Life Sciences Commons^™

Investigating The Role Of Tryptophan In The Native Photo-Crosslinking Of A Cys-Containing Transmembrane Helix To A Membrane Lipid Double Bond, Michael Jay Telehany

Undergraduate Honors Theses

Our research group has previously discovered that a Cys residue within a transmembrane (TM) helix can directly photo-crosslink to a membrane lipid via an oxythiolation addition reaction to the double bond within the lipid, with a reaction yield of 10-20%. The pH-low Insertion Peptide (pHLIP) serves as our model TM helix, while the POPC lipid bilayer is our model membrane. We had long believed that the Trp residues within the sequence of pHLIP served as the key chromophore for this reaction, and thus they were essential for the formation of the TM helix-lipid adduct. To test this hypothesis, I synthesized …

Nicotinamide Riboside And Beta-Hydroxybutyrate Activate Parallel Pathways For C. Elegans Lifespan Extension, Mckenzie Peters

Undergraduate Honors Theses

Supplementation with nicotinamide riboside (NR), a form of vitamin B3 and a precursor of nicotinamide adenine dinucleotide (NAD⁺) extends lifespan in the nematode C. elegans and delays aging-related pathologies in mammals. During aging, levels of NAD⁺ decline causing metabolic dysfunction and oxidative damage. Studies in C. elegans found that when NR was administered during larval development it induced the mitochondrial unfolded protein response (UPR^mt), which is frequently associated with lifespan extension. Both calorie restriction (CR) and ketogenic diets (KD) have been shown to extend lifespan, in part through increasing NAD⁺ and through increasing levels …

Synthesis And Biological Testing Of Small-Molecule Mitochondrial Complex I Inhibitors, Willough Sloan

Undergraduate Honors Theses

This thesis delineates two main projects: the first outlines the structure elucidation efforts toward a Diels-Alder adduct of a novel reaction for the synthesis of chimaphilin, a naphthoquinone-based natural product with apoptotic or antiproliferative activity in certain cancer cells^1,2. The structure elucidation extends to derivatives of chimaphilin synthesized by the same cyclization reaction. While Diels-Alder reactions are usually regioselective, ¹H-NMR and ¹³C-NMR of the adducts was inconclusive and indicated the possibility of regioisomer presence, with one regioisomer being chimaphilin (or derivatives). A multitude of crystallization methods were carried out in order to be able to analyze …

The Regulation Of Atg9a-Mediated Aggrephagy By An Ulk1-Independent Atg13-Atg101 Complex, Joshua Youngs

Undergraduate Honors Theses

Aggrephagy, a type of autophagy, is an essential cellular process by which protein aggregates are collected and broken down in the lysosome. Protein aggregates are implicated in several diseases including Alzheimer’s disease, diabetes, and cancer. Here, we investigate the ATG13-ATG101 protein complex, a sub-complex of the canonical ULK1 complex whose regulatory role in aggrephagy is not completely understood. We also develop a protein fragment complementation (PFC) assay using the biotin ligase TurboID to study the functions of the ATG13-ATG101 complex with increased specificity. We demonstrate that ATG13 is required for optimal degradation of p62-ubiquitin condensates. We also show that a …

The Synthesis Of 3-Formyltyrosine For The Purpose Of In Virto Fluorescent Visualization Of Microtubules, Angelina Bonacasa

Undergraduate Honors Theses

Microtubules and the desire to visualize them has been of utmost importance in understanding the behavior of the cytoskeleton. Even further, scientists are using this knowledge to elucidate cancerous activities as they occur within cells. In order to acquire this knowledge, the following methods have been established: the expression of tubulin after it has been fused with a fluorescent protein, the insertion of tubulin that has been exogenously labeled, and the use of fluorescent-probe conjugated microtubule ligands, such as paclitaxel. These methods, however, tend to distort the protein’s native function, thereby preventing an accurate analysis. This concern drives the need …

Computational Investigation Of Calmodulin Photocontrol With The Help Of An Azobenzene Derivative, Jeremy Wells

Undergraduate Honors Theses

The ability to control the activity and binding capability of enzymes in a reversible manner offers tremendous control over biological processes. Photocontrol, in particular, is promising in that electromagnetic radiation can be fine-tuned in terms of its strength, location, and duration. Photosensitive compounds, such as the azobenzene family, experience an isomerization at certain wavelengths, and attaching these compounds to enzymes has the potential to alter their structure and activity. Calmodulin (CaM) is a Ca2+ -sensitive signaling protein that has the ability to affect several downstream processes in eukaryotes and is an excellent target for photocontrol due to its small size …

Severe Hypoxia Up-Regulates Gluconeogenesis In Daphnia, Morad C. Malek

Undergraduate Honors Theses

Hypoxia is a significant low oxygen state that has complex and diverse impacts on organisms. In aerobes, various adaptive responses to hypoxia are observed that vary depending on the level of oxygen depletion and previous adaptation, hence the continued attention to hypoxia as an important abiotic stressor. Adaptive responses to hypoxia are primarily governed by the hypoxia-inducible factors (HIFs), which activate downstream genetic pathways responsible for oxygen transport and metabolic plasticity. In aquatic habitats, oxygen availability can vary greatly over time and space. Therefore, aquatic organisms’ adaptation to hypoxia is likely pervasive, especially in genotypes originating from waterbodies prone to …

Vitamin D And Its In Vitro Therapeutic Action Mediated Through Vdr Rather Than Pdia3, Jaeden Pyburn

Undergraduate Honors Theses

Brain calcification is a common occurrence in the aging process, with >20% of individuals over the age of 65 showing hardened plaques in the basal ganglia. Loss of the vitamin D receptor (VDR) in transgenic mice leads to formation of calcified plaques in the basal ganglia and thalamus within the mice. Vitamin D signals through two known vitamin D responsive proteins, protein disulfide isomerase A3 (PDIA3) and VDR. In vitro, vitamin D has been demonstrated to suppress calcification in osteoblast-like cells. Here, we aim to elucidate which of either PDIA3 or VDR transduce vitamin D mediated suppression of calcification in …

Glypro As A Self-Immolative Spacer For The Release Of Payloads From Antibody-Drug Conjugates, Justin Michael Howe

Undergraduate Honors Theses

Antibody-drug conjugates (ADCs) are an increasingly popular modality for targeted drug delivery in many oncological and immunological applications. The paratope of a monoclonal antibody (mAb) directs the delivery of a conjugated therapeutic payload to antigen expressing cells, resulting in a controlled transport of payload to a desired cell type. Internalization of the ADC followed by lysosomal degradation results in the release of a payload to perform its biochemical function. A chemical linker between the drug and the antibody is responsible for the stability of the conjugate in circulation alongside mediating the release of an unmodified payload under lysosomal conditions. Currently, …

A Fret Flow Cytometry-Based Screening Assay For Multiplex Analysis Of Metabolites In T. Brucei, Ronald A. Zegarra

Undergraduate Honors Theses

Kinetoplastid parasites are a significant public health issue in some tropical and subtropical regions of the world. Kinetoplastid parasites all require glycolysis for survival, with host glucose key for ATP production. One such parasite, Trypanosoma brucei, exclusively metabolizes glucose in its bloodstream form. Trypanosomal glycolysis is unique because it displays unconventional structural features. Hence, glucose metabolism has been studied extensively in T. brucei and is a therapeutic target in kinetoplastid parasites.The lack of in vivo analytical techniques for measuring vital glycolytic metabolites in situ has restricted the ability of researchers to test, with high sensitivity and specificity, the essential roles …

Exploration Of Fluorinated Α,Β-Dehydroamino Acids And Their Structure, Austin Lesueur

Undergraduate Honors Theses

This thesis explores the synthesis of fluorinated α,β-dehydroamino acids, specifically a fluorinated dehydrovaline derivative. Previous work has been done on the equivalent dehydrovaline derivative without fluorine present and this work builds toward the fluorinated version with the goal of comparing the two structurally. The synthesis presented here pulls from previous synthetic strategies employed for dehydrovaline while also exploring the synthetic impact of the electronegative fluorine atoms.

Proteomic Analysis Of Mycobacteriophage Crimd, William Moeller

Undergraduate Honors Theses

Bacteriophages represent a large portion of the biomatter on our planet, and many of them have yet to be fully characterized. Here we discuss the proteomic analysis of a particular Bacteriophage, Mycobacteriophage CrimD. This phage was discovered on the Campus of William & Mary and has had its genome characterized. We took the next logical step of proteomic analysis.

In our analyses we made use high pressure liquid chromatography paired with linear ion trap mass spectrometry to analyze the proteome of CrimD at specific time points after the infection of its host, Mycobacterium smegmatis. Additionally, we used nanospray ionization with …

Telsam-Target Protein Fusions Can Form Diffraction-Quality Crystals Without Direct Inter-Polymer Contacts, Moriah Longhurst

Undergraduate Honors Theses

X-ray diffraction is a robust method for determining the detailed 3D structures of specific proteins. However, this requires the formation of well-ordered protein crystals, a process that is time-consuming, expensive, and only has about a 10-30% success rate. New methods are needed to enable the efficient crystallization of challenging proteins. One such technique is explored here, which utilizes a protein polymer (the sterile alpha motif domain of the human protein translocation Ets leukemia, or TELSAM) as a crystallization chaperone to form a more ordered crystal lattice of target proteins and drive crystallization. This method was successfully used to crystallize, collect …

Building An Ins-1 Cdna Library For A Genome-Wide Crispr-Cas9 Screen, Idongesit Ekpo

Undergraduate Honors Theses

By the year 2040, an estimated 642 million people are expected to have diabetes globally. Diabetes results from an elevation of metabolic stressors, such as glucotoxicity, lipotoxicity, oxidative stress and apoptosis. In type 2 diabetes, these stressful conditions contribute to the malfunction and loss of functional insulin-producing β-cells. Current treatment methods for diabetes include insulin therapy, islet transplant and anti-diabetes medication. These treatments are not curative and ignore other factors that contribute to the pathogenesis of diabetes beyond insulin resistance and islet β-cell failure. Previous research on β-cells has focused on ways to replace functional β-cell mass, trigger β-cell proliferation, …

Therapeutic Drug Monitoring Of Apixaban Using Chromogenic Kits, Brooke Vogel

Undergraduate Honors Theses

Apixaban is a novel oral anticoagulant that prevents clotting by directly inhibiting Factor Xa in the coagulation cascade. Due to its different pharmacokinetics, previous standards for testing anticoagulant concentrations are ineffective at measuring apixaban. In this study, Hyphen Biomed Biophen Direct Xa Inhibitor and Biophen Heparin chromogenic kits from Aniara Diagnostica were used along with a NanoDrop™ One/One^C Microvolume UV-Vis Spectrophotometer to see if either of these kits provide acceptable precision and accuracy for the quantification of apixaban in plasma samples, as well as if there is a significant difference in these two kits at varying concentrations of apixaban. …

Modification, Verification Of Sequence And Optimization Of Expression Of P297f An Inactive Mutant Of Flavonol Specific Glucosyltransferase From Grapefruit (Cp3gt), Sarah Fox

Undergraduate Honors Theses

Citrus fruits are widely consumed and can offer various health benefits. One enzyme found in grapefruits, Citrus paradisi flavonol specific 3-O-glucosyltransferase (CP3GT), catalyzes the addition of glucose to one specific flavonoid class and at only one site. These flavonoids are plant secondary metabolites that can be used in a variety of plant functions including signaling and protection. The only class of flavonoids that CP3GT glucosylates is flavonols, and this specificity is of interest to study for potential benefits in biotechnology and enzyme modeling. In order to study this enzyme and its structure, a variety of mutants were created using site-directed …

Effects Of Nicotinamide Riboside And Beta-Hydroxybutyrate On C. Elegans Lifespan, Jeffery Peters

Undergraduate Honors Theses

The nicotinamide riboside (NR) form of vitamin B₃and the ketone body ß-hydroxybutyrate (BHB) are two of the most promising natural compounds yet identified for the treatment of aging and aging-related diseases. Forms of vitamin B₃are precursors for the synthesis of the coenzymes nicotinamide adenine dinucleotide (NAD(H)) and nicotinamide adenine dinucleotide phosphate (NADP(H)). In aged cells levels of NAD⁺decline, decreasing metabolism and decreasing activity of protective sirtuin protein deacetylases. In aged cells NR, but not more common forms of vitamin B3, boost NAD⁺levels. BHB is naturally produced by the body when individuals fast …

Subcellular Localization Of Tobacco Sabp2 Under Normal And Stress Conditions, Sanjeev Das

Undergraduate Honors Theses

Subcellular Localization of Tobacco SABP2 under Normal and Stress Conditions

Salicylic acid (SA), a phytohormone, plays an important role in plant physiology. SA mediated innate immune pathway is an important pathway for plant immunity against pathogens. Plants resisting pathogen infection synthesize higher levels of Methyl Salicylate (MeSA), which is then converted to SA by the esterase activity of Salicylic Acid Binding Protein 2 (SABP2). The high level of the converted SA leads to enhanced pathogen resistance. The study of subcellular localization of a protein is critical in explaining its potential biochemical functions. SABP2 tagged with eGFP was expressed transiently in …

Electrophysiological Characterization Of The Inhibitory Effects Of 2-Amino-4-Bis (Aryloxy Benzyl) Amino Butanoic Acids On Alanine Serine Cysteine Transporter 2 And Sodium Coupled Neutral Amino Acid Transporter 2, Paul Serguei Zakrepine

Undergraduate Honors Theses

Alanine Serine Cysteine Transporter 2 (ASCT2) is a member of the solute carrier 1A (SLC1A) family of transport proteins. It is a Na+ dependent, obligatory neutral amino acid exchanger with the capability to transport glutamine and it is a primary glutamine transport protein in cancer cells. This glutamine transport capability confers an important physiological role for ASCT2 in the maintenance of intracellular amino acid pools for various metabolic and cell signaling pathways. Because of this, ASCT2 is found to be overexpressed in many cancers, which rely heavily on glutamine as an essential nutrient for cell survival and growth. A wealth …

Optimization Of Adc Linkers: Design And Evaluation Of A Fret-Based Adc Linker-Library, Jared T. Miller

Undergraduate Honors Theses

Success of Antibody-drug conjugates (ADCs) relies on the maintained integrity of a chemical linker fusing a therapeutic payload to a monoclonal antibody. Recent reports have revealed the lead linker ValCitPABC has poor stability in rodent models compared to mammalian counterparts, resulting in many clinical investigations predicting poorer ADC efficacy due to premature payload release in these model systems. Optimization of this chemical linker to be resistant both in mouse and human models would streamline ADC progression into clinical trials. Herein we describe the synthesis and development of a FRET-based assay for evaluating linker stability in vitro. Evaluation of lysosomal release …

The Chelation Of Metal Ions By Vicibactin, A Siderophore Produced By Rhizobium Leguminosarum Atcc 14479, Joshua Stinnett

Undergraduate Honors Theses

Vicibactin is a small, high-affinity iron chelator produced by Rhizobium leguminosarum ATCC 14479. Previous work has shown that vicibactin is produced and secreted from the cell to sequester ferric iron from the environment during iron-deplete conditions. This ferric iron is then transported into the cell to be converted into ferrous iron. This study uses UV-Vis spectroscopy as well as ion trap-time of flight mass spectroscopy to determine that vicibactin does form a complex with copper(II) ions, however, at a much lower affinity than for iron(III). Stability tests have shown that the copper(II)-vicibactin complex is stable over time. The results of …

Synthesis Of Candidate Natural Killer T Cell Ligands, Teron Haynie, Shenglou Deng, Paul B. Savage

Undergraduate Honors Theses

Natural Killer T (NKT) cells are a subset of T cells that express an invariant T cell receptor (TCR) that recognizes lipid antigens in context of the CD1d molecule. CD1d presents both exogenous and endogenous glycolipids on the surface of antigen presenting cells (APCs). Multiple exogenous lipids capable of NKT cell stimulation have been characterized, but confirmed endogenous ligands are relatively few in number. Recently, a-galactosylceramides were shown to be endogenous NKT cell ligands. We have observed that a-galactosylceramides cyclize in acidic conditions. Since the biosynthetic pathway of lipid presentation via CD1d likely passes through the acidic lysosome, we propose …

2d Nmr Structural Study Of A Dna Duplex Containing Two Unnatural Base Pairs, Weston Preising

Undergraduate Honors Theses

DNA is the genetic blueprint responsible for the traits of living organisms. The "genetic alphabet" consists of four molecules called nucleobases, represented by the letters A, T, G, and C strung together in a "strand." A DNA duplex consists of two "strands" held together such that A is across from T and G across from C, referred to A-T and G-C "base pairs". Recently, the genetic alphabet or code has been expanded by synthetic biologists in an effort to unveil new insights to the machinery of DNA replication, and potentially develop new medicines to cure diseases like HIV. The new …

Determination Of The Substrate Specificity Of Citrus Paradisi Flavonol Specific 3-O-Glucosyltransferase Mutant D344p, Nathan R. Spaulding

Undergraduate Honors Theses

Plants produce a vast array of secondary metabolites. A group of phenolic compounds, the flavonoids, are metabolites ubiquitous among plants and are known to aid in processes such as plant reproduction, UV defense, pigmentation and development. In relation to human health, flavonoids have been found to possess anti-inflammatory, anti-cancer, and antioxidant properties. Flavonoid’s ability to participate in so many interactions is due in part to their subclass variation and further chemical modification. One such modification is glucosylation, where a glucose molecule is added to the flavonoid substrate. The enzymes that catalyze these reactions are known as glucosyltransferases (GT). Citrus paradisi …

The Effect Of R382w Mutation On Citrus Paradisi Flavonol Specific 3-O-Glucosyltransferase, Kathleen King

Undergraduate Honors Theses

Flavonoids are a class of plant metabolites with C6-C3-C6 structure responsible for many biological functions, including coloration and defense. Citrus paradisi, grapefruit, contains a wide variety of flavonoids which are grouped by the extent of modification, examples of which are flavonols, flavones, and flavanones. A major modification is the addition of glucose by glucosyltransferases (GTs) to stabilize the structure and provide ease of transport. Glucosyltransferases can be highly substrate and regiospecific. With Cp3OGT, glucose is added at the 3-hydroxy position. This 3GT only accepts flavonols as its substrate; however, a Vitis vinifera (grape) 3-GT can accept both flavonols and …

In Vitro Investigation Of The Effect Of Exogenous Ubiquitin On Processes Associated With Atherosclerosis, Chase W. Mussard

Undergraduate Honors Theses

Atherosclerosis, characterized by the build-up of cholesterol, immune cells and cellular debris within arterial walls, is accelerated following myocardial infarction by poorly understood mechanisms. Ubiquitin, a small, well-studied intracellular protein involved in protein turnover via the proteasome pathway, has recently been shown to exert extracellular effects on cardiac myocytes, in vitro, and in mice undergoing myocardial remodeling. This study investigates the potential role of extracellular ubiquitin in atherosclerosis by determining its effects on two critical atherosclerotic processes: the migration of vascular smooth muscles cells and the uptake of modified LDL by monocyte/macrophages in foam cell formation. In the presence …

Identification Of N-Acylethanolamine Hydrolyzing Enzyme In Solanum Lycopersicum, Derek A. Stuffle

Undergraduate Honors Theses

N-acylethanolamines (NAEs) are fatty acid derivatives that occur naturally in plant and animal systems. In mammals, they regulate physiological functions, including neurotransmission, immune responses, vasodilation, embryo development and implantation, feeding behavior, and cell proliferation. NAEs are metabolized by fatty acid amide hydrolase (FAAH), which belongs to the amidase signature family. It is hypothesized that putative FAAH functions as the catalyst in the metabolism of N-acylethanolamine in tomato plants. To test the hypothesis, FAAH protein homologs were identified in tomato via in silico analysis. Among the six homologs identified, FAAH1 and FAAH2 were selected for further validation. This study …

Genetic Variation In Long-Term And Short-Term Physiological Changes In Daphnia Magna During Acclimation To High Temperature, Bret L. Coggins

Undergraduate Honors Theses

The aquatic zooplankton crustacean Daphnia magna must be able to tolerate thermal stress in order to survive their native shallow ponds that are susceptible to drastic seasonal and diurnal temperature fluctuations as well as to globally increasing temperatures. Survival in such variable environments requires plastic responses that must include fundamental aspects of Daphnia biochemistry and physiology. Adaptive response to selection favoring such plastic phenotypes requires the presence of genetic variation for plastic response in natural populations. Adverse effects of elevated temperature on aquatic organisms are diverse and so are their plastic responses; among the most severe challenges aquatic organisms face …

Venom Peptide Induced Inhibition Of Escherichia Coli Atp Synthase, Sofiya Azim

Undergraduate Honors Theses

ATP is the main cellular energy generated by the enzyme ATP synthase in almost all organisms from bacteria to vertebrates. While malfunction of the ATP synthase complex is responsible for several disease conditions, the enzyme itself can be used as a potent molecular drug target to combat many diseases including microbial infections, cancer, tuberculosis, and obesity. Recent widespread escalation of antibiotic resistant microbes in general and E. coli in particular demands novel alternative approaches to combat microbial infections. Inhibition of ATP synthase by inhibitors such as peptides is known to deprive microbes of required energy, resulting in microbial cell death. …

Expression Of Human Neutrophil Cathepsin G In Pichia Pastoris, Evan T. Perry

Undergraduate Honors Theses

Cathepsin G (CatG), a serine protease found in the azurophil granules of neutrophils, participates in killing engulfed microorganisms. CatG is a poorly understood enzyme, in part because it can only be obtained as mature enzyme purified from human blood, and because it seems to have dual specificity for chymotrypsin-like and trypsin-like substrates. Therefore, yeast Pichia pastoris was used to express immature recombinant human CatG to provide a source of the enzyme free of biohazards and to allow study of its dual specificity and C-terminal processing. To avoid potential cleavage by a yeast kexin protease, the amino sequence was modified without …