Cryptococcus neoformans is a pathogenic fungus that can cause cryptococcosis, affecting the lungs and central nervous system with potentially morbid consequences. This pathogen is particularly aggressive in individuals with impaired T-cell function, such as those with AIDS or on immunosuppressive medications. There are currently no vaccines available for this pathogen and a limited arsenal of antifungals is available. Our lab has developed a C. neoformans strain that produces mouse IFN-ɣ, called H99ɣ, that induces protective immunity against subsequent infection with wild-type C. neoformans in mouse models of cryptococcosis. We aim to use variants of this strain to better understand the immune response against Cryptococcus and develop new therapies. In this study, our goal is to evaluate the efficacy of various newly developed C. neoformans vaccine mutants to induce protective immune responses against C. neoformans. RNA will be isolated from tissues extracted from mice immunized with the different C. neoformans strains: H99ɣ, LW10, LW10ɣ, sre1ΔLW10ɣ, and sgl1ΔLW10ɣ and the mRNA transcripts of immune cells responding to subsequent infection with C. neoformans evaluated. By using the information derived from these transcripts, we aim to identify key determinants of protection against cryptococcosis. Using the transcriptomic data, we can determine the best candidate to further evaluate for its capacity to elicit protective immune responses in immune-compromised hosts.

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by amyloid-beta (Aβ) plaques, tau tangles, and neuroinflammation, contributing to cognitive decline. Recent research highlights systemic inflammation, particularly obesity-induced inflammation, as a key factor in exacerbating AD pathology. Obesity promotes chronic, low-grade inflammation, increasing pro-inflammatory cytokines that cross the blood-brain barrier and amplify Aβ deposition. Simultaneously, metabolic dysfunction-associated fatty liver disease (MAFLD) has emerged as a major health concern linked to oxidative stress and dysregulation of lipid metabolism. Excessive saturated fat intake impairs mitochondrial function, elevates reactive oxygen species (ROS), and activates inflammatory pathways such as NF-κB, contributing to liver damage. The Nrf2 pathway plays a protective role by upregulating antioxidant enzymes like glutathione peroxidase (GPX1), though its exact influence on MAFLD progression remains unclear. This study investigates the impact of diet on oxidative stress and lipid metabolism using a murine model. Mice were placed on either a Typical American Diet (TAD) or a Mediterranean Diet (MED) for three months beginning at four months of age, followed by gene expression analysis using reverse transcriptase polymerase chain reaction. Findings reveal diet- and sex-dependent differences in gene expression, emphasizing the likely importance of dietary modifications in mitigating disease progression.

Partner and Localizer of BRCA2 (PALB2) is a necessary linker protein between BRCA1 and BRCA2. In order to create this connection it interacts directly with BRCA1 via a coiled-coil domain in both proteins. Facilitating this linkage directs cells to fix double stranded DNA breaks (DSBs) through homologous recombination. The mutation L35P has been shown to disrupt this linkage forcing the cell to complete repair through alternate pathways that are not as accurate. This inaccuracy can lead to the accumulation of mutations and increase the risk of breast and ovarian cancers. The L35P variant within the coiled-coil domain of PALB2 has been linked with hereditary breast and ovarian cancer. However, it is unknown if loss of leucine in the interface is causing the decrease in binding or if it is the introduction of a proline into the coiled-coil region that is destroying the secondary structure thereby inhibiting binding. We are studying five 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. We are investigating the structure and BRCA1-interaction of these VUS to directly connect structural changes in the coil to functional deficiencies. Currently we have found that these proline variants are inhibiting binding with BRCA1 through measuring heat exchange with isothermal titration calorimetry. We also plan on evaluating these variants through circular dichroism as well to assess if the secondary structure of PALB2 is affected as well.

Malesia is a vast phytogeographic region in Southeast Asia, spanning roughly one-fifth of the world’s circumference and considered one of the most biodiverse regions of the world. It is divided into three subregions: Sahul, Sunda, and Wallacea, primarily distinguished by their geological history and differences in floristic composition. Research based on fossil-calibrated phylogenetic trees has begun to provide insights into the historical phytogeography of Malesia, specifically regarding the reciprocal migration of plant lineages across the Sunda and Sahul regions known as the “Sunda-Sahul floristic exchange (SSFE).” This study aims to test the SSFE hypothesis with the use of the Asian tropical blueberry clade of tribe Vaccinieae (Ericaceae). Silica-dried specimens from previous fieldwork, garden-grown plants of wild origin, and herbarium specimens were used to extract genomic DNA. The samples were sequenced with the Angiosperms353 bait set, and a dated phylogenomic tree was constructed, incorporating all available genomic data from online repositories. Divergence time analysis and ancestral area reconstruction was performed to test the hypotheses of the SSFE. This research will serve as a steppingstone towards resolving the phylogeny and evolutionary history of tribe Vaccinieae. It will also form a foundation for assessing the conservation status of micro-endemic and threatened Asian tropical blueberry species, especially in Malesia. Lastly, this study will highlight the crucial role of botanical gardens and herbaria as vital repositories of natural history collections.

Zebra mussels (Dreissena polymorpha) are an invasive bivalve of significant ecological and economic importance due to their widespread invasion and disruption of aquatic ecosystems and commercial infrastructure. Their ability to spread from the northern Great Lakes to the southern areas of the United States is due in large by their reproductive strategy. Zebra mussels release eggs and sperm into the water column where fertilization and subsequent larval development occurs. Two key steps in the fertilization process are the ability of sperm to bind and penetrate the egg surface and the ability of the egg to prevent more than one sperm from entering the egg (polyspermy). In many other species, proteases play a key role in these processes; however, there is there is variability between aquatic species, such that elucidating specific mechanisms is unique to individual organisms. Here, I investigate the potential role of proteases in sperm binding and entry. To discern these mechanisms in zebra mussels, I exposed fertilization processes to small-molecule inhibitors. Based on the observations of the phenotypic changes upon exposure, implications can be made to specific molecules or groups of molecules involved in Dreissena polymorpha sperm-egg interactions. These implications point to the further investigation and development of small-molecule inhibitors of Dreissena polymorpha fertilization.

Understanding and documenting the diversity and distribution of species on Earth is crucial, especially in the face of habitat loss and species extinction. If we do not document this diversity, we risk losing valuable understanding of the natural world, including species with ecological, medicinal, or economic significance. Ferns, one of the oldest lineages of land plants, still hold many scientific mysteries, particularly in highly diverse tropical regions.
Herbarium specimens—dried plants collected over centuries—serve as windows into the past, allowing botanist to study plant diversity across time and space. Combined with modern DNA analyses, these collections help unravel evolutionary relationships, identify new species, and improve our understanding of biodiversity. My research focuses on Elaphoglossum, one of the most diverse and taxonomically challenging fern genus. Using herbarium specimens and molecular phylogenetics studies, I am revising a group of Andean ferns known as the Elaphoglossum dendricola clade. This research aims to clarify species boundaries, describe new species, resolve their evolutionary relationships and assess their conservation status.
This poster presents preliminary results and future directions of my research, highlighting the importance of integrating herbarium revisions and taxonomy with modern molecular tools to uncover hidden fern diversity.

Arctic wolf spiders (Pardosa glacialis) are dominant terrestrial predators in the High Arctic, yet the extent to which their diets are influenced by aquatic subsidies remains uncertain. Previous research suggests that aquatic insects do serve as a key food source for shoreline predators, transferring both nutrients and contaminants such at mercury (THg) from aquatic to terrestrial ecosystems. Aquatic insects have unique carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopic signatures that differentiate them from terrestrial insects that allow for identification of aquatic-derived energy in terrestrial food webs. The purpose of this case study is to examine the stable isotope composition of P. glacialis collected at varying distances (0, 10m, and 35m) near a pond located in northwest Greenland to establish local food web dynamics and assess potential pathways of contaminant transfer. Understanding these dynamics will provide insight into how THg is distributed among trophic levels and across distances in riparian environments. P. glacialis were collected in traps placed at three distances from pond shoreline (0, 10m, and 35m). The specimens were then analyzed for THg and stable isotope ratios. We hypothesized that spiders collected closer to the shoreline will display isotopic values indicative of a more aquatic-based diet as well as higher THg concentrations. Conversely, with increasing distances from pond shoreline, we expect to see isotopic signatures suggestive of a more terrestrial diet and lower THg. Given mercury’s neurotoxic and bio accumulative properties, results of this study will provide insight not only into aquatic-terrestrial linkages in Arctic ecosystems but also the potential threats that the trophic movement of contaminants may pose to wildlife.

Cancer cells undergo metabolic reprogramming to sustain their uncontrolled proliferation and survival. One of the most well-known metabolic adaptations in cancer is the Warburg effect, where cells preferentially use glycolysis to generate ATP even in the presence of oxygen, leading to increased lactate production. While traditionally considered a metabolic waste product, recent research suggests that lactate plays a crucial role in cancer metabolism, serving as a key fuel for oxidative phosphorylation (OXPHOS) and influencing tumor progression. This study explores the metabolic fate of lactate in cancer cells, investigating its role beyond glycolysis and its contribution to tumor bioenergetics.
Building from the previous in vivo isotope-tracing studies, we examine how lactate, rather than glucose, serves as the primary substrate for the tricarboxylic acid (TCA) cycle in tumors under basal metabolic conditions. Additionally, we explore the role of malate dehydrogenase 1 (MDH1) in lactate metabolism and its potential implications for cancer cell survival.
By using a phenotype-to-mechanism approach, we first identified a distinct cell phenotype in the presence of an unmetabolized metabolite, followed by hypothesis-driven experiments to elucidate the molecular targets. We found that both L- and D-lactate are potent inducers of regulatory T cell differentiation and significantly increase global histone acetylation. Given these observations, we hypothesized that lactate directly regulates histone-modifying enzymes in the nucleus. To investigate this, we employed thermal proteome profiling (TPP) coupled with high-resolution protein mass spectrometry and discovered that both L- and D-lactate act as potent inhibitors and direct allosteric regulators of class 1 and 2 histone deacetylases (HDACs), as confirmed with purified HDAC2. Interestingly, the similar effects of D-lactate—despite its lack of metabolism in mammalian cells—suggest that lactate’s influence on HDAC activity is independent of its metabolic function. Ongoing structural and biochemical studies aim to map the precise lactate-binding site within HDACs.
These findings contribute to the emerging understanding of lactate as a signaling molecule capable of modulating gene expression, promoting tumor growth, and influencing immune cell differentiation through epigenetic mechanisms. This study highlights the complex metabolic and regulatory interplay within the tumor microenvironment and underscores the need for further investigation into targeting lactate metabolism as a potential therapeutic strategy in cancer treatment.

Comparing DC1s and DC2s Immune Response Against Cryptococcus neoformans

Elizabeth West*, Natalia Castro Lopez, Floyd Wormley Jr.
Department of Biology, Texas Christian University, Fort Worth, TX, USA

Abstract

Cryptococcus neoformans is a fungal pathogen that poses a threat to immunocompromised individuals, and there is currently no vaccine. Dendritic Cells (DCs) play a crucial role in the cell’s immune response and will be studied to determine an effective treatment. In this study, we will analyze the immune response of two groups of conventional dendritic cells (cDCs), cDC1s (CD103+, driven from GM-CSF + FLT3) and cDC2s (CD11B+, driven from GM-CSF) to determine their ability to produce a protective immune response against Cryptococcus neoformans. We grew bone marrow dendritic cells in the conditions stated above and then exposed to IFN-ɣ, cell wall extract (CWE), or both. After, we used a calcineurin (cna) knockout strain to simulate exposure to the wild-type strain, which allows us to analyze the cell’s immune response. RNA purification technique will be performed to isolate the RNA, which will then be analyzed via RT-PCR. We will analyze DC1s and DC2s responses by evaluating the transcripts, including NOS2, Arg1, and IL-2. This study will help us understand the role of DCs in the protective immune response. We hypothesize that DC1s (CD103+) will elicit a stronger Th1 response, increased by IFN-γ treatment compared to DC2s eliciting a different immune response. By comparing transcript expression levels of DC1s and DC2s, we can study the role of dendritic cell subsets in producing memory for protective immune response against Cryptococcus neoformans.

The fathead minnows (Pimephales promelas; FHMs) have been the most utilized small fish model in North American ecotoxicity assessments for decades. However, the behavior of FHMs across their lifespan remains poorly characterized relative to other small fish models. Given the growing recognition of the importance of evaluating ecologically-relevant behavioral endpoints in environmental monitoring, aquaculture, and ecotoxicology, there is a need to develop assays to assess such behaviors in fish across multiple life stages. One class of ecologically-relevant behaviors is predator avoidance behaviors, which hold importance for the survival and propagation of fish populations. While the predator avoidance behaviors of adult FHMs (e.g., shelter seeking/hiding, freezing) have been well documented, there has yet to be a comprehensive study characterizing the responses of larval FHMs to chemical predator stimuli. Thus, the present study aimed to develop a behavioral assay that assesses predator avoidance behaviors of FHMs across multiple life stages. The specific predator stimulus was alarm cue, a chemical released from damaged or injured epidermal club cells of FHMs to signal conspecifics of a predator attack. In turn, the objectives were to 1) verify that the use of alarm cue collected from pond-reared donors induced predator avoidance behaviors, as measured via ToxTrac, an open-source tracking software, in adult fathead minnows, and 2) develop a predator avoidance assay for use in 14 days post-hatch (dph) larval FHMs using the alarm cue from pond-reared donors verified in adult FHMs. Exposure of adult FHMs to alarm cue collected from pond-reared donors induced significant changes in the predator avoidance behaviors detected by ToxTrac, verifying its use as a predator stimulus for lab-reared FHMs. Moreover, this study represents the first characterization of the behavioral response of 14 dph FHMs to alarm cue from pond-reared donors, providing insight into the maturation of predator avoidance behaviors of FHMs. Future work may investigate the sensitivity of the larval predator avoidance assay to chemicals with known neurological effects to validate its use as an ecologically-relevant behavioral assay in an aquaculture, ecotoxicity, or environmental management context.

White-nose syndrome (WNS), caused by a fungus called Pseudogymnoascus destructans, has caused dramatic declines in North American bat populations, with mortality rates exceeding 90% in some species. WNS has spread widely, now to southern regions such as Texas, and presents new challenges for disease modeling due to differences in climate and bat hibernation behavior. This study developed a open patch epidemiological model integrating bat populations from the Northeastern United States to examine how migration and disease exposure affect population dynamics. By modifying a standard SIR model, we analyzed interactions between wild and robust bat genotypes at varying levels of migration and frequency of disease pulses. Preliminary findings suggest that increased migration favors robust genotypes, while frequent disease pulses initially favor robustness but may eventually penalize it if disease prevalence remains low. These insights enhance our understanding of regional disease dynamics and provide a framework for conservation strategies aimed at mitigating WNS-driven biodiversity loss.

Cryptococcus is an invasive fungus that causes cryptococcosis, an infection that highly affects immunocompromised people. There are currently a limited number of antifungals available to treat Cryptococcus, and with the increased in antimicrobial resistance, we need different alternatives to treat fungal infections. Our lab has identified proteins involved in the synthesis of eicosanoids, which are lipid signaling molecules involved in regulating the immune response. Moreover, fungi can produce eicosanoids using different enzymes that humans do, opening a line to identify new drug targets using these pathways. Previously, our lab had identified genes upregulated in the presence of the eicosanoid’s precursor, arachidonic acid. Our goal is to use bioinformatics to predict and characterize the protein structure, using AlphaFold2, a machine learning application based on a deep neural network, and using this tool, identify small molecules that will bind to the proteins and help make drug design more efficient.

Mercury (Hg) emitted in temperate and tropical regions can be transported to the Arctic where it is disproportionately deposited across the landscape. In aquatic systems, inorganic forms of Hg can be methylated to the toxic and bioaccumulative species, methylmercury (MeHg). In temperate zones, riparian spiders that specialize in consuming adult insects emerging from aquatic systems (e.g., Araneidae and Tetragnathidae) accumulate high concentrations of MeHg and have been used as sentinels of MeHg contamination. In addition, these taxa frequently accumulate concentrations of MeHg that may pose a risk to arachnivorous songbirds. Although these taxa are useful sentinels in risk assessment studies in the temperate zone, they are not present in the High Arctic. The purpose of the present study was to assess the potential of a generalist spider species, the Arctic wolf spider (Pardosa glacialis), to serve as a sentinel of Hg pollution in the Arctic. In summer 2022, we collected 1460 wolf spiders and 8090 emergent aquatic insects (Chironomidae) from six ponds in Northwest Greenland (centered around 76.5° N, 68.8° W). Spiders and insects were composited by body size and collection site. Hg concentrations for spiders and insects ranged from 230 - 1100 ng/g dry weight (dw) and 75 - 297 ng/g dw, respectively. Spider Hg concentrations were strongly correlated with insect Hg concentrations (R2 = 0.83), suggesting that wolf spiders can be used as sentinels of Hg contamination in Arctic lentic systems and had Hg concentrations that exceeded risk thresholds for arachnivorous songbirds.

Bacteriophages, the most abundant biological entities on Earth, specifically infect bacteria. These viruses initiate the lytic cycle, hijacking the cellular machinery of their bacterial hosts to replicate, which ultimately leads to the host's destruction. Phage therapy has shown promising results in treating antibiotic-resistant infections, though clinical trials are ongoing to fully establish its safety and efficacy. Identifying suitable phages is crucial in developing successful therapy due to the specificity of bacteriophage-host interactions.
Our study refined methods for isolating and studying bacteriophages against Enterobacter aerogenes, a critical ESKAPE pathogen contributing to antibiotic resistance. We evaluated two isolation techniques: the overnight enrichment assay and direct isolation via the whole plate spotting assay. Our comparison found an advantage of the direct isolation method—it not only matched the efficacy of the overnight enrichment but surpassed it by offering accelerated results and minimizing resource utilization. A key refinement for purification was the incorporation of calcium chloride into the soft agar, which markedly enhanced plaque clarity and visibility. Moreover, our exploration of DNA extraction techniques revealed the superiority of zinc chloride precipitation over commercial kits, with the former delivering higher DNA yield and purity.
We isolated three phages, K-1, BB-1, and M-1, effective against E. aerogenes. Noteworthy, phage BB-1 exhibited a rapid lytic cycle, clearing plates in under 10 hours. Future research will focus on examining their infectivity across Enterobacter strains, lysis of host cells, and absorption rates. We will also analyze their genome sequences to determine their novelty and potential for addressing antibiotic resistance.

Both Breast Cancer Gene 1 (BRCA1) and Partner and Localizer of BRCA 2 (PALB2) interact through their coiled-coil domains and are critical for proper functioning of DNA repair through homologous recombination. Individuals who carry pathogenic variants in either protein have an increased risk of developing breast cancer. Multiple variations of unknown significance (VUS) have been documented within the coiled-coil region of each protein, meaning a person carries a variation in either BRCA1 or PALB2 but there is not enough data to know the clinical significance of those variants. In this study, we analyzed the structural effects of five proline VUS within the binding region of BRCA1 and PALB2, three variants that have been discovered in patients and two variants that have not yet been discovered in patients. We used a known benign valine variant and a known pathogenic proline variant as our negative and positive controls, respectively. Because proline variants are known to disrupt protein structure, we hypothesize the proline variants will inhibit coiled-coil formation and, in turn, disrupt interaction between BRCA1 and PALB2. Each coiled-coil construct was generated in vitro and its structure analyzed using circular dichroism first individually and then in the presence of its wild-type binding partner. While all proline variants affected the structure of BRCA1, they had different degrees of impact depending on where they are located in the coiled-coil. This suggests that proline variants impact the ability of BRCA1 to form a coiled-coil in the presence of PALB2 and may be pathogenic. Notably, however, the BRCA1 proline variants seem to cause different structural changes from the pathogenic PALB2 proline variant. This prompts further research to determine the structural effects on the residue level and to correlate structural changes with functional changes.

The presence of Reactive Oxidative Species (ROS) in the brain have been linked to the etiology of Alzheimer’s disease and neurodegeneration. In this project, novel antioxidant Indole derivative drugs were tested on BV-2 microglial cells using RT-qPCR to assess their ability to activate antioxidant gene expression. Nuclear factor erythroid 2–related factor 2 (Nrf2) is a gene transcription factor that is activated by oxidative stress and binds to a sequence called the Antioxidant Response Element (ARE), a region upstream of the DNA promoter sequence. Nrf2 activates transcription of antioxidative genes. Based on theoretical docking studies, we hypothesize that the novel compounds will disrupt the interaction between Nrf2 and its inhibitor KEAP, releasing Nrf-2 and enabling it to translocate to the nucleus. The novel antioxidant drugs should either increase the transcription of Nrf2-activated genes or reduce overall levels of antioxidative stress within cells. We tested for antioxidant properties by measuring Hemeoxygenase-1 (HO-1) and Nrf2 mRNA levels in BV-2 cells in the presence of these compounds.

Alzheimer’s disease (AD) is a neurodegenerative disease that is the most common cause of dementia. There is currently no cure for AD, which means the best alternative is developing preventative strategies, such as adoption of the Mediterranean diet (MD), which has been shown to reduce risk of AD development and mortality. In comparison, a typical American diet has been shown to increase risk of AD development. Although the ability of dietary factors to alter the propensity of development of AD is well established, the mechanisms through this is mediated is unknown. One largely unexplored mechanism of dietary-induced AD prevalence is epigenetic modification to genes associated with AD. The most studied epigenetic modification, DNA methylation of cytosines, has been known to alter gene expression levels. Therefore, this study aims to determine whether dietary influences can induce epigenetic modifications, and subsequently modify expression of genes associated with AD. To do this, DNA was extracted from hippocampal tissue of mice on either a MD or TAD, as well as their offspring who were consuming a control diet. The offspring were included to determine if differential methylation patterns are heritable, thereby implicating transgenerational effects and predisposition to AD development or protection. An epigenetic array was used to identify loci that were differentially methylated between diets, and qPCR was used to determine if differential methylation resulted in significant differences in gene expression. No loci were found to be significantly differentially methylated (p-val<0.0001) with an effect size of 10% or more, nor differentially expressed upon qPCR analysis.

Estrogen receptor alpha (ERα) and BRCA1 play an important role in the development of breast cancer, and multiple pathways link these two proteins together. Previous studies have identified the ligand binding domain (LBD) of ERα and residues 1 through 258 of BRCA1 as important in the direct physical interaction between these two proteins. This study aimed to characterize the binding kinetics of this interaction in the presence and absence of 17β-estradiol (estrogen) with a shortened BRCA1 construct (residues 177-258); however, binding between ERα LBD and this BRCA1 construct could not be detected through fluorescence emission spectroscopy or isothermal titration calorimetry (ITC). Synthesizing ERα LBD presented challenges with low yield, so the purification protocol was refined to cool bacterial cultures at an OD600 of 0.2 during growth and add dithiothreitol during lysis for improved yield. A 24% decrease in fluorescence intensity upon addition of estrogen to ERα LBD confirmed the ligand-binding functionality of the protein. Additionally, Stern-Volmer studies verified that the estrogen binding site on ERα LBD is located in close vicinity to the tryptophan residues in the protein since fluorescence quenching was more efficient in the absence of estrogen. Finally, factors contributing to the absence of ERα-BRCA1 binding are discussed, including the length of the BRCA1 construct used or the potential necessity of an additional protein, BARD1.

As antibiotic resistance increases and antibiotic development dwindles, new antimicrobial agents are needed. Recent advances in nanoscale engineering have increased interest in metal oxide nanoparticles, particularly zinc oxide nanoparticles, as antimicrobial agents. Zinc oxide nanoparticles are particularly promising due to their broad-spectrum antibacterial activity and low production cost. Despite many studies demonstrating the effectiveness of zinc oxide nanoparticles, the antibacterial mechanism is still unknown. Previous work has implicated the role of reactive oxygen species such as hydrogen peroxide, physical damage of the cell envelope, and/or release of toxic Zn2+ ions as possible mechanisms of action. To evaluate the role of these proposed methods, we assessed the susceptibility of S. aureus mutant strains, ΔkatA and ΔmprF, to zinc oxide nanoparticles. These assays demonstrated that hydrogen peroxide and electrostatic interactions are not crucial for mediating zinc oxide nanoparticle toxicity. Instead, we find that a soluble factor accumulates in Mueller Hinton Broth over time that mediates toxicity and that removal of Zn2+ through chelation reverses this toxicity. Furthermore, we find that the physical separation of zinc oxide nanoparticles and bacterial cells using a semi-permeable membrane still allows for growth inhibition. We conclude that soluble Zn2+ is the primary mechanism by which zinc oxide nanoparticles mediate toxicity in Mueller Hinton Broth. Future work investigating how factors such as particle morphology (e.g., size, polarity, surface defects) and media contribute to Zn2+ dissolution could allow for the synthesis of zinc oxide nanoparticles that possess chemical and morphological properties best suited for antibacterial efficacy.

BRCA1 and PALB2 proteins suppress tumor formation by promoting homologous recombination when DNA damage has occurred. Mutations in BRCA1 and PALB2 are associated with a higher prevalence of breast and ovarian cancers. Phosphorylation of BRCA1 and PALB2 occurs upon DNA damage and is vital for maintaining genomic integrity. The molecular mechanism of how phosphorylation directs the activation of these proteins is unknown. It is established that phosphorylation of BRCA1 and PALB2 occurs in or near the coiled-coil regions of both proteins. The proteins use this domain to heterodimerize, so we hypothesize that the phosphorylation events could promote efficient BRCA1/PALB2 interactions. Our study aims to determine the effect of phosphorylation on the BRCA1/PALB2 binding affinity. The serine and threonine residues that are phosphorylated on BRCA1 or PALB2 were mutated to a glutamic acid to mimic phosphorylation. Glutamic acid carries a negative charge and thus mimics the negative charge added to the protein upon phosphorylation. We overexpressed and purified the protein using a bacterial expression system and measured their heterodimerization affinity with isothermal titration calorimetry (ITC). We will share ITC data suggesting phosphorylation of PALB2 does not affect its binding affinity to BRCA1. The phosophomimicking mutations in BRCA1 have also been generated, both individually and in tandem, and we will share results from these binding studies that are ongoing and hypotheses generated from our results regarding phosphorylation as an activation switch to control BRCA1/PALB2 interactions.

The spread of red imported fire ants (Solenopsis invicta; RIFA) has frequently been cited as a factor contributing to the decline of the Texas horned lizard (Phrynosoma cornutum; THL). Two hypotheses for this are: 1) direct lizard mortality due to RIFA, and 2) displacement of THL’s main food source, harvester ants (Pogonomyrmex spp.), by RIFA. A new third hypothesis suggests that the invasion of RIFA could be causing a decline in hatchling THL food resources, as their diet is mainly composed of small ant species. Many studies have attempted widespread treatment to eradicate RIFA; however, this could have unintended consequences for non-target ant species that THL depend on. Using a targeted application method, we sought to reduce RIFA populations over the summers of 2022 and 2023 at four sites located at Mason Mountain Wildlife Management in central Texas, a locality with an ongoing THL reintroduction program. At each site, hot dog baits were placed 5 meters apart in 10x10 grids. At treatment sites, one teaspoon of Amdro (a common ant poison) was applied to baits with RIFA thirty minutes after placement. After Amdro was applied, baits were left for 30 minutes and then collected. Treatments were repeated monthly May – August. The effects of each targeted poisoning were evaluated using pitfall traps and ant abundance measurements from baits. Results showed that treatment may have decreased RIFA abundance for both years and had variable effects on hatchling food abundance. Future studies will increase sample size to better detect potential treatment effect.

The Identification of Novel Genes Related to Iron Acquisition in Bacillus Anthracis Sterne

Jessica Guilhas, Kyle Gallegos, Julio Manceras, Mariah Green, Jacob Malmquist, Shauna M. McGillivray

Bacillus anthracis, the causative agent of anthrax, is a spore-forming, gram-positive bacterium. Its virulence mechanisms are of interest due to its potential use as a biological weapon and high lethality. For B. anthracis to survive and reproduce in a host, it must evade the host's immune response and acquire nutrients. One important nutrient B. anthracis must acquire is iron. Iron is a limiting nutrient in the host because it is usually found sequestered to hemoglobin or bound to host proteins such as transferrin. To acquire iron, pathogens must strip it from the host proteins. To find genes important for iron acquisition from hemoglobin, we screened genetic mutants created through transposon mutagenesis. Media was chelated to remove all divalent cations, including iron, and then hemoglobin was added as the sole iron source. The mutants that were unable to grow were chosen to be tested in a larger volume hemoglobin assay. We confirmed the phenotype of several mutants using this larger volume assay and we are working to confirm the site of transposon disruption via PCR. The mutants thus identified include a mutation in a dUTPase gene and an L-aspartate oxidase gene, neither of which has been previously linked to iron acquisition from hemoglobin. Future directions include making independent mutations and/or complement the disrupted genes to confirm the gene disruption is linked to loss of iron acquisition from hemoglobin. This study allows for a further understanding of how B. anthracis acquires iron and sheds new light on potentially novel virulence mechanisms.

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the formation of amyloid beta (Aβ) plaques in the brain and is the seventh leading cause of death in the United States. Chronic inflammation and oxidative stress associated with AD leads to neuronal cell death. A cellular protective mechanism against oxidative stress involves the Nuclear factor erythroid 2-related factor (Nrf2) pathway. Nrf2 is responsive to the reactive oxygen species (ROS) produced when the cell is under oxidative stress, leading to its translocation into the nucleus where it activates transcription of genes that produce antioxidant enzymes like heme oxygenase-1 (HO-1). To study this pathway in neurons, our lab chose to use the mouse hippocampal HT-22 neuronal cell line. Our previous attempts to grow these cells in culture proved difficult, leading us to hypothesize that providing a growth-enhancing surface of collagen would provide a more stable surface in which to propagate these cells. Here we show that HT-22 cells grown on rat tail collagen provide a model system to investigate the Nrf2 pathway. We also demonstrate that HT-22 cells are viable on tissue culture plastics without the need for collagen.

Approximately 1 in 9 Americans over the age of 65 has Alzheimer’s disease (AD). As the size of this age group is expected to more than double by 2040, the AD prevalence is likewise predicted to increase rapidly. Two key risk factors for late-onset AD include poor diet and obesity. Therefore, long-term nutritional strategies could potentially reduce the development of hallmark AD biomarkers, such as amyloid beta (Aβ), later in adulthood. Researchers have found that diets extremely rich in saturated fats are associated with increased Aβ production in both the cortex and hippocampus of rodents. Conversely, plant-based Mediterranean diets (MD) that are plentiful in unsaturated fatty acids were shown to mitigate Aβ in rodents.

The relationship between diet and AD biomarkers has been explored in prior animal research, yet most studies utilize extremely high fat diets (40-60% kcal fat) or supplement with individual MD nutritional components. To address these limitations, we designed comprehensive, macronutrient-matched Mediterranean and typical American diets (TAD) that mimic human diets in Mediterranean regions and the U.S., respectively. C57BL/6J mice were weaned onto one of the two diets at postnatal day 21. Following 6 months of diet consumption, we found that the TAD increased soluble Aβ1-42 in the brain. Additionally, mice on the TAD had excess hepatic lipid deposition, which is a hallmark of insulin resistance and metabolic dysregulation, a comorbidity linked to AD risk.

Exploring EncT Efflux Pump Functionality and their Role in Lipid Signaling
Gabby Linares, Sawyer Diaz, Natalia Castro-Lopez, Floyd Wormley Jr.
Department of Biology, Texas Christian University

Cryptococcus neoformans, a fungal pathogen mainly affecting immunocompromised individuals, has sparked interest in lipid signaling research due to its role in pathogenesis. Eicosanoids, derived from fatty acids, are crucial in virulence and immune modulation; with C. neoformans lacking human enzyme homologs for eicosanoids biosynthesis, we want to identify the enzymes involved in the biosynthesis of cryptococcal eicosanoids and test their potential as antifungal targets. This project is focused on the EncT gene, encoding an efflux pump, which we observed to be upregulated in response to lipid precursors. Using CRISPR technology, we produced an EncT knockout (KO) strain and the corresponding reconstituted strain, aiming to discern shifts in virulence factors like melanin production, capsule formation, and urea production, among others, comparing the knockout, wild-type, and reconstituted strains and, subsequently, employing a mouse model of pulmonary cryptococcosis to delve deeper into virulence dynamics. Our initial results show early production of melanin EncT KO compared to the WT strain and no changes in the capsule formation or growth at 37°C.