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The Insulin/Igf Signaling Regulator Cytohesin/Grp-1 Modulates Sensitivity To Excitotoxicity In C. Elegans, Nazila Tehrani

Dissertations, Theses, and Capstone Projects

Excitotoxicity is a form of neurodegeneration that serves as the main underlying cause of brain damage in stroke/brain ischemia, and a contributing factor in a range of neurological diseases such as Epilepsy, ALS, Alzheimer, and Huntington's disease. In excitotoxicity, over-activation of glutamate receptors causes necrotic neuronal cell death. In spite of intense study of excitotoxicity, the molecular mechanisms that lead from glutamate receptor activation to necrotic death remain a mystery. Aging neurons are known to be more vulnerable to excitotoxicity and less likely to recover, but the underlying reasons for the increased cellular vulnerability are unknown. To gain insight into …

Suitability Of Great South Bay, New York To Blooms Of Pfiesteria Piscicida And P. Shumwayae Prior To Superstorm Sandy, October 29, 2012, Pawel Tomasz Zablocki

Theses and Dissertations

Pfiesteria piscicida and P. shumwayae are toxic dinoflagellates implicated in massive fish kills in North Carolina and Maryland during 1990s. A set of physical, chemica l, and biological factors influence population dynamics of these organisms. This study employs i nformation gathered from relevant literature on temperature, salinity, dissolved oxygen, pH, turbulent mixing, and dissolved nutrients, bacteria, algae, microzooplankton, mesozooplankton, bivalve m ollusks, finfish, and other toxic dinoflagellates, which influence Pfiesteria population dynamics. The research focused on whether conditions in the Great South Bay, Long Island, New York were suitable to blooms of Pfiesteria species prior to the passage of superstorm …

Phylogeography Of Southeast Asian Flying Foxes (Chiroptera: Pteropodidae: Pteropus), Susan Man Shu Tsang

Dissertations, Theses, and Capstone Projects

Flying foxes (Pteropus) are a genus of Old World fruit bats that are important seed dispersers and pollinators for plants native to the 200,000+ islands in Southeast Asia, yet they are some of the most poorly known bats in the world. They comprise some of the largest known bat species, and are morphologically relatively conserved on the genus level. Pteropus is the most species-rich genus within Pteropodidae, though the origin for this diversity remains incompletely understood. In Chapter 1, I discuss the importance of Pteropus to the ecosystem and as reservoir hosts. In Chapter 2, a molecular phylogeny is presented …

Proton Pumping In Cytochrome C Oxidase, Jianxun Lu

Dissertations, Theses, and Capstone Projects

Cytochrome c oxidase (CcO) is a large trans-membrane protein, which is the final enzyme in the respiratory electron transport chain in mitochondria or aerobic bacteria. It implements proton pumping through the mitochondrial membrane against the electrochemical gradient, by utilizing the chemical energy released by reducing O₂ to water. The active site of the chemical reaction is called the Binuclear Center (BNC) that is made up of heme a₃, Cu_B, a Tyrosine residue and their ligands. The protein is reduced four times by electron from cytochromes c to reduce O₂ and to generate four different …

Testing Visual Ecology Hypotheses In Avian Brood Parasite-Host Systems: The Role Of Uv-Light Perception And Egg-Nest Contrast In Foreign Egg Rejection, Zachary Aidala

Dissertations, Theses, and Capstone Projects

Color signals are highly important features of animal communication systems, particularly among birds, which possess exquisitely complex visual perception systems. Birds possess tetrachromatic vision, and some species are sensitive to ultraviolet (UV) wavelengths. Because human and avian visual systems dramatically differ (i.e. humans are not sensitive to UV wavelengths), biologically relevant sensory models are necessary to accurately assess the function of avian color signals. In this dissertation, I primarily use brood parasite-host interactions as a model for studying the behavioral function of avian-perceivable visual stimuli. In Chapter 1, I review the importance of employing biologically relevant sensory-perceptual visual models when …

Control Of Cell Cycle Progression By Mtor, Amrita Chatterjee

Dissertations, Theses, and Capstone Projects

Over the past few years it has become apparent that cancer cells require the activation of a set of intra-cellular signals that promote cell cycle progression and survival. One of the most common survival signals activated in human cancers is mediated by mTOR -the mammalian target of rapamycin. mTOR is a critical nutrient and energy sensor in cells that lets the cell know that there is sufficient material available for a cell to double its mass and divide. mTOR causes the phosphorylation of downstream targets ribosomal subunit S6 kinase and eukaryotic initiation factor 4E (eIF4E) binding protein-1 (4E-BP1), which promotes …

Climate-Smart Agriculture: Farmer's Bane Or Boon?, Jeeva Mary Jacob

Dissertations, Theses, and Capstone Projects

Climate-Smart Agriculture (CSA) is one of the solutions that simultaneously address the issues of food security, climate change and agricultural productivity. It has been gaining momentum in the last five years among policy circles and development organizations have prioritized CSA interventions in developing countries around the world. In this paper, CSA interventions are examined from the small farmer's perspective and the purpose of this paper is to find out whether Climate-Smart Agriculture truly empowers the farmer in the face of climate change. Such a study emerged from the fact that in the past, agricultural interventions like the Green Revolution promised …

Nuclear Pore Protein Nup211 Is Essential For Cell Cycle Progression And Cell Shape Maintenance In Fission Yeast, Ayisha R. Sookdeo

Dissertations, Theses, and Capstone Projects

The nuclear pore complexes (NPCs) are large multi-protein channels that traverse the nuclear envelope and mediate nucleo-cytoplasmic transport. Proteomic studies have revealed that NPCs are composed of about thirty different proteins called nucleoporins. I explored a particular nucleoporin, Nup211, in fission yeast. nup211 is an essential gene; its deletion is lethal and causes morphological defects. In this study, I characterized the cell morphological defects caused by the down-regulation of Nup211 and found that restoring the N-terminal domain of Nup211 was sufficient to rescue the lethal phenotype and partially suppress the morphological defects. Additionally, I investigated the role Nup211 plays in …

Tcr Alpha Lcr And Non-Lcr Cis-Elements Contributing To Tissue Specific Expression Of The Tcr Alpha Gene In Thymic And Peripheral T Cells, Martina Kucerova-Levisohn

Dissertations, Theses, and Capstone Projects

Orchestrated expression of multiple genes residing in the complex TCRα/δ/Dad1 locus requires tight control from multiple cis-acting elements. The TCRα locus control region (LCR), is positioned between TCRα and Dad1 gene, and has been implicated in the differential expression of both genes. In this study, we focus our work on the hypersensitive site (HS)1 prime (HS1'), located 3' of the classical Eα enhancer, within the TCRα LCR. We investigated its non- redundant role in TCRα expression in thymic and peripheral T cells as assayed by in vivo and in vitro studies. Furthermore, formation of HS1' in both lymphoid and …

Development Of Functional Interactions Among Cortical And Trabecular Traits During Growth Of The Lumbar Vertebral Body, Melissa Ramcharan

Dissertations, Theses, and Capstone Projects

Variation in bone traits that contribute to increased fracture risk in the elderly is mainly established in adulthood. Previous studies have shown that in adults, cortical and trabecular traits are functionally related. How variations in traits develop to establish mechanical function in adult bone is not well understood. In this study, we examined temporal changes in the development of cortical and trabecular traits during growth in mouse lumbar vertebral body structures that have a wide range of genetic variants. We determined a sequence of events among traits that would suggest how functional bone structures developed. Examining bones in A/J, C57/BL6 …

Population Genomic Inference Of Ecology, Conservation, Evolution, And Demographic History Of Atlantic Seahorses And Pipefishes (Syngnathidae), Joel Thomas Boehm

Dissertations, Theses, and Capstone Projects

In the Atlantic Ocean powerful directional ocean currents can play a significant role in the formation and persistence of marine species. Syngnathidae fishes have a sparse fossil record, high morphological plasticity, and many of these species are difficult to observe in the wild, therefore they frequently lack life history information and the status of regional lineages and species designations are often obscure. In this dissertation I explore the ecology, evolution, and conservation of primarily Atlantic seahorses (Hippocampus) and pipefish (Syngnathus) in four core chapters, using differing genetic datasets ranging from mitochondrial DNA to genome-wide RAD sequences. Most Synganthids have the …

The Neurophysiology Of Intersensory Selective Attention And Task Switching, Jeremy W. Murphy

Dissertations, Theses, and Capstone Projects

Our ability to selectively attend to certain aspects of the world and ignore others is fundamental to our day-to-day lives. The need for selective attention stems from capacity limitations inherent in our perceptual and cognitive processing architecture. Because not every elemental piece of our environment can be fully processed in parallel, the nervous system must prioritize processing. This prioritization is generally referred to as selective attention. Meanwhile, we are faced with a world that is constantly in flux, such that we have to frequently shift our attention from one piece of the environment to another and from one task to …

Using Multiconformation Continuum Electrostatics Model For Pka And Proton Transfer Pathway Calculations In Protein, Xuyu Zhu

Dissertations, Theses, and Capstone Projects

Residue protonation state changes and proton transfer reactions in protein are basic and ubiquitous reactions in biological chemistry. The Multiconformation Continuum Electrostatics (MCCE) program is applied here to calculate the pKa of residues in the specially engineered protein staphylococcal nuclease (SNase) and further modified to investigate the unidirectional proton transfer mechanism in the proton pump protein bacteriorhodopsin. The pKa$_s$ are obtained by Monte Carlo sampling of coupled side chain protonations and positions as a function of pH in MCCE. The pKa$_s$ of 96 acids and bases introduced into buried sites in the SNase protein were calculated and the results compared …

Functional Characterization Of The Plant 15-Cis-Zeta-Carotene Isomerase Z-Iso, Jesus Alonso Beltran Zambrano

Dissertations, Theses, and Capstone Projects

Vitamin A deficiency is a widespread health issue in the tropics. To solve this issue, efforts are underway to increase provitamin A carotenoids such as β-carotene in staple crops which can be achieved by breeding, metabolic engineering or a combination of both approaches. However, rational strategies to improve carotenoid content in crops require sufficient knowledge of pathway regulation. Therefore, to better understand how plants synthesize provitamin A and to guide metabolic engineering strategies in crops such as maize, the functional characterization of the new ζ-carotene isomerase (Z-ISO) is of significant importance.

Z-ISO was recently discovered in maize and Arabidopsis (Chen …

De Novo Design And Engineering Of Functional Metal And Porphyrin-Binding Protein Domains, Bernard Howard Everson

Dissertations, Theses, and Capstone Projects

In this work, I describe an approach to the rational, iterative design and characterization of two functional cofactor-binding protein domains. First, a hybrid computational/experimental method was developed with the aim of algorithmically generating a suite of porphyrin-binding protein sequences with minimal mutual sequence information. This method was explored by generating libraries of sequences, which were then expressed and evaluated for function. One successful sequence is shown to bind a variety of porphyrin-like cofactors, and exhibits light- activated electron transfer in mixed hemin:chlorin e6 and hemin:Zn(II)-protoporphyrin IX complexes. These results imply that many sophisticated functions such as cofactor binding and electron …

Tonic And Phasic Inhibitory Mechanisms Mediating Sensorimotor Decision-Making In The Goldfish Auditory Startle Circuit, Paul C.P. Curtin

Dissertations, Theses, and Capstone Projects

This work describes related studies of cellular and synaptic signaling mechanisms involved in the balance of excitation and inhibition in the goldfish auditory startle circuit. The general purpose of these experiments was to identify novel mechanisms that contribute to action selection at different stages of the motor control hierarchy. The methods applied to achieve this goal tested the effects of selective antagonists for target receptor systems on sound-evoked excitation and inhibition of startle.

Chapter 2 describes a study of a poorly-understood serotonergic mechanism, the 5-HT_5A receptor, that was not previously functionally characterized in native tissues or associated with neural …

Neural Mechanisms Underlying The Perception Of Three-Dimensional Shape From Texture: Adaptation And Aftereffects, Carole Filangieri

Dissertations, Theses, and Capstone Projects

Input into the visual system is two-dimensional (2D) and yet we effortlessly perceive the world around us as three-dimensional (3D). How we are able to accurately extract 3D shape information from the 2D representations that fall on the retina remains largely unknown. Although much research has been conducted that investigates higher levels of form processing (i.e. face recognition), less is known about the mechanisms that underlie the perception of simple 3D shape. Previous studies in our lab have shown that our ability to perceive 3D shape from texture cues relies on the visibility of orientation flows -- patterns that run …

Evolution Of Bat-Trypanosome Associations And The Origins Of Chagas Disease, Christian Miguel Pinto

Dissertations, Theses, and Capstone Projects

Trypanosoma cruzi is a genetically diverse parasite that causes Chagas disease, one of the most important zoonoses in the Americas. This generalist parasite of mammals belongs to a clade mostly comprised of bat parasites, the T. cruzi clade. The origins (i.e., biogeographic history and evolution of hosts associations) of this parasite are far from being understood, and the main areas that need further study are: species limits within T. cruzi sensu lato, further studies on the diversity of T. cruzi clade members and their hosts, and research on adaptations of the hosts to trypanosome infections. In this dissertation I explore …

Search For Host Factors Involved In Attachment Of Agrobacterium Tumefaciens To Plants, Anna Petrovicheva

Dissertations, Theses, and Capstone Projects

Agrobacterium tumefaciens is able to infect a diverse array of plants and causes crown gall disease. Typically these bacteria attach to plant roots and transform the plant cells to induce tumors. The mechanism of this attachment in the infection process is not yet fully understood. Using wild type Arabidopsis thaliana, Columbia-0, and several Arabidopsis mutant lines as a binding target, we screened for A. thaliana mutants with altered adhesion.

The A. thaliana mutant lines were selected in The Arabidopsis Information Resource (TAIR) according to possible location of the resulting protein and similarity to known transformation mutants. Of these mutants …

Conformational Heterogeneity And Exchange Within The Junction Of The Human U2-U6 Snrna Complex Measured By 19f Nmr Spectroscopy, Caijie Zhao

Dissertations, Theses, and Capstone Projects

Pre-mRNA splicing, the process by which non-coding sequences are removed and coding sequences are ligated, plays an important role in the maturation of precursor messenger RNA molecules prior to their translation into proteins. In eukaryotes, splicing is catalyzed by the spliceosome, a large and dynamic nuclear macromolecular "machine" that comprises five small nuclear (sn)RNA molecules and more than one hundred proteins. Among the RNA components, the complex formed between the U2 and U6 snRNA molecules is implicated in catalytic activity. In this dissertation, I have used ¹⁹F NMR techniques to characterize the conformation ("fold") and dynamics of a protein-free …

Integrating Phylogenomics, Biogeography And Systematics To Explore The Taxonomy And The Rise Of The Ratsnakes, Xin Chen

Dissertations, Theses, and Capstone Projects

Understanding the evolutionary processes that create the spectacular diversity of organisms, both in species numbers and form, is a primary goal for biologists. Global ratsnakes are a species-rich assemblage with high morphological and ecological diversity and a distribution that encompasses both the Old World (OW) and the New World (NW). To explore the mechanism leading to the divergence of the ratsnakes, I tested the hypotheses regarding the area of origin and global dispersal, and examined the patterns of diversification and trait evolution. Given adaptive radiation via ecological opportunity, a diversity-dependent diversification pattern and an early burst trait evolutionary pattern are …

Estimation Of Outer-Middle Ear Transmission Using Dpoaes And Fractional-Order Modeling Of Human Middle Ear, Maryam Naghibolhosseini

Dissertations, Theses, and Capstone Projects

Our ability to hear depends primarily on sound waves traveling through the outer and middle ear toward the inner ear. Hence, the characteristics of the outer and middle ear affect sound transmission to/from the inner ear. The role of the middle and outer ear in sound transmission is particularly important for otoacoustic emissions (OAEs), which are sound signals generated in a healthy cochlea, and recorded by a sensitive microphone placed in the ear canal. OAEs are used to evaluate the health and function of the cochlea; however, they are also affected by outer and middle ear characteristics. To …

Physiological And Subjective Aspects Of Positive Mood In Relation To Executive Functioning: The Potential Moderating Role Of Personality, Luz Helena Ospina

Dissertations, Theses, and Capstone Projects

Positive affect has been demonstrated to improve aspects of cognition. However, recent studies reveal that positive affect may hinder the same cognitive processes, such as executive functioning, memory and creativity. These discrepant findings may be due to differing levels of physiological arousal, a component of the circumplex model of affect, which has been largely ignored in affective research. For example, one recent study suggests that positive valence coupled with varying levels of physiological arousal (i.e., low, moderate, and high) may differentially affect performance on tasks of verbal fluency and memory. Furthermore, one other explanation for these inconsistent findings may relate …

Systematics And Biogeography Of Orthaea Kloztsch (Ericaceae: Vaccinieae), Nelson Salinas

Dissertations, Theses, and Capstone Projects

In the first chapter a study of the distribution patterns of the neotropical Vaccinieae (Ericaceae) is presented. Five areas of endemism were recovered: Central America, northern Chocó, southern Chocó, eastern Ecuador, and Yungas. Divergence times estimations indicate that the Andean clade of Vaccinieae migrated to South America during the Late Oligocene or Early Miocene (28.9-17.84 MA), and most of the subsequent diversification took place during the Tertiary. The Yungas was the first Andean area to be colonized, and several dispersals towards the north expanded their distribution range. Both areas of endemism and dispersal events were influenced by geological processes, such …

Sex Dependent Efficacy Of Taurine As A Treatment For Cocaine Drug Use: A Study Of Reward, Kevin Uribe

Dissertations and Theses

No abstract provided.

Effects Of Temperature Stress On Coral Fluorescence And Reflectance, Andrea Gomez

Dissertations and Theses

Around the world, climate change, land-based pollution and fishing impacts are recognized as principal threats to coral reef ecosystems. Sea surface temperatures, in particular, are expected to change dramatically over the next decades and result in high coral mortality in some regions. Through controlled experiments, I examined changes in coral fluorescence and reflectance in response to water temperature alterations to assess the potential of employing these signatures as a diagnostic tool to measure coral health. At the NOAA Coral Culture and Collaborative Research Facility, I conducted controlled laboratory-based heat stress experiments on three Caribbean species of coral: Acropora cervicornis, Orbicella …

Effects Of Acetyl Salicyclic Acid On Drosophila Models Of Cancer-Inflammation, Roma Rajwani

Dissertations and Theses

Chronic inflammation is a fundamental condition underlying many human disease pathologies including diabetes, cancer, and neurodegeneration. Indeed, one of the most commonly-used anti-inflammatory drugs, aspirin, has been shown to be effective in the treatment of many cancers. To understand the mechanistic linkages between inflammation and cancer, we used Drosophila models in which hyperactive immune signaling causes overproliferation of the hematopoietic system leading to the production of inflammatory blood tumors. In mutant animals, hematopoietic cells divide uncontrollably and exhibit pre-mature differentiation giving rise to large sticky cells. Some mutant cells infiltrate and adhere to cells of the fat body. The fat …

Characterization Of The Interaction Between Ftsz-Ring Stabilizer Zapc And The Conserved Protease Clpxp In E. Coli Cytokinesis, Andrea Cardenas Arevalo

Dissertations and Theses

Cell division in bacteria requires the assembly of a macromolecular protein machinery at midcell that is spatiotemporally regulated during the bacterial cell cycle. Central to the process of division is the assembly of a cytokinetic ring-like structure, termed the Z-ring, formed by polymers of the essential tubulin-homolog FtsZ. Polymerization of FtsZ is regulated by a number of proteins that bind FtsZ and regulate its assembly/disassembly mechanisms. Despite being extensively studied, the molecular nature of the diverse protein-protein interactions that regulate the assembly of FtsZ during early stages of division is not well understood. Here, I focus on an FtsZ-ring stabilizer …

"Model Complexity And Variable Selection In Maxent Niche Models: Analyses For Rodents In Madagascar", Peter Galante

Dissertations and Theses

Ecological niche models (ENMs) characterize the relationship between localities where a species is known to occur and the abiotic characteristics of these regions. While widely used, ENMs remain subject to several outstanding issues, including those related to model complexity and violation of modeling assumptions (e.g., representative sampling). Critical in resolving these issues is a better understanding of the effectiveness of model selection techniques. Here, I compare two strategies for optimizing ENMs: an information-criterion approach (AICc) and a sequential approach that assesses model performance on withheld data. I do so for a single species using two datasets, one with all available …

Development And Maintenance Of Thymic Epithelial Microenvironment, Varan J. Singh

Dissertations and Theses

Thymus is a primary lymphoid organ responsible for proper development and selection Of T-­‐cells. The thymic microenvironment, however, undergoes age related involution, Resulting in a reduction of the repertoire of T-­‐cells that are produced, and a decreased Capacity to respond to new antigen. Even though significant thymic epithelial turnover occurs, it is unclear if postnatal thymic progenitors/stem cell are responsible for the maintenance of the TEC microenvironment. Here we use the K5rtTA:TetO-­‐H2BGFP transgenic model to identify a slow cycling potential stem cells/progenitor population in the postnatal thymus. These cells were isolated, expanded in culture, and successfully differentiated into adipocytes, chondrocytes …