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.

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.

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.

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.

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.

Hydrilla verticillata is an invasive aquatic plant found in freshwater systems throughout the United States. Invasions pose a threat to plants and animals that come into contact with the rapidly expanding hydrilla, and recreational activities such as fishing and boating are disrupted when densely packed mats of vegetative material form near the surface of the water. These invasions have historically been controlled using the herbicide fluridone, but resistant hydrilla populations have emerged with mutations in the pds gene associated with the production of phytoene desaturase. These resistant mutant plants are outwardly indistinguishable from the susceptible wildtype, and as such it can be challenging for aquatic systems managers to identify whether or not fluridone can be considered as an effective treatment option without some form of genetic testing. The existing standard process for identifying resistant mutants is a lengthy process that relies on amplifying and sequencing the pds gene. Our work has sought to utilize the process of double-mismatch allele-specific qPCR (DMAS-qPCR) to create a quicker and more cost-effective tool to aid in understanding the extent of fluridone resistant hydrilla. Having designed sets of primers specific to the mutations found within the pds gene, the next step is to apply this method to screening hydrilla samples from a variety of geographies in order to outline the spread of the resistant mutant populations.

The prevalence of antimicrobial-resistant bacteria is a rapidly growing public health crisis. This, combined with a decline in the development of novel antimicrobial therapies, makes the search for unique drug targets essential. Previous work from our lab has identified a promising antimicrobial drug target within Bacillus anthracis, the regulatory ATPase, ClpX. ClpX is essential for virulence in B. anthracis and critical for resistance to a host of cell envelope-targeting antimicrobials. ClpX works with ClpP to form a global protease that regulates a wide range of proteins, including transcriptional regulators. Previously, we conducted a microarray of a ΔclpX mutant and found 119 genes with altered expression. One such gene, msrB, has been studied for reactive oxygen species tolerance in other pathogens. This gene encodes for methionine sulfoxide reductase, an antioxidant enzyme that restores functionality to oxidized methionine residues. Increased msrB expression was seen with oxacillin exposure in S. aureus, indicating a potential connection between MsrB and cell wall-targeting antimicrobials. In B. anthracis Sterne, loss of msrB induces sensitivity to penicillin, but unlike ΔclpX, this phenotype is not seen with daptomycin or LL-37. This suggests that the role of msrB in antimicrobial tolerance may be limited to cell wall active antibiotics. Further experiments will include testing the ΔmsrB mutant with additional cell wall-specific antimicrobials (e.g., bacitracin and vancomycin). Our research provides additional information regarding the role of MsrB in the bacterial cell and its potential suitability as a pharmacological target to increase susceptibility to antibiotics.

Understanding the diversity and distribution of species on Earth is crucial in the face of contemporary threats to biodiversity, such as climate change and unsustainable economic practices. Unfortunately, the process of documenting and describing biodiversity often cannot keep pace with habitat loss and species extinction, especially in tropical regions where the number of undescribed and poorly known species is highest, and where biodiversity is most severely threatened. If this diversity is not documented, it will mean a loss of valuable understanding of the natural world and a failure to recognize species whose societal values remain undiscovered or underappreciated. This research will assess the extinction risk of selected fern species to understand their conservation status. The focus lies on understanding the classification, distribution, and conservation status of a group of species within the fern genus Elaphoglossum, the Elaphoglossum dendricola Clade, consisting of around 12 species distributed in the Tropical Andes, mostly at high altitudes (over 2400 m). This assessment aims to serve as a baseline for future conservation studies of this neotropical group of ferns.

Due to widespread anthropogenic emissions and a global atmospheric cycle, mercury contaminates all aquatic ecosystems, including in the Arctic, at concentrations above pre-industrial baselines. Many seabirds nest in large colonies in the Arctic and are at elevated risk of mercury contamination due to their planktivorous and piscivorous diets and long lifespan. We investigated temporal trends of mercury contamination in five species of seabirds from northwest Greenland. Blood samples were collected regularly since 2010 from adult Atlantic puffins (Fracterula arctica), black guillemots (Cepphus grylle), black-legged kittiwakes (Rissa tridactyla), dovekies (Alle alle) and thick-billed murres (Uria lomvia). Samples were analyzed for total mercury using direct mercury analysis. All species had average blood mercury concentrations between 212 and 769 ng/g-wet weight, concentrations associated with a low risk for mercury toxicity. Individual black guillemots and thick-billed murres had blood mercury concentrations >1,000 ng/g wet weight, concentrations associated with moderate risk for mercury toxicity. Preliminary analyses suggest an overall increase in mercury concentrations in black-legged kittiwakes, dovekies and thick-billed murres over the study period. Comparable temporal studies in the Arctic have shown wide variation in mercury contamination trends. The results of the present study contribute to the understanding of regional mercury trends in the Arctic and efforts to assess the impact of the Minamata Convention.

Silicon-Perovskite tandem solar cells are some of the leading emerging technology solar cells due to their high photoconversion efficiency or the ability to turn light into electricity. These solar cells rely on the ability to harvest a higher percentage of the solar spectrum due to the differences in the two materials. MHPs are an ionic crystal that have the chemical formula ABX3 where A is a monovalent cation (+1) such as cesium, methylammonium or formamidinium; B is a divalent cation (+2) such as lead or tin, and X is a halide such as chloride, bromide, or iodide. Porous silicon is crystalline silicon that has been etched to form pores with properties dependent upon the etching conditions. Porous silicon that has been etched such that the silicon area between the pores is between 1-4nm becomes photoluminescent (PL). It has been shown that the optoelectronic properties of metal halide perovskite (MHPs) grown within porous silicon (pSi) are highly dependent upon the surface area, pore size, and surface chemistry of the pSi. This interaction has led us to investigate the fundamental interactions that occur when nanoscale porous silicon encounters nanoscale MHP, namely the possibility of energy/charge transfer.
We have evaluated two different experimental designs. The first entails adsorbing ligand passivated MHP quantum dots onto a solid piece of luminescent mesoporous Si membrane and allow the solvent to evaporate. The change in luminescence from the pSi can be used to monitor the impact the perovskite has upon the pSi by monitoring the change in intensity and wavelength. The second approach as previously described utilizes MHP quantum dots (QDs) dispersed in toluene which is then titrated with non-luminescent pSi and the PL monitored. The primary impact of the pSi upon the light emission of the perovskite QDs is a significant reduction in the intensity of the emission. Comparisons of different pSi with hydride terminated versus oxide terminated surfaces show a dependence upon the surface chemistry to the change in PL. The PL lifetimes will be measured, and comparisons made to determine the mechanism of energy transfer.