Fall Interdisciplinary Research Symposium (FIReS) Presentation Abstracts

According to the World Health Organization, infectious diseases account for three of the top ten global causes of death. Antimicrobial drug discovery to treat such illnesses surged in mid-twentieth century but has sharply declined in recent years. At the same time, antimicrobial-resistant “superbug” infections are on the rise. Plants produce a robust supply of novel metabolic compounds including many antimicrobial agents. However, with the advent of modern antibiotic drugs, natural plant-derived antibiotic sources have largely been left unexplored. Therefore, our work is focused on screening poorly explored medicinal plants in the hopes of discovering novel antimicrobial drugs. To do this, we have been testing extracts of various plants found in the Valpo medicinal garden for their effects against twelve bacterial and fungal microbes of interest. To date, methanol and hexane extracts of both aerial and reproductive portions of 8 plants have been screened, with three plants showing especially promising activities. Both raspberry leaf and yarrow flower methanol extracts were seen to inhibit growth of both Gram-positive and Gram-negative bacteria, with little activity against the fungal organisms tested. Chokeberry leaf methanol extracts had similar trends, but with overall less activity. Moreover, we are currently working to separate the methanolic chokeberry leaf and raspberry leaf crude extracts using column chromatography to eventually determine the specific compounds responsible for these antibacterial activities. These data highlight the importance of plants as an invaluable pharmaceutical resource at a time when antimicrobial drug discovery has plateaued.

The creation of novel antimicrobial agents is currently at the forefront of modern healthcare due to a stark decrease in antimicrobial drug development in recent years and due to the increasing rise of “superbugs” that are resistant to more than one type of antimicrobial treatment, which are predicted by 2050 to cause 10 million deaths/year. Our research is focused on testing bacterial and fungal pathogens against methanolic and hexane extracts of various medicinal plants, such as Argemone mexicana. From previous work by our group, several antimicrobial compounds were isolated from the roots and leaves of A. mexicana, including berberine, chelerythrine and sanguinarine (work published in PLOS ONE in 2021). Since then, we have synthesized multiple rationally-designed variants of these original phytocompounds (fourteen berberine and four chelerythrine variants) and have tested these A. mexicana-inspired phytocompounds for altered antimicrobial activities. Interestingly, several of these variant compounds show increased antibacterial effects against gram-positive bacteria, yet reduced toxicity against the eukaryotic fungal cell lines tested. Moreover, based on an alkaline phosphatase (ALP) assay, it appears that the altered antimicrobial actions of some of these unique variants may be due a changes in the permeability of the cell envelope, resulting in the leakage of intracellular proteins. A manuscript is being prepared to publish these exciting findings in a peer-reviewed scientific journal. Our current work is focused on testing additional poorly-explored medicinal plants, as well as designing and synthesizing new variants of bioactive molecules in the hopes of discovering new and/or more effective drugs.

Bothrops atrox, a snake species endemic to South America, is often associated with traditional medicinal practices due to its therapeutic potential against various diseases. Recent studies have identified the presence of unique peptides, enzymes, and proteins in B. atrox venom, suggesting their roles in inhibiting the growth of specific bacteria and showing cytotoxic effects against certain mammalian cell lines. Notably, venom peptides like Batroxin I and enzymes such as L-amino acid oxidases (LAAOs) and metalloproteinases exhibit substantial bioactive properties. This research project aims to explore the antimicrobial prowess of B. atrox venom by screening venom extracts of various polarities against twelve distinct microorganisms. The underlying objective is to isolate and characterize the therapeutic compounds responsible for these activities. This work is currently ongoing and funded by a Valpo CWR Undergraduate Research Grant awarded to Daryush Mansuri for the 2023-2024 academic year. By delineating the antimicrobial attributes of specific compounds in B. atrox venom, this research contributes to the broader understanding of its medicinal viability and sets the stage for potential drug development targeting antibiotic-resistant pathogens.

C. albicans is an opportunistic fungus which under not yet well defined cues shifts morphology from yeast to filamentous and becomes invasive. During sepsis, estrogen levels are elevated. Thus, we hypothesized that estrogen could act as a signal for C. albicans to become filamentous. In this study, we used 3 media: minimum, spider, and YEPD to test the effect of estrogen and fetal bovine serum (FBS, positive control) on C. albicans filamentous growth. Our experimental setup was: control, 0.1 nM estrogen, 10% FBS, and FBS with estrogen. Every day for 2 days, we took 5 random pictures using a brightfield microscope and scored one if filaments were visible or zero if filaments were not visible. Our results show in YEPD that FBS and FBS + estrogen had significantly more pictures with filaments compared to control at day 1 and 2 (P=0.001, ANOVA Dunnett post hoc). In minimum, FBS + E2 had significantly less pictures than control (P<0.04 ANOVA Dunnett post hoc) at day 1. On day 2, FBS + E2 had significantly less pictures with filaments than FBS (P=0.006) suggesting an antagonistic effect of estrogen on FBS. In spider, no difference was found among the conditions (P=0.2 ANOVA). Estrogen did not significantly increase nor decrease filamentation in any of our conditions. Our preliminary results highlight the importance of growth media when designing and analyzing a study on filamentous growth, as different media can induce different filamentous responses from C. albicans.

Fungal infections are a serious concern, as they impact many people and have high mortality rates for those who are immunocompromised. As a result of increased drug resistant microbes, there is always a need for new drugs to combat these infections, without causing side effects in humans. Taking advantage of structural differences in the fungal form of the essential Methionine Synthase (MetSyn) enzyme, one can design compounds to selectively bind to the fungal enzyme, inhibiting fungal growth, while leaving the mammalian enzyme unaffected. We are designing, and optimizing the synthesis of, a variety of inhibitors using pterin and deazaguanine-based molecules as a scaffold to mimic folate, an essential substrate for MetSyn function. We have been testing these molecules’ activity in a microbial growth assay.

Pathogenic bacterial and fungal infections are some of the leading causes of death in the population at large. Antimicrobial-resistant “superbugs” have become a growing issue worldwide as well as on the International Space Station, and there is a great need to explore new and alternative pathways for fighting these diseases. Through a collaborative project, we have explored extracts of the Argemone mexicana plant to isolate antimicrobial agents found within this plant. We have already identified three key molecules, notably berberine, which give this plant antimicrobial properties. Guided by the structures of these plant-derived molecules, our current work is now focused on designing and synthesizing new variants of these bioactive molecules in the hopes of discovering new, more potent, drugs. Thus far, several of our synthetic variants have shown promising activity over the original phytochemicals isolated from the plant. In continuing our work, we have performed a similar process with the Aronia melanocarpa plant and found that it shows excellent antimicrobial potential.

Plastics are synthetic polymers currently present in nearly every aspect of life. From bottles, foam packaging, and food containers to clothes, electronics, medical equipment, and more, plastic usage has become commonplace. Plastics are widespread, lasting pollutants in all ecosystems. Nanoplastics, defined as plastic pieces less than a micrometer in diameter, are readily formed from the fragmentation of larger plastic pieces. Nanoplastics formed or present in water were studied to determine sources, sizes and quantities as well as interactions with other substances. Polyethylene (PE) and polyethylene terephthalate (PET) microplastics were mixed with pure water and a liquid organic compound to create nanoplastics. Mixtures were shaken, subjected to further ultrasound mixing, and the suspensions were extracted with diisopropyl ether to remove the liquid organic. Quantification of extraction efficiency was attempted with GC-MS, massing after evaporation, and fluorescent dye and fluorescent detection. In addition, nanoplastics mixtures were analyzed using Raman spectroscopy and microscopy before and after extractions. We determined that pure laboratory water contains nanoplastic particles, that mixing of PE microplastics in water creates nanoplastics, and that a variety of liquid organic compounds function as solubilizers, significantly accelerating nanoplastics formation. We also found that nanoplastic particles exhibit different Raman spectra under certain conditions, suggesting interactions between nanoplastics and solubilizer molecules.

We present a proof of concept demonstration of solar thermochemical energy storage. The James Markiewicz Solar Energy Research Facility (SERF) at Valparaiso University uses concentrated sunlight to reduce hematite at 1500 ?, evolving oxygen and producing magnetite. Magnetite can then be dissolved in water at pH 5 using hydroxyethylidene diphosphonic acid (HEDP). Aqueous Fe2+ serves as the anode for the reduction of water to hydrogen, as demonstrated by a visual H2 detection assay. Finally, alkaline solutions of Fe3+ + HEDP upon concentration produce a precipitate characterized as goethite ?-FeOOH by Raman spectroscopy, completing the cycle.

Regulations imposed on air quality have a direct impact to respiratory health. The relationship of particulate matter to respiratory health has been improving and the link to health problems has only grown stronger. The purpose of this investigation was to quantitatively study and monitor air quality trends of particulate matter using low cost air quality sensors in Northwest Indiana (NWI). Multiple PurpleAir air quality index (AQI) sensors were placed across several cities in NWI. A years’ worth of data was accumulated on the sensors’ memory cards taking a data point every ten seconds. The processed data consisted of particulate matter of 2.5 microns and smaller (PM2.5), although the smallest size fraction of 0.3 microns and smaller were the primary focus. PM2.5 concentrations were graphed on a monthly basis representing concentration, temperature, and pressure as well as a log normal distribution depicting number of points and concentration. The distribution of PM2.5 concentration within different cities and counties represented little variation of particulate concentration. There exist many “non-distribution” like trends where month to month variations from the natural distribution of particulate concentration could be found. Characteristics of the PurpleAir air quality sensors are convenient for communities focused on environmental justice, however the air samplers are not accounting for all metrics of air quality. More work needs to be completed towards understanding the limitations and capabilities of the low cost air quality sensors.

White dwarfs are the final stage of stellar evolution for most stars – those less than about eight times the mass of the Sun. In these cases the star has ejected its outer layers, leaving a superheated core behind to cool. White dwarfs that are part of a binary system, or have a companion star, lead to many interesting astrophysical situations, and so are important objects to understand. In this study, we look specifically at binary white dwarf systems where the second object is a main sequence star. After the discovery of a binary system, it is necessary to create a working model to better understand the physical characteristics of the system. This is accomplished using data about the changing brightness of the system and measures of the speed of the stars toward and away from us as they orbit one another. We built preliminary models for two white dwarf binary systems – WD1136+667 and Gaia-DR2-3150 – which we describe in this presentation. Both of these systems are part of a larger Hubble Space Telescope program studying very hot white dwarfs.

A white dwarf is formed from the leftover core of a main sequence star. During the asymptotic giant branch phase, a star’s outer layer greatly expands such that it can engulf a nearby companion, creating a common envelope around the star’s core and the companion. This causes the orbit between these stars to tighten, the resulting change in angular momentum ejects this common envelope into the interstellar medium, leaving a binary system consisting of a hot white dwarf and the original companion orbiting very close to one another. We seek to identify these binary systems in order to not only determine the fraction of white dwarfs in binary systems, but also to later investigate their physical parameters. This will allow for a better understanding of the common envelope phase in the evolution of binary systems as well as the planetary nebulae which result from them. From a list of 112 hot white dwarf targets, we use spectral energy distributions to search for possible binary systems. Using Jupyter Notebook and Python, a preliminary blackbody fit was performed, identifying 22 binary candidates. A more precise fit was then performed using a synthetic spectra given by SVO Theory Server, which includes stellar atmosphere absorption features and corrects the data for reddening and extinction. With these, we find 16 candidates. We then note, using images from the SIMBAD CDS Portal, whether there appears to be any additional objects within a radius 10 arcseconds of our target. Four (EC11575-1845, UCAC2 46706450, PN A66 65, and PN K 1-6) of the 16 candidates did not appear to be encroached by additional light. Another two (LoTr 1 and HS 1857+5144) of the 16 continue to display binary photometric features when contamination is subtracted. These six objects have been identified as binaries by other researchers and their natures are discussed. The likelihood of the remaining 10 being true binary systems is also discussed. The results are then used to discuss possible implications for the overall binary fraction of the sample.

Researchers are currently unsure which molecules are responsible for spectral features known as the unidentified infrared emission (UIE) bands observed in planetary nebulae. Infrared emission spectroscopy can be used to identify molecules by assigning spectral peaks to specific molecular vibrations. Scientists have speculated that UIE bands come from either polycyclic aromatic hydrocarbons (PAHs) or mixed aromatic/aliphatic organic nanoparticles (MAONs) with heteroatom substitutions. Starting from these proposals, we have systematically calculated the theoretical infrared spectra of various candidate molecules using B3LYP density functional theory and qualitatively compared them to the experimental UIE spectra. Our calculations confirm that the 3.4 ?m feature is due to aliphatic C-H stretching and show that the intensity of the 6.2 ?m feature can be enhanced with nitrogen substitution depending on its location. We also show that nitrogen substitution can produce the 8.6 ?m feature in PAH dimers. The calculated infrared spectra of n-butyl linked nitrogen-substituted pyrene and tetracene dimers contain most of the UIE features found in planetary nebulae NGC 7027 and IRAS 21282 + 5050. Future plans will involve devising a method to make a quantitative comparison of calculated infrared spectra to experimental UIE spectra along with performing calculations for molecules with other types of heteroatom substitutions. These findings are important for understanding the chemical evolution of planetary nebulae.

Many fascinating and important processes in space occur in binary systems consisting of a white dwarf and a companion star in a very close orbit. Because of this, understanding this type of system is important to our overall understanding of our universe. These binary systems are born within planetary nebulae. However, only 26 such systems within planetary nebulae have been fully modeled, which isn’t a large enough number to result in meaningful statistical data. In order to work towards increasing this number, I used the PHOEBE modeling software to obtain ranges for the secondary temperature, primary and secondary radii, secondary albedo, and system inclination for the close binary system in the planetary nebula Hf2-2. I constrained the primary temperature to a 20 kK range based on a previously published spectrum analysis, while the primary’s mass was held constant due to not having radial velocities available. I present here the resulting ranges for the parameters.

Gravitational wave (GW) astronomy has witnessed several milestones in recent years, and will continue to do so with the launch of the Laser Interferometer Space Antenna (LISA). Detecting GWs with frequencies ranging from 0.1 mHz to 1 Hz, LISA’s primary signal source is expected to be binary white-dwarf (WD) systems. This study delves into the relatively untouched territory of detecting eccentricity within these systems; in both the individually resolvable signal from single systems and the unresolvable GW foreground created by a population of such systems. Such work builds on previous studies only considering binary WD systems with exclusively circular orbits. We present our results from exploring the orbital frequency vs. eccentricity parameter space of these systems, and discuss the implications of the findings. The research aimed to determine the signal-to-noise ratio (SNR) of detections across this parameter space, shedding light on the detectability of systems with varying eccentricities. Additionally, this work is poised to evaluate the extent of any GW foreground emanating from a galactic population of binary WD systems. Although this portion of the research is ongoing, it holds great promise in understanding the cumulative impact of these systems on the GW landscape.