover the roles selection plays in predisposing populations to be successful invaders. Northern pike (Esox lucius) are native to the Holarctic region but have been widely introduced across Europe and North America. For example, pike were introduced to the area around Anchorage, Alaska in the 1970s and have since spread throughout southcentral Alaska. This species represents a major threat to populations of native fish species, especially multiple species of salmonid. Current management efforts appear to fall short as many pike populations have increased following removal. Part of this growth is likely from the ability of pike to disperse into marine environments, allowing them to colonize new bodies of freshwater. However, whether this ability to disperse is genetic – and therefore heritable - remains unknown. If there are alleles that predispose some populations of pike to be successful invaders, then such populations should be the target of multifaceted eradication efforts. To that end, several populations of pike – consisting of known residents and dispersers - from south-central Alaska were analyzed using whole genome sequencing to a) determine if there are alleles associated with dispersal ability and b) to determine if and to what extent populations are predisposed to dispersal behaviors. Overall, this research will improve our understanding of the genetic basis of invasive biology, identify populations of pike that should become a priority for eradication, and help protect native fish species.

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

Riff Ram, Bah Zoo, What did Proline Do?: Investigation of Proline Variants in PALB2

Type: Graduate
Author(s): Jamison Speed Biology Maddie Adam Biology Styrling Murray Biology
Advisor(s): Mikaela Stewart Biology

Partner and Localizer of BRCA2 (PALB2) is a necessary linker protein between BRCA1 and BRCA2 that directs the cells towards homologous recombination in the presence of double-strand breaks (DSB). When this linkage is disrupted, the cell routes the repair towards non-homologous end joining or single-stranded annealing, which are not as efficient or accurate in their repair of DSB. With inefficient DNA repair, mutations accumulate that increase the risk of the development of cancer. It has been documented that mutation L35P in PALB2 is pathogenic and leads to a decrease in HR in cells. However, it is unknown if the loss of leucine at this position is causing a decrease in BRCA1 binding or if it is the introduction of a proline into the coiled coil region that is disrupting the secondary structure, thereby inhibiting binding. We are studying 5 variants of unknown significance (VUS) from PALB2 that are within the coiled coil and are also proline substitutions. One of these mutations is within the binding interface and the other four are on the backside of the coil opposite the predicted binding interface. We aim to answer if it is the introduction of a proline that is destroying the secondary structure and preventing binding. Isothermal titration calorimetry data suggests that all proline variants thus far, regardless of proximity to the interface, inhibit binding with BRCA1. We will pair binding data with the secondary structure analysis and thermal stability of these variants (using circular dichroism) to better connect variant structure with PALB2 dysfunction. 

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.