International Conference of Undergraduate Research (ICUR)

Emily Callison

Quantifying the Growth Rate of Cryptococcus neoformans in Macrophage-Like Cells Using Live Cell Imaging

Faculty Mentor: Dr. David Nelson

Cryptococcosis is a severe fungal infection affecting the lungs and central nervous system. The causative agent of cryptococcosis is Cryptococcus neoformans (Cn), a facultative intracellular pathogen found ubiquitously in environmental reservoirs. Exposure to Cn occurs through inhalation of its airborne spores, which enter the lungs and initiate the pathogenic cycle. In the lungs, Cn encounters alveolar macrophages (AMs), which typically engulf and eliminate the pathogen through phagocytosis. However, Cn evades destruction by employing immune-evasion strategies, including vomocytosis—a process where the cell expels the pathogen unharmed—facilitating its dissemination and leading to life-threatening fungal meningitis in immunocompromised hosts. Current in vitro models, such as the J774 macrophage-like cell line, inadequately represent AMs, limiting our understanding of these processes. This study proposes Fetal Liver-Derived Alveolar-like Macrophages (FLAMs) as a more suitable in vitro model for studying the Cn infection. While previous studies indicate that FLAMs better resemble the AM phenotype and preliminary data from our lab show that FLAMs can ingest Cn, it remains unclear whether Cn can replicate within FLAMs and escape via vomocytosis, similarly to J774 cells. The primary objective of this study was to compare the intracellular replication rate of Cn in FLAMs and J774 cells. Using live-cell imaging, we standardized and quantified replication rates over time, revealing that Cn replicates at similar rates in both cell lines. This further validates FLAMs as a superior in vitro model for studying AM-Cn interactions. Future work will focus on comparing the vomocytosis capabilities between the two cell lines.

Andrew Hetrick

Seasonal Variations in the Ecology of Harmful Algal Blooms In the Stones River, Tennessee, USA using eDNA and PCR

Faculty Mentor: Dr. Frank Bailey

Harmful Algal Blooms (HABs) are becoming an increasing concern towards water quality and produce toxins that harm people and wildlife. One of the algal toxins of concern, microcystin, is produced by cyanobacteria and acts as a liver toxin. One of the primary bloom-forming genera that produce microcystins is Microcystis spp. The ability of cyanobacteria to produce the toxin depends on the presence of the microcystin synthetase gene cluster within its genome.  We used polymerase chain reaction (PCR) techniques on cultured algae to amplify genes that can inform algal community structure in field samples. DNA primers that are capable of detecting genetic sequences for cyanobacteria, Microcystis, and microcystin synthetase E were utilized. Minimum concentrations for detecting bacteria via PCR were determined before use on field samples. These primer sets were then applied to field samples from the East Fork of the Stones River to infer the variation in cyanobacteria communities and toxin-gene presence through time.  The Biotechnological data was compared with microcystin concentration, nutrient levels, pH, dissolved oxygen, conductivity, and bioaccumulation in aquatic emergent insects and spiders.  The presence of target sequences for Microcystis and microcystin synthetase E were found to show a strong relationship with toxin concentrations.  Cultured algal cells will be used again to develop methods that quantify the amount of a gene in a sample for the three primer sets.  The relationship between toxin gene presence and microcystin levels indicates that there are future applications of using its abundance in the prediction of harmful algal blooms.

Ariel Nicastro

Improving Zinc Oxide Nanorod Synthesis for Enhanced Electrochemical Sensor Performance

Faculty Mentor: Dr. Suman Neupane

Zinc oxide (ZnO) is a biocompatible inorganic semiconductor with light-emitting and semiconducting properties, making it suitable for diverse applications, including medicine, cosmetics, and nanotechnology. Its wide bandgap and high electron mobility make it particularly promising for advanced sensing technologies. This study focuses on optimizing the hydrothermal synthesis of ZnO nanorods by investigating the effects of autoclave temperature and surfactants. The goal is to produce nanorods with enhanced crystallinity, diameters below 50 nm, and large length-to-diameter ratios—key attributes for improved ZnO-modified sensor performance. X-ray diffraction confirmed the crystalline structure of the synthesized ZnO, while scanning and transmission electron microscopy characterized the nanorod morphology. UV-visible spectroscopy revealed strong absorption at 370 nm, corresponding to a 3.35 eV bandgap, validating the material’s potential for sensor applications. The optimized ZnO nanorods are designed to enhance the sensitivity, accuracy, and scalability of ZnO-modified electrochemical sensors. Sensor performance will be assessed using cyclic voltammetry to track current responses to voltage changes. Future work will refine ZnO integration with electrode materials, explore alternative synthesis methods, and investigate the role of ZnO modification for biosensors and photoelectric sensors. By addressing critical synthesis challenges, this research advances the reliability and cost-effectiveness of ZnO-based sensors, paving the way for their broader use in environmental monitoring, healthcare, and industrial quality control.

Chet Muny

Determining Trophic Movement of Riparian Systems Using Tetragnathid Spiders as a Sentinel Species

Faculty Mentor: Dr. Frank Bailey

The most reported cyanotoxins are hepatotoxins called microcystins. Microcystins are potent hepatotoxins. They are strong inhibitors of the serine/threonine phosphatases which control key biological pathways such as cell proliferation death. This interference triggers a chain of events that leads to eventual death of animal cells. Microcystin targets the liver and induces hepatocyte death. Microcystis blooms that produce microcystin are becoming increasingly more common due to human activity, potentially moving onto terrestrial ecosystems through trophic – food chain – transfer. Tetragnathid spiders’ diets primarily consist of aquatic emergent insects (insects that develop in water before emerging), making them indicators of movement between aquatic and terrestrial ecosystems.  Water, sediment, spiders, and insects were collected biweekly at three sites at Walter Hill Dam. All samples, except water, underwent a methanol extraction and analyzed for microcystin concentrations. Previous studies indicated terrestrial transfer of microcystin from mayflies to birds; we expect similar relationships between insects and tetragnathid spiders.  Microcystin concentrations were confirmed in aquatic insects and tetragnathid spiders. Considering spiders’ diets are primarily insects, a probable cause of spider microcystin levels being elevated is from consumption of insects. Microcystin concentrations in water, sediment, insect, and spiders were found to change seasonally. Globally, microcystin contamination has caused animal and human deaths. Knowing the potential of it to bioaccumulate can help us understand how to contain it. Future directions for this research will focus more on triggers of microcystin production.