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Full-Text Articles in Life Sciences

Investigation Of Chemotaxis Genes And Their Functions In Geobacter Species, Hoa T. Tran Sep 2009

Investigation Of Chemotaxis Genes And Their Functions In Geobacter Species, Hoa T. Tran

Open Access Dissertations

Geobacter species are δ-Proteobacteria and are often predominant in the Fe(III) reduction zone of sedimentary environments. Their abilities to remediate contaminated environments and to produce electricity have inspired extensive studies. Cell motility, biofilm formation, and type IV pili, which have been shown to be regulated by chemotaxis genes in other bacteria, all appear important for the growth of Geobacter species in changing environments and for electricity production. The genomes of Geobacter species show the presence of a significant number of chemotaxis gene homologs, suggesting important roles for them in the physiology of Geobacter species, although gene functions are not ...


Determinants For Stop-Transfer And Post-Import Pathways For Protein Targeting To The Chloroplast Inner Envelope Membrane, Antonio Americo Barbosa Viana Sep 2009

Determinants For Stop-Transfer And Post-Import Pathways For Protein Targeting To The Chloroplast Inner Envelope Membrane, Antonio Americo Barbosa Viana

Open Access Dissertations

Chloroplast biogenesis relies on the import of thousands of nuclear encoded proteins into the organelle and proper sorting to their sub-organellar compartment. The majority of nucleus-encoded chloroplast proteins are synthesized in the cytoplasm and imported into the organelle via the Toc-Tic translocation systems of the chloroplast envelope. In many cases, these proteins are further targeted to subcompartments of the organelle (e.g. the thylakoid membrane and lumen or inner envelope membrane) by additional targeting systems that function downstream of the import apparatus. The inner envelope membrane (IEM) plays key roles in controlling metabolite transport between the organelle and cytoplasm, and ...


Fabrication Of Protein-Polysaccharide Particulates Through Thermal Treatment Of Associative Complexes, Owen Griffith Jones Sep 2009

Fabrication Of Protein-Polysaccharide Particulates Through Thermal Treatment Of Associative Complexes, Owen Griffith Jones

Open Access Dissertations

Mixed solutions of β-lactoglobulin and anionic polysaccharides, specifically pectin, were formed into associative complexes through pH reduction from neutral conditions. Thermal treatment of these associative complexes was investigated as a function of biopolymer composition, heating conditions, pH, and ionic strength. Thermal treatment of β-lactoglobulin-pectin complexes at pH 4.5 – 5.0 was found to create protein-based particulates of consistent and narrow size distribution (diameter ~ 150 – 400 nm). These particulates were relatively stable to further pH adjustment and to high levels of salt (200 NaCl). Particle characteristics were maintained after re-suspending them in aqueous solutions after they have been either frozen ...


Tyrosine Phosphorylation Events In Mouse Sperm Capacitation, Enid Arcelay Sep 2009

Tyrosine Phosphorylation Events In Mouse Sperm Capacitation, Enid Arcelay

Open Access Dissertations

Mammalian sperm are not able to fertilize immediately upon ejaculation; they become fertilization-competent after undergoing changes in the female reproductive tract collectively termed capacitation. Although it has been established that capacitation is associated with an increase in tyrosine phosphorylation, little is known about the role of this event in sperm function. In this work we used a combination of two dimensional gel electrophoresis and mass spectrometry to identify proteins that undergo tyrosine phosphorylation during capacitation. Some of the identified proteins are the mouse orthologues of human sperm proteins known to undergo tyrosine phosphorylation. Among them we identified VDAC, tubulin, PDH ...


Investigations Into The Potential For 3,4-Methylenedioxymethamphetamine To Induce Neurotoxic Terminal Damage To Serotonergic Neurons, Dominik Biezonski Sep 2009

Investigations Into The Potential For 3,4-Methylenedioxymethamphetamine To Induce Neurotoxic Terminal Damage To Serotonergic Neurons, Dominik Biezonski

Open Access Dissertations

High doses of 3,4-methylenedioxymethamphetamine (MDMA; "Ecstasy") are known to reduce levels of various serotonergic markers outside of the raphe nuclei. To test the hypothesis that these deficits reflect a degeneration of distal axons/terminals, we investigated the effects of an MDMA binge (10mg/kg x 4) on the relative protein and genetic expression of several serotonergic markers in rats, as well as the effects of this compound on the quantity of serotonergic terminals in these animals. In experiment I, we examined whether MDMA alters serotonin transporter (SERT) levels as determined by lysate binding and immunoblotting analyses. Both methods of ...


The Activity Of Eg5 And Dynein During Mammalian Mitosis, Nicholas P. Ferenz Sep 2009

The Activity Of Eg5 And Dynein During Mammalian Mitosis, Nicholas P. Ferenz

Open Access Dissertations

The development and maintenance of multicellular organisms depends fundamentally on cell division, a series of events largely mediated by the mitotic spindle. Errors in spindle formation and/or function are often associated with severe consequences, most notably cancer. In order to elucidate the cause of such errors and the potential for therapeutic intervention, it is imperative to attain a clear understanding of how cell division normally operates. In this regard, this dissertation focuses on the activity of two microtubule-based motor proteins, Eg5 and dynein, prior to and immediately following nuclear envelope breakdown during mitosis. I show that prophase microtubules are ...


Notch1 Modulation Of Lymphoid Target Genes, Ok Hyun Cho Sep 2009

Notch1 Modulation Of Lymphoid Target Genes, Ok Hyun Cho

Open Access Dissertations

Over the past decades, information has accumulated concerning the mechanism how an exterior signal induced by ligand on neighboring cells is transmitted to the nucleus through the Notch receptor and the cellular effects of Notch signaling on the regulation of differentiation, proliferation and apoptosis in many cell types. However, the function and the mechanism of Notch signaling in peripheral T cells still remains to be addressed. Therefore, we asked whether Notch1 is involved in CD8+ cytolytic effector T cell (CTLs) maturation and effector functions and how Notch1 exerts its cellular function in the nucleus and in the cytoplasm. The maturation ...


Development Of Structured Delivery Systems Using Nanolaminated Biopolymer Layers, Young-Hee Cho Sep 2009

Development Of Structured Delivery Systems Using Nanolaminated Biopolymer Layers, Young-Hee Cho

Open Access Dissertations

The objectives of this study were to carry out research to better understand of the formation, stability and properties of multilayer emulsions containing nano-laminated biopolymer coatings, and to utilize this information to develop food-grade delivery systems. The effect of various preparation parameters on the formation and stability of multilayer emulsions was investigated: droplet concentration; mean droplet diameter; droplet charge; biopolymer concentration. β-lactoglobulin (β-Lg) stabilized emulsions (0.5 – 10 wt% oil) containing different pectin concentrations (0 to 0.5 wt%) were prepared at pH 7 (where lipid droplets and pectin molecules were both anionic) and pH 3.5 (where lipid droplets ...


Distribution And Diversity Of Planktonic Ciliates: Patterns And Processes, Mary Doherty Sep 2009

Distribution And Diversity Of Planktonic Ciliates: Patterns And Processes, Mary Doherty

Open Access Dissertations

The nature and extent of microbial biodiversity remain controversial with persistent debates over patterns of distributions (i.e. cosmopolitanism vs. endemism) and the processes that structure these patterns (neutrality vs. selection). We used culture-independent approaches to address these issues focusing on two groups of ciliates, the Oligotrichia (Spirotrichea) and Choreotrichea (Spirotrichea). To assess the diversity of these ciliates, we designed primers specific to SSU rDNA of ciliates within these clades, and investigated (1) geographic and temporal distributions along three coastal sites in the Northwest Atlantic; (2) the relationship between ciliate communities in the benthos and the plankton along the New ...


Ciliate Biodiversity And Phylogenetic Reconstruction Assessed By Multiple Molecular Markers, Micah Dunthorn Sep 2009

Ciliate Biodiversity And Phylogenetic Reconstruction Assessed By Multiple Molecular Markers, Micah Dunthorn

Open Access Dissertations

Ciliates provide a powerful system within microbial eukaryotes in which molecular genealogies can be compared to detailed morphological taxonomies. Two groups with such detailed taxonomies are the Colpodea and the Halteriidae. There are about 200 described Colpodea species that are found primarily in terrestrial habitats. In Chapters 1 and 2, taxon sampling is increased to include exemplars from all major subclades using nuclear small subunit rDNA (nSSU-rDNA) sequencing. Much of the morphological taxonomy is supported, but extensive non-monophyly is found throughout. The conflict between some nodes of the nSSU-rDNA genealogy and morphology-based taxonomy suggests the need for additional molecular marker ...


Piping Plover (Charadrius Melodius) Conservation On The Barrier Islands Of New York: Habitat Quality And Implications In A Changing Climate, Jennifer Ruth Seavey Sep 2009

Piping Plover (Charadrius Melodius) Conservation On The Barrier Islands Of New York: Habitat Quality And Implications In A Changing Climate, Jennifer Ruth Seavey

Open Access Dissertations

Habitat loss is the leading cause of species extinction. Protecting and managing habitat quality is vital to an organism's persistence, and essential to endangered species recovery. We conducted an investigation of habitat quality and potential impacts from climate change to piping plovers (Charadrius melodius) breeding on the barrier island ecosystem of New York, during 2003-2005. Our first step in this analysis was to examined the relationship between two common measures of habitat quality: density and productivity (Chapter 1). We used both central and limiting tendency data analysis to find that density significantly limited productivity across many spatial scales, especially ...


Seasonal Home Range Sizes, Transboundary Movements And Conservation Of Elephants In Northern Tanzania, Alfred P. Kikoti Sep 2009

Seasonal Home Range Sizes, Transboundary Movements And Conservation Of Elephants In Northern Tanzania, Alfred P. Kikoti

Open Access Dissertations

Although the unprotected lands of northern Tanzania support large numbers of elephants, and provide critical linkages for wildlife movements across the region, there is little information on the dispersal patterns of elephants in these unprotected lands. Our home range measures (100% MCP) of 21 elephants with satellite collars in four study regions were highly variable (191 to 3,698 km2). Home range sizes (95% fixed kernel) of bulls were typically larger than those of females, and wet season ranges were typically larger than dry season ranges. There were large differences in average home range sizes reflected varying strategies for obtaining ...


Engineering The Nanoparticle Surface For Protein Recognition And Applications, Mrinmoy De May 2009

Engineering The Nanoparticle Surface For Protein Recognition And Applications, Mrinmoy De

Open Access Dissertations

Proteins and nanoparticles (NPs) provide a promising platform for supramolecular interaction. We are currently exploring both fundamental and applied aspects of this interaction. On the fundamental side, we have fabricated a series of water-soluble anionic and cationic NPs to interact with cationic and anionic proteins respectively. A Varity of studies such as, activity assay, fluorescence titration, isothermal titration calorimetry etc. were carried out to quantify the binding properties of these functional NPs with those proteins. Those studies reveal the prospect of tuning the affinity between the nanoparticles and proteins by the surface modification. On the application side, we have used ...


Early Rearing Experience, Hypothalamic-Pituitary-Adrenal (Hpa) Activity, And Serotonin Transporter Genotype: Influences On The Development Of Anxiety In Infant Rhesus Monkeys (Macaca Mulatta), Amanda Dettmer May 2009

Early Rearing Experience, Hypothalamic-Pituitary-Adrenal (Hpa) Activity, And Serotonin Transporter Genotype: Influences On The Development Of Anxiety In Infant Rhesus Monkeys (Macaca Mulatta), Amanda Dettmer

Open Access Dissertations

A gene x environment interaction exists in the expression of anxiety for both human and nonhuman primates, such that individuals who are carriers of the (s) allele of the serotonin transporter genotype ( 5-HTT LPR) and exposed to early life stress are more at risk for exhibiting anxiety. The hypothalamic-pituitary-adrenal (HPA) axis has also been implicated in anxiety disorders but the relationship between early life/genotype, HPA activity, and anxiety is not well understood. Further, studies linking the HPA axis to anxiety have relied on "point" samples (blood and salivary cortisol) which reflect moments in time rather than long-term activity. The ...


Visuospatial Reasoning In Toddlers: A Correlational Study Of Door Task Performance, Iris Louella Price May 2009

Visuospatial Reasoning In Toddlers: A Correlational Study Of Door Task Performance, Iris Louella Price

Open Access Dissertations

Previous research using violation-of-expectation paradigms suggests that very young infants have a good understanding of unobserved physical events. Yet toddlers appear to lack this knowledge when confronted with the door task, a visuospatial reasoning task which parallels ones used in the habituation/looking time studies. Many studies have been conducted in an effort to determine why toddlers perform poorly on the door task yet the answer remains unclear. The current study used a correlational approach to investigate door task performance from both psychological (executive function), and neuroscience (prefrontal cortex) perspectives. Children between the ages of 2 ½ - 3 years were ...


Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones May 2009

Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones

Open Access Dissertations

Abstract (Summary) Wood turtles ( Glyptemys insculpta ) are of conservation interest rangewide. Anecdotal accounts demonstrate that some populations have been decimated since 1850, and recent studies demonstrate that declines are still underway. From 2004-2008 I investigated the ecology of wood turtles in Massachusetts and New Hampshire. I obtained between one and five years of annual home range data for 150 turtles, and evaluated population structure at 31 sites in five major watersheds. Seasonal floods displaced 7% of wood turtles annually in one watershed, and accounted for elevated mortality. Twelve wood turtles were displaced < 16.8 km, and two were displaced over a 65-foot dam. Several turtles overwintered at their displacement site and two returned successfully, indicating that floods are a mechanism of population connectivity. Several homing turtles ended up in new areas. Turtles occupied stream segments with gradient < 1%, lower than generally available. Agricultural machinery accounted for most observed mortality, followed by automobiles and mammals. Female turtles exhibit smaller home ranges in agricultural areas. Older turtles move farther from the river than do young turtles, possibly reflecting their familiarity with a former landscape. Population density ranged from 0-40.4 turtles/river-kilometer. The highest densities occur in central New Hampshire and lower densities occur in the Housatonic watershed. Population density is negatively correlated with agriculture at both riparian and watershed scales, and responds unimodally to forest cover. Wood turtle populations in western Massachusetts are declining by 6.6-11.2% annually. I estimated ages of turtles by assessing shell-wear rates from photographs. Wood turtles regularly achieve ages over 80 years, and like related species, do not exhibit clear signs of senescence. Old wood turtles are reproductively dominant, and their survival rates are twice as high as young turtles. Carapace scutes appear to require 80 years to become worn. Population modeling indicates that wood turtle populations are declining in New England due to anthropogenic and natural factors. Conservation efforts must address the effects of agriculture on adult survival. Climate change may negatively affect northeastern wood turtles through increased flooding. Populations in mountainous areas may be likely candidates for conservation because they don't occupy prime agricultural land, but may be more susceptible to floods.


Modulation Of Macrophage Responses To Borrelia Burgdorferi In Acute Murine Lyme Carditis, Chris Martin Olson May 2009

Modulation Of Macrophage Responses To Borrelia Burgdorferi In Acute Murine Lyme Carditis, Chris Martin Olson

Open Access Dissertations

The Lyme disease spirochete Borrelia burgdorferi is the only known human pathogen that directly activates invariant natural killer T (iNKT) cells. The number and activation kinetics of iNKT cells vary greatly among different strains of mice. Here, we report the role of the iNKT cell response in the pathogenesis of Lyme disease using C57BL/6 (B6) mice, a strain with optimal iNKT cell activation that is resistant to the development of spirochetal-induced inflammation. During experimental infection of B6 mice with B. burgdorferi , iNKT cells localize to the inflamed heart where they are activated by CD1d-expressing macrophages. Activation of iNKT cells ...


The Conformational Gymnastics Of The Escherichia Coli Seca Molecular Machine And Its Interactions With Signal Sequences, Jenny Lynn Maki May 2009

The Conformational Gymnastics Of The Escherichia Coli Seca Molecular Machine And Its Interactions With Signal Sequences, Jenny Lynn Maki

Open Access Dissertations

Protein secretion is a selective and regulated process that is essential in all organisms. In bacteria the preprotein translocase SecA, either free in the cytosol or associated with the SecYEG translocon, recognizes and binds most post-translational secretory proteins containing an N-terminal signal sequence. In Gram-negative bacteria, the molecular chaperone SecB binds many of the preproteins to keep them in a translocation-competent state. Subsequently, SecB delivers the preproteins to the translocon-associated SecA, which binds the signal sequence and also interacts with mature regions of the preprotein. After the preprotein/SecA/SecYEG complex has formed, the energy derived from ATP hydrolysis by ...


Delayed Anesthetic Preconditioning And Metallothioneins I+Ii: Novel Mediators Of Anesthetic-Induced Protection, Scott David Edmands May 2009

Delayed Anesthetic Preconditioning And Metallothioneins I+Ii: Novel Mediators Of Anesthetic-Induced Protection, Scott David Edmands

Open Access Dissertations

Ischemic injury is a common and debilitating outcome of natural illness and as a complication of commonly performed medical procedures. Whereas naturally occurring ischemic insults are often the result of unpredictable events, such as in the case of stroke or heart attack, the risk of operative and perioperative ischemia is somewhat better characterized in the clinical setting. Given the prevalence and severity of outcomes in ischemic injury, there is significant interest in developing better pharmacological and procedural approaches to improve patient outcomes. One approach that has shown significant promise in the laboratory setting, particularly in the context of planned medical ...


Antioxidant Distribution And Effectiveness In A Model Muscle System, Ann T Ballesteros Feb 2009

Antioxidant Distribution And Effectiveness In A Model Muscle System, Ann T Ballesteros

Doctoral Dissertations 1896 - February 2014

Gallic acid esters (GAE) of varying alkyl chain length were used to determine how antioxidant physical location and partitioning influence hemoglobin-catalyzed lipid oxidation. Specific GAE used were propyl gallate (PG), octyl gallate (OG), and lauryl gallate (LG). GAE partitioning experiments were performed with either isolated cod muscle membranes or washed cod muscle, which primarily contain polar membrane lipids and myofibrillar proteins. Canola oil was used in some experiments to determine how neutral lipids impact partitioning behavior. GAE distribution was determined spectrophotometrically in the recovered membranes, aqueous phase, and oil layer after employing differential centrifugation. Oxidation was monitored by measuring thiobarbituric ...


Factors Influencing The Stability Of Carotenoids In Oil-In-Water Emulsions, Caitlin Suzanne Boon Feb 2009

Factors Influencing The Stability Of Carotenoids In Oil-In-Water Emulsions, Caitlin Suzanne Boon

Doctoral Dissertations 1896 - February 2014

Lycopene has recently received interest as an antioxidant in human tissues. These same antioxidant properties present challenges in preventing oxidative degradation within food products. In this research, degradation of lycopene in model emulsion systems was examined to better understand the chemical stability of this potential functional food ingredient.

Lycopene in corn oil or hexadecane was used to make oil-in-water emulsions using small molecule surfactants. Emulsion color loss was used to estimate lycopene loss and was monitored using an integrating sphere. Lipid hydroperoxide and hexanal formation was used to monitor the development of lipid oxidation.

Oxidation and color loss were found ...


Landscape Ecology Of Large Fires In Southwestern Forests, Usa, Sandra L Haire Feb 2009

Landscape Ecology Of Large Fires In Southwestern Forests, Usa, Sandra L Haire

Doctoral Dissertations 1896 - February 2014

The recent increase in large fires in southwestern forests has prompted concern regarding their ecological consequences. Recognizing the importance of spatial patterns in influencing successional processes, I asked: (1) How do large fires change plant communities?; (2) What are the implications of these changes for ponderosa pine forests?; and (3) What is the relationship of fire severity to gradients of climate, fuels, and topography? To address the first two questions, I studied succession in the woody plant community at two sites that burned in high-severity fire: La Mesa fire in northern New Mexico (1977) and Saddle Mountain in northern Arizona ...