Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 59

Full-Text Articles in Life Sciences

Understanding How Sequence Differences Among Glutamate Transporters Might Contribute To Their Differential Function In Glutamate Clearance In C. Elegans, Irving Estevez Jan 2020

Understanding How Sequence Differences Among Glutamate Transporters Might Contribute To Their Differential Function In Glutamate Clearance In C. Elegans, Irving Estevez

Dissertations and Theses

In the nervous system, high circuit resolution requires efficient post-signaling clearance of the neurotransmitter. Glutamate-mediated neurotransmission involves the release of glutamate (Glu) into the synaptic cleft by the presynaptic cell and binding to glutamate receptors (GluR) on the postsynaptic cell, leading to activation of a signal transduction cascade. Neurotransmission is eventually terminated by Glu uptake via glutamate transporters (GluT). Inefficient Glu clearance is detrimental to precise rapid signaling, can lead to blurring of circuit resolution by inadvertent Glu spillover to nearby circuits, and may even be neurotoxic. While classical views depict synapses as insulated by glia, recent technological advances show ...


A Mendelian Randomization Study Of Coronary Artery Disease And Three Amino Acids: Alanine, Glycine, And Glutamine, Allan Uribe Jun 2019

A Mendelian Randomization Study Of Coronary Artery Disease And Three Amino Acids: Alanine, Glycine, And Glutamine, Allan Uribe

Dissertations and Theses

Cardiovascular disease is the leading cause of death worldwide. Coronary Artery Disease (CAD) accounts for the majority of those deaths. Observational studies have identified risk factors that have been helpful in lowering the death rate, including hypertension, high cholesterol, diabetes, smoking, physical inactivity and poor diet. The effects of these risk factors on CAD remain unclear. To clarify the effect of three amino acids, alanine, glutamine, and glycine on CAD I applied a two sample Mendelian randomization analysis to extensively genotyped observational data. In a sample with up to 184,000 individuals and approximately 60,000 controls, SNPs that reached ...


Multi-Locus Phylogenetic Inference Of The Howler Monkey (Alouatta) Radiation In South America., Esmeralda Ferreira Jan 2019

Multi-Locus Phylogenetic Inference Of The Howler Monkey (Alouatta) Radiation In South America., Esmeralda Ferreira

Dissertations and Theses

Abstract

Howler monkeys (Alouatta) are the most widely distributed New World primates, ranging from southern Mexico to northern Argentina. They occur in tropical rain forests, flooded and gallery forests, and deciduous and semi-deciduous environments. Despite their importance as seed dispersers, howlers have also been known to be ecological indicators. Available phylogenetic hypotheses for this genus have used chromosomal characters, morphological characteristics, and a limited number of molecular markers and specimens. In spite of these analyses, branching patterns among howler species lineages conflict between studies or remain unresolved. Using 14 unlinked non-coding intergenic nuclear regions under both a concatenated Bayesian approach ...


Mechanisms Of Microglia Mediated Apolipoprotien E Neurotoxicity, Pardeep Singh Jan 2019

Mechanisms Of Microglia Mediated Apolipoprotien E Neurotoxicity, Pardeep Singh

Dissertations and Theses

No abstract provided.


Evolution Of Floral Morphology And Symmetry In The Miconieae (Melastomataceae), Maria Gavrutenko Jan 2018

Evolution Of Floral Morphology And Symmetry In The Miconieae (Melastomataceae), Maria Gavrutenko

Dissertations and Theses

Analyses of evolution of floral morphology and symmetry broaden our understanding of the drivers of angiosperm diversification. Integrated within a flower, labile floral characters produce different phenotypes that promote variable interactions with pollinators. Thus, investigation of floral evolution may help infer potential historic transitions in pollinator modes and ecological pressures that generated present diversity. This study aims to explore morphological evolution of flowers in Miconieae, a species-rich Neotropical tribe within family Melastomataceae. Despite a constrained floral plan, Melastomataceae manage to achieve a variety of floral traits appealing to diverse pollinator types, with majority of the species requiring specialized “buzz pollination ...


Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack Jan 2018

Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack

Dissertations and Theses

Thymic epithelial cells (TEC) are essential for a proper adaptive immune response by regulating thymocyte development and establishing central tolerance. In the thymus, TECs differentially express Wnt proteins, which activate canonical and non-canonical Wnt signaling pathways. Wnt signaling is thought to regulate cell survival, proliferation, and development although the direct molecular mechanisms in TECs have yet to be elucidated. The inducible inhibition of canonical Wnt signaling with Dkk1 leads to a rapid loss of TEC progenitors as well as a decline in mature Aire-expressing mTECs. Therefore, we explore the role of Wnt ligands potentially responsible for stimulating and/or regulating ...


The Effect Of Stress Induced Premature Senescence On The Expression Of Heterogeneous Ribonucleoieoprotein, Yuriy Pechenyy Jan 2018

The Effect Of Stress Induced Premature Senescence On The Expression Of Heterogeneous Ribonucleoieoprotein, Yuriy Pechenyy

Dissertations and Theses

The role of heterogeneous nuclear ribonucleoproteins (hnRNP) in cellular senescence is yet to be defined. Cellular senescence is a terminal growth arrest in somatic cells. It is thought to be the consequence of telomeric shortening that acts as a DNA damage signal. Conversely, cells induced into premature senescence (SIPS) by oxidative stress, is independent of telomere attrition. Premature senescence has been proposed to be physiologically relevant as it can be induced by treatment with chemotherapeutic agents. In particular, we are studying the roles of hnRNP A1 and A2 in the maintenance of the senescence phenotype. hnRNPs are a family of ...


The Geographic Mosaic Of Wolbachia Infection In Melanitis Leda Butterfly Populations, Brandon E. Latorre Jan 2018

The Geographic Mosaic Of Wolbachia Infection In Melanitis Leda Butterfly Populations, Brandon E. Latorre

Dissertations and Theses

Insects are the most species-rich multicellular taxon on the planet, and it is estimated that more than half of all insect species are infected with the endosymbiont Wolbachia. This bacterium can manipulate the reproduction of its host and potentially affect host evolution. Most surveys investigating patterns of Wolbachia infection in nature sample limited numbers of individuals; population-level investigations into geographic differences in infection status that might affect host evolution are few. To investigate geographic variability among populations of a single species, we assayed 133 Melanitis leda butterflies (Lepidoptera: Nymphalidae: Satyrinae) for Wolbachia infection collected throughout its range in the Old ...


Bone Marrow Derived Progenitor Cells And Their Contributions To The Thymic Stroma, Mohammed Hoque Jan 2018

Bone Marrow Derived Progenitor Cells And Their Contributions To The Thymic Stroma, Mohammed Hoque

Dissertations and Theses

The thymus serves as the primary lymphoid organ responsible for the development and selection of a self-tolerant T cell repertoire. In paradox to its critical functions for the adaptive immune response, the thymus undergoes a profound age associated decline beginning in early adult life resulting in significant decline in T-cell function.Thymic epithelial cells (TECs) are the most critical component of the thymic microenvironment and undergo rapid turn-over, so understanding the cellular mechanisms responsible for the maintenance of TEC number and organization will be critical in counteracting age associated involution, particularly in cancer patients, due to enhanced degeneration in response ...


Enzymatically Active Microspheres For Self-Propelled Colloidal Engines, Jungeun Park Jan 2017

Enzymatically Active Microspheres For Self-Propelled Colloidal Engines, Jungeun Park

Dissertations and Theses

Micro- and nano-motors have attracted numerous attentions from various scientific areas due to their potential applications. Most studies on self-propelled colloidal engines have exploited catalytic decomposition of hydrogen peroxide to drive the motor. Since the hydrogen peroxide is caustic, it is not suitable to use in biological applications, encouraging people to develop “greener” fuels. The aim of this research is to study a new transduction mechanism for self-propulsion not tied to hydrogen peroxide, and which can in particular be used with biological molecules as fuels. In this study, we focus on making particles with enzymatic activity which can effectively decompose ...


Are Weevils Picky Eaters? Community Structure And Host Specificity Of Neotropical Saproxylic Beetles (Coleoptera: Curculionidae), Jhunior A. Morillo Jan 2017

Are Weevils Picky Eaters? Community Structure And Host Specificity Of Neotropical Saproxylic Beetles (Coleoptera: Curculionidae), Jhunior A. Morillo

Dissertations and Theses

Abstract Primary saproxylic beetles play a major role in forest nutrient cycling and making deadwood accessible to other decomposers. Understanding beetle host preferences and patterns of community assembly is critical for their conservation, and for predicting which species might become invasive. This project aims to investigate the ecological and host specificity, as well as the community composition of curculionids in a mosaic of old-growth (OG) and secondary forest on the Osa Peninsula, Costa Rica. The subfamily Scolytinae was expected to be the most species-rich and abundant. Ambrosia beetles were expected to have more generalist species than other curculionids. Old growth ...


A Phylogenetic And Environmental Analysis Of Brazilian Placosoma Lizards, Kai A. Farje-Van Vlack Jan 2017

A Phylogenetic And Environmental Analysis Of Brazilian Placosoma Lizards, Kai A. Farje-Van Vlack

Dissertations and Theses

Placosoma is a genus comprised of the Brazilian spectacled lizards P. champsonotus, P. cipoense, P. cordylinum, P. glabellum, and P. limaverdorum. While P. champsonotus, P. cordylinum, and P. glabellum occupy the southern coast of Brazil, P. cipoense is found in the montane grasslands north of that range, and P. limaverdorum was recently discovered in forest isolates that persist within the semi-arid Caatinga. This study elucidates the ecological and evolutionary relationships among these morphologically similar lizards. Using mitochondrial and nuclear gene sequences, genus-wide phylogenies were inferred through Bayesian inference and a species tree approach, and reconciled with geographical and climate data ...


Synthetic Functionalized Scaffolds For Culture And Maintenance Of Primary Human Hepatocytes, Douglas Macpherson Jan 2016

Synthetic Functionalized Scaffolds For Culture And Maintenance Of Primary Human Hepatocytes, Douglas Macpherson

Dissertations and Theses

There is deficit in the number of human livers that are available for transplantation. Additionally, there is no reliable model for the liver environment available for laboratory research. Tissue engineering provides alternatives for organ transplantation. We have created a supramolecular biomaterial out of simple peptide and saccharide building blocks to act as a hydrogel scaffold to support culture of liver cells. Using a self-­‐assembling peptide fiber decorated with functional molecules, we were able to culture primary human hepatocytes demonstrate their viability and maintenance of phenotype. The hydrogel material was formed by co-assembly in aqueous buffer and characterized using transmission ...


"Molecular Analysis Of Virulence Factors Unique To Leptopilina Heterotoma-A Parasitic Wasp Of Drosophila Spp.", Noelle Dziedzic Jan 2016

"Molecular Analysis Of Virulence Factors Unique To Leptopilina Heterotoma-A Parasitic Wasp Of Drosophila Spp.", Noelle Dziedzic

Dissertations and Theses

Endoparasitioid wasps of Drosophila spp. frequently avoid or overcome the immune defense mechanisms of their fly hosts. Leptopilina heterotoma (Lh) is a generalist wasp species, successful on many Drosophila spp. world-wide. During oviposition, the female wasp introduces venom proteins and virus-like particles (VLPs) into developing fly larvae. VLPs are endocytosed by plasmatocytes, a macrophage-like blood cell that is the most abundant hemocyte present in the circulating hemolymph. Once internalized, VLPs destroy plasmatocytes by programmed cell death. To understand the contributions of VLP proteins in VLP trafficking within host cells, we took advantage of proteomic data from purified Lh VLPs. Two ...


Revised Distributional Estimates For The Recently Discovered Olinguito (Bassaricyon Neblina), Using Museum And Science Records, Beth E. Gerstner Jan 2016

Revised Distributional Estimates For The Recently Discovered Olinguito (Bassaricyon Neblina), Using Museum And Science Records, Beth E. Gerstner

Dissertations and Theses

In the context of global change, a necessary first step for the conservation of species is gaining a good understanding of their distributional limits. This is especially important for biodiversity hotspots with high endemism such as the Northern Andes. The olinguito (Procyonidae: Bassaricyon neblina) is a recently described, medium-sized carnivoran found in Northern Andean cloud forests. A preliminary distributional model was published along with the original description, and I here provide revised distributional estimates using updated locality records and more current ENM methods. I build ecological niche models in Maxent using occurrence data (georeferenced museum records and citizen science-derived photo-vouchers ...


Expression And Function Of A Putative Cox-Like Gene In D. Melanogaster, Michelle S. Batchu Jan 2016

Expression And Function Of A Putative Cox-Like Gene In D. Melanogaster, Michelle S. Batchu

Dissertations and Theses

Cyclooxygenases (COX) are the enzymes that catalyze the conversion of arachidonic acid into prostaglandins. In mammals, isoform COX-1 is constitutively expressed, whereas the isoform COX-2 gene expression is induced, primarily at sites of inflammation. While eicosanoids play a major role in inflammation in insects, their existence in fruit flies has not been reported. Recent computational analyses by Qi and Singh (2014) have identified putative COX-like enzymes in the fruit fly Drosophila melanogaster. Here we compare the expression patterns of these enzymes and the effects of their knockdown in immune cells of D. melanogaster third instar larvae. Because of high genetic ...


The Impact Of Forest Successional Status On Community Structure Of Neotropical Cerambycid Beetles, Lin Li Jan 2015

The Impact Of Forest Successional Status On Community Structure Of Neotropical Cerambycid Beetles, Lin Li

Dissertations and Theses

Due to anthropogenic activities, tropical rain forests face many challenges in sustaining biodiversity and maintaining global climates. This project examines how forest successional status affects community composition of saproxylic cerambycids, which, as early colonists of moribund trees, have an important role in nutrient cycling. In the lowland rain forest of Costa Rica, thirty-nine trees in five plant families (Fabaceae, Lecythidaceae, Malvaceae, Moraceae, and Sapotaceae) were sampled in a mosaic of old growth and secondary forest. They yielded 3545 cerambycid individuals in 49 species. Species richness was almost identical in old growth and secondary forest; but abundance was higher in old-growth ...


Refinement Of Feedforward Projections, Neuronal Density, And Characterization Of Synapsesin Layer 4 Of Ferret Primary Visual Cortex, Violeta Contreras Ramirez Jan 2015

Refinement Of Feedforward Projections, Neuronal Density, And Characterization Of Synapsesin Layer 4 Of Ferret Primary Visual Cortex, Violeta Contreras Ramirez

Dissertations and Theses

No abstract provided.


Sex Dependent Efficacy Of Taurine As A Treatment For Cocaine Drug Use: A Study Of Reward, Kevin Uribe Jan 2015

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

Dissertations and Theses

No abstract provided.


The Drosophila Dynamin, Shibire, Contributes To Blood Cell Division And Differentiation, But May Not Be Required For Host Defence Against Parasitic Wasps, Adam D. Hudgins Jan 2015

The Drosophila Dynamin, Shibire, Contributes To Blood Cell Division And Differentiation, But May Not Be Required For Host Defence Against Parasitic Wasps, Adam D. Hudgins

Dissertations and Theses

No abstract provided.


Effects Of Temperature Stress On Coral Fluorescence And Reflectance, Andrea Gomez Jan 2015

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 ...


Characterization Of The Interaction Between Ftsz-Ring Stabilizer Zapc And The Conserved Protease Clpxp In E. Coli Cytokinesis, Andrea Cardenas Arevalo Jan 2015

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 ...


"Model Complexity And Variable Selection In Maxent Niche Models: Analyses For Rodents In Madagascar", Peter Galante Jan 2015

"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 ...


Development And Maintenance Of Thymic Epithelial Microenvironment, Varan J. Singh Jan 2015

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 ...


The Widespread Skink Mabuya Dorsivittata Reveals Complex Patterns Of Genetic Diversity In South America, Danielle Rivera Jan 2015

The Widespread Skink Mabuya Dorsivittata Reveals Complex Patterns Of Genetic Diversity In South America, Danielle Rivera

Dissertations and Theses

No abstract provided.


A Phylogeographic Study Of Two Neotropical Bird Species, The Red-Headed Manakin (Pipna Rubrocapilla) And The White-Crowned Manakin (Dixiphia Pipra)., Ivandy Castro-Astor Jan 2014

A Phylogeographic Study Of Two Neotropical Bird Species, The Red-Headed Manakin (Pipna Rubrocapilla) And The White-Crowned Manakin (Dixiphia Pipra)., Ivandy Castro-Astor

Dissertations and Theses

No abstract provided.


Caffeine's Attenuation Of Cocaine-Induced Deficiency In Acoustic Startle Response By Inhibition Of Adenosine In A Sex And Dose Dependent Manner, Lauren B. Malave Jan 2014

Caffeine's Attenuation Of Cocaine-Induced Deficiency In Acoustic Startle Response By Inhibition Of Adenosine In A Sex And Dose Dependent Manner, Lauren B. Malave

Dissertations and Theses

No abstract provided.


Chytrid Loads, Pathogen Prevalence, And Contemporary Host Source-Sink Dynamics In Dry Vs. Wet Forests; Evaluating Refugia From Disease In Australian Torrent Frogs., Barbara Rizzo Jan 2014

Chytrid Loads, Pathogen Prevalence, And Contemporary Host Source-Sink Dynamics In Dry Vs. Wet Forests; Evaluating Refugia From Disease In Australian Torrent Frogs., Barbara Rizzo

Dissertations and Theses

No abstract provided.


The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro Jan 2014

The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro

Dissertations and Theses

No abstract provided.


Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong Jan 2014

Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong

Dissertations and Theses

No abstract provided.