Digital Commons Network^™

Amylin Structure, Aggregation, And Pancreatic Β Cell Toxicity, Sharadrao Patil

MCB Articles

In most type 2 diabetes patients, amyloid plaques have been found juxtaposed with membranes of pancreatic β-cells. These plaques are composed of amyloid fibrils of the 37 residue endocrine hormone amylin and cause distinct changes in cell membrane morphology associated with the destruction of β-cells. Research is still ongoing to identify the toxic species involved and the mechanisms by which mature fibrils or oligomers cause cytotoxicity. The projects undertaken were designed to study the molecular structural features of amylin, mechanism of amyloid aggregation and, to develop cytotoxicity inhibitors. We determined the structure of human amylin bound to SDS micelles using …

A First Survey Of The Centipedes Of Great Smoky Mountains National Park, Joseph Desisto

Holster Scholar Projects

No abstract provided.

Genome-Wide Analysis Of Drosophila Circular Rnas Reveals Their Structural And Sequence Properties And Age-Dependent Neural Accumulation, Sarah Olson, Brenton R. Graveley

UCHC Articles - Research

Circularization was recently recognized to broadly expand transcriptome complexity. Here, we exploit massive Drosophila total RNA-sequencing data, >5 billion paired-end reads from >100 libraries covering diverse developmental stages, tissues, and cultured cells, to rigorously annotate >2,500 fruit fly circular RNAs. These mostly derive from back-splicing of protein-coding genes and lack poly(A) tails, and the circularization of hundreds of genes is conserved across multiple Drosophila species. We elucidate structural and sequence properties of Drosophila circular RNAs, which exhibit commonalities and distinctions from mammalian circles. Notably, Drosophila circular RNAs harbor >1,000 well-conserved canonical miRNA seed matches, especially within coding regions, and coding …

Diversity Of Cortical Interneurons In Primates: The Role Of The Dorsal Proliferative Niche, Nevena V. Radonjić, Fani Memi, Xiaojing Yu, Igor Jakovcevski, Nada Zecevic

UCHC Articles - Research

Evolutionary elaboration of tissues starts with changes in the genome and location of the stem cells. For example, GABAergic interneurons of the mammalian neocortex are generated in the ventral telencephalon and migrate tangentially to the neocortex, in contrast to the projection neurons originating in the ventricular/subventricular zone (VZ/SVZ) of the dorsal telencephalon. In human and nonhuman primates, evidence suggests that an additional subset of neocortical GABAergic interneurons is generated in the cortical VZ and a proliferative niche, the outer SVZ. The origin, magnitude, and significance of this species-specific difference are not known. We use a battery of assays applicable to …

Ploidy Number For Panicum Virgatum (Switchgrass) From The Long Island Sound Coastal Lowland Compared To Upland And Lowland Cultivars., Tanisha Williams, Carol Auer

Plant Science Articles

Panicum virgatum L. (switchgrass) is a native, perennial grass in North America with important ecological function in ecoregions including the Long Island Sound Coastal Lowland in the Northeastern United States. In recent decades, switchgrass has become a model lignocellulosic bioenergy crop with a large research portfolio describing its distribution, genetics, genomics, phenology, traits, gene flow, and cultivation. Switchgrass has been divided into two ecotypes, the Lowland ecotype which is tetraploid (2n= 4x= 36 chromosomes) and the Upland ecotype which is tetraploid or octaploid (2n= 8x= 72). While most switchgrass research has focused on genotypes from the Midwest or Southeastern regions, …

Supplemental Materials For Largemouth Bass Respirometry Research: Data Archived In Support Of Open-Access Publication, Jan-Michael Hessenauer, Jason Vokoun

Department of Natural Resources and the Environment Articles

Fisheries induced evolution (FIE) is hypothesized to cause changes in the life history, physiology and behavior of exploited fish stocks. Most studies evaluating FIE have occurred in exploited marine stocks which offer little opportunity for replication and few unexploited stocks exist for comparison. Inland recreational fisheries, however, offer the opportunity to replicate experiments in multiple systems, and while rare, unexploited populations exist for comparison. We measured the resting metabolic rate of four populations of largemouth bass, two exploited and two unexploited, to evaluate whether patterns of resting metabolic rates conformed to expectations for fisheries induced evolution. This document contains the …

A Site-Specific Integrated Col2.3gfp Reporter Identifies Osteoblasts Within Mineralized Tissue Formed In Vivo By Human Embryonic Stem Cells., Xiaonan Xin, Xi Jiang, Liping Wang, Mary Louise Stover, Shuning Zhan, Jianping Huang, A. Jon Goldberg, Yongxing Liu, Liisa T. Kuhn, Ernst J. Reichenberger, David W. Rowe, Alexander C. Lichtler

UCHC Articles - Research

The use of human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) for study and treatment of bone diseases or traumatic bone injuries requires efficient protocols to differentiate hESCs/iPSCs into cells with osteogenic potential and the ability to isolate differentiated osteoblasts for analysis. We have used zinc finger nuclease technology to deliver a construct containing the Col2.3 promoter driving GFPemerald to the AAVS1 site (referred to as a “safe harbor” site), in human embryonic stem cells (H9Zn2.3GFP), with the goal of marking the cells that have become differentiated osteoblasts. In teratomas formed using these cells, we identified green …

Investigating Propargyl-Linked Antifolates In Inhibiting Bacterial And Fungal Dihydrofolate Reductase, Joshua Andrade

Honors Scholar Theses

Antimicrobial agents have been invaluable in reducing illness and death associated with bacterial infection. However, over time, bacteria have evolved resistance to all major drug classes as a result of selective pressure. The advancement of new drug compounds is therefore vital. The Anderson-Wright Lab has focused on developing potent and selective inhibitors of dihydrofolate reductase (DHFR), an enzyme key in cell proliferation and survival, in several pathogenic species. The lab has found that a set of compounds, known as propargyl-linked antifolates, are DHFR inhibitors that are both biologically effective and have strong pharmacokinetic properties.

The efficacy of novel propargyl-linked antifolates …

Asymmetric Temporal Interactions Of Sound-Evoked Excitatory And Inhibitory Inputs In The Mouse Auditory Midbrain, Munenori Ono, Douglas L. Oliver

UCHC Articles - Research

In the auditory midbrain, synaptic mechanisms responsible for the precise temporal coding of inputs in the brainstem are absent. Instead, in the inferior colliculus (IC), the diverse temporal firing patterns must be coded by other synaptic mechanisms, about which little is known. Here, we demonstrate the temporal characteristics of sound-evoked excitatory and inhibitory postsynaptic currents (seEPSCs and seIPSCs, respectively) in vivo in response to long-duration tones. The seEPSCs and seIPSCs differ in the variability of their temporal properties. The seEPSCs have either early or late current peaks, and the early-peaked currents may be either transient or sustained varieties. The seIPSCs …

Biphasic Effects Of Fgf2 On Odontoblast Differentiation Involve Changes In The Bmp And Wnt Signaling Pathways, Karen Sagomonyants, Mina Mina

UCHC Articles - Research

Odontoblast differentiation during physiological and reparative dentinogenesis is dependent upon multiple signaling molecules, including Fibroblast Growth Factors (FGFs), Bone Morphogenetic Proteins (BMPs) and Wingless/Integrated (Wnt) ligands. Recent studies in our laboratory showed that continuous exposure of primary dental pulp cultures to FGF2 exerted biphasic effects on the expression of markers of dentinogenesis. In the present study we examined the possible involvement of the BMP and Wnt signaling pathways in mediating the effects of FGF2 on dental pulp cells. Our results showed that stimulatory effects of FGF2 on dentinogenesis during the proliferation phase of growth were associated with increased expression of …

Evaluation Of An Integrated Framework For Biodiversity With A New Metric For Functional Dispersion, Steven J. Presley, Michael R. Willig

Open Access Author Fund Awardees' Articles

Growing interest in understanding ecological patterns from phylogenetic and functional perspectives has driven the development of metrics that capture variation in evolutionary histories or ecological functions of species. Recently, an integrated framework based on Hill numbers was developed that measures three dimensions of biodiversity based on abundance, phylogeny and function of species. This framework is highly flexible, allowing comparison of those diversity dimensions, including different aspects of a single dimension and their integration into a single measure. The behavior of those metrics with regard to variation in data structure has not been explored in detail, yet is critical for ensuring …

Genetic Determinants Of Amidating Enzyme Activity And Its Relationship With Metal Cofactors In Human Serum, Eric D. Gaier, Alison Kleppinger, Martina Ralle, Jonathan Covault, Richard E. Mains, Anne M. Kenny, Betty A. Eipper

UCHC Articles - Research

Abstract

BACKGROUND:

α-amidation is a final, essential step in the biosynthesis of about half of all peptide hormones and neurotransmitters. Peptidylglycine α-amidating monooxygenase (PAM), with enzymatic domains that utilize Cu and Zn, is the only enzyme that catalyzes this reaction. PAM activity is detected in serum, but its significance and utility as a clinical biomarker remain unexplored.

METHODS:

We used well-established enzymatic assays specific for the peptidylglycine-α -hydroxylating monooxygenase (PHM) and peptidyl-α-hydroxyglycine α-amidating lyase (PAL) domains of PAM to quantify amidating activity in the sera of 144 elderly men. Relationships between PHM and PAL activity and serum levels of their …

Simple Signaling Molecules For Inductive Bone Regenerative Engineering, Bret D. Ulery, Stephen J. Nelson, Meng Deng, Kevin W. H. Lo, Yusuf M. Khan, Cato T. Laurencin

UCHC Articles - Research

Abstract

With greater than 500,000 orthopaedic procedures performed in the United States each year requiring a bone graft, the development of novel graft materials is necessary. We report that some porous polymer/ceramic composite scaffolds possess intrinsic osteoinductivity as shown through their capacity to induce in vivo host osteoid mineralization and in vitro stem cell osteogenesis making them attractive synthetic bone graft substitutes. It was discovered that certain low crystallinity ceramics partially dissociate into simple signaling molecules (i.e., calcium and phosphate ions) that induce stem cells to endogenously produce their own osteoinductive proteins. Review of the literature has uncovered a variety …

Human Esc-Derived Mscs Outperform Bone Marrow Mscs In The Treatment Of An Eae Model Of Multiple Sclerosis, Xiaofang Wang, Kumiko Ijichi, Debayon Paul, Adam S. Lazorchak, Joel S. Pachter, Stephen J. Crocker, Ren-He Xu

UCHC Articles - Research

Current therapies for multiple sclerosis (MS) are largely palliative, not curative. Mesenchymal stem cells (MSCs) harbor regenerative and immunosuppressive functions, indicating a potential therapy for MS, yet the variability and low potency of MSCs from adult sources hinder their therapeutic potential. MSCs derived from human embryonic stem cells (hES-MSCs) may be better suited for clinical treatment of MS because of their unlimited and stable supply. Here, we show that hES-MSCs significantly reduce clinical symptoms and prevent neuronal demyelination in a mouse experimental autoimmune encephalitis (EAE) model of MS, and that the EAE disease-modifying effect of hES-MSCs is significantly greater than …

Synthetic Lethality Induced By A Strong Drosophila Enhancer Of Expanded Polyglutamine Tract, Ping Zhang, Qiming Wang, Hannah Hughes, Gino Intrieri

Open Access Author Fund Awardees' Articles

Proteins containing an expanded polyglutamine tract are neurotoxins. The expanded polyglutamine proteins influence a variety of cellular functions. In Drosophila the GMR-Gal4/UAS expression system has been widely used in an eye-based model to study human neurodegenerative diseases. This system has facilitated the isolation and characterization of abundant Drosophilagenes that interact with the expanded polyglutamine proteins. We used the GMR-Gal4/UAS system to express three proteins containing an expanded polyglutamine tract, or an expanded polyglutamine tract alone. Doubling the dose of these proteins resulted in pupal lethality, indicating that these toxic proteins induced a sensitized condition that is prone to synthetic lethality. …

Developing Crosslinking Constructs Of Protein Kinase R, Prisma E. Lopez

Honors Scholar Theses

Protein Kinase R (PKR) is a key component of the innate immune antiviral response. PKR is activated upon binding to dsRNA. However, recent studies have shown that PKR can also bind to and become activated by duplex RNAs containing complex secondary structure. The mechanism of PKR binding and activation by these RNAs is currently not known. The approach taken here to determine the mechanism of PKR binding by these RNAs is through the development of PKR constructs that are capable of covalently binding to RNAs. Constructs were created by site-specific incorporation of an unnatural, photoactivatable amino acid within PKR. These …

Theta Dynamics In Rat: Speed And Acceleration Across The Septotemporal Axis, Lauren L. Long, James R. Hinman, Chi-Ming Chen, Monty A. Escabi, James J. Chrobak

Open Access Author Fund Awardees' Articles

Theta (6–12 Hz) rhythmicity in the local field potential (LFP) reflects a clocking mechanism that brings physically isolated neurons together in time, allowing for the integration and segregation of distributed cell assemblies. Variation in the theta signal has been linked to locomotor speed, sensorimotor integration as well as cognitive processing. Previously, we have characterized the relationship between locomotor speed and theta power and how that relationship varies across the septotemporal (long) axis of the hippocampus (HPC). The current study investigated the relationship between whole body acceleration, deceleration and theta indices at CA1 and dentate gyrus (DG) sites along the septotemporal …

Astroglial Boundary Formation And Epha4 Signaling In Neuroblast Migration, Nicholas B. Gallo

University Scholar Projects

Adult neurogenesis, the process of generating new neurons from neural precursors, is a highly complex process that is limited to two specific areas of the brain, the dentate gyrus of the hippocampus and the subventricular zone (SVZ). Despite continued research investigating neurogenesis in these two regions, we still lack a fundamental understanding of the molecular mechanisms of neural cell division, migration, differentiation, and integration in the postnatal brain. In particular, the rostral migratory stream (RMS), which is a cellular migratory route for newly generated neuronal precursors that travel from the SVZ to the olfactory bulb, will provide a useful model …

Astroglial Boundary Formation And Epha4 Signaling In Neuroblast Migration, Nicholas B. Gallo

Honors Scholar Theses

Adult neurogenesis, the process of generating new neurons from neural precursors, is a highly complex process that is limited to two specific areas of the brain, the dentate gyrus of the hippocampus and the subventricular zone (SVZ). Despite continued research investigating neurogenesis in these two regions, we still lack a fundamental understanding of the molecular mechanisms of neural cell division, migration, differentiation, and integration in the postnatal brain. In particular, the rostral migratory stream (RMS), which is a cellular migratory route for newly generated neuronal precursors that travel from the SVZ to the olfactory bulb, will provide a useful model …

Chemical Profiling And Biological Activity Of Two Tunicate-Associated Marine Bacteria, Lyubina Yankova

Honors Scholar Theses

Marine natural products have recently been an increasingly abundant source of novel antibiotics. Given that there is an increasing resistance to current drug therapies, finding new sources such as marine natural products is essential. Tunicate-associated marine bacteria can be a significant source of antibacterial compounds. Two tunicates of the species Eudistoma were collected from Portobelo National Park on the Salmedina Reef of Panama in the Caribbean Sea. Bacteria associated with the tunicate were isolated, cultured, extracted, and fractionated. Fractions were tested against an array of clinically relevant bacterial pathogens in the BioMAP assay. Two fractions MB0086E and MB0088E demonstrated activity …

An Examination Of The Phylogenetic Diversity Of Green Algae (Chlorophyceae) That Symbiose With Spotted Salamanders (Ambystoma Maculatum) In The Egg Stage., Crystal Xue

Honors Scholar Theses

In 1909, the species Oophila amblystomatis Lambert ex Wille was described for green algae that symbiose with salamanders in the egg stage (Wille). There are two hypotheses about the source of algae: 1) that algae enter from the surrounding water once the egg clutch is laid in a pond, and 2) that they are acquired from the maternal reproductive tract. We developed a third hypothesis developed to account for the salamander reproductive cycle. Male salamanders lay spermatophores, which are protein-filled capsules, on plant matter in and around ponds. Spermatophores are exposed to the environment before use by females in internal …

Characterizing And Improving The Oral Sensations And Preference Of Polyphenol-Rich Aronia Berry Juice, Jeeha Park

Honors Scholar Theses

Background: Aronia berries (chokeberries) have very high levels of health-promoting polyphenols yet cause "choking" sensations due to bitterness and astringency. We aimed to describe oral sensations and palatability of aronia juice by variations in harvest time and oral sensory phenotype. Sensory blocking combinations were tested to improve juice acceptability. Methods: Ripe aronia berries were harvested at 7 time points and juiced for oral sampling by 50 adults who underwent bitter taste phenotyping. The adults reported quality intensities of prototypical tastes, foods, and aronia juices. Ethyl butyrate (10ppm) and/or sucrose (0.15 and 0.3M) were added to prototypical oral stimuli and aronia …

The New Normal: Goodness Judgments Of Non-Invariant Speech, Julia R. Drouin

Honors Scholar Theses

Previous research has found that perceptual learning, or normalizing the idiosyncratic phonemes of speech, causes a shift in speech sound category boundaries. The present study examined if perceptual learning was limited to the boundary or if also caused a shift in internal category structure. Seventeen individuals participated in three behavioral tasks to explicate this question. In the Lexical Decision task, participants were trained in either /s/-biasing or /ʃ/- biasing context. In the Goodness Judgment task, participants rated a continuum of sounds on perceived /s/ goodness using a designated scale. Finally, in the Phoneme Identification task, participants listened to the same …

Do Visitors Affect Zebra Behavior In Zoos?, Christine Conte

Honors Scholar Theses

I investigated the effects of visitors on the behavior of two zebra species (Equus grevyi and Equus burchelli) at eight zoos on the East Coast of the United States. I used instantaneous time sampling to record zebra behavior and visitor data. I used these data to run Bayesian hierarchical models and determined that visitors do not negatively affect zebra behavior. This is a positive finding for zoos, since it means that zebras, a highly skittish prey animal, are not disturbed in their exhibits. My data suggest there are behavioral differences between the zebra herds at different zoos, which …

Mutagenesis Of 8-Oxoguanine Adjacent To An Abasic Site In Escherichia Coli Cells Proficient Or Deficient In Dna Polymerase Iv, Savas T. Tsikis

Honors Scholar Theses

It is well established that clustered DNA damages or multiply damaged sites (MDS) are the result of ionizing radiation and that they are characterized by an enhanced mutagenic potential. As a model MDS, we have evaluated the mutagenic and cytotoxic properties of the ubiquitous oxidative DNA damage 8-oxoguanine (G^8-oxo) adjacent to the abasic site lesion (Z) using a single stranded M13mp7L2 vector. The recombinant DNA was used to transform wild type E. coli strains and strains deficient in the translesion DNA polymerase of the Y-family, DNA polymerase IV, in the presence or absence of SOS induction. The percent …

Characterization Of A Putative Cephalotoxin From The Hemocytes Of Euprymna Scolopes, Jessie E. Scott

University Scholar Projects

Many organisms have beneficial microbial symbionts, and complex interactions between the immune system and the bacteria must occur to allow these symbioses to persist. The host immune system must recognize and preferentially tolerate the beneficial microorganisms, while simultaneously eliminating harmful pathogens. The Hawaiian bobtail squid, Euprymna scolopes, is a model organism for host-microbe interactions because of the unique light organ symbiosis. Hemocytes, the squid’s primary immune cell, infiltrate and patrol the light organ and continuously interact with the symbiont Vibrio fischeri. Using this model, several innate immunity genes have been shown to be differentially expressed in the hemocytes …

Modeling The Adaptive Immune Response To Mutation-Generated Antigens, Rory J. Geyer

University Scholar Projects

Somatic mutations may drive tumorigenesis or lead to new, immunogenic epitopes (neoantigens). The immune system is thought to represses neoplastic growths through the recognition of neoantigens presented only by tumor cells. To study mutations as well as the immune response to mutation-generated antigens, we have created a conditional knockin mouse line with a gene encoding, 5’ to 3’, yellow fluorescent protein (YFP), ovalbumin (which is processed to the immunologically recognizable peptide, SIINFEKL), and cyan fluorescent protein (CFP), or, YFP-ovalbumin-CFP. A frame shift mutation has been created at the 5’ end of the ovalbumin gene, hence YFP should always be expressed, …

Characterization Of The Ependymal Barrier Due To Human Aging And Injury In Murine Models, Ye Sun

University Scholar Projects

Ventriclulomegaly, or the expansion of the ventricles in the brain, is a phenomenon associated with age and injury to the brain. The ependymal layer that encases the ventricles displays certain degrees of plasticity and regenerative ability due to its associated stem cell niche, the subventricular zone (SVZ). Previous research in the Conover Lab has shown that in the mouse, which maintains an actively proliferating SVZ into adulthood, there is an intact ependymal monolayer throughout normal aging, with maintained lateral ventricle size with some degree of stretching. In contrast, the human SVZ declines in proliferative capacity after infancy, and age-related changes …

Evolution Of Splicing Regulatory Networks In Drosophila, C. Joel Mcmanus, Jodi Eipper-Mains, Brenton R. Graveley

UCHC Articles - Research

The proteome expanding effects of alternative pre-mRNA splicing have had a profound impact on eukaryotic evolution. The events that create this diversity can be placed into four major classes: exon skipping, intron retention, alternative 5′ splice sites, and alternative 3′ splice sites. Although the regulatory mechanisms and evolutionary pressures among alternative splicing classes clearly differ, how these differences affect the evolution of splicing regulation remains poorly characterized. We used RNA-seq to investigate splicing differences in D. simulans, D. sechellia, and three strains of D. melanogaster. Regulation of exon skipping and tandem alternative 3′ splice sites (NAGNAGs) were …

Modeling The Adaptive Immune Response To Mutation-Generated Antigens, Rory J. Geyer

Honors Scholar Theses

Somatic mutations may drive tumorigenesis or lead to new, immunogenic epitopes (neoantigens). The immune system is thought to represses neoplastic growths through the recognition of neoantigens presented only by tumor cells. To study mutations as well as the immune response to mutation-generated antigens, we have created a conditional knockin mouse line with a gene encoding, 5’ to 3’, yellow fluorescent protein (YFP), ovalbumin (which is processed to the immunologically recognizable peptide, SIINFEKL), and cyan fluorescent protein (CFP), or, YFP-ovalbumin-CFP. A frame shift mutation has been created at the 5’ end of the ovalbumin gene, hence YFP should always be expressed, …