Digital Commons Network^™

The Effects Of Nutrient Availability And Season On The Somatotropic Axis In Free-Ranging Alaskan Moose (Alces Alces), Amanda A. Parillo

Master's Theses

No abstract provided.

The River Discontinuum: Applying Beaver Modifications To Baseline Conditions For Restoration Of Forested Headwaters, Denise Burchsted, Melinda Daniels, Robert Thorson, Jason Vokoun

Center for Integrative Geosciences

Billions of dollars are being spent in the United States to restore rivers to a desired, yet often unknown, reference condition. In lieu of a known reference, practitioners typically assume the paradigm of a connected watercourse. Geological and ecological processes, however, create patchy and discontinuous fluvial systems. One of these processes, dam building by North American beavers (Castor canadensis), generated discontinuities throughout precolonial river systems of northern North America. Under modern conditions, beaver dams create dynamic sequences of ponds and wet meadows among free-flowing segments. One beaver impoundment alone can exceed 1000 meters along the river, flood the valley laterally, …

Changes In The Proliferation Of The Subventricular Zone Neural Stem Cell Pool Throughout Aging In The Murine Brain, Olayinka Edwards

Honors Scholar Theses

Previous studies regarding subventricular zone (SVZ) neural stem cells (NSCs) have either observed global changes in the SVZ niche containing NSCs or an impure NSC population. By imaging wholemount preparations of mouse brains and staining with molecular markers specific for proliferating NSC nuclei, the study was able to give a more accurate depiction of the SVZ NSC population than its predecessors. This study will quantify the percentage of proliferating NSCs at various ages of adult murine brain development in order to elucidate a possible correlation between NSC division kinetics and the declining neurogenic output witnessed with aging.

Egf Receptor Kinase Activity Is Required For Gap Junction Closure And For Part Of The Decrease In Ovarian Follicle Cgmp In Response To Luteinizing Hormone, Rachael P. Norris, Marina Freudzon, Viacheslav O. Nikolaev, Laurinda A. Jaffe

UCHC Articles - Research

The meiotic cell cycle in mouse oocytes is arrested in prophase, and then restarted when luteinizing hormone (LH) acts on the surrounding granulosa cells. The granulosa cells keep meiosis arrested by providing a source of cGMP that diffuses into the oocyte through gap junctions, and LH restarts the cell cycle by closing the junctions and by decreasing granulosa cell cGMP, thus lowering oocyte cGMP. Epidermal growth factor receptor (EGFR) activation is an essential step in triggering LH-induced meiotic resumption, but its relationship to the cGMP decrease in the follicle is incompletely understood, and its possible function in causing gap junction …

Mhc Class I And Tcr Avidity Control The Cd8 T Cell Response To Il-15/Il-15rα Complex, Thomas A. Stoklasek, Sara L. Colpitts, Henry M. Smilowitz, Leo Lefrançois

UCHC Articles - Research

IL-15 operates via a unique mechanism termed transpresentation. In this system, IL-15 produced by one cell type is bound to IL-15Rα expressed by the same cell and is presented to apposing cells expressing the IL-15Rβ/γC complex. We have shown that administering soluble IL-15Rα complexed with IL-15 can greatly enhance IL-15 activity. We now show that the naive CD8 T cell response to exogenous IL-15/IL-15Rα complex is MHC class I dependent. In the absence of β2 microglobulin, naive CD8 T cells scarcely proliferated in response to IL-15/IL-15Rα complex, whereas memory cells proliferated, although to a lesser extent, compared with levels in …

The Decade Of The Dendritic Nmda Spike, Srdjan D. Antic, Wen-Liang Zho, Anna R. Moore, Shaina M. Shor, Katerina D. Ikonomu

UCHC Articles - Research

In the field of cortical cellular physiology, much effort has been invested in understanding thick apical drites of pyramidal neurons and the regenerative sodium and calcium spikes that take place in the apical trunk. Here we focus on thin dendrites of pyramidal cells (basal, oblique, and tuft dendrites), and we discuss one relatively novel form of an electrical signal (“NMDA spike”) that is specific for these branches. Basal, oblique, and apical tuft dendrites receive a high density of glutamatergic synaptic contacts. Synchronous activation of 10–50 neighboring glutamatergic synapses triggers a local dendritic regenerative potential, NMDA spike/plateau, which is characterized by …

Determining Optimal Storage Arrangements For Open Access Data Sets, As For Nsf Data Management Plan Requirements, David B. Lowe

Published Works

Document is a proposed draft of a decision tree to be used in determining what approach to take for making data available in order to comply with open access requirements for data management, as per National Science Foundation requirements.

A Detailed Mathematical Model Predicts Serial Engagement Of Ige-Fcεri Complexes Can Enhance Syk Activation In Mast Cells, Michael L. Blinov

UCHC Articles - Research

The term serial engagement was introduced to describe the ability of a single peptide, bound to a MHC molecule, to sequentially interact with TCRs within the contact region between a T cell and an APC. In addition to ligands on surfaces, soluble multivalent ligands can serially engage cell surface receptors with sites on the ligand, binding and dissociating from receptors many times before all ligand sites become free and the ligand leaves the surface. To evaluate the role of serial engagement in Syk activation, we use a detailed mathematical model of the initial signaling cascade that is triggered when FcepsilonRI …

Crystal Structure Of The Gerbc Component Of A Bacillus Subtilis Spore Germinant Receptor, Yunfeng Li, Barbara Setlow, Peter Setlow, Bing Hao

UCHC Articles - Research

The nutrient germinant receptors (nGRs) of spores of Bacillus species are clusters of three proteins that play a critical role in triggering the germination of dormant spores in response to specific nutrient molecules. Here we report the crystal structure of the C protein of the GerB germinant receptor, so called GerBC, of Bacillus subtilis spores at 2.3 Å resolution. The GerBC protein adopts a previously uncharacterized type of protein fold consisting of three distinct domains, each of which is centered by a β sheet surrounded by multiple α helices. Secondary structure prediction and structure-based sequence alignment suggest that the GerBC …

Early Signals During Cd8+ T Cell Priming Regulate The Generation Of Central Memory Cells, Joshua J. Obar, Leo Lefrancois

UCHC Articles - Research

The CD8⁺ T cell response to infection is characterized by the appearance of short-lived (CD127^low killer cell lectin-like receptor G 1–high) and memory-precursor (CD127^high killer cell lectin-like receptor G 1–low) effector cells. How and when central-memory T (T_CM; CD62L^high CCR7⁺) cell and effector-memory T(T_EM; CD62L^low CCR7⁻) cell subsets are established remains unclear. We now show that the T_CM cell lineage represents an early developmental branchpoint during the CD8⁺ T cell response to infection. Central-memory CD8⁺ T cells could be identified prior to the peak …

Acoustic Cues For Sound Source Distance And Azimuth In Rabbits, A Racquetball And A Rigid Spherical Model, Duck O. Kim, Brian Bishop, Shigeyuki Kuwada

UCHC Articles - Research

There are numerous studies measuring the transfer functions representing signal transformation between a source and each ear canal, i.e., the
head-related transfer functions (HRTFs), for various species. However, only a handful of these address the effects of sound source distance on HRTFs. This
is the first study of HRTFs in the rabbit where the emphasis is on the effects of sound source distance and azimuth on HRTFs. With the rabbit placed in an
anechoic chamber, we made acoustic measurements with miniature microphones placed deep in each ear canal to a sound source at different positions (10–160 cm distance, ±150° azimuth). …

Investigating The Diversity Of Radial Glia Fates In The Rat Neocortex, Abraham William Aron

Honors Scholar Theses

Radial Glia (RG) are a mitotically active population of cells which reside within the ventricular zone at the lateral ventricle and give rise to the pyramidal neurons and astrocytes of the neocortex. Through cellular divisions, RG produce two daughter cells, one which resides in the ventricular zone and becomes another RG while the other is an immature progenitor which migrates away from the ventricle and populates the growing cortex. RG have been found to be a heterogeneous population of cells which express different surface antigens and genetic promoters which may influence the cellular fate of their progeny. In this study …

Alkylphenol Contamination In Homarus Americanus, Jennifer Renee Urban

Honors Scholar Theses

Alkylphenols are pollutants that are present in marine sediments and fishes. In earlier work it has been discovered that alkylphenols are present in the Homarus americanus, or the American lobster. Research suggests that alkylphenols could behave as endocrine disruptors as they have been found to affect juvenile hormone activity. It has been hypothesized that lobsters may be able to rid themselves of alkylphenol contamination through secreting these compounds into the environment or sequestering them in their tissues. In this study, I address the question of how lobsters may rid themselves of alkylphenols by analyzing hemolymph, muscle, gill, and shell samples …

Dopaminergic Innervation Of The Subventricular Zone In The Murine Brain, Linda Beth Drozdowicz

Honors Scholar Theses

The subventricular zone (SVZ) is one of two areas in the brain that, in a healthy mouse, continually generate neurons throughout adulthood. While it was previously thought that only the A9 neurons of the substantia nigra sent dopaminergic afferents to the SVZ, recent studies suggest that the A10 neurons of the ventral tegmental area may innervate this area. This project has aimed to discover which, if either, model is correct.

Examination of the Aphakia (AK) mouse was used to determine the role of distinct midbrain regions in SVZ regulation. Additionally, intraperitoneal injections of the chemical MPTP were used to deduce …

Characterization Of The Putative Xyloglucan Glycosyltransferase Gt14 In Arabidopsis Thaliana, Najam R. Syed

Honors Scholar Theses

Plant cell walls largely consist of matrix polysaccharides that are linked to cellulose microfibrils. Xyloglucan, the primary hemicellulose of the cell wall matrix, consists of a repeating glucose tetramer structure with xylose residues attached to the first three units ('XXXG'). In Arabidopsis thaliana, the core XXXG structure is further modified by enzymatic addition of galactose and fucose residues to the xylose side chains to produce XLXG, XXLG, XLLG and XLFG structures. GT14 is a putative glycosyltransferase in the GT47 gene family. Initial predictions of GT14's hydrophobic regions, based on its translated amino acid sequence, are almost identical to its Arabidopsis …

Determination Of The Myogenic Potential Of Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells, Rory Coleman

Honors Scholar Theses

Human embryonic stem cells (hESCs) have the potential to

differentiate to all adult somatic cells. This property makes hESCs a very promising area of research for the treatment of disorders in which specific cell populations need to be restored. Despite this potential, research that focuses on producing mesodermally derived cell populations from hESCs is decidedly limited, notwithstanding the prevalence of disorders involving mesodermal tissues for which treatment options are limited. Skeletal muscle myoblasts are derivatives of mesodermal cells and are characterized by the expression of the MyoD gene. These cells are difficult to obtain from hESCs in a reproducible and …

The Effect Of Heavy Metal Stress On Avian Proximal Tubule Urate Secretion, Carla L. Maffeo

Honors Scholar Theses

In both humans and birds, urate is an important antioxidant when maintained at normal plasma concentrations. Though human kidneys primarily reabsorb filtered urate, while those of birds perform mostly secretion, both maintain urate levels at ~300microM. The importance of maintaining urate levels within the homeostatic range was observed when the study of several prominent diseases revealed an association with hyperuricemia.

This study examined the effect of elevated zinc concentration on avian urate secretion. Here, acute exposure of chicken proximal tubule epithelial cells (cPTCs) to zinc stress had no effect on urate secretion, but prolonged zinc-induced cellular stress inhibited active transepithelial …

Assessing The Phylogenetic Utility Of Dna Barcoding Using The New Zealand Cicada Genus Kikihia, Megan Ribak

Honors Scholar Theses

DNA Barcoding (Hebert et al. 2003) has the potential to revolutionize the process of identifying and cataloguing biodiversity; however, significant controversy surrounds some of the proposed applications. In the seven years since DNA barcoding was introduced, the Web of Science records more than 600 studies that have weighed the pros and cons of this procedure. Unfortunately, the scientific community has been unable to come to any consensus on what threshold to use to differentiate species or even whether the barcoding region provides enough information to serve as an accurate species identification tool. The purpose of my thesis is to analyze …

Oxygen Supplementing, Biocompatible Outer Membranes For Enhanced Performance Of Implantable Glucose Sensors, Hardeep Singh

Honors Scholar Theses

Lack of linearity and sensitivity, oxygen dependence, biofouling and tissue inflammation hinder the development of implantable biosensors for continuous monitoring of glucose. Herein, we report the development of stacked outer membranes based on LBL/PVA hydrogels that improve sensor sensitivity, linearity, oxygen independence and counter biofouling and inflammation. While the inner LBL membrane affords tunable diffusivity, the outer PVA is capable of releasing anti-inflammatory drugs/tissue response modifying agents to counter acute and chronic inflammation, and to induce neo-angiogenesis at the implant site. Sensors were fabricated by immobilizing GOx enzyme on top of 50 μm platinum wires, followed by deposition of stacked …

Changes In Mirna Expression In A Model Of Microcephaly, Shan Parikh

Honors Scholar Theses

miRNAs function to regulate gene expression through post-transcriptional mechanisms to potentially regulate multiple aspects of physiology and development. Whole transcriptome analysis has been conducted on the citron kinase mutant rat, a mutant that shows decreases in brain growth and development. The resulting differences in RNA between mutant and wild-type controls can be used to identify genetic pathways that may be regulated differentially in normal compared to abnormal neurogenesis. The goal of this thesis was to verify, with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), changes in miRNA expression in Cit-k mutants and wild types. In addition to confirming miRNA expression …

Alterations In The Cellular Composition Of The Mouse Bladder Following Ovariectomy, Partial Bladder Outlet Obstruction, And Aging, Diane Holly Smith

Honors Scholar Theses

Detrusor underactivity (DU) increases susceptibility to urinary retention and accordingly further complicates the management of urinary incontinence. Bladder muscle stretch, a lack of estrogen, and aging are 3 notable DU risk factors. The aim of this research is to better characterize the changes in cellular composition of the bladder that result from these 3 risk factors to gain a better understanding of DU pathogenesis and pathobiology. This research focuses on the effects of a lack of estrogen while also providing an outline for determining the effects of bladder muscle stretch and aging on the cellular composition of the bladder.

Macroh2a1 Regulation During The Cell Cycle Of Mouse Embryonic Stem Cells, Persis S. Thomas

Honors Scholar Theses

MacroH2A is a core histone variant that plays an important role in the X-inactivation process during differentiation of embryonic stem cells. It has been shown that macroH2A changes in localization during the cell cycle of somatic cells. This study aims to determine how macroH2A changes during the cell cycle of embryonic stem cells. Male and female mouse embryonic stem cells were transfected with a GFP::macroH2A construct and the relationship between macroH2A and the cell cycle was determined using FACS. This study shows that macroH2A is altered during the cell cycle of embryonic stem cells as it is in somatic cells …

Scoping Out The Shorebirds Of Summer, Milan Bull

Wrack Lines

The best places to go birding along Connecticut's shoreline and the delightful avian life you'll find there, are featured. Illustrated lavishly with photos from Connecticut Audubon.

Inhibitory Role Of Sphingosine 1-Phosphate Receptor 2 In Macrophage Recruitment During Inflammation, Jason Michaud, Timothy Hla, Dong-Soon Im

UCHC Articles - Research

Macrophage recruitment to sites of inflammation is an essential step in host defense. However, the mechanisms preventing excessive accumulation of macrophages remain relatively unknown. The lysophospholipid sphingosine 1-phosphate (S1P) promotes T and B cell egress from lymphoid organs by acting on S1P receptor 1 (S1P₁R). More recently, S1P₅R was shown to regulate NK cell mobilization during inflammation, raising the possibility that S1P regulates the trafficking of other leukocyte lineages. In this study, we show that S1P₂R inhibits macrophage migration in vitro and that S1P₂R-deficient mice have enhanced macrophage recruitment during thioglycollate peritonitis. …

Racial And Ethnic Disparities In Low Birth Weight Delivery Associated With Maternal Occupational Characteristics, John D. Meyer, Nicholas D. Warren, Susan T. Reisine

UCHC Articles - Research

Objectives

Work characteristics and maternal education have both been associated with low birth weight (LBW) delivery. We sought to examine the relative contribution of these two factors to LBW delivery and determine whether ethnic/racial differentials in educational attainment and work characteristics might play a role in well-described disparities in LBW.

Methods

Scores for work substantive complexity (SC) derived from the O*NET were imputed to maternal occupation for Connecticut singleton births in 2000. Risks for LBW were estimated separately for black, Hispanic, and white mothers using logistic regression controlling for maternal covariates.

Results

Using white mothers as a referent, working is …

Prognostic Value Of Ishak Fibrosis Stage: Findings From The Halt-C Trial, Herbert L. Bonkovsky

UCHC Articles - Research

Background and Aims

Studies of the prognostic value of Ishak fibrosis stage are lacking. We utilized multi-year follow-up of the Hepatitis C Antiviral Long Term Treatment Against Cirrhosis (HALT-C) Trial to determine whether individual Ishak fibrosis stages predicted clinical outcomes in patients with chronic hepatitis C.

Methods

Baseline liver biopsies from 1,050 patients with compensated chronic hepatitis C who had failed combination peginterferon and ribavirin were reviewed by a panel of expert hepatopathologists. Fibrosis was staged with the Ishak scale (ranging from 0=no fibrosis to 6=cirrhosis). Biopsy fragmentation and length as well as number of portal tracts were recorded. We …

Memory Cd8+ T Cell Differentiation, Joshua J. Obar, Leo Lefrancois

UCHC Articles - Research

In response to infection or effective vaccination, naive antigen-specific CD8+ T cells undergo a dramatic highly orchestrated activation process. Initial encounter with an appropriately activated antigen-presenting cell leads to blastogenesis and an exponential increase in antigen-specific CD8+ T cell numbers. Simultaneously, a dynamic differentiation process occurs, resulting in formation of both primary effector and long-lived memory cells. Current findings have emphasized the heterogeneity of effector and memory cell populations with the description of multiple cellular subsets based on phenotype, function, and anatomic location. Yet, only recently have we begun to dissect the underlying factors mediating the temporal control of the …

Use Of Virtual Cell In Studies Of Cellular Dynamics, Leslie M. Loew, Boris M. Slepchenko

UCHC Articles - Research

The Virtual Cell (VCell) is a unique computational environment for modeling and simulation of cell biology. It has been specifically designed to be a tool for a wide range of scientists, from experimental cell biologists to theoretical biophysicists. The models created with VCell can range from the simple, to evaluate hypotheses or to interpret experimental data, to complex multi-layered models used to probe the predicted behavior of spatially resolved, highly non-linear systems. In this Chapter, we discuss modeling capabilities of VCell and demonstrate representative examples of the models published by the Virtual Cell users.

Expansion Of The Eukaryotic Proteome By Alternative Splicing, Brenton R. Graveley

UCHC Articles - Research

The collection of components required to carry out the intricate processes involved in generating and maintaining a living, breathing and, sometimes, thinking organism is staggeringly complex. Where do all of the parts come from? Early estimates stated that about 100,000 genes would be required to make up a mammal; however, the actual number is less than one-quarter of that, barely four times the number of genes in budding yeast. It is now clear that the ‘missing’ information is in large part provided by alternative splicing, the process by which multiple different functional messenger RNAs, and therefore proteins, can be synthesized …

Environmental And Endogenous Factors Influencing Emigration In Juvenile Anadromous Alewives, Benjamin I. Gahagan, Eric T. Schultz, Katie E. Gherard

EEB Articles

We analyzed juvenile anadromous alewife migration at Bride Lake, a coastal lake in Connecticut, during summer 2006 and found that migration on 24-hour and seasonal timescales was influenced by conditions of the environment and characteristics of the individual. To identify environmental cues of juvenile migration, we continuously video recorded fish at the lake outflow and employed information-theoretic model selection to identify the best predictors of daily migration rate. More than 80% of the approximately 320,000 juveniles that migrated from mid-June to mid-August departed in three pulses lasting one or two days. Pulses of migration were associated with precipitation events, transient …