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Full-Text Articles in Life Sciences

Genetic Interactions Between The Guanine Nucleotide Exchange Factor Gefmeso And Gtpase Signaling Components In The Drosophila Wing Reveal Microenvironment Dependent Variation Within Gtpase Signaling N, Ashley Megan Iketani Jan 2012

Genetic Interactions Between The Guanine Nucleotide Exchange Factor Gefmeso And Gtpase Signaling Components In The Drosophila Wing Reveal Microenvironment Dependent Variation Within Gtpase Signaling N, Ashley Megan Iketani

Electronic Theses and Dissertations

The Ras superfamily of GTPases are important regulators of morphogenesis involved in control of cytoskeletal dynamics, intracellular trafficking, apical-basal polarity and cell migration. Mis-regulation of GTPase signaling interferes with development and is linked to pathogenesis. Traditionally, GTPase signaling has been depicted as a series of independent linear pathways. However, recently it has become apparent that multiple GTPases can interact to regulate a single cellular process, functioning in poorly understood networks of cross talk between pathways during development. Jim Fristrom (unpublished data) identified a mutation (18-5) that interacts with components of the GTPases Rho1, Rala, and Cdc42 signaling in multiple developmental …


Light-Activated Binary Nucleotide Reagent For Inactivation Of Dna Polymerase, Evan M. Cornett Jan 2012

Light-Activated Binary Nucleotide Reagent For Inactivation Of Dna Polymerase, Evan M. Cornett

Electronic Theses and Dissertations

This work explores a binary reagent approach to increase the specificity of covalent inhibitors. In this approach, two ligand analogs equipped with inert pre-reactive groups specifically bind a target biopolymer. The binding event brings the pre-reactive groups in proximity with each other. The two groups react, generating active chemical intermediates that covalently modify and inactivate the target. In the present study we compare the new approach with the traditional single-component reagent strategy using DNA polymerase from bacteriophage T4 as a model target biopolymer. We report the design and synthesis of two analogs of deoxythymidine triphosphate, a natural DNA polymerase substrate. …


Placing Birds On A Dynamic Evolutionary Map: Using Digital Tools To Update The Evolutionary Metaphor Of The "Tree Of Life", Sonia Stephens Jan 2012

Placing Birds On A Dynamic Evolutionary Map: Using Digital Tools To Update The Evolutionary Metaphor Of The "Tree Of Life", Sonia Stephens

Electronic Theses and Dissertations

This dissertation describes and presents a new type of interactive visualization for communicating about evolutionary biology, the dynamic evolutionary map. This web-based tool utilizes a novel map-based metaphor to visualize evolution, rather than the traditional "tree of life." The dissertation begins with an analysis of the conceptual affordances of the traditional tree of life as the dominant metaphor for evolution. Next, theories from digital media, visualization, and cognitive science research are synthesized to support the assertion that digital media tools can extend the types of visual metaphors we use in science communication in order to overcome conceptual limitations of traditional …


Adaptive Tolerance To Ocean Acidification In The Marine Sponge: Chondrilla Nucula, Sylvester Lee Jan 2012

Adaptive Tolerance To Ocean Acidification In The Marine Sponge: Chondrilla Nucula, Sylvester Lee

Electronic Theses and Dissertations

The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has led to a 30% increase in ocean acidification over pre-industrial levels. Although most ocean acidification research thus far has focused on calcifying organisms such as corals, the potential of this increase in acidity (H+ ions) to cause acid-base imbalances in soft-bodied animals such as sponges has been grossly overlooked. Furthermore, many studies on ocean acidification have not considered the elevated temperatures that are predicted to accompany future climate change conditions. Sponges are crucial components to coral reef systems, providing food, nutrients, structure, and support. The sponge Chondrilla nucula …


Effects Of Hydrologic Connection On Physicochemical Conditions And Algal Properties In Backwaters Of The Lower Mississippi River, Orathai Pongruktham Jan 2012

Effects Of Hydrologic Connection On Physicochemical Conditions And Algal Properties In Backwaters Of The Lower Mississippi River, Orathai Pongruktham

Electronic Theses and Dissertations

In the last 50-100 years, the Mississippi River has been extensively engineered for flood control and navigation purposes. These modifications have substantially decreased the frequency of flooding and degree of contact of the river with its historical floodplain. However, in many areas within the current levee system there remain numerous secondary channels and other backwater sites with which the river is hydrologically connected on a seasonal basis. In this study, the relationships of surface hydrologic connection with the main channel of the Lower Mississippi River to limnological properties and development of phytoplankton biomass in three backwater sites having different patterns …


Valproic Acid-Induced Teratogenesis In Japanese Rice Fish (Oryzias Latipes) Embryogenesis, Mengmeng Wu Jan 2012

Valproic Acid-Induced Teratogenesis In Japanese Rice Fish (Oryzias Latipes) Embryogenesis, Mengmeng Wu

Electronic Theses and Dissertations

Valproic acid (VPA) was introduced as an antiepileptic in 1967 in France and it has become the most prescribed anticonvulsive drug therapy worldwide since then. In the clinic, valproic acid is selected to treat absence seizures, myoclonic seizures, generalized tonic-clonic seizures, atonic attacks and partial seizures. Epilepsy is the second most comneurologic disorder that affects pregnant women (0.5%–1%). Approximately 1 out of 250 pregnant women are taking antiepileptic drugs. Valproic acid is designated as a human teratogen, which induces major congenital anomalies, facial dysmorphic features, and autistic-like behaviors, which affect verbal, cognitive, communicative, and social abilities of affected children. We …


Biochemical Studies Of Abce1, Lynn Sims Jan 2012

Biochemical Studies Of Abce1, Lynn Sims

Electronic Theses and Dissertations

The growth and survival of all cells require functional ribosomes that are capable of protein synthesis. The disruption of the steps required for the function of ribosomes represents a potential future target for pharmacological anti-cancer therapy. ABCE1 is an essential Fe-S protein involved in ribosomal function and is vital for protein synthesis and cell survival. Thus, ABCE1 is potentially a great therapeutic target for cancer treatment. Previously, cell biological, genetic, and structural studies uncovered the general importance of ABCE1, although the exact function of the Fe-S clusters was previously unclear, only a simple structural role was suggested. Additionally, due to …


Effect Of Predation Risk And Food Availability On Parental Care And Nest Survival In Suburban And Wildland Florida Scrub-Jays, Joseph M. Niederhauser Jan 2012

Effect Of Predation Risk And Food Availability On Parental Care And Nest Survival In Suburban And Wildland Florida Scrub-Jays, Joseph M. Niederhauser

Electronic Theses and Dissertations

Individual organisms often use cues from their natural environments to determine many behavioral and life-history "decisions." These "decisions" are usually adaptive, i.e. a response to selection, because the environmental cues on which they are based reliably correlate with increased fitness over time. When the selected behavioral response to a natural cue no longer provides a fitness benefit, then selection for a new response may occur but individuals maintaining the previously selected response may suffer reduced survival and reproduction. Especially in human-modified landscapes individuals making a maladaptive behavioral or life-history choice based on those formerly reliable environmental cues may be faced …


Fine-Scale Geographic Variation Of Stable Isotope And Fatty Acid Signatures Of Three Fish Species In The Indian River Lagoon, Fl, Jennifer Fletcher Odom Jan 2012

Fine-Scale Geographic Variation Of Stable Isotope And Fatty Acid Signatures Of Three Fish Species In The Indian River Lagoon, Fl, Jennifer Fletcher Odom

Electronic Theses and Dissertations

The Indian River Lagoon, Florida, is a unique closed “bar built” estuary system that has little interchange with the Atlantic Ocean and which is home to many resident species. Three fish species were investigated to see if their isotopic and fatty acid signatures differed based on geographic location. The goal was to assess the degree of resolution of spatial variation that is possible when using stable isotope and fatty acid signature analysis to interpret feeding habits and potential linkages between feeding habits and health status. Spotted seatrout (n=40), pinfish (n=60) and white mullet (n=60) were collected over a 4 week …


Signals Delivered By Interleukin-7 Regulate The Activities Of Bim And Jund In T Lymphocytes, Shannon Moore Ruppert Jan 2012

Signals Delivered By Interleukin-7 Regulate The Activities Of Bim And Jund In T Lymphocytes, Shannon Moore Ruppert

Electronic Theses and Dissertations

Interleukin-7 (IL-7) is an essential cytokine for lymphocyte growth that has the potential for promoting proliferation and survival. While the survival and proliferative functions of IL-7 are well established, the identities of IL-7 signaling components in pathways other than JAK/STAT, that accomplish these tasks remain poorly defined. To this end, we used IL-7 dependent T-cells to examine those components necessary for cell growth and survival. Our studies revealed two novel signal transducers of the IL-7 growth signal: BimL and JunD. IL-7 promoted the activity of JNK (Jun N-terminal Kinase), and that JNK, in turn, drove the expression of JunD, a …


Dispersal, Gene Flow, And Adaptive Evolution During Invasion: Testing Range-Limit Theory With The Asian Tiger Mosquito, Kimberly Medley Jan 2012

Dispersal, Gene Flow, And Adaptive Evolution During Invasion: Testing Range-Limit Theory With The Asian Tiger Mosquito, Kimberly Medley

Electronic Theses and Dissertations

Understanding the factors that make non-native species successful invaders is an important step towards mitigating spread. At the same time, species invasions can serve as natural experiments to test range-limit theory. Range-limit theory postulates declines in local abundance (abundant center model) and genetic diversity (central-peripheral hypothesis) towards range edges because of underlying environmental gradients. Such declines constrain adaptation to marginal habitats via gene swamping. However, broader evolutionary theory predicts intermediate rates of immigration into range-edge populations can relieve genetic drift and improve adaptive potential. I tested hypotheses generated from theory while illuminating aspects affecting of the invasion of the Asian …


The Effects Of Phosphatidylserine On Reaction Time And Cognitive Function Following An Exercise Stress, Adam John Wells Jan 2012

The Effects Of Phosphatidylserine On Reaction Time And Cognitive Function Following An Exercise Stress, Adam John Wells

Electronic Theses and Dissertations

Phosphatidylserine (PS) is an endogenously occurring phospholipid that has been shown to have cognition and mood enhancing properties in humans, possibly through its role as an enzyme co-factor in cellular signal transduction. Specifically, PS has been identified as activator of classical isoforms of protein kinase C, an enzyme known to be involved in the growth and differentiation of neural cells, and is therefore thought to play a role in the protection of neurons. The purpose of this study was to examine the effects of supplementation with PS and caffeine on measures of cognition, reaction time and mood prior to and …


Phosphatidic Acid Increases Lean Body Tissue And Strength In Resistance Trained Men, David Williams Jan 2012

Phosphatidic Acid Increases Lean Body Tissue And Strength In Resistance Trained Men, David Williams

Electronic Theses and Dissertations

Phosphatidic Acid (PA) is a natural phospholipid compound derived from lecithin which is commonly found in egg yolk, grains, fish, soybeans, peanuts and yeast. It has been suggested that PA is involved in several intracellular processes associated with muscle hypertrophy. Specifically, PA has been reported to activate protein synthesis through the mammalian target of rapamycin (mTOR) signaling pathway and thereby may enhance the anabolic effects of resistance training. To our knowledge, no one has examined the effect of PA supplementation in humans while undergoing a progressive resistance training program. To examine the effect of PA supplementation on lean soft tissue …


Quantifying The Impacts Of Oyster Reef Restoration On Oyster Coverage, Wave Attenuation And Seagrass Fragment Retention In Mosquito Lagoon, Florida, Stephanie Garvis Jan 2012

Quantifying The Impacts Of Oyster Reef Restoration On Oyster Coverage, Wave Attenuation And Seagrass Fragment Retention In Mosquito Lagoon, Florida, Stephanie Garvis

Electronic Theses and Dissertations

The goal of this project was to determine the effects of oyster reef restoration on oyster coverage, wave height dissipation and seagrass recruitment. First, to assess the current versus historical coverage of natural, dead and restored oyster reefs within Mosquito Lagoon, aerial photographs from 2009, provided by Saint Johns River Water Management District, were digitized using ArcGIS software. Live reefs, restored reefs and dead reefs were screen digitized using a reef ‘signature’ in order to estimate the area of each type of reef. The 2009 maps were used as a guide to digitizing the historical aerial photographs (1943, 1951, 1967, …


Expression Of Lipase From Mycobacterium Tuberculosis In Nicotiana Tobacum And Lactuca Sativa Chloroplasts, Bethany Lloyd Jan 2012

Expression Of Lipase From Mycobacterium Tuberculosis In Nicotiana Tobacum And Lactuca Sativa Chloroplasts, Bethany Lloyd

Electronic Theses and Dissertations

Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis (M. tuberculosis), is a global threat and the leading cause of death among individuals infected with HIV. TB treatment requires multi-drug cocktails, due to the increasing rates of drug resistance of the bacterium. With multi-drug cocktails, strains have been documented to be resistant to all major drugs in the fight against TB. Since the strains are drug resistant, it calls for an increasing need for vaccine and treatment development for the purpose of preventing and managing the disease. The most widely distributed vaccine against TB is Bacillus Calmette-Gue´rin (BCG). Apart from being …


Cerium Oxide Nanoparticles Act As A Unique Catalyst And Scavenge Nitric Oxide And Peroxynitrite And Decrease Rns In Vitro And In Vivo, Janet Dowding Jan 2012

Cerium Oxide Nanoparticles Act As A Unique Catalyst And Scavenge Nitric Oxide And Peroxynitrite And Decrease Rns In Vitro And In Vivo, Janet Dowding

Electronic Theses and Dissertations

Cerium oxide nanoparticles (CeO2 NPs)(nanoceria) have been shown to possess a substantial oxygen storage capacity via the interchangeable surface reduction and oxidation of cerium atoms, cycling between the Ce4+ and Ce3+ redox states. Reduction of Ce4+ to Ce3+ causes oxygen vacancies or defects on the surface of the crystalline lattice structure of the particles, generating a cage for redox reactions to occur. The study of the chemical and biological properties of CeO2 NPs has expanded recently, and the methods used to synthesize these materials are also quite diverse. This has led to a plethora of studies describing various preparations of …


Conservation And Population Biology: Genetics, Demography And Habitat Requirements Of The Atlantic Coast Beach Mice, Haakon Myklevoll Kalkvik Jan 2012

Conservation And Population Biology: Genetics, Demography And Habitat Requirements Of The Atlantic Coast Beach Mice, Haakon Myklevoll Kalkvik

Electronic Theses and Dissertations

The conservation biology field seeks to preserve biodiversity and the processes shaping that variation. Conservation biology is intimately tied to evolutionary research, in order to identify evolutionary distinct lineages that may be in danger of disappearing. Interestingly, patterns and processes of lineage divergence and persistence change with respect to spatial and temporal scale. I seek to evaluate biodiversity, the factors that have shaped this heterogeneity, and how this variability persists. To accomplish this I used a phylogeographic approach as well as niche and population modeling on the Peromyscus maniculatus species group found widely distributed in North America. My emphasis was …


Manipulation Of Host Signal Transduction Pathways And Cytoskeleton Functions By Invasive Bacterium Listeria Monocytogenes And Chlamydia Trachomatis, Shahanawaz Jiwani Jan 2012

Manipulation Of Host Signal Transduction Pathways And Cytoskeleton Functions By Invasive Bacterium Listeria Monocytogenes And Chlamydia Trachomatis, Shahanawaz Jiwani

Electronic Theses and Dissertations

Infectious disease remains one of the leading causes of morbidity and mortality worldwide. Many bacteria that cause disease have the capacity to enter into eukaryotic cells such as epithelial cells and tissue macrophages. Gaining access into the intracellular environment is one of the most critical steps in their survival and/or in pathogenesis. The entry mechanisms employed by these organisms vary considerably, but most mechanisms involve sabotaging and manipulating host cell functions. Invasion of epithelial cells involves triggering host signal transduction mechanisms to induce cytoskeleton rearrangement, thereby facilitating bacterial uptake. My work focuses on understanding the molecular mechanisms employed by bacterial …


Beyond Building A Tree: Phylogeny Of Pitvipers And Exploration Of Evolutionary Patterns, Allyson Fenwick Jan 2012

Beyond Building A Tree: Phylogeny Of Pitvipers And Exploration Of Evolutionary Patterns, Allyson Fenwick

Electronic Theses and Dissertations

As generic and higher-scale evolutionary relationships are increasingly well understood, systematists move research in two directions: 1) understanding specieslevel relationships with dense taxon sampling, and 2) evaluating evolutionary patterns using phylogeny. In this study I address both foci of systematic research using pitvipers, subfamily Crotalinae. For direction one, I evaluate the relationships of 96% of pitvipers by combining independent sets of molecular and phenotypic data. I find the inclusion of species with low numbers of informative characters (i.e. less than 100) negatively impacts resolution of the phylogeny, and the addition of independent datasets has no effect on or a small …


Defective Dynamics Of Mitochondria In Amyotrophic Lateral Sclerosis And Huntington's Disease, Wenjun Song Jan 2012

Defective Dynamics Of Mitochondria In Amyotrophic Lateral Sclerosis And Huntington's Disease, Wenjun Song

Electronic Theses and Dissertations

Mitochondria play important roles in neuronal function and survival, including ATP production, Ca2+ buffering, and apoptosis. Mitochondrial dysfunction is a common event in the pathogenesis of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD); however, what causes the mitochondrial dysfunction remains unclear. Mitochondrial fission is mediated by dynamin-related protein 1 (DRP1) and fusion by mitofusin 1/2 (MFN1/2) and optic atrophy 1 (OPA1), which are essential for mitochondrial function. Mutations in the mitochondrial fission and fusion machinery lead to neurodegeneration. Thus, whether defective mitochondrial dynamics participates in ALS and HD requires further investigation. ALS is a fatal …


Novel Immunogens Of Cellular Immunity Revealed Using In Vitro Human Cell-Based Approach, Brian Schanen Jan 2012

Novel Immunogens Of Cellular Immunity Revealed Using In Vitro Human Cell-Based Approach, Brian Schanen

Electronic Theses and Dissertations

In the last 150 years, tremendous headway has been made in our understanding of the human immune system. Pioneers in the field such as Paul Ehrlich, Elie Metchnikoff, Louis Pasteur, Robert Koch and Walter Reed carried out seminal studies that established the groundwork for our understanding of humoral and cellular immunity in humans. However, this direct line of evidence into human immunology was diverted in the mid-20th century with the adoption of a model which allowed for investigators to use a reductionist-approach with the promise to resolve immunity at a molecular level. This revolutionary model was the scientific commercialization of …


Life History Response To Infection And The Potential For Dishonest Signals In The Ground Cricket, Allonemobius Socius, Emily Copeland Jan 2012

Life History Response To Infection And The Potential For Dishonest Signals In The Ground Cricket, Allonemobius Socius, Emily Copeland

Electronic Theses and Dissertations

In order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as “life-history trade-offs”. Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual signal, which provides an honest signal of the male’s infection status to potential mates. However, if individual residual reproductive value is low, they may instead increase their reproductive investment to maximize reproductive success before the end of their …


Pedometers Accelerometers And Observational Methods: A Comparison Of Measurements Of Physical Activity In Fourth-Grade Students., Amanda E. Greene Dec 2011

Pedometers Accelerometers And Observational Methods: A Comparison Of Measurements Of Physical Activity In Fourth-Grade Students., Amanda E. Greene

Electronic Theses and Dissertations

In recent years physical inactivity among students has become a matter of great concern. Nearly 65% of students do not meet the daily recommended level of physical activity, which is 60 minutes or more of moderate to vigorous physical activity each day, with 50% of that time being spent in moderate to vigorous levels of activity (CDC, 2010b). As a result, the 21st century has shown to be a time of many health problems such as, obesity, diabetes, and heart disease. In fact, nearly one third of all children are considered obese or overweight (Slawta & DeNeui, …


Use Of Isometric Mid-Thigh Pull To Determine Asymmetrical Strength Differences In Ncaa D-I Athletes., Ethan Monroe Owens Dec 2011

Use Of Isometric Mid-Thigh Pull To Determine Asymmetrical Strength Differences In Ncaa D-I Athletes., Ethan Monroe Owens

Electronic Theses and Dissertations

The purpose of this study is to investigate the use of isometric mid-thigh pulls to determine lower-limb asymmetrical strength differences in NCAA D-I athletes. Sixty-six subjects (40 males and 26 females) performed 2 maximal effort isometric pulls over two force plates sampling at 1000 Hz each. Peak force was scaled for body weight, and rate of force development was examined from 0-200ms. Results of the study show subjects' produced significantly greater scaled force with the left leg as compared to the right leg; however, no significant differences existed for rate of force development (RFD). Men exhibited significant differences between both …


Synthesis Of Resveratrol Esters And Aliphatic Acids., Stanley Mofor Jing Dec 2011

Synthesis Of Resveratrol Esters And Aliphatic Acids., Stanley Mofor Jing

Electronic Theses and Dissertations

Resveratrol (RV) is a naturally occurring phytoalexin of the stilbenoid family produced by some plant species, and present in grape skin, peanuts, and red wine. It has been found to exhibit anti-cancer, anti-inflammatory, anti-viral, anti-aging, cardio protective, and anti-oxidant properties. Bioavailability is a huge setback that limits the potentials of RV. As a result, efforts have been made to design and synthesize RV esters and aliphatic acids in an attempt to increase its bioavailability, solubility in water, and possibly improving its biological activities. Resveratrol esters, 3,5,4'-triacetyloxystilbene (2) and Methyl 1,1',1''- (3,4',5-stilbenyl)-1,6-hexanedioate (3) have been synthesized. Compound 3 is a new …


Isolation Of A Rhodococcus Soil Bacterium That Produces A Strong Antibacterial Compound., Ralitsa Bogomilova Borisova Dec 2011

Isolation Of A Rhodococcus Soil Bacterium That Produces A Strong Antibacterial Compound., Ralitsa Bogomilova Borisova

Electronic Theses and Dissertations

Rhodococci are notable for their ability to degrade a variety of natural and xenobiotic compounds. Recently, interest in Rhodococcus has increased due to the discovery of a large number of genes for secondary metabolism. Only a few secondary metabolites have been characterized from the rhodococci (including 3 recently described antibiotics). Twenty-four new Rhodococcus strains were isolated from soils in East Tennessee using acetonitrile enrichment culturing and identified using 16S rRNA analysis. Forty-seven Rhodococcus strains were screened for antibiotic production using a growth inhibition assay. One strain, MTM3W5.2, had 90% similarity to the Rhodococcus opacus 16S rRNA gene sequence and produced …


But Does It Work? The Impact Of Social Media Use On Interpretive Outcomes And Place Attachments At San Francisco Bay Area Parks, Eric Knackmuhs Dec 2011

But Does It Work? The Impact Of Social Media Use On Interpretive Outcomes And Place Attachments At San Francisco Bay Area Parks, Eric Knackmuhs

Electronic Theses and Dissertations

Many parks are now using social media sites to connect with visitors but little is known about how effective these efforts have been. This study examined the influence of social media use on interpretive outcomes and place attachment. Visitors to four parks in the San Francisco Bay Area were surveyed twice, once as they exited the park (n = 529) and a second time via email (n = 216) six to ten weeks after visiting. In both surveys, respondents were asked how they use social media to experience parks and to what extent they experienced interpretive outcomes (intellectual and emotional …


Feeding Practices Of Mothers In The Gobi Desert Of Mongolia, Julie F. Tate Dec 2011

Feeding Practices Of Mothers In The Gobi Desert Of Mongolia, Julie F. Tate

Electronic Theses and Dissertations

The diets of Mongolia infants are deficient in vitamins and minerals and complementary foods are introduced too early. Breastfeeding is the best source of nutrition for infants until 6 months of age. A survey of 50 Mongolian mothers with children under the age of 5 in the town of Sainshand, Dornogobi, was conducted in July 2011. Mongolian infants are among the highest percent of infants in the world who are exclusively breastfed for the first 6 months of their lives, thus providing them with excellent nutrition. However, complementary feedings and supplements are not appropriately used or understood. Therefore, the diets …


An Evaluation Of Coating Material Dependent Toxicity Of Silver Nanoparticles, Thilini Upekshika Silva Dec 2011

An Evaluation Of Coating Material Dependent Toxicity Of Silver Nanoparticles, Thilini Upekshika Silva

Electronic Theses and Dissertations

Silver nanoparticles (AgNPs) synthesized using numerous types of coating materials may exhibit different toxicity effects. The study evaluated coating material dependent toxicity by selecting 3 types of AgNP synthesis methods with different coating materials (citrate, polyvinyl pyrrolidone, and branched polyethyleneimine, coated AgNPs as citrate-AgNPs, PVP-AgNPs, and BPEI-AgNPs respectively). Two acute aquatic toxicity tests were performed; 48hr D. magna and MetPLATE E. coli toxicity tests. Significantly different toxicity effects were observed in D. magna test exhibiting lethal median concentrations (LC50) for citrate-AgNPs, PVP-AgNPs, and BPEI AgNPs respectively as, 2.7, 11.2, and 0.57μg/L. Median inhibitory concentrations (EC50) for MetPLATE tests were 1.27, …


Effect Of Pesticides On Salicylic Acid Binding Protein 2 (Sabp2) And Plant Defense, Joannes Petrus Yuh Dec 2011

Effect Of Pesticides On Salicylic Acid Binding Protein 2 (Sabp2) And Plant Defense, Joannes Petrus Yuh

Electronic Theses and Dissertations

Tobacco SABP2 has been shown to display high affinity for salicylic acid (SA) and methylsalicylate (MeSA) and plays an important role in SAR signal development. Using biochemical approach, SABP2 has been shown to demonstrate strong esterase activity in converting MeSA to SA. Recent study shows that tetra fluoroacetophenone, a synthetic analog of SA, competitively inhibits SABP2 esterase activity as well as suppresses SAR signal development in tobacco mosaic virus (TMV)-infected tobacco plants. Not much has been studied on the effect of pesticides on plant defenses. Because both AChE and SABP2 are esterase-like proteins belonging to α/β hydroxylase superfamily, we hypothesize …