Between Dec 19, 2024 and Jan 2, 2025, datasets can be submitted to DRUM but will not be processed until after the break. Staff will not be available to answer email during this period, and will not be able to provide DOIs until after Jan 2. If you are in need of a DOI during this period, consider Dryad or OpenICPSR. Submission responses to the UDC may also be delayed during this time.

University Honors Program

Persistent link for this communityhttps://hdl.handle.net/11299/99161

Browse

Browsing University Honors Program by Subject "Biology"

Now showing 1 - 9 of 9
  • Thumbnail Image
    Item
    Chloroplast capture between Clarkia xantiana xantiana and Clarkia xantiana parviflora
    (2022) Suri, Amal M.
    Introgression occurs when genetic material from one gene pool gets incorporated into another gene pool. Introgression of chloroplast genomes is when one species inherits the chloroplast genome of another species, termed chloroplast capture. Understanding introgression can provide invaluable insight into reproductive barriers and speciation. Clarkia xantiana xantiana and Clarkia xantiana parviflora are subspecies that diverged about 65,000 years ago. Subspecies xantiana is an outcrossing species, while ssp. parviflora is a selfing species. We hypothesized that chloroplast capture is likely occurring between the two subspecies in sympatric areas, where they co-occur. In this study, we performed a phylogenetic analysis with about 200 complete chloroplast genomes of the subspecies from 6 different hybrid zones and 16 allopatric sites to determine whether chloroplast capture occurred. Additionally, we sampled more vigorously from 4 sympatric sites, where we then performed Polymerase Chain Reaction on those individuals to determine chloroplast genotype. In accordance with current theory, we found that chloroplast capture was asymmetric such that, chloroplasts flowed mainly from the selfing species, ssp. parviflora, into the outcrossing species, ssp. xantiana. There was, however, notable variation in asymmetry among sympatric populations.
  • Thumbnail Image
    Item
    Death Receptors 4 and 5 and Idiopathic Pulmonary Fibrosis
    (2016) Miller, Scott;
    Idiopathic pulmonary fibrosis (IPF) is an irreversible lethal interstitial lung disease with an unknown cause, killing about 40,000 people per year. In IPF, lung fibroblasts become abnormally activated during tissue repair process, creating excessive scar tissue and avoiding cell death. The results from this research study suggest that the apoptotic pathway mediated by TRAIL (tumor necrosis factor-related apoptotic-inducing ligand) receptors, death receptors 4 and 5 (DR4 and DR5), is aberrant in IPF in the presence of a polymerized collagen matrix. Compared to control fibroblasts, IPF fibroblasts express lower levels of DR4 and DR5, making them more resistant to TRAIL-mediated apoptosis. Furthermore, our study suggests that DR4 may be regulated by the transcription factor FoxO3a. Previous research has shown FoxO3a to be important in conferring an apoptosis-resistant IPF fibroblast phenotype, and these results further support this idea.
  • Thumbnail Image
    Item
    Dopamine binds a D1-D2 heteromer coupled to Gq to activate a phospholipase C dependent mechanism to increase dendritic branching in the developing Medium Spiny Neuron
    (2018-05-04) Pelkey, Lauren, J
    The Medium Spiny Neuron (MSN) composes approximately 95% of the neurons in the striatum in the brain. MSNs are GABAergic neurons that modulate the movement and reward pathways. Cortical and substantia nigra pars compacta neurons release glutamate and dopamine on MSNs, respectively. These inputs are required for the MSN to grow into its typical highly branched, spiny morphology. The Lanier lab found that dopamine increases dendritic branching in the developing MSN. The goal of the current study is to find the mechanism by which dopamine enhances MSN dendritic arborization. The hypothesis is that dopamine increases dendritic branching by binding a D1-D2 heteromer coupled to Gq, which activates phospholipase C (PLC). A striatal-cortical co-culture prepared from day 16 mouse embryos was used to grow MSNs with their afferent cortical neurons. The experimental treatments were: 1) D1 receptor agonist SKF81297, D2 receptor agonist quinpirole, and both SKF81297 & quinpirole, 2) chemogenetic activation of Gq, and 3) PLC antagonist U73122. Treatments were administered in vitro at day 4, and regularly administered until fixation at day 19. It was found that SKF81297 and quinpirole, together and in isolation, were not able to replicate dopamine’s increased branching effect. In addition, it was found that Gq activation, using a chemogenetic approach, resulted in increased branching almost to the same extent as dopamine addition caused. Further, U73122 had no effect on branching on its own, but U73122 significantly attenuated dopamine’s branching effects. Taken together, this data support the hypothesis that dopamine enhances branching by binding a D1-D2 heteromer coupled to Gq, to activate phospholipase C.
  • Thumbnail Image
    Item
    Functional Magnetic Resonance Imaging and Spectroscopy of Ovarian Cancer
    (2013-09-23) Rattigan, Deviney;
    The goal of this study was to determine the feasibility and clinical utility of acquiring quantitative, multi-parametric, high-field Magnetic Resonance Imaging/Magnetic Resonance Spectroscopy for presurgical characterization of normal ovaries, benign and malignant ovarian tumors as well as to assess the response to chemotherapy.
  • Thumbnail Image
    Item
    How Global Change Shapes Our World: Nitrogen and Salt Addition Affect Phytoplankton Morphology in a Small Freshwater Lake
    (2024) Rodgers, Amanda;
    Global environmental change has accelerated the deposition of nitrogen and salt into freshwaters. These changes affect the morphology of freshwater microbes, especially phytoplankton, which serve as primary producers for these ecosystems. Morphology reflects a microbe’s response to energy demands, selection, and environmental disturbance. In this pilot experiment, a handmade suspension device held samples from Cedar Bog Lake (East Bethel, MN) in three nitrogen conditions (17.6 mM NaNO3, 9 mM NaNO3, 0 mM NaNO3) crossed with two salt conditions (10 mM of NaCl or 0 mM of NaCl) plus a DI water control for BG11 media in triplicate on the surface of the lake for three weeks. I used flow cytometry to quantify community-level within-sample morphology using circle fit, area-based diameter (ABD) volume, aspect ratio, elongation, ABD area, compactness, particles/mL, and perimeter. A principal components analysis (PCA) revealed trait correlations between ABD area and ABD volume, and between circle fit, elongation, and compactness. A two-way analysis of variance (ANOVA) on the first three principal components (highly significant, accounting for 94.89% of the total variance) revealed a significant effect of nitrogen and a marginally significant effect of salt on principal component three, but no effect of treatment on the first two principal components. Nitrogen had a significant effect on particles/mL but treatment did not affect any of the other morphological traits individually. These results indicate that climate change has a complicated effect on freshwater microbial morphology at the community level. Future studies should focus on long-term changes in morphology in the field, focusing on the effects of nitrogen.
  • Thumbnail Image
    Item
    The importance of the N13 residue to the activity of the metabolite repair enzyme 2-succino lyase (2SL)
    (2022) Park, Sophia;
    A wide variety of metabolite damage reactions exist alongside long-established biochemical pathways. Succination is a spontaneous damage reaction that can occur between fumarate, an intermediate in the citric acid cycle, and cysteinyl residues of proteins. Succination of cysteinyl residues produces the toxic protein modification S-(2-succino) cysteine (2SC). High cellular levels of 2SC are found in association with mitochondrial stress, diabetes, and cancer, directly contributing to the pathogenesis of human diseases through their various deleterious effects on important metabolic proteins. Recently, a catabolic pathway to repair 2SC damage has been identified in the bacterial species Enterococcus italicus and Dickeya dadantii. The breakdown step in this pathway is performed by 2-succino lyase (2SL), a member of the lyase I-like superfamily of enzymes. The metabolite repair function of 2SL is clear. However, the key active site residues that enable 2SL activity, as opposed to the many other diverse functions of lyase Ilike superfamily enzymes, are unknown. Here we explore the significance of one candidate residue, N13, to 2SL activity by introducing a point mutation (N13I) and comparing the mutant 2SL activity to the wildtype 2SL (WT). A spectrophotometric coupled enzyme assay was performed to determine the kinetic parameters of both the N13I and WT. N13I had a significantly lower Vmax and a significantly higher Km. However, this extreme difference in parameters contradicts the preliminary HPLC data we collected which indicated a much smaller activity difference between the WT and N13I enzymes. We anticipate that the continuation of this research will contribute to the efforts to functionally characterize other lyase I-like superfamily members as 2SC lyases. More broadly, we hope that the characterization of 2SC lyases will uncover their associated—and potentially clinically significant—metabolite repair pathways.
  • Thumbnail Image
    Item
    New Classical Conditioning Models of Drug Use in Mice
    (2018) Katherine, Hill;
    Conditioned Place Preference (CPP) is one of the models most frequently used to study drug use and addiction in animals such as mice and rats. CPP has a number of advantages, including low cost, ease of use and versatility. However, the model also has disadvantages: the novelty confound, difficulty in creating dose-effect curves, and inability to study discrete cues. It is important to determine whether alternate classical conditioning models can eliminate some of the limitations of CPP while maintaining its advantages. Here we did not find conditioned preference to odors. However, we were able to both demonstrate and later eliminate taste aversion. We found that mice did not spend more time investigating a scent after it had been repeatedly paired with morphine. Mice did develop an aversion for flavored food after it had been paired with morphine, which is consistent with previous research. Most importantly, when mice were given repeated injections of morphine to postpone withdrawal, they no longer developed an aversion for flavored food that was paired with morphine. Our results demonstrate that it may be possible to eliminate aversion and possibly even to create a preference for food paired with a drug, despite the fact that previous research has almost exclusively shown taste aversion. Demonstrating the practicability of eliminating taste aversion is the first step in establishing CTP as a viable model for drug abuse. Although more research is needed to further develop the model, CTP could serve as a useful complement or even replacement for CPP.
  • Thumbnail Image
    Item
    A Novel Assay to Study Jagged-1 Trafficking
    (2017) Vadhul, Raghav;
    The Notch signaling pathway is an evolutionarily conserved cell-signaling system that plays an important role in cell differentiation and other processes. Notch signaling is activated when a ligand binds to the Notch protein at the cell surface, thereby initiating a series of events that leads to modification of gene expression. Notch and one of its ligands, Jagged-1, are found at elevated levels in metastatic prostate cancer, indicating that increased Notch signaling is responsible for metastasis of prostate cancer. If Jagged-1 were prevented from reaching the cell surface in the first place, prostate cancer metastasis could be averted. However, more knowledge about the trafficking of Jagged-1 is required to achieve that goal. This study hopes to develop a novel assay that could aid in the study of protein trafficking. A preliminary quantitative assay showed that the manufactured single chain variable fragment antibody bound to the Jagged-1 receptor at the cell surface and exhibited luciferase activity. Another qualitative assay showed that both receptor and antibody could be visualized fluorescently and that the internalization of the antibody could be tracked visually. These experiments will serve as a starting point for more extensive assays which will further optimize these techniques. This knowledge can then be utilized to combat cancer metastasis by blunting the expression of Jagged-1 at the cell surface.
  • Thumbnail Image
    Item
    Regulation of Human HRASI Minisatellite Stability During Stationary Phase
    (2011-12-14) Brosnan, Laura;
    The majority of eukaryotic cells exist in a quiescent state outside of the cell cycle known as stationary phase, or G0. Although quiescent cells are non-proliferating, they retain the ability to reenter the cell cycle. Events such as DNA alterations can take place in stationary phase cells that are associated with a risk for inappropriate reentry into the cell cycle and the development of cancer. Such alterations can occur in repetitive tracts of DNA known as minisatellites. When change in the number or order of minisatellite repeat units occurs, rare alleles of minisatellite tracts may arise. Many of these rare alleles are associated with human diseases, including cancer, diabetes, and epilepsy. Previous work in our lab has demonstrated that certain genes are involved in regulating the stability of a synthetic minisatellite in stationary phase cells. In order to relate these findings to the association between minisatellites and human disease, we inserted the human minisatellite associated with the HRAS1 oncogene into the ADE2 gene of S. cerevisiae to determine how its stability is regulated during stationary phase. Our lab has developed a novel assay for studying stationary phase minisatellite stability in S. cerevisiae. When minisatellites are destabilized and undergo a change in repeat number or order, a novel color phenotype known as blebbing occurs. Blebbing mutants were constructed and we found that the zinc transporter ZRT1, the DNA repair gene RAD27, the checkpoint gene RAD53, the Polε subunit DPB3, and several checkpoint genes (including MRC1, TOF1, CSM3) regulate the stability of the human HRAS1 minisatellite. Upon examination of minisatellite alterations in these blebbing mutants, we saw both expansions and contractions of the minisatellite tract; through further analysis, these alterations were found to be dependent upon homologous recombination.