Life Sciences Commons^™

In Vitro Characterization Of Unmodified And Pyroglutamylated Alzheimer's Amyloid Beta Peptide, Jason Matos

Electronic Theses and Dissertations

Plaques of amyloid β peptide (Aβ) are a hallmark trait of Alzheimer’s disease (AD). However, the precise role of Aβ aggregates is not well understood. Recent studies have identified that naturally occurring N-terminal truncation and pyroglutamylation of Aβ significantly increases its neurotoxicity by an unknown mechanism. Content of pyroglutamylated Aβ (pE-Aβ) in AD brains has been shown to reach up to 50% of total Aβ. Modified pE-Aβ co-aggregates with Aβ by a seeding mechanism and forms structurally distinct and highly toxic oligomers. We studied structural transitions of the full-length Aβ1-42, its pyroglutamylated form AβpE3-42, their 9:1 (Aβ1-42/AβpE3-42) and 1:1 molar …

Effects Of Mechanical Habitat Disturbance On The Diversity And Network Structure Of Plant-Bee Interaction Networks In Central Florida, Karlie Carman

Electronic Theses and Dissertations

Ecological interactions within a community shape the structure of ecosystems and influence ecosystem function. Plant-pollinator interactions exist as mutualistic exchange networks that may collapse as habitat loss occurs, thereby threatening the overall health of an ecosystem. Understanding the impacts of human-mediated habitat disturbance on ecological interactions is therefore crucial for conservation efforts. Archbold Biological Station (ABS) in Venus, Florida contains over 2000 hectares of protected Florida scrub habitat nested within a human-dominated environment that is threatened by anthropogenic habitat disturbance. In past studies, over 113 bee species and 157 associated host plants, many endemic to the Lake Wales Ridge, have …

Effects Of Biotic Interactions On Coastal Wetland Communities With Applications For Restoration, Melinda Donnelly

Electronic Theses and Dissertations

Coastal wetland plants serve as ecological engineers in a physiologically stressful environment and the loss of coastal wetlands can cause negative effects throughout the estuarine system. Due to increased degradation of coastal habitats worldwide, interest in restoration has increased around the world. An understanding of the biotic processes affecting species distribution and diversity is critical for future conservation, management, and restoration of coastal wetlands. The purpose of my study was to test the effects of biotic interactions on native coastal wetland plants and determine how these interactions may be incorporated into current and future restoration projects. I had three primary …

Establishment Of Methods For Isolation Of Pnmt+ Cardiac Progenitor Cells, Namita Varudkar

Electronic Theses and Dissertations

Cardiovascular disease is the leading cause of death in the United States. Millions of patients suffer each year from endothelial dysfunction and/or debilitating myocardial damage resulting in decreased quality of life and increased risk of death or disablement. Current pharmacological approaches are only partly effective at treating cardiovascular disease, and hence, better strategies are needed to provide significant improvements in treatment options. Cardiac stem/progenitor cells have the potential to regenerate myocardial tissue and repair damaged heart muscle. There are many different types of cardiac progenitor cells, and each may have certain unique properties and characteristics that would likely be useful …

Genetic And Biochemical Characterization Of The Roles Of Two Putative Purine Transporters In The Infectious Cycle Of Borrelia Burgdorferi, Sunny Jain

Electronic Theses and Dissertations

Lyme disease, the most common tick borne disease in United States, is caused by the bacterial pathogen Borrelia burgdorferi. In nature, B. burgdorferi exists in an enzootic infectious cycle between an arthropod vector and mammalian hosts. Identification and characterization of the genes essential for B. burgdorferi survival throughout its infectious cycle is an important step toward understanding the molecular mechanisms involved in B. burgdorferi pathogenesis. B. burgdorferi contains a small genome, which lacks the genes encoding for the enzymes required for de novo synthesis of amino acids, fatty acids and nucleic acid precursors. Therefore, the spirochete is dependent upon the …

Unintended Outcomes Of Farmers' Adaptation To Climate Variability: Deforestation And Conservation In Calakmul And Maya Biosphere Reserves, Claudia Rodriguez-Solorzano

Dartmouth Scholarship

Minimizing the impact of climate change on farmer livelihoods is crucial, but adaptation efforts may have unintended consequences for ecosystems, with potential impacts on farmers’ welfare. Unintended outcomes of climate adaptation strategies have been widely discussed, however, empirical exploration has been neglected. Grounded in scholarship on climate adaptation, environmental governance, social–ecological systems, and land-use change, this paper studies whether farmers’ climate adaptation contributes to deforestation or forest conservation. The paper draws on interviews with 353 farmers from 46 communities in Calakmul Biosphere Reserve in Mexico and Maya Biosphere Reserve in Guatemala. Farmers in the area of study have implemented adaptation …

Bipolar Nanosecond Electric Pulses Are Less Efficient At Electropermeabilization And Killing Cells Than Monopolar Pulses, Bennett L. Ibey, Olga N. Pakhomova, Caleb C. Roth, Shu Xiao, Karl Schoenbach, Andrei G. Pakhomov

Bioelectrics Publications

Multiple studies have shown that bipolar (BP) electric pulses in the microsecond range are more effective at permeabilizing cells while maintaining similar cell survival rates as compared to monopolar (MP) pulse equivalents. In this paper, we investigated whether the same advantage existed for BP nanosecond-pulsed electric fields (nsPEF) as compared to MP nsPEF. To study permeabilization effectiveness, MP or BP pulses were delivered to single Chinese hamster ovary (CHO) cells and the response of three dyes, Calcium Green-1, propidium iodide (PI), and FM1-43, was measured by confocal microscopy. Results show that BP pulses were less effective at increasing intracellular calcium …

Efficacy Of Autologous Bone Marrow Buffy Coat Grafting Combined With Core Decompression In Patients With Avascular Necrosis Of Femoral Head: A Prospective, Double-Blinded, Randomized, Controlled Study, Yuanchen Ma, Tao Wang, Junxing Liao, Honglin Gu, Xinpeng Lin, Qing Jiang, Max Bulsara, Minghao Zheng, Qiujian Zheng

Health Sciences Papers and Journal Articles

Introduction

Avascular necrosis of femoral head (ANFH) is a progressive disease that often leads to hip joint dysfunction and even disability in young patients. Although the standard treatment, which is core decompression, has the advantage of minimal invasion, the efficacy is variable. Recent studies have shown that implantation of bone marrow containing osteogenic precursors into necrotic lesion of ANFH may be promising for the treatment of ANFH.

Methods

A prospective, double-blinded, randomized controlled trial was conducted to examine the effect of bone-marrow buffy coat (BBC) grafting combined with core decompression for the treatment of ANFH. Forty-five patients (53 hips) with …

Effect Of Acute L-Alanyl-L-Glutamine (Sustamine) And Electrolyte Ingestion On Plasma Electrolytes, Physiologic Measures, And Neuromuscular Fatigue During Endurance Exercise, William Mccormack

Electronic Theses and Dissertations

The purpose of this study was to compare the efficacy of two dose levels of L-Alanyl-LGlutamine in a commercially available sports drink to the sports drink only on time to exhaustion, neuromuscular fatigue and physiological measures during prolonged endurance exercise. Twelve endurance-trained males (23.5±3.7 yrs; 175.5±5.4 cm; 70.7±7.6 kg) performed four trials, each consisting of 1 hr treadmill runs at 75% of VO2peak followed by a run to exhaustion at 90% of VO2peak. The trials differed in type of hydration. One trial consisted of no hydration (NHY), another required ingestion of only a sports drink (ET), and two trials required …

Validation Of A Novel Hypothesis Of Generating Foam Cells By Its Use To Study Reverse Cholesterol Transport, Bhaswati Sengupta

Electronic Theses and Dissertations

Generation of foam cells, an essential step for reverse cholesterol transport (RCT) studies, uses the technique of receptor dependent macrophage loading with radiolabeled acetylated Low Density Lipoprotein (Ac-LDL). In this study, we used the ability of a biologically relevant detergent molecule, Lysophosphatidylcholine (Lyso PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabelled cholesterol / Lyso PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month storage. Macrophages incubated …

A Time-Course Analysis Of Behavioral Plasticity And Differential Gene Expression Patterns In Response To Density In Schistocerca Americana (Orthoptera: Acrididae), Steven Gotham

Electronic Theses and Dissertations

Phenotypic plasticity is the ability of the genotype to express alternative phenotypes in response to different environmental conditions and this is considered to be an adaptation in which a species can survive and persist in a rapidly changing environment. Some grasshoppers and locusts are capable of expressing an extreme form of density-dependent phenotypic plasticity, known as locust phase polyphenism. At low population density, the individuals typically have a cryptic coloration as nymphs, are less active, and only seek out conspecifics for reproductive purposes. At high density, however, they develop a drastically different phenotype in which they have a conspicuous coloration, …

Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall

Electronic Theses and Dissertations

Cerium oxide nanoparticles are established scavengers of reactive oxygen and nitrogen species. They have many potential biomedical applications that depend on their physicochemical properties and mode of preparation. Recent studies have found these nanoparticles possess phosphatase mimetic activity. Studying such catalytic activities will qualify their biomedical applications and render information on their bioavailability and potential toxicity. Two oxidation states of cerium exist in these nanoparticles (3+ or 4+). It is hypothesized that the oxidation state of cerium in the nanoparticles determines the amount of adsorbed water on the crystal lattices. This in turn governs their activity as phosphatases. Nanoparticles with …

Remediation Of Tetracycline From Water Sources Using Vetiver Grass (Chrysopogon Zizanioides L. Nash) And Tetracycline-Tolerant Root-Associated Bacteria, Aparupa Sengupta

Dissertations, Master's Theses and Master's Reports - Open

Antibiotics are emerging contaminants worldwide. Due to insufficient policy regulations, public awareness, and the constant exposure of the environment to antibiotic sources has created a major environmental concern. Wastewater treatment plants (WWTP) are not equipped to filter-out these compounds before the discharge of the disinfected effluent into water sources (e.g., lakes and streams) and current available technologies are not equipped to remediate these compounds from environmental sources. Hence, the challenge remains to establish a biological system to remove these antibiotics from wastewater. An invitro hydroponic remediation system was developed using vetiver grass (Chrysopogon zizanioides L. Nash) to remediate tetracycline …

Development And Validation Of The Anterior Cruciate Ligament Injury-Risk-Estimation Quiz (Acl-Iq), Erich J. Petushek

Dissertations, Master's Theses and Master's Reports - Open

Over 2 million Anterior Cruciate Ligament (ACL) injuries occur annually worldwide resulting in considerable economic and health burdens (e.g., suffering, surgery, loss of function, risk for re-injury, and osteoarthritis). Current screening methods are effective but they generally rely on expensive and time-consuming biomechanical movement analysis, and thus are impractical solutions. In this dissertation, I report on a series of studies that begins to investigate one potentially efficient alternative to biomechanical screening, namely skilled observational risk assessment (e.g., having experts estimate risk based on observations of athletes movements). Specifically, in Study 1 I discovered that ACL injury risk can be accurately …

Application Of An Imputation Method For Geospatial Inventory Of Forest Structural Attributes Across Multiple Spatial Scales In The Lake States, U.S.A., Ram K. Deo

Dissertations, Master's Theses and Master's Reports - Open

Credible spatial information characterizing the structure and site quality of forests is critical to sustainable forest management and planning, especially given the increasing demands and threats to forest products and services. Forest managers and planners are required to evaluate forest conditions over a broad range of scales, contingent on operational or reporting requirements. Traditionally, forest inventory estimates are generated via a design-based approach that involves generalizing sample plot measurements to characterize an unknown population across a larger area of interest. However, field plot measurements are costly and as a consequence spatial coverage is limited. Remote sensing technologies have shown remarkable …

A Theoretical Study Of Interaction Of Nanoparticles With Biomolecule, Chunhui Liu

Dissertations, Master's Theses and Master's Reports - Open

Many types of materials at nanoscale are currently being used in everyday life. The production and use of such products based on engineered nanomaterials have raised concerns of the possible risks and hazards associated with these nanomaterials. In order to evaluate and gain a better understanding of their effects on living organisms, we have performed first-principles quantum mechanical calculations and molecular dynamics simulations. Specifically, we will investigate the interaction of nanomaterials including semiconducting quantum dots and metallic nanoparticles with various biological molecules, such as dopamine, DNA nucleobases and lipid membranes.

Firstly, interactions of semiconducting CdSe/CdS quantum dots (QDs) with the …

Enzyme Optimization For Lignocellulose Hydrolysis Using Mechanistic Modeling, Adam S. Marlowe

Dissertations, Master's Theses and Master's Reports - Open

A novel mechanistic model for the saccharification of cellulose and hemicellulose is utilized to predict the products of hydrolysis over a range of enzyme loadings and times. The mechanistic model considers the morphology of the substrate and the kinetics of enzymes to optimize enzyme concentrations for the enzymatic hydrolysis of cellulose and hemicellulose simultaneously. Substrates are modeled based on their fraction of accessible sites, glucan content, xylan content, and degree of polymerizations. This enzyme optimization model takes into account the kinetics of six core enzymes for lignocellulose hydrolysis: endoglucanase I (EG1), cellobiohydrolase I (CBH1), cellobiohydrolase II (CBH2), and endo-xylanase (EX) …

Ionic Liquid Extraction Unveils Previously Occluded Humicbound Iron In Peat Porewater, Timothy J. Veverica

Dissertations, Master's Theses and Master's Reports - Open

Extracellular iron reduction has been suggested as a candidate metabolic pathway that may explain a large proportion of carbon respiration in temperate peatlands. However, the o-phenanthroline colorimetric method commonly employed to quantitate iron and partition between redox species is known to be unreliable in the presence of humic and fulvic acids, both of which represent a considerable proportion of peatland dissolved organic matter. We propose ionic liquid extraction as a more accurate iron quantitation and redox speciation method in humic-rich peat porewater. We evaluated both o-phenanthroline and ionic liquid extraction in four distinct peatland systems spanning a gradient of physico-chemical …

Beyond Roots Alone: Novel Methodologies For Analyzing Complex Soil And Minirhizotron Imagery Using Image Processing And Gis Tools, Justina A. Silva

Dissertations, Master's Theses and Master's Reports - Open

Quantifying belowground dynamics is critical to our understanding of plant and ecosystem function and belowground carbon cycling, yet currently available tools for complex belowground image analyses are insufficient. We introduce novel techniques combining digital image processing tools and geographic information systems (GIS) analysis to permit semi-automated analysis of complex root and soil dynamics. We illustrate methodologies with imagery from microcosms, minirhizotrons, and a rhizotron, in upland and peatland soils. We provide guidelines for correct image capture, a method that automatically stitches together numerous minirhizotron images into one seamless image, and image analysis using image segmentation and classification in SPRING or …

Denitrification In Soils: From Genes To Environmental Outcomes, Jianqiu Zheng

Dissertations, Master's Theses and Master's Reports - Open

Denitrification is an important process of global nitrogen cycle as it removes reactive nitrogen from the biosphere, and acts as the primary source of nitrous oxide (N₂O). This thesis seeks to gain better understanding of the biogeochemistry of denitrification by investigating the process from four different aspects: genetic basis, enzymatic kinetics, environmental interactions, and environmental consequences. Laboratory and field experiments were combined with modeling efforts to unravel the complexity of denitrification process under microbiological and environmental controls.

Dynamics of denitrification products observed in laboratory experiments revealed an important role of constitutive denitrification enzymes, whose presence were further confirmed …

Sub-Canopy Temperature Dynamics Of A Native Tree Plantation From A Lowland Tropical Rainforest In Costa Rica, Victor D. Carmona-Galindo, Traci-Lynn Hirai, Stacie Samuelson, Cherie Hale, Elizabeth Braker

Biology Faculty Works

With urbanization encroaching upon forestlands, characterizing microclimates in secondary forests will be important for the sustainable management of microclimates in agroforestry systems. We used micro-sensors to characterize changes in temperature at different heights in the sub-canopy of both secondary forest and 15-year-old agroforestry plots. Results show that while agroforestry plots had different temperature profiles from the secondary forest, the monoculture plot (consisting of Pentaclethra macroloba) had temperatures similar to the profile found in the secondary forest. This suggests that the replication of temperature profiles in a secondary forest may be independent of the number of tree species in a plot …

Drosophila Hematopoiesis: Markers And Methods For Molecular Genetic Analysis, Cory J. Evans, Ting Liu, Utpal Banerjee

Biology Faculty Works

Analyses of the Drosophila hematopoietic system are becoming more and more prevalent as developmental and functional parallels with vertebrate blood cells become more evident. Investigative work on the fly blood system has, out of necessity, led to the identification of new molecular markers for blood cell types and lineages and to the refinement of useful molecular genetic tools and analytical methods. This review briefly describes the Drosophila hematopoietic system at different developmental stages, summarizes the major useful cell markers and tools for each stage, and provides basic protocols for practical analysis of circulating blood cells and of the lymph gland, …

Stage-Dependent Plasticity Of The Anterior Neural Folds To Form Neural Crest, Maxellende Ezin

Biology Faculty Works

The anterior neural fold (ANF) is the only region of the neural tube that does not produce neural crest cells. Instead, ANF cells contribute to the olfactory and lens placodes, as well as to the forebrain and epidermis. Here, we test the ability of the ANF to form neural crest by performing heterotopic transplantation experiments in the chick embryo. We find that, at the neurula stage (HH stage 7), the chick ANF retains the ability to form migrating neural crest cells when transplanted caudally to rostral hindbrain levels. This ability is gradually lost, such that by HH9, this tissue appears …

The Taxonomic Status And Geographic Distribution Of The European Hare (Lepus Europaeus Pallas, 1778) In Turkey (Mammalia: Lagomorpha), Yasi̇n Demi̇rbaş, İrfan Albayrak

Turkish Journal of Zoology

This study was based on 125 specimens of hares collected from 61 different localities in Turkey between 2006 and 2010. We present diagnostic characters, pelage coloration, external, cranial and phallic measurements, skull and phallus features, hair structure, and collection localities of hares from Turkey. Additionally, we analyze morphometric variations of 5 regional populations according to the physiography/orography of the study area. Among the morphometric variables, 10 characters (weight, tail length, basal length, condylobasal length, rostral breadth, height of braincase, foramen incisiva length, occipitonasal length, profile length, and mandible length) are found to be significantly different between the populations (ANOVA, P < 0.01). Principal component analysis of 22 morphometric measurements is performed, and 71.56% of total variance is explained through 5 principle components. The Thracian specimen is distinguished from other populations on the first 2 canonical discriminant functions and the cluster dendrogram. The hair structure, as examined by scanning electron microscope, is found to be flattened and imbricate. Our Anatolian specimens are discussed at the subspecies level, comparing them to the relevant literature, and it is concluded that Lepus europaeus in Anatolia is represented by only one subspecies, Lepus europaeus syriacus.

Morphological Examination Of The Resting Egg Structure Of 3 Cladoceran Species [Ceriodaphnia Quadrangula (O. F. Müller, 1785), Daphnia Longispina (O. F. Müller, 1776), And D. Magna Straus, 1820], Murat Kaya, Sevi̇l Erdoğan

Turkish Journal of Zoology

Morphological characteristics of the resting egg, which is important to ensure the continuity of generations, were examined to understand if there were morphologically significant differences among 3 cladoceran species. Resting eggs floating on the water surface were collected by a plankton net with a mesh size of 100 \mum from Mamasın Dam Lake in November 2012 and were left to dry at room temperature in the laboratory. In this study, the size, shape, and color of the ephippium and the size of the egg/eggs enclosed in the ephippium were comparatively analyzed by stereomicroscope and scanning electron microscope. It was observed …

Rumen Ciliate Fauna (Ciliophora, Protista) Of Turkish Domestic Goats Living In İzmir, Turkey, Gözde Gürelli̇

Turkish Journal of Zoology

Species composition and distribution of rumen ciliates were investigated in the rumen contents of 15 domestic goats living in İzmir, Turkey. Nineteen species and 10 morphotypes belonging to 7 genera were identified. The mean number of ciliates was (94.3 ± 33.4) × 10^4 cells mL^{-1} rumen contents, which is higher than that of other goat hosts reported from Turkey and the world. The mean number of ciliate species per host was 9.2 ± 3.4. Entodinium semahatae, E. rostratum, and Ophryoscolex purkynjei m. bifidoquadricinctus are new host records for goats. This is only the second reported occurrence of E. semahatae in …

Biological Diversity And Seasonal Variation Of Mesozooplankton In The Southeastern Black Sea Coastal Ecosystem, İlknur Yildiz, Ali̇ Muzaffer Feyzi̇oğlu

Turkish Journal of Zoology

In this study, the seasonal distribution of mesozooplankton was investigated between 1999 and 2006 at a station located in the southeastern Black Sea region. A total of 40 cruises were done within the southeastern continental shelf throughout this period in order to collect mesozooplankton samples. A total of 10 mesozooplankton species were identified. The average annual highest abundances of species were 67,770 ind./m^2 in 2000 (Penilia avirostris), 50,048 ind./m^2 in 2001 (Sagitta setosa), 42,143 ind./m^2 in 2006 (Oikopleura dioica), 27,987 ind./m^2 in 2005 (Acartia clausi), 25,792 ind./m^2 in 2001 (Oithona similis), 24,806 ind./m^2 in 2005 (Pseudocalanus elongatus), 12,094 ind./m^2 in …

A Behavioral Analysis Of Achromatic Cue Perception By The Ant Cataglyphis Aenescens (Hymenoptera; Formicidae), Volkan Aksoy, Yilmaz Çamlitepe

Turkish Journal of Zoology

Behavioral responses of Cataglyphis aenescens foragers to various monochromatic light stimuli were tested. Foragers were trained to associate lights of 370 (UV), 440 (blue), 540 (green), and 640 nm (red) with a food reward on a circular orientation platform and were then tested to determine the threshold intensity values of these wavelengths they could perceive. Foragers significantly responded to all wavelengths at training intensities but their homeward orientation diminished with decreasing stimulus intensity. The results showed that UV and green lights could be perceived at lower intensities compared to blue and red lights. Foragers were further trained in a Y-maze …

Age-Dependent Variations In The Venom Proteins Of Vipera Kaznakovi Nikolsky, 1909 And Vipera Ammodytes (Linnaeus, 1758) (Ophidia: Viperidae), Hüseyi̇n Arikan, Bayram Göçmen, Naşi̇t İğci̇, Bahadir Akman

Turkish Journal of Zoology

Polyacrylamide disc gel electrophoresis and densitometry analysis were used to analyze venom extracts of Vipera kaznakovi (16.5, 30, and 55 cm) and Vipera ammodytes (28.5, 36.7, and 51.5 cm) specimens of 3 different lengths. V. kaznakovi specimens were collected from Hopa (Artvin Province); 2 V. ammodytes specimens were from Ağva (İstanbul Province) and the longest one was from Yuvacık (Kocaeli Province). The electropherograms of the venom protein samples showed age-dependent qualitative and quantitative variations.

Herpetofauna Of The Vicinity Of Akşehir And Eber (Konya, Afyon), Turkey, Durmuş Ci̇han, Cemal Varol Tok

Turkish Journal of Zoology

In this research, 29 species of 11 amphibian and reptile families were detected in the endorheic basin of Akşehir and Eber. Of these species, 5 are anurans, 1 is a tortoise, 1 is a turtle, 9 are lizards, and 13 are snakes. In addition, the chorotype classification of the species recorded in the study area and their distributions depending on plants are also provided. It was established that specimens of subspecies Ophisops elegans macrodactylus and O. e. centralanatolia were sympatrically found in the vicinity of Ortaköy and Tuzlukçu. Moreover, in addition to the species determined in previous studies, Platyceps najadum …