Mysid shrimp (Americamysis bahia) have been utilized in routine marine toxicity assessments for decades. While mysids are a well-established model, there a key gaps in understanding how chemical exposure impacts their endocrine systems. Crustacean growth occurs through molting (i.e., shedding old exoskeleton), a process regulated by hormones, primarily ecdysteroids. Ecdysteroids are a class of steroid hormones that share similar chemical structures to vertebrate hormones (i.e., 17β-estradiol and testosterone), which have been suggested to disrupt molting in some invertebrates. Through powerful tools, like transcriptomics, potential genetic biomarkers may be identified following chemical exposure. These biomarkers could provide the basis for future research aimed at screening endocrine disrupting compounds using invertebrate models. The objectives of this work were to 1) assess whether known vertebrate endocrine disruptors (e.g., 17β-estradiol and trenbolone) would induce alterations in molting and growth and, 2) compare gene expression profiles between vertebrate endocrine disruptors and a model ecdysteroid (i.e., ponasterone A) using transcriptomic analysis. Ponasterone A induced predictable alterations in mass, molting, and ecdysteroid-related gene expression, reinforcing both the use of this compound as a positive control and these endpoints for assessing invertebrate endocrine disruptors. Vertebrate endocrine disruptors induced varied responses in the endpoints assessed, but neither acted in a manner comparable to ponasterone A. Future work may investigate the potential for differentially expressed genes identified in the transcriptomic analysis for screening of invertebrate endocrine disruptors.

Metabolic syndrome (MetS) is a cluster of concurrent cardiometabolic risk factors, including increased waist circumference, hypertension, elevated triglyceride level, reduced high-density lipoprotein (HDL) cholesterol level, and hyperglycemia. The key pathophysiology of MetS is insulin resistance, resulting in a disruption of glucose and lipid metabolism in the liver and adipose tissue, which increases the risk of type II diabetes, cardiovascular disease, and stroke. The development of insulin resistance and related conditions is multifaceted, but risk can be mitigated with lifestyle modifications, including improved nutrition. In the US, a typical American diet (TAD) is full of highly processed foods high in saturated fats and refined sugars and is associated with increased insulin resistance and obesity risk. In contrast, adherence to a plant-based Mediterranean diet (MD) rich in unsaturated fats, fiber, and non-refined carbohydrates has been found to reduce disease risk. Despite the contrasting nutritional compositions, the average macronutrient distributions of these two human diet styles are similar (approximately 50% kcal carbohydrates, 15% kcal protein, and 35% kcal fat). Due to the comparable macronutrient ratios but contrasting nutritional composition, direct comparative analysis could uncover metabolic and cellular differences relating to their associated health outcomes.

There are few rodent studies in the literature that directly compare a TAD and MD. Further, studies often utilize a high-fat diet, consisting of 40-60% kcal fat, or individual nutrient supplements, such as olive oil, rather than comprehensive diet models. To address these limitations, our lab developed comprehensive, macronutrient-matched TAD and MD models that more closely mimic human diets in the U.S. and Mediterranean, respectively. A previous study in our lab found that six months of TAD consumption resulted in elevated body weight, increased inflammation, and excess hepatic lipid deposition, in comparison to the MD. Our current study looked to further characterize MetS under this diet model, specifically investigating obesity, insulin resistance, and dyslipidemia markers. Male and female C57BL/6J mice consumed either the TAD or MD from the age of 4 to 7 months. We found that after three months on diet, there were elevations in hepatic steatosis and serum cholesterol levels in both males and females on the TAD. However, other findings suggested early signs of insulin resistance in TAD males, but not females. Future studies will investigate MetS after 6 months on diet to better elucidate insulin resistance development and potential sex differences.

BRCA1 protects genomic stability by signaling for the homologous recombination pathway, DNA repair, and transcriptional regulation. A pathogenic mutation in the BRCA1 region causes a higher predisposition to the development of breast and ovarian cancer. Our lab is exploring the different enzymatic functions of BRCA1 by looking at its role in histone ubiquitylation, leading to transcriptional regulation of certain parts of the genome. Join us to see our plan for connecting molecular mechanisms of a large, multi-functional gene to the phenotype of an organism. A homolog of BRCA1 is conserved in C. elegans as BRC-1. We propose that mononucleosome ubiquitylation is a key mechanism contributing to the cellular functions of BRC-1. Understanding the significance of mononucleosome ubiquitylation in BRC-1 with C. elegans gives insight into the mechanisms of genetic variations in BRCA1 and further expands C. elegans’ function as a model organism. We have generated a C. elegans mutant with two point mutations that alter the ability of BRC-1 protein to interact with the nucleosome and ubiquitinate 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 mononucleosome ubiquitylation-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. We also share preliminary results regarding the role of nucleosome ubiquitylation in transcription regulation and reactive oxygen species generation. Our findings further the understanding of the many enzymatic functions of the large BRCA1 gene.

Mercury is emitted from various anthropogenic processes in temperate and tropical regions and is transported to northern latitudes via air and ocean currents. Although there are few point sources of mercury in the Arctic, elevated mercury levels have been observed in Arctic predators such as marine mammals, seabirds, fish, and spiders. This is concerning due to mercury’s known neurotoxic and teratogenic effects. Mercury deposited in the Arctic can be converted into its bioavailable form, methylmercury (MeHg), by aquatic bacteria. It can then be transferred into nearby terrestrial habitats by aquatic emergent insects. A previous study indicated that Arctic wolf spiders (Pardosa glacialis) collected from the shoreline of ponds had elevated concentrations of MeHg. In temperate zones, adult aquatic insects typically disperse within 30 meters of freshwater sources, suggesting that upland predators may consume fewer emergent aquatic insects, thereby reducing their contamination from these sources. While Arctic wolf spiders are ubiquitous predators across the tundra, it is unclear whether spiders collected in upland habitats are similarly contaminated with MeHg. The purpose of this study was to investigate the movement of mercury from aquatic to terrestrial food webs on the Pituffik Peninsula of northwest Greenland. Specifically, we examined the effects of shoreline proximity on mercury concentrations in Arctic wolf spiders. We collected Arctic wolf spiders and their insect prey at varying distances (0m, 10m, and 35m) from six freshwater ponds. We found a positive relationship between mercury concentrations and body size in P. glacialis. Spiders captured 35 meters away from the shoreline had significantly lower mercury concentrations than those captured at 0m or 10m from the shoreline. These results suggest that the dispersal of Arctic emergent aquatic insects declines with increasing distance from the shoreline and that emergent insects are an important source of mercury for Arctic wolf spiders.

The ClpXP protease plays a critical role in bacterial responses to external stressors, protein recycling, and virulence. The protease is highly conserved and composed of two subunits: ClpX, a regulatory ATPase, which recognizes and unfolds proteins, and ClpP, the proteolytic subunit. Our lab has identified that ClpX plays a role in resistance to cell-envelope targeting antibiotics and is critical for virulence in B. anthracis Sterne. However, it is unlikely that ClpX is directly mediating these effects. Rather, these effects are likely due to the dysregulation of the protein network maintained by ClpXP, which includes proteins involved in gene expression, such as transcription factors. Previously, we conducted a microarray and identified 119 differentially expressed genes between wild-type B. anthracis Sterne and a ΔclpX strain. One of the genes identified from the microarray is msrA/B, a fusion of the msrA and msrB methionine sulfoxide reductases (msr). Msr enzymes restore functionality to oxidized methionine residues; MsrA reduces S-form Met(O), and MsrB reduces R-form Met(O). Research with these enzymes has primarily focused on their role in resistance to reactive oxygen species (ROS). However, in S. aureus, msrA1 and msrB expression was induced upon exposure to oxacillin and other cell-wall active antimicrobial agents and not by ROS, indicating a potential connection between msrA/B and cell wall-targeting antibiotics. In B. anthracis Sterne, loss of msrA/B increases susceptibility to penicillin and vancomycin. However, this phenotype is not seen with cell-membrane targeting agents such as daptomycin, suggesting that the role of msrA/B in antimicrobial resistance may be limited to cell-wall active antibiotics. We are currently investigating the role in resistance to ROS but have seen no susceptibility to either H2O2 or paraquat. Future studies will look at changes in msrA/B expression in response to a variety of antibiotics and ROS stressors to better understand the role of this enzyme in regulating the response to these stressors in B. anthracis.

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.

Understanding and documenting the diversity and distribution of species on Earth is crucial, especially in the face of habitat loss and species extinction. Without this knowledge, 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 tropical regions where diversity is high and under-explored.
Herbarium specimens—dried plants collected and preserved over centuries—serve as critical windows into the past, allowing botanists to study plant diversity across time and space. When combined with modern tools such as imaging and DNA analyses, these collections become powerful data sources for unraveling evolutionary relationships, discovering new species, and improving our understanding of biodiversity. Our research focuses on Elaphoglossum, one of the most diverse and taxonomically challenging fern genera. Using herbarium specimens, powerful microscopes, and molecular phylogenetic studies, we are conducting a systematic review of the Elaphoglossum dendricola clade, a group of Andean ferns. Our aims are to clarify species boundaries, uncover undescribed species, reconstruct evolutionary relationships, and evaluate the conservation status of these ferns.
This poster presents preliminary results and outlines future directions of our research in tropical ferns, highlighting the importance of integrating collections-based taxonomy and molecular phylogenetics to explore and preserve tropical fern diversity.

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.