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Full-Text Articles in Life Sciences

Biophysical Studies Of Axonal Transport, Leslie Cyle Conway Apr 2014

Biophysical Studies Of Axonal Transport, Leslie Cyle Conway

Doctoral Dissertations

Intracellular transport provides a mechanism by which cellular material, such as organelles, vesicles, and protein, can be actively transported throughout the cell. This process relies on the activity of the cytoskeletal filament, microtubules, and their associated motor proteins. These motors are able to walk along microtubule tracks while carrying cellular cargos to enable the fast, regulated transport of these cargos. In cells, these microtubule filaments act as a binding platform for numerous different motor species as well as microtubule-associated proteins (MAPs). In addition, these filaments often form higher order structures, such as microtubule bundles. How motors navigate such complex, crowded ...


Honesty And Carotenoids In A Pigmented Female Fish, Alexandria Christine Brown Apr 2014

Honesty And Carotenoids In A Pigmented Female Fish, Alexandria Christine Brown

Doctoral Dissertations

The carotenoid tradeoff hypothesis states that diet-derived carotenoids are tradedoff among competing physiological demands, but this statement is rarely tested in ornamented females. The following dissertation tests the carotenoid tradeoff hypothesis in reverse sexually dimorphic convict cichlids (Amantitlania siquia) using carotenoidsupplemented diet treatments and a field-based study of carotenoid intake. Spectral, microscopic, and chemical analysis determined how females allocated the pigments to tissues and how those decisions affected their ventral patch coloration. The results presented in the current study show that carotenoids enhance offspring growth and survival, lower oxidative stress, and reduce the time to clear a parasite. The two ...


Reactive Probes For Manipulating Polyketide Synthases, And Photoreactive Probes For Strained Alkyne Click Chemistry, Jon William Amoroso Apr 2014

Reactive Probes For Manipulating Polyketide Synthases, And Photoreactive Probes For Strained Alkyne Click Chemistry, Jon William Amoroso

Doctoral Dissertations

Polyketides are a broad class of natural products that have received attention from the scientific community because they are a rich mine of bioactive structures. The common thread that binds the class together is the method by which they are synthesized, by large enzymatic complexes called polyketide synthases (PKSs) which display assembly line like organization. A great deal of effort has been put into studying PKSs, but their mechanistic steps are still not perfectly understood. In order to further the study of PKSs and their components, we have developed a series of reactive small molecules that covalently modify specific sites ...


Allosteric Regulation Of Dengue Virus Type 2 Protease, Muslum Yildiz Apr 2014

Allosteric Regulation Of Dengue Virus Type 2 Protease, Muslum Yildiz

Doctoral Dissertations

Dengue Fever is a global problem with a worldwide effectiveness that put 2.5 Billion people under the risk, infect 50 million people and causes 30000-50000 people death each year. DHF was first recognized in the 1950s during the dengue epidemics in the Philippines and Thailand. By 1970 nine countries had experienced epidemic DHF and now, the number has increased more than fourfold and continues to rise. Today emerging DHF cases are causing increased dengue epidemics in the Americas, and in Asia, where all four dengue viruses are endemic. Vaccine development against Dengue Virus has been impossible to date, due ...


Loss Of Cell Surface Agal During Catarrhine Evolution: Possible Implications For The Evolution Of Resistance To Viral Infections And For Oligocene Lineage Divergence, Idalia Aracely Rodriguez Apr 2014

Loss Of Cell Surface Agal During Catarrhine Evolution: Possible Implications For The Evolution Of Resistance To Viral Infections And For Oligocene Lineage Divergence, Idalia Aracely Rodriguez

Doctoral Dissertations

The divergence of the two superfamilies belonging to the Infraorder Catarrhini –Cercopithecoidea (Old World monkeys) and Hominoidea (apes, including humans) – is generally assumed to have occurred during the Oligocene, between 38 and 20 million years ago. Genetic studies indicate that this time period was one of active genetic evolution under strong purifying selection for catarrhine primates. This includes selective pressures on the glycoprotein galactosyltransferase 1 (GGTA1) gene and subsequent inactivation “clocked” at approximately 28 ma, possibly prior to the Cercopithecoidea/Hominoidea split. The GGTA1 gene codes for an a1,3 galactosyltransferase (GT) enzyme that synthesizes a terminal disaccharide, a ...


The Inflammatory Response To Acute Muscle Injury, Kevin O'Fallon Apr 2014

The Inflammatory Response To Acute Muscle Injury, Kevin O'Fallon

Doctoral Dissertations

The overall goal of this dissertation was to examine inflammatory and regenerative responses to acute skeletal muscle damage and to define molecular mediators of repair. Study I examined the effects of an oral anti-inflammatory supplement on exercise-induced muscle damage (EIMD) and systemic inflammation in a human model. Quercetin has been shown in animal and in vitro models to downregulate nuclear factor-kappa beta (NF-κB) nuclear transactivation and monocyte chemoattractant protein 1 (MCP-1) secretion, which regulate muscle regeneration and inflammatory signaling between muscle and immune cells after injury. Subjects ingested quercetin (N=15) or placebo (N=15) before and after performing 24 ...


Vocal Performance In Songbirds: Territorial Defense And The Development Of Male Song And Female Mating Preferences, Dana L. Moseley Apr 2014

Vocal Performance In Songbirds: Territorial Defense And The Development Of Male Song And Female Mating Preferences, Dana L. Moseley

Doctoral Dissertations

The evolution of sexually selected signals has been a major topic of scientific research since Darwin. In recent years, scientists have focused on how elaborate signals can indicate honest information about the quality of their bearers, as predicted by reliability theory. A key concept relating to how mating displays could reliably reveal quality is "performance." Animals face limits in display production, and producing high-­‐performance displays depends on the adept coordination of multiple motor systems. Thus, by observing motor performance, signal-­‐receivers can assess the quality of signalers. Birdsong is a prime example of a display that involves motor challenges ...


Increasing Nutrient Density Of Food Crops Through Soil Fertility Management And Cultivar Selection, Md. J. Meagy Apr 2014

Increasing Nutrient Density Of Food Crops Through Soil Fertility Management And Cultivar Selection, Md. J. Meagy

Doctoral Dissertations

The mineral nutrient density of vegetables has fallen in the past fifty years. As a result, some people are suffering chronic diseases due to shortage of mineral elements in these foods. The causes of this decline in nutritive value of vegetables have been attributed to a depletion of soil fertility and to a decrease in nutrient concentration in modern cultivars of vegetables. Lettuce (Lactuca sativa L.) is the most widely used leafy vegetable around the world. Research is needed to develop a nutrient content of lettuce that was help to supply adequate mineral nutrition to people. The objectives of the ...


Identification And Epidemiological Features Of Important Fungal Species Causing Sooty Blotch On Apples In The Northeastern United States, Angela Marie Madeiras Apr 2014

Identification And Epidemiological Features Of Important Fungal Species Causing Sooty Blotch On Apples In The Northeastern United States, Angela Marie Madeiras

Doctoral Dissertations

The sooty blotch and flyspeck (SBFS) complex causes blemishes on apples in humid, temperate growing regions worldwide. In contrast to flyspeck etiology, the many species of fungi causing sooty blotch (SB) have not been well studied. The first set of objectives in this study was to use PCR to identify SB species isolated from apples and selected reservoir hosts in the northeastern United States, and to identify patterns of species distribution on hosts and among sites. Results indicated that Geastrumia polystigmatis was the predominant species on apples, whereas Peltaster species were more common on reservoir hosts. Species distribution varied among ...


Cd4 Silencing In Thymocytes Is Opposed By The Enforced Association Of P300 Hat, Hdac1 Or Suv39h1 With Runx Transcription Factors, Christyne Ayne Kane Apr 2014

Cd4 Silencing In Thymocytes Is Opposed By The Enforced Association Of P300 Hat, Hdac1 Or Suv39h1 With Runx Transcription Factors, Christyne Ayne Kane

Doctoral Dissertations

The transcription factors Runx1 and Runx3 are required for permanent silencing of CD4 in maturing CD8+ thymocytes. Runx binding to consensus sites within the CD4 silencer region is required for CD4 silencing post-positive selection. The Runx nuclear matrix targeting sequence (NMTS) is required for CD4 silencing and is implicated in binding to the histone acetyltransferase (HAT) p300, histone deacetylases (HDAC), and histone methyltransferase (HMT) SUV39H1 proteins. Epigenetic modifications of chromatin or post-translational modifications of Runx itself as a result of Runx association with these enzymes may be important for establishment of long-term CD4 silencing. In this study, we show that ...


Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He Apr 2014

Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He

Doctoral Dissertations

Rapid detection technologies with high sensitivity and selectivity for pathogenic bacteria are critical in food safety and quality assurance. Traditional laboratory benchtop techniques (i.e. culture and colony counting) are time consuming and require complex sample handling. Microfluidics-based Lab-on-a-Chip (LOC) systems offer a detection alternative where all detection steps are on one portable miniaturized device. The miniaturization of rapid foodborne pathogen detection at a low cost is especially ideal for resource-limited settings or for field-use. The goal of this study was to develop a disposable miniaturized microfluidic device for on-site pathogen detection.

Capillary-driven microfluidics have been introduced in this study ...


Roosting, Site Fidelity, And Food Sources Of Urban Gulls In Massachusetts: Implications For Protecting Public Water Supplies, Daniel E. Clark Apr 2014

Roosting, Site Fidelity, And Food Sources Of Urban Gulls In Massachusetts: Implications For Protecting Public Water Supplies, Daniel E. Clark

Doctoral Dissertations

Anyone who has spent time in coastal New England has seen gulls flying overhead and heard their familiar sound; gulls may be one of the most recognizable birds in the world. There are over 50 species of gulls worldwide, and many of them are closely associated with human development or activities. In Massachusetts, there are several common gull species including herring (Larus argentatus), great black-back (Larus marinus), laughing (Leucophaeus atricilla), and ring-billed (Larus delawarensis).

While coastal encounters with gulls are ubiquitous, gulls can also be found inland, and ring-billed and herring gulls are now a common sight at lakes, parks ...


Anaerobic Microbes And Communities In The Context Of Soil And The Equine Digestive Tract, Amy Biddle Apr 2014

Anaerobic Microbes And Communities In The Context Of Soil And The Equine Digestive Tract, Amy Biddle

Doctoral Dissertations

Soil and herbivore gut environments present different challenges to plant degrading bacteria in terms of nutrient availability, fluctuations in moisture, pH and temperature, and temporal constraints, however complex communities of microbes in each serve similar roles in hydrolyzing and fermenting the diverse components of plant biomass. This dissertation describes four projects with the underlying purpose to further understand the structure and functioning of anaerobic plant degrading communities. (1) A three-year microcosm experiment using enrichment and serial transfers to reduce the diversity of a complex soil community over time, tested the hypothesis that changes in community structure would be consistent across ...