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Articles 121 - 150 of 367
Full-Text Articles in Biology
Synthetic Functionalized Scaffolds For Culture And Maintenance Of Primary Human Hepatocytes, Douglas Macpherson
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 electron …
Expression And Function Of A Putative Cox-Like Gene In D. Melanogaster, Michelle S. Batchu
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 …
"Molecular Analysis Of Virulence Factors Unique To Leptopilina Heterotoma-A Parasitic Wasp Of Drosophila Spp.", Noelle Dziedzic
"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
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) …
The Impeccable Timing Of The Apple Maggot Fly, Rhagoletis Pomonella (Dipetera: Tephritidae), And Its Implications For Ecological Speciation, Monte Arthur Mattsson
The Impeccable Timing Of The Apple Maggot Fly, Rhagoletis Pomonella (Dipetera: Tephritidae), And Its Implications For Ecological Speciation, Monte Arthur Mattsson
Dissertations and Theses
Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping explain the role of ecology in generating biodiversity. Adaptive radiations are often propelled by selective fitness tradeoffs experienced by individuals that invade new habitats, resulting in reproductive isolation from ancestral conspecifics and potentially cladogenesis. Host specialist insects are among the most speciose organisms known and serve as highly useful models for studying adaptive radiations. We are just beginning to understand the pace and degree with which these insects diversify. The apple maggot, Rhagoletis …
Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner
Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner
Dissertations and Theses
In order to complete their life cycles, vertebrates require oxygen and water. However, environments are not always forgiving when it comes to constantly providing these basic needs for vertebrate life. The annual killifish Austrofundulus limnaeus is possibly the most well described extremophile vertebrate and its embryos have been shown to tolerate extremes in oxygen, salinity, and water availability. This phenotype is likely a result of the annual killifish life history, which includes periods of temporary habitat desiccation and oxygen deprivation, and requires the production of stress-tolerant embryos that depress metabolism in a state of suspended animation, known as diapause. Over …
The Role Of Pyrococcus Furiosus Transcription Factor E In Transcription Iniitiation, Robyn Lynn Eustis
The Role Of Pyrococcus Furiosus Transcription Factor E In Transcription Iniitiation, Robyn Lynn Eustis
Dissertations and Theses
All sequenced archaeal genomes encode a general transcription factor, TFE, which is highly conserved and homologous to the alpha subunit of the eukaryotic transcription factor TFIIE. TFE functions to increase promoter opening efficiency during transcription initiation, although the mechanism for this is unclear. The N-terminus of TFE contains a common DNA binding motif, a winged helix. At the tip of this winged helix is a highly conserved region of aromatic amino acids that is close to DNA during initiation. TFE activation can compensate for mutations in another transcription factor, TFB2, which is homologous to TFIIB. P. furiosus encodes two paralogs …
Neurobiology Of Seasonal Life-History Transitions, Ashley Rae Lucas
Neurobiology Of Seasonal Life-History Transitions, Ashley Rae Lucas
Dissertations and Theses
Many animals exhibit seasonal changes in life-history stages, and these seasonal transitions are often accompanied by dramatic switches in behavior. While the neuroendocrine mechanisms that regulate such behavioral transitions are poorly understood, arginine vasotocin (AVT) and neuropeptide Y (NPY) are excellent candidates because they regulate reproductive and feeding behavior, respectively. In this study, I asked if seasonal changes in AVT and/or NPY are concomitant with spring migration away from the breeding grounds, as male and female red-sided garter snakes (Thamnophis sirtalis parietalis) are transitioning from reproductive to non-reproductive behavior during this time. To address this question, I collected …
Investigations Of Larval Pacific Lamprey Entosphenus Tridentatus Osmotic Stress Tolerance And Occurrence In A Tidally-Influenced Estuarine Stream, Gregory Shell Silver
Investigations Of Larval Pacific Lamprey Entosphenus Tridentatus Osmotic Stress Tolerance And Occurrence In A Tidally-Influenced Estuarine Stream, Gregory Shell Silver
Dissertations and Theses
Pacific lamprey is a culturally valuable species to indigenous people, and has significant ecological importance in freshwater and marine ecosystems. Over the past several decades, constrictions in range and reductions in Pacific lamprey abundance have been observed in Western North America, and may be indicators of range-wide declines. In the face of declining populations, the U.S. Fish and Wildlife Service has partnered with tribal, state, federal, and local entities to implement a regional Pacific lamprey conservation agreement aimed at reducing threats to Pacific lamprey and improving their habitats and population status. Research needs identified in the conservation agreement include assessing …
Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue
Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue
Dissertations and Theses
Genetic mutation is the ultimate source of new phenotypic variation in populations. The importance of mutation cannot be understated, and constitutes a significant evolutionary force. Although single mutations may have little to no impact on organismal performance or fitness, when multiplied across the total number of potential sites within the genome, mutation can have a large impact. Accurate measurement of the rates, molecular mechanisms, and distributions of effects of mutations are critical for many applications of evolutionary theory. Despite the importance of both deleterious and beneficial mutations, their genome-wide patterns and phenotypic consequences are poorly understood when considering the mitochondrial …
Effects Of Acetyl Salicyclic Acid On Drosophila Models Of Cancer-Inflammation, Roma Rajwani
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 …
Effects Of Temperature Stress On Coral Fluorescence And Reflectance, Andrea Gomez
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
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
"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
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 …
The Widespread Skink Mabuya Dorsivittata Reveals Complex Patterns Of Genetic Diversity In South America, Danielle Rivera
The Widespread Skink Mabuya Dorsivittata Reveals Complex Patterns Of Genetic Diversity In South America, Danielle Rivera
Dissertations and Theses
No abstract provided.
The Impact Of Forest Successional Status On Community Structure Of Neotropical Cerambycid Beetles, Lin Li
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
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.
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
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.
Sex Dependent Efficacy Of Taurine As A Treatment For Cocaine Drug Use: A Study Of Reward, Kevin Uribe
Sex Dependent Efficacy Of Taurine As A Treatment For Cocaine Drug Use: A Study Of Reward, Kevin Uribe
Dissertations and Theses
No abstract provided.
Assessment Of Arbuscular Mycorrhizal Symbiosis On Invasion Success In Brachypodium Sylvaticum, Caitlin Elyse Lee
Assessment Of Arbuscular Mycorrhizal Symbiosis On Invasion Success In Brachypodium Sylvaticum, Caitlin Elyse Lee
Dissertations and Theses
The effects that mutualistic soil biota have on invasive species success is a growing topic of inquiry. Studies of the interactions between invasive plants and arbuscular mycorrhizal fungi (AMF) have shown changes in AMF community composition, reductions in AMF associations in invasive plants, and changes in native species fitness and competitive outcomes in invasive-shifted AMF communities. These findings support the degraded mutualist hypothesis, where invasive species alter the mutualist community composition, resulting in detrimental associations with the new mutualist community for native species. Here I present two studies that examine various aspects of the arbuscular mycorrhizal fungal (AMF) mutualism in …
Characterization Of Functional Domains Of Cul3, An E3 Ubiquitin Ligase, Using Chimeric Analysis, Jennifer Anne Mitchell
Characterization Of Functional Domains Of Cul3, An E3 Ubiquitin Ligase, Using Chimeric Analysis, Jennifer Anne Mitchell
Dissertations and Theses
Modification of cellular proteins with molecules of ubiquitin is an important process that regulates the activity of cellular proteins. Cullin RING ligases (CRLs) are multi-subunit complexes that act in concert with E2 enzymes to attach molecules of ubiquitin to protein substrates. There are seven CRLs in mammalian cells (Cul1, Cul2, Cul3, Cul4A, Cul4B, Cul5, and Cul7) that are highly homologous in sequence and structure. CRLs possess a highly conserved C- terminal domain that interacts with E2 enzymes, and a more variable N- terminal domain which recruits substrates through distinct substrate adapter molecules. Despite the structural similarity, these CRLs recognize distinct …
The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai
The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai
Dissertations and Theses
The hyperthermophile archaeon, Pyrococcus furiosus encodes two eukaryotic TFIIB family proteins, TFB1 and TFB2. TFB1 is very similar to TFIIB in terms of sequence homology and function, whereas TFB2 is unusual as it is missing highly conserved sequences in its N-terminal domain that are present in TFIIB and TFB1. Despite this, TFB2 is effective in transcription process, albeit with lower efficiency compared to TFB1. Other archaea also contain multiple TFBs, but unlike Pyrococcus furiosus TFB2, these multiple TFBs have higher sequence homology to each other and have similar transcription efficiencies. Photochemical cross-linking experiments have shown that the B-reader of TFB …
Temperature Dependent Transcription Initiation In Archaea: Interplay Between Transcription Factor B And Promoter Sequence, Ming-Hsiao Wu
Temperature Dependent Transcription Initiation In Archaea: Interplay Between Transcription Factor B And Promoter Sequence, Ming-Hsiao Wu
Dissertations and Theses
In Pyrococcus furiosus (Pfu), a hyperthermophile archaeon, two transcription factor Bs, TFB1 and TFB2 are encoded in the genomic DNA. TFB1 is the primary TFB in Pfu, and is homologous to transcription factor IIB (TFIIB) in eukaryotes. TFB2 is proposed to be a secondary TFB that is compared to TFB1, TFB2 lacks the conserved B-finger / B-reader / B-linker regions which assist RNA polymerase in transcription start site selection and promoter opening functions respectively. P. furiosus, like all Archaea, encodes a single transcription factor E (TFE), that is homologous to the N-terminus of transcription factor II …
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.
Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong
Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong
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
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.
The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro
The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro
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
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.
Kos Modulation Of Mitochondrial Fission And Fusion, Herman Kucharavy
Kos Modulation Of Mitochondrial Fission And Fusion, Herman Kucharavy
Dissertations and Theses
No abstract provided.