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Student Research

Students at Creighton have the opportunity to become involved with research work sponsored by science faculty throughout the University. Individuals with sufficient motivation and time can conduct independent research projects that may be presented at scientific meetings, and even published in scientific journals. More information on student research opportunities is available through the Center for Undergraduate Research and Scholarship (CURAS).

Recent Research

Students conducting independent research normally present their work each April at the Department of Biology Research Colloquium. Below is a list of recent presentations, representing work with faculty from the Biology Department, other departments and schools at Creighton, and other institutions.

Kennedy-Kainoa Tamashiro

I Got it from Mama: Exploring trans-generational effects of maternal infection on offspring fitness
Kennedy-Kainoa Tamashiro, Disha Chandra , and Dr. Amy Worthington
Department of Biology, Creighton University

Full Poster

Ensuring that sufficient resources are available to each system of the body requires a strategic allocation of energy. To examine the physiological trade-off between immunity and reproduction, we explored the effects of a long-lived parasitic infection on female sand crickets, Gryllus firmus, with our observations focused on reproductive capacity and quality of resulting offspring. Reproductive capacity was quantified by the following: mating success, ovarian mass, number of eggs laid, hatching success of laid eggs, and average hatchling size. Immunocompromised mothers may invoke an elevated immune response in their offspring, called trans-generational immune priming. Although this may help offspring survive their own parasitic infection, over-investing in immunity as a juvenile may result in decreased reproductive capacity as an adult. To study this, the progeny of infected and healthy females were raised and their immune function (e.g. LD50 dose and melanization capabilities), body growth, and reproductive investment (sperm viability and ovarian mass) measured. Our results suggest that the average proportion of ovarian mass to total body mass and average number of eggs laid are significantly decreased in infected females during infection, preventing the production of offspring. Currently, we are investigating the reproductive capacity of post-infection females and the quality of their offspring.

Lauren Barbush

Investigating the Therapeutic Potential of Piperlongumine Derivatives for Noise-induced Hearing Loss
L. Barbush*, S. Hati**, J. Zuo**, M. Zallocchi**
*Department of Biology, Creighton University and **Department of Biomedical Sciences, Creighton University School of Medicine

Full Poster

Preliminary evidence from our group suggests that piperlongumine – an extract from the Indian long pepper (Piper longum) – has therapeutic potential against noise-induced hearing loss (NIHL). When cells in the inner ear are exposed to excessive noise, there's an increase in neurotransmitters released. This causes inflammation (activation of NF-κB pathway) and cell death. In cancer systems, piperlongumine regulates the NF-κB pathway. Similarly, piperlongumine may be protecting the noise-injured cells by inhibiting NF-κB. We propose that by modifying the chemical structure of piperlongumine, we will 1) improve its efficacy for protection against NIHL; and 2) increase its potency at inhibiting the NF-κB pathway. We synthesized and screened 34 piperlongumine derivatives in a zebrafish model for NIHL. We also measured the degree of NF-κB inhibition by piperlongumine and its derivatives in a NF-κB zebrafish reporter line and in mouse embryonic fibroblasts. We found five derivatives that significantly protect hair cells against NIHL. These derivatives performed better than the original piperlongumine molecule. Moreover, piperlongumine and its protective derivatives prevented cell death by, at least in part, inhibiting the NF-κB pathway.

Curtis Lin

Yellow is for Beetles but Blue is for Bees: Differential sampling using pollinator vane traps.
C. Lin, and T. Burk
Department of Biology, Creighton University

The first important step in any biological conservation effort is determining the population status of the species at a site. For pollinating insects, several different techniques have been used. An increasingly popular technique uses commercially-available Blue or Yellow Vane Traps. We set out two pairs of Vane Traps, each with one Blue and one Yellow trap, in patches of flowers known to be highly attractive to pollinators, at Glacier Creek Preserve in Bennington, Nebraska. Six sampling sessions were conducted, approximately every two weeks between July and September 2021, with traps in place for 24 hours each session, from one afternoon to the next. We found that Blue Traps captured significantly more insects overall than did Yellow Traps. Yellow Traps captured significantly more beetles, while Blue Traps captured significantly more bees and butterflies. Our results indicate that use of multiple sampling methods may be necessary to accurately sample pollinator populations at sites of conservation importance.

Armond Isaak

Determination of lysine acetylation susceptibility of DksA and its effects on global metabolism in B. burgdorferi
Isaak, Armond J.1, Boyle, William. K.2, Sorensen, Hannah S.2, Zalud, Amanda K.2, and Bourret, Travis J.2
1Department of Chemistry and Biochemistry, Creighton University, and 2Department of Medical Microbiology and Immunology, Creighton University School of Medicine

Full Poster

For its infectious cycle, the Lyme disease spirochete Borrelia burgdorferi must overcome a variety of environmental stresses. The DnaK suppressor protein (DksA) is a global gene regulator in B. burgdorferi that helps regulate the expression of genes required for infectivity, however, the molecular mechanisms driving DksA-dependent changes in gene expression are unclear. Lysine acetylation is a reversible post-translational modification (PTM) that contributes to the regulation of virulence gene expression in a variety of bacteria pathogens. In silico analysis of B. burgdorferi DksA suggests that five lysines (L118, L119, L121, L122, and L124) located in the C-terminus of DksA are likely targets for acetylation. In B. burgdorferi, lysine acetylation is carried out nonenzymatically through endogenously produced acetyl-phosphate (Ac-PO4). In this study, I observed that recombinant DksA is subject lysine acetylation following incubation with Ac-PO4 in vitro. Additionally, our previous work suggested DksA may contribute to lysine acetylation through its regulation of ackA, a gene that encodes an enzyme that produces Ac-PO4. Currently, I am comparing the profiles of acetylated proteins in wild-type and dksA-deficient B. burgdorferi strains to the contribution of DksA to lysine acetylation.

Samuel Rogers

NAD(P)H Phasor-FLIM Imaging Indicates Metabolic Differences Between Cancerous Tissue and Healthy Tissue
Samuel J. Rogers1, George Varghese1, Michael G. Nichols1,2, Tyler B. Farr1, Hayden M. Hubbs1, Connor J. Kalhorn1, Cecilia Myers1, Alicia C. Nguyen/1, Daniel R. Snyder1, Thien Q. Tran1, Daniel H. Wood1, Dan L. Pham2, Laura A. Hansen2
1Department of Physics, Creighton University, Omaha, NE, and 2Department of Biomedical Sciences, Creighton University, Omaha, NE

As cancerous tissue develops, it becomes more metabolically aggressive than healthy tissue. Cancerous tissue shows increased proliferation and therefore demands greater energy production. Our research uses NAD(P)H phasor-Fluorescence Lifetime Imaging Microscopy (FLIM) imaging to detect metabolic changes in vivo that are characteristic of skin cancer. The goal is to develop a non-invasive optical biopsy as an alternative for punch biopsies - the current standard diagnostic tool. We utilized NAD(P)H phasor-FLIM imaging to observe differences in NAD(P)H fluorescence intensity and NAD(P)H bound fraction between UVA treated and sham treated SKH1 mice. We also measured collagen within the epidermis and dermis with FLIM and second harmonic generation. Measuring collagen allows us to assess architectural shifts that are indicative of tumorigenesis. During our longitudinal study, we correlated changes in non-invasive measurements of metabolism with visual observations of UVA-induced papillomas. These observations were then verified with standard histological and immunofluorescence imaging. Our data suggests UVA treated SKH1 mice show a decrease in NAD(P)H bound fraction. Ultimately, our methods suggest a potential alternative to the punch biopsy – a non-invasive biopsy with the use of phasor-FLIM.

Abigail Jacobi

Development of a Multiplex PCR that Identifies Oral Pathogens Associated with Digestive Cancers.
A. Jacobi, C. Rudick, N*, Hanson PhD*.
*Department of Medical Microbiology and Immunology, Creighton University Medical School.

An association has been found between digestive cancers and specific oral pathogens found in saliva and cancerous tissue. The goal of this project is to develop a multiplex PCR that is able to rapidly identify the presence of specific oral pathogens, increasing the chances for early detection of colorectal, pancreatic, and esophageal cancers.Primers were developed for Porphyromonas gingivalis, Fusobacterium spp., Aggregatibacter spp., Tannerella spp., Streptococcus mitis and SLCOA1. All target genes were amplified by PCR, cloned into vectors, and inserted into chemically competent E. coli. The procedure was optimized using the control markers by altering primer and template concentrations.A multiplex PCR assay has been successfully designed to identify the presence of Porphyromonas gingivalis, Fusobacterium spp., Aggregatibacter spp., and Tannerella spp., with Streptococcus mitis and SLCOA1 as internal controls. Next, TaqMan probes will be developed so the multiplex can be performed using qPCR. Saliva samples will be collected from healthy patients and those with confirmed periodontal disease. These samples will be used to test the multiplex assay and determine the presence of the target organisms.

Adam Wilson

Reproductive Ecology and Post-Pollination Processes of Water-Pollinated Stuckenia pectinata
Adam D. Wilson*, Christie Dang, Emma Baker, Neha Lamsal, Sabrina DuMond, and Mackenzie L. Taylor
*Creighton University

Water-pollination, or hydrophily, has allowed angiosperms to colonize aquatic environments where they provide habitat, wave attenuation, and nutrient cycling. Hydrophily occurs when pollen is transferred across or beneath the water surface. Mature pollen grains are released from anthers 58 and are transported until the pollen contacts a receptive stigma. Hydrophily has known correlations with pollen traits, but the consequences of a transition from wind-pollination to hydrophily are not well understood. Understanding post-pollination events in a comparative context will highlight key reproductive traits that allow hydrophily to be a viable pollen transfer mechanism.

Amanda Cohen

Simon Says...Jump! The neural manipulation of crickets by parasites
A. Cohen and Dr. A. Worthington
Department of Biology, Creighton University

Full Poster

Parasitic relationships exist across phyla and can change an organism’s reaction to their environment to benefit the parasite’s survival, rather than the host’s. The exact mechanism of how this occurs however, remains a mystery. Here, I propose neural manipulation, resulting in behavioral changes, and will use the host-parasite relationship between the sand field cricket (Gryllus firmus) and the horsehair worm (Paragordius varius) to demonstrate this. I will use High Performance Liquid Chromatography (HPLC) to quantify the levels of two vital neurochemicals that modulate behavior (octopamine and serotonin) in the brains of healthy and infected crickets at two critical timepoints of the host-parasite interaction (host sexual maturity and parasite emergence from its host). In addition, I will use histological staining methods to quantify the volume of the lateral accessory lobes and central complex (two areas of the cricket’s brain) to determine if plasticity is occurring in infected crickets. Using this proposed experiment, I will be able to 1) see if predictable neurochemical changes occur in infected crickets and 2) determine if neuroplasticity occurs in infected crickets. This research will further our understanding of how parasites manipulate hosts to their benefit and continue to expand our knowledge of the brain.

Jennifer Omann

Flower evolution in Nymphaeaceae
J. Omann, E. Manke, M. McGlynn, and M.L. Taylor
Department of Biology, Creighton University

Flowering plants are found all over the world and produce flowers in many shapes and sizes. Many of these structural differences, in combination with other factors, have evolved to attract certain pollinators. But floral function is unchanging – to facilitate sexual reproduction and ensure genetic diversity among offspring. One relatively small family displays great size variation – the waterlilies. Victoria ­flowers often grow to the size of a dinner plate, whereas Euryale's average diameter of 5 cm; even within Nymphaea, there is significant size variation. How do the internal floral anatomical structures, particularly the carpel, change as the flower gets larger? By focusing on the female reproductive structure, particularly the pollen-tube pathway, we can gauge the role of reproduction in eliciting these adaptations, as well as how the reproductive structures have adapted to suit different pollinators. We will collect samples, measuring select morphological traits, such as floral cup diameter, ovary size and display size. We will use comparative phylogenetic methods to determine patterns of flower evolution in this family. Data on morphological evolution from this early-diverging family will aid our understanding of flower evolution for all flowering plants.

Hayden Hubbs

Impact of Cell Culture Conditions on Assessment of Cellular Metabolism in Vitro by NSD(P)H Phasor-FLIM with Application to in Vivo Diagnostic Imaging for Non-Invasive Biopsy
Hayden M. Hubbs1, Tyler B. Farr1, Connor J. Kalhorn 1, Cecilia Myers1, Alicia C. Nguyen1, Samuel J. Rogers1, Daniel R. Snyder1, Thien Q. Tran1, George Varghese1, Daniel H. Wood1, Dan L. Pham3, Laura A. Hansen2, Michael G. Nichols1,2
1Department of Physics and 2School of Biomedical Sciences, Creighton University, Omaha NE 68178, and 3Department of Biomedical Engineering3, University of Wisconsin, Madison WI

Background: Hallmarks of cancer such as deranged proliferation and altered metabolism characterize tumorigenesis and can be measured with non-invasive technologies such as Fluorescence Lifetime Imaging (FLIM) of endogenous coenzyme NADH. Hypothesis: The overall NAD(P)H bound fraction would change under various oxygenation conditions and thereby signal a shift in dependence on the electron transport chain when cells were grown in a hypoxic environment. Furthermore, the inhibition of HER2 in cells would also alter the bound fraction. Results: We observed that while cell growth rates and NAD(P)H bound fractions decreased in low HER2-expressing SCC cells grown under hypoxic conditions, growth rates and bound fraction of NAD(P)H in high HER2-expressing SCC cells increased. In breast cancer cell lines, hypoxic conditions led to a decreased NAD(P)H bound fraction and slower growth regardless of HER2 status, while variation in electron transport chain activity was more pronounced in HER2 overexpressing cell lines. Conclusion: These results demonstrate that non-invasive phasor FLIM imaging can quantify changes in cancer cell metabolism induced by both the oxygenation of the tumor as well as the overexpression of HER2.

Miranda Chavira and Zach Rinke

Structural and functional evolution of protein complexes in K. lactis Spindle Pole Bodies.
Z. Rinke, A. Kotula, M. Chavira, M. Tsui, and M. Rysko
Department of Biology, Creighton University

Spindle pole bodies (SPBs) are essential components of yeast cells involved in chromosomal division. The structure and localization of SPBs between species of yeast are remarkably variable. The goal of this study is to explore the structural evolution of yeast SPBs in two taxonomically close species of yeast, Saccharomyces cerevisiae and Kluyveromyces lactis. We analyzed K. lactis SPB proteins by individually tagging all 18 homologs of the S. cerevisiae SPB with green florescent protein (GFP) and analyzing their localization in K. lactis. We confirmed the localization of each K. lactis homolog to the SPB or noted significant differences in localization using confocal microscopy. We further studied the SPB structure in K. lactis by assessing the ability of each K. lactis homolog to replace S. cerevisiae SPB proteins in S. cerevisiae deletion strains. We used GFP tagging of the replacement proteins to confirm correct substitution and localization within the cell. In the future we will continue testing all 18 K. lactis SPB homologs for localization to the SPB and rescue capability within S. cerevisiae. Analysis of regions and proteins conserved, or variable provides valuable insight into noncritical regions of SPB and possible factors influencing its evolution.

Ramya Rengarajan

Live long or prosper: An investigation of immunological memory and its reproductive costs in insects
R. Rengarajan, C. Craig, A. Cohen, AM. Worthington
Department of Biology

It was originally believed that invertebrates relied solely on non-specific immune responses to fight off pathogens, yet recent research suggests they may have an acquired immune response comparable to the mammalian immune system called immune priming. This response would allow invertebrates to retain a memory of pathogens and respond stronger and more quickly if they become infected a second time. However, immune priming has only been tested in a few species of insect and requires more investigation to confirm that it is indeed occurring. Using the sand cricket, Gryllus firmus, I will experimentally test for whether crickets maintain the memory of past pathogens and what negative effects this might have on their reproduction. To test the strength of the immune system after injection with either a novel or familiar pathogen, I will measure two key immune parameters in the blood (PO and lytic activity), as well as overall survival rates from infection. Additionally, by examining the reproductive trade-offs that occur in response to upregulating the immune system, this will be one of the first studies to identify whether immune priming has significant costs associated with this process important for survival.

John Quigley

The effect of climate and land use on blowouts in the Nebraska Sandhills
J. Quigley and M.A. Vinton, PhD
Department of Biology and Environmental Science Program, Creighton University

The Nebraska Sandhills comprise one of the most intact temperate grassland ecosystems in the world where plant cover is essential for stabilizing dunes of sand. Drought, overgrazing, or other disturbances can cause decreases in vegetation, allowing formation of sandy depressions of wind erosion (blowouts). We utilized National Agriculture Imagery Program (NAIP) imagery to determine the current trend of blowout size in this most recent decade (2009-2018). Furthermore, UAVs (unmanned aerial vehicles or “drones”) can detect change at a much smaller spatial scale. We used aircraft-imagery as well as images taken from a DJI Phantom 4 Pro V2.0 drone to detect small-scale changes in vegetation in topographically identical grazed and ungrazed plots. Normalized Difference Vegetation Index (NDVI)—an index of greenness—was used to calculate the relative quantity of vegetation present. Results indicate that blowouts have continued to decrease in size, perhaps due to a pattern of increased rainfall and temperature over the decade. Drone imagery indicates that cattle grazing can decrease NDVI, which suggests grazing can lead to a decline in vegetation and an increase in blowout formation. Overall, our study on blowout dynamics in the Nebraska Sandhills contributes to a more complete understanding of the conservation of this unfragmented landscape.

Emma Goldsmith

Comprehensive Remote Estimation of Chlorophyll-a, Total Suspended Solids, and Color Dissolved Organic Matter using Sentinel 2 Imagery for Coastal Georgia, USA
E. Goldsmith, J. Schalles
Environmental Science Program and Department of Biology, Creighton University

There is heavy dependence on in-situ measuring techniques for gauging water quality. In- situ measurements are costly and can be dangerous. This poses the question: how do we assess water quality safely with more cost and energetic efficiencies? Remote sensing is an answer to this question. I am developing an algorithm to overlay onto Sentinel 2 images using ENVI, an advanced computer software application ( I am validating my satellite pixel-based algorithm using in-situ water quality measurements around four major Georgia tidal watersheds on the South Atlantic Bight. By collecting satellite imagery from Sentinel 2, I hypothesize that with a set of algorithms, I can provide a rapid assessment of water quality based on total suspended solids (TSS), Chlorophyll-a (Chla) and Color Dissolved Organic Matter (CDOM) on the inshore and offshore regions of the South Atlantic Bight (SAB). There are apparently no singular, unified, rapid and comprehensive remote sensing algorithms in the literature for simultaneous estimates of TSS, Chla and CDOM. My goal is to address this gap in the literature and put forth a comprehensive algorithm that addresses all these factors.

Jessica Jagelski

Efforts to Complete the Horsehair Worm (C. morgani) Life Cycle: Exploring the Relationship Between Wood Roaches and Mayflies.
J. Jagelski , J. Shea*, C. Brockhouse*
Department of Biology, Creighton University

Full Poster

The horsehair worm, Chordodes morgani (C. morgani), is a parasite that resides in Nebraskan waters. C. morgani plays an important role in ecology, but scientific knowledge of its life cycle remains incomplete. The known life cycle consists of an aquatic host, such as a mayfly, which transfers C. morgani to a terrestrial host, like a wood roach. While it is known that wood roaches can contract C. morgani, it is unclear how this occurs. In the laboratory setting, wood roaches can consume mayflies and contract C. morgani, but it is unresolved whether this predatorily pathway occurs in the wild. Discovering the truth of this relationship brings scientists one step closer to completing the life cycle of C. morgani. Scrutinizing the wood roaches’ diet may reveal the C. morgani life cycle. It is possible to determine whether mayflies are part of the wood roaches’ natural diet through eDNA analysis of gut contents of a wood roach. This process will include isolating mayfly mitochondrial DNA (mtDNA) from DNA isolated from woodroach gut contents, amplifying it through a PCR assay with species-specific primers, then sequencing the PCR products for identification.

Noah Powell and Kollyn Weimer

Examining RNase for Host Defense Capability.
D. Law*, N. Powell*, K. Weimer*, S. Cho*
*Department of Biology, Creighton University

The RNase A superfamily is a group of proteins that was believed to simply cleave RNA. However, in recent years it has been discovered that certain human RNases have immune functions. We then started to ask if RNases in other organisms had this function as well. Before we can start this research, a control was needed. After some research we chose human RNase 1, 3, and 5 as the controls we will use. Each of these controls will be used for a separate phase of testing. RNase 1 is a protein known to degrade RNA effectively. RNase 3 has known immune function. RNase 5 does neither, so it was used as a negative control. After isolating and creating a plasmid with the human genes, we then used two E. coli  strains to generate these proteins. These proteins will be used as a standard for comparison with alternative RNases from varying species.    

Luke Klahs, Julie Srail and Caleb Williams

Analysis of pollen tube growth in pondweed (Stuckenia pectinata)
J. L. SrailC. WilliamsL. KlahsE. C. Baker, and M. Taylor
Department of Biology, Creighton University

Pondweed (Stuckenia pectinata) is in the minority of angiosperms that exhibit hydrophily, or water pollination. Despite this rare pollination syndrome, pondweed is an extremely common freshwater plant, causing the lack of literature on its reproductive ecology to be more striking. In this experiment we pollinated pondweed by hand in the greenhouse and collected samples at 15-minute consecutive timepoints. Then we observed the flowers under a UV microscope. Next, we measured pollen tube length to calculate pollen tube growth rate. We also recorded ovule entry to determine time to fertilization.  This investigation will give us critical information about the reproductive ecology of this ubiquitous and unique angiosperm.   

Marie Day

The Relationship Between Dental Modifications and Dental Pathologies in the Classic Period Maya
M. Day and E. Blankenship-Sefczek
Department of Cultural and Social Studies

Dental modification is a sign of cultural identity and can be associated with higher status. Ultimately, this may manifest as comparatively better oral heath in individuals with modification than those without. However, despite overall better oral health, modifications could affect caries formation and dental attrition. This study looked at Classic period Maya individuals (n=42) from high, middle and lower status. I predicted that modification-affected teeth would exhibit more caries and attrition compared to non-modified teeth. Type and location of dental modification, caries and dental attrition were recorded following standard protocol. Results show that prevalence of modification is not different between social groups. Despite the presence of caries and attrition in all social groups, modified teeth did not show differences in prevalence or severity. Contrary to predicted, our findings suggest that in this population, modification did not differentially affect the presence and severity of caries and attrition.   

Kollyn Weimer

Examining RNase for Host Defense Capability.
D. Law*, N. Powell*, K. Weimer*, S. Cho*
*Department of Biology, Creighton University

The RNase A superfamily is a group of proteins that was believed to simply cleave RNA. However, in recent years it has been discovered that certain human RNases have immune functions. We then started to ask if RNases in other organisms had this function as well. Before we can start this research, a control was needed. After some research we chose human RNase 1, 3, and 5 as the controls we will use. Each of these controls will be used for a separate phase of testing. RNase 1 is a protein known to degrade RNA effectively. RNase 3 has known immune function. RNase 5 does neither, so it was used as a negative control. After isolating and creating a plasmid with the human genes, we then used two E. coli  strains to generate these proteins. These proteins will be used as a standard for comparison with alternative RNases from varying species.    

Jackson Snyder

Alteration of behavior in aquatic snails due to larval infections of Paragordius varius
J. Snyder*
*Department of Biology, Creighton University

Paragordius varius is a hairworm species that parasitizes multiple hosts. When fully grown in the terrestrial, definitive host, the hairworm can manipulate the behavior of its host, causing them to enter aquatic environments where the fully developed worms can emerge and mate and lay eggs. When these eggs hatch, the larvae encyst in a paratenic host that will transfer the hairworm’s cyst stage from the aquatic to the terrestrial environment. Typically, this paratenic host is an aquatic insect, but cysts are commonly found in aquatic snails (Physa sp.). This study asks if aquatic snails can serve as a paratenic host for P. varius by comparing the behavior of infected and uninfected snails in a 20-hour period. If hairworms manipulate the behavior of their paratenic host to facilitate their transmission to the terrestrial environment, then infected snails will spend more time above the water line than uninfected snails. If aquatic snails can serve as a paratenic host for P. varius, then this will represent another example of parasite manipulation of the host to facilitate the parasite’s life cycle.

Eli Blaney

Comparing machine learning algorithm predictions of protein functional relationships
E. Blaney, S. Cho
Department of Biology, Creighton University


Protein-protein interactions have been discovered and digitally collected over time, giving rise to large collections of protein data. Machine learning algorithms can be fed structural and relational information about pairs of proteins to predict the strength of arbitrary protein relationships from their structural data. However, various machine learning approaches can perform very differently, and inefficiencies can cause significant setbacks in research. By assessing the viability of several classification algorithms trained on this protein data, each algorithm can be studied to find potential enhancements that can lead to more accurate and consistent predictions.

Amanda Cohen and Alexandria Jones

Simon Says... Jump! The neural manipulation of crickets by their parasites
Amanda Cohen, Allie Jones, Amy Worthington
Department of Biology, Creighton University


Parasites are able to significantly change the physiology and behavior of their hosts to benefit their own growth and survival. Exactly how parasites are able to control the complex behaviors of another organism is not fully understood, despite being a fairly ubiquitous characteristic of most host-parasite relationships. I propose investigating and then manipulating the neural mechanisms of host behavior-manipulation by focusing on the bizarre host-parasite relationship between the sand field cricket (Gryllus firmus) and the horsehair worm (Paragordius varius). I will use High Performance Liquid Chromatography (HPLC) to quantify the levels of two vital neurochemicals that modulate cricket behavior (octopamine and serotonin) in the brains of healthy and infected crickets at two critical timepoints of the host-parasite interaction (host sexual maturity and parasite emergence from its host). Using the proposed experiment, I will: 1) determine if there is a correlation between parasitic horsehair worm infection and the alteration of important neural signaling molecule levels in the host’s brain; and 2) identify whether predictable alterations in brain chemistry align with the two critical timepoints in the host-parasite interaction when the most dramatic behavioral manipulations occur; This research will further the understanding of parasites and how they manipulate their hosts’ behavior to their own benefit.

Krista Chang

Do patterns of fluctuating asymmetry reflect the strength of natural and sexual selection in the sand cricket?
K. Chang, M. Whalen, G. Rivera, and A.M. Worthington
Department of Biology, Creighton University


Rationale: Natural and sexual selection can shape morphologies to increase individual performance, and the degree of symmetry has shown to impact the functionality of paired traits. As a result, traits vital for locomotion or reproduction may rely more heavily on overall symmetry to remain functional than other non-vital structures. Fluctuating asymmetry (FA) refers to deviations from perfect symmetry in bilateral structures and may serve as a useful tool in evaluating the strength of selection acting on individuals. In the sand cricket (Gryllus firmus), two distinct morphs with unique life histories exist: Short-wing (SW) and Long-wing (LW). Because the two morphs and the two sexes rely on different structures to maximize fitness, we expect to see predictable differences in FA between morphs and sexes.Methods: Four groups of crickets were reared, frozen, and processed: LW male, LW female, SW male, and SW female. Various bilateral structures were extracted, measured, and analyzed for bilateral differences and relative levels of FA. Results and Conclusion: Data analysis is not yet complete, but primary results are inconclusive; they show significant variations in fluctuating asymmetry across the different groups, but not in the ways we expected.

Karis Choy and Monroe Pruett

Are Monarch Butterflies Pollinators?
Monroe Pruett, Dr. Mackenzie Taylor, Dr. Theodore Burk, Karis Choy, and Jenn Omann
Department of Biology, Creighton University

Presentation Video

Monarch butterflies, Danaus plexippus, are a well-known species of butterfly due to their beauty and unique migration, of some populations, from Mexico to the Midwest regions in North America and Canada. Monarch butterflies are at risk due to human interference. Along with the declining population of monarch butterflies, the environmental impact monarchs have in their surrounding ecosystems is at jeopardy, including the possibility of monarchs being crucial pollinators in prairie ecosystems. ​It is unknown if monarchs are successful pollinators or skillful nectar thieves. There is little published research on pollination by monarchs. My methods will provide compelling data to address the question: Are monarchs pollinators? In Summer 2020, I have investigated the question of whether monarchs in the field are carrying pollen and if so, where on the butterfly they carry pollen. This is important because where the butterflies carry pollen will tell me how they pollinate. I also collected pollen from each species of flower in the prairie to create a pollen record for Glacier Creek Prairie Preserve.

Armond Isaak

Determination of lysine acetylation susceptibility of DksA in Borrelia burgdorferi
A. Isaak, W. Boyle*, H. Sorenson*, T. Bourret*
*Department of Medical Microbiology and Immunology, Creighton University School of Medicine


For successful completion of its infectious cycle, the Lyme disease spirochete Borrelia burgdorferi must overcome a wide range of environmental stresses. B. burgdorferi harbors a limited repertoire of gene regulatory proteins and the molecular mechanisms underlying their ability to directly respond to environmental changes remain enigmatic. Recently, we described the role for the DnaK suppressor protein (DksA) in the regulation of B. burgdorferi gene expression that is in accord with its role in coordinating the stringent response upon encountering environmental stresses. Many proteins were identified as targets of lysine acetylation by acetyl-phosphate during in vitro growth. Lysine acetylation is a reversible post-translational modification (PTM) that contributes to the regulation of virulence gene expression in bacteria pathogens. In silico analysis of B. burgdorferi DksA suggests that five lysines located in the C-terminus are likely targets for acetylation. The objective here is to determine the susceptibility of DksA to lysine acetylation and characterize its impact on the gene regulatory activity required for B. burgdorferi to complete its infectious cycle. Therefore, the hypothesis that DksA-dependent gene regulatory activity is modulated by lysine acetylation will be tested.

Alexandria Jones

Mischief Managed: How Parasites Manipulate Their Hosts
A. Jones, A. Cohen, and A.M. Worthington
Department of Biology, Creighton University


Parasites have evolved impressive manipulative mechanisms to maximize their fitness. Using male sand field crickets, Gryllus firmus, I will identify major behavioral and neural changes of crickets infected with the long-lived parasitic horsehair worm, Paragordius varius, at critical timepoints in this host-parasite interaction. During early developmental stages, both prioritize survival, resource acquisition, and growth. Upon cricket maturity, however, crickets shift their behaviors to maximize reproductive fitness, subsequently risking parasite survival. The parasite manipulates its host to minimize such behaviors and ensure optimal emergence environment. I will perform behavioral assays (courtship calling, aggression, locomotion, water-seeking) to analyze host manipulation by the parasite and analyze neurotransmitter levels in the cricket’s brain at two critical time points in this host-parasite interaction. By linking modified behaviors of infected cricket to manipulated neurotransmitter levels, I will explore the causal neurological mechanisms leading to host behavioral manipulation during critical time points of an intricate host-parasite interaction.

Lindsey Theut

Synthesis and antimicrobial evaluation of 1,2,3-triazole containing phenanthridines.
L.R. Theut and J.T. Fletcher
Department of Chemistry, Creighton University

Presentation Video Slides

1,3,4-Trisubstituted-1,2,3-triazolium salts have been shown to possess antibacterial and antifungal properties, though these properties vary depending on the substituents utilized. This project’s aim was to compare the antimicrobial properties of ring-fused 1,2,3-triazolium salt analogs representing the 1,2,3-triazole-containing phenanthridine ring system to their analogous non-fused triazolium salts. 1,5-Disubstituted-1,2,3-triazoles were prepared from a base-catalyzed click reaction between terminal alkyne and aryl azide reactants. The ring-fused 1,2,3-triazole-containing phenanthridine analogs were prepared by an intramolecular Pd-catalyzed cross-coupling “fusion” reaction of 2-bromoaryl-substituted triazole precursors. Triazolium salts were prepared by N3 benzylation of each analog, which were screened for antimicrobial properties using a microdilution minimum inhibitory concentration assay against Gram-positive bacteria, Gram-negative bacteria and yeast. Analogs possessing 4-tert-butylbenzyl substituents at the N3 position had the strongest antimicrobial potency, and fused-ring chloro-substituted analogs were significantly more potent than their non-fused counterparts. Details regarding the synthesis, characterization, and antimicrobial assays of these compounds will be presented.

Nicole Haen

Investigation of age-related patterns of immune function in honeybees
N. Haen, C. Fassbinder-Orth
Department of Biology, Creighton University

Presentation Video

Colony Collapse Disorder (CCD) is an abnormal phenomenon where a large number of worker bees disappear from the colony leading to abrupt colony loss. The aging process of worker bees directly relates to the longevity of the colony and its health and can be measured through the use of various physiological parameters that change with age. One example is the phenoloxidase system, which is an important defense found in invertebrates leading to the melanization of pathogens. To better understand the age-related patterns of honeybees we investigated their immune function through a phenoloxidase assay. Pupae, Hatchling, Nurse, Guard, Forager, and Drone age classes of Honeybees were collected from different hives. The thoraxes of each bee were weighed and homogenized in PBS. We then measured and normalized the phenoloxidase activity. Young honeybees, larvae and hatchlings, showed a limited amount of phenoloxidase activity. The young adult honeybees, nurses and guards, showed a 1580% increase in phenoloxidase activity. As the honeybees age to foragers and drones, the level of phenoloxidase activity decreases by 26% and 78% respectively. Our results suggest that phenoloxidase is closely related to the age of the working class of honeybees.

George Borkovich and Jacob Meyer

Nicotine dose modifies the effects of environment on drug discrimination.
Hanson, T., Kellerman, K., Holter, K. Meyer, J., Okelberry, H., Borkovich, G., Bever, K. and Stairs, D.J.
Department of Psychological Science, Creighton University

Presentation Video

This study investigated whether the effects of environmental enrichment are altered with different training doses of nicotine in a drug discrimination paradigm. Isolated rats (IC) and Enriched rats (EC) were trained to discriminate saline from either a 0.2 or 0.4 mg/kg training dose of nicotine. Following acquisition, lower doses of nicotine were substituted to determine the level of nicotine generalization. Next, doses of varenicline were substituted. Finally, methamphetamine’s ability to substitute for nicotine was tested. IC rats met acquisition criterion faster compared to EC rats. The 0.4 mg/kg dose of nicotine led to faster acquisition compared to the 0.2 mg/kg nicotine dose. Results from the nicotine generalization curves showed no effect by training dose or enrichment. Varenicline showed greater nicotine substitution in EC rats, although with the 0.2 mg/kg training dose, both EC and IC rats displayed a trend to greater levels of varenicline substitution. Methamphetamine partially substituted for both doses. Methamphetamine substitution was higher in IC rats only when the animals were trained with the 0.2 mg/kg nicotine dose. Data indicated that the training dose of nicotine can differentially alter acquisition of nicotine drug discrimination and the ability of different drugs to substitute in EC and IC rats.

Karis Choy and Adam Wilson

Reproductive Ecology of Stuckenia pectinata
A. Wilson, M. Pruett, N. Lamsal, K. Choy, and M. Taylor*.
*Department of Biology, Creighton University

Presentation Video

Water-pollination, or hydrophily, occurs when a flower releases pollen that then floats along the water’s surface to the stigma of a flower. Water-pollination is a rare method of pollen transfer demonstrated in a handful of flowering plant families. Hydrophilous plants provide food and habitat, but also attenuate waves and are primary producers in aquatic environments. Despite the key roles that hydrophilous plants fulfill within ecosystems, information about hydrophilous traits is lacking, especially regarding the development of pollen after it arrives at a flower. Such information is key to understanding the reproductive consequences of a shift from a terrestrial environment to an aquatic environment. Post-pollination development is shaped by selection on pollen and carpel traits, including those that determine the ability of flowers to self-pollinate and pollinate other flowers. To obtain information about water-pollination, Stuckenia pectinata was examined to characterize stigma receptivity, pollen load, seed set, and its ability to self. Water-pollination is discussed regarding its efficiency and traits that allow it to be a viable pollen transfer mechanism.

Matt Lawler and Russell Lee

Environmental factors affecting the emergence of Chordodes morgani and host growth in Parcoblatta fulvescens
M. Lawler, R. Lee, J. Shea
Department of Biology, Creighton University

Presentation Video Slides

The horsehair worm, Chordodes morgani, deposits its eggs on submerged branches. Through semi-aquatic hosts, such as the mayfly, C. morgani cysts make their way on land where wood roaches (Parcoblatta fulvescens) consume them. During laboratory study, C. morgani took about 70 days to emerge from roaches. In the field, we only found horsehair worms in July, suggesting either that roaches were infected two months earlier or that infection is stalled throughout the year. However, lab conditions do not replicate field conditions, specifically temperature and food availability. Our preliminary study found that growth rate of infected roaches was greater than sham-infected roaches (p<0.01). We sorted roaches into four categories: normal-starved, normal-fed, cold-starved, and cold-fed. Each category consists of at least five exposed to C. morgani cysts and at least two sham-infected. Roaches were individually housed with bark and a moistened cotton ball. Fed roaches received cat food. Cold roaches were kept in a 4 degree Celsius refrigerator. All roaches were measured for length weekly. After 8 weeks, we will submerge roaches weekly to test infection. We predict that normal-fed roaches will have the fastest rate of emergence and highest growth percentages. Results will help us predict the field life cycle of C. morgani.

Emily Fraser

Morphology and Decline of Achatinella
E. Fraser and A. Kraemer
Biology Department, Creighton University


Human activity has impacted nearly every terrestrial environment on the planet, which has led to the decline and extinction of many species. This study seeks to understand the relationship between species extinction and the decline of morphological diversity, with a particular focus on the endemic Hawaiian tree snails, subfamily Achatinellinae. Tree snails are valuable species to study because they are highly susceptible to changing environmental conditions. This role as indicator species may help us predict how other species may react to continued environmental change. The proposed research contains the following objectives: 1) collect morphological data on Achatinella shells and 2) determine what morphological variation (including shape, color, and pattern) have been lost in the last century. Preliminary data shows a shift in the trajectory of morphological decline around the year 1960, shortly after a new snail predator was released in Hawaii. This study demonstrates that the loss of species diversity in ecosystems is only part of the story, and that we must also consider the unique attributes of the species being lost to understand the full impact of extinction.

Rasika Mukkamala

Regulation of fibrotic marker genes in primary human lung fibroblasts from Idiopathic Pulmonary Fibrosis and control patients
Rasika Mukkamala1,2, Tammy Trudeau3, Oliver Eickelberg3
1Webb-Waring Center, University of Colorado School of Medicine,2Creighton University, College of Arts and Sciences, Omaha, Nebraska 3Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado-Anschutz Medical Campus, Aurora, Colorado

Idiopathic Pulmonary Fibrosis (IPF) is a chronic pulmonary disease that affects the cellular composition of the lung, through extensive scarring and increased amounts of secreted extracellular matrix. IPF currently has no known cause or cure. 1 Fibroblasts are a type of connective tissue that is involved in the production of extracellular matrix proteins and produce collagen. These cells are known to be in higher concentrations in fibrotic lung diseases, including IPF.1A recent published paper from Croft et. al suggests that there are two subsets of fibroblast activation protein (FAP) in inflammation or tissue damage in arthritis. FAP+THY+, resulted in a more severe inflammatory arthritis, whereas, FAP+THY- mediated bone and cartilage damage with little effect on inflammation. These distinct fibroblast subsets will be identified in lung fibroblasts through the techniques of western blot, qPCR, and immunofluorescence. 3,4 The hypothesis for this experiment is that: Fibroblasts with Idiopathic Pulmonary Fibrosis will produce more FAP than the control fibroblasts. Our conclusions found that Fibroblasts with Idiopathic Pulmonary Fibrosis produce less or equal amounts of FAP as the control fibroblasts do.

Anne Marie Backer and Matthew Pon

Evaluation of a Nanoparticle Formulation as a Blood Brain Barrier Antiretroviral Drug Vehicle and Treatment
Matthew Pon1, Anne Marie Backer1, Andrew Kochvar1, Subhra Mandal2, Christopher Destache2, Annemarie Shibata1
1Department of Biology, 2School of Pharmacy and Health Professions, Creighton University

Despite combination antiretroviral therapies (cART)’s reduction of HIV infections and AIDS-related deaths, there are several cART challenges. This includes HIV associated neurocognitive disorder (HAND), arising from low viral replication within the CNS, and patient discontinuation due to aversive side effects. Dolutegravir (DTG) is an HIV integrase inhibitor, showing low viral mutation rates, but also high patient discontinuation due to drug-induced neuropathies. We are investigating modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles’ potential as a trans-blood-brain barrier vehicle for efficient and less cytotoxic DTG delivery. We propose human holo-transferrin-conjugated(hhTf) PLGA-DTG-NP may reduce drug cytotoxicity and have observed NP entry into CNS cells. We observed increased viability using DTG NP in CNS cell lines when compared to DTG solution at the same concentrations. Viability in NP treated SHSY5Y neurons was >20% higher than in solution treatments at 24hr and 48hr but not at 96hr between 10, 1, 0.1, 0.01 ug/mL. Between solution and nanoparticle treatments, BV2 microglia showed >50% higher viability at 24hr and 48hr at tested concentrations and by 20% at 96hr below 1ug/ml. Preliminary ELISA assays showed no significant release of inflammatory cytokines IL-6 and TNF-alpha between conditions in SHSY5Y. RTPCR analysis for inflammatory cytokine production between treatments are on-going.