Life Sciences Commons^™

Effects Of Melatonin On Heartbeat And Possible Identification Of A Melatonin Receptor In Drosophila Melanogaster, Tricia L. Vankirk

Electronic Theses and Dissertations

Chapter 1 of this manuscript is a literature review that serves as an introduction to the entire dissertation. Chapter 2 examines the effects of the melatonin injection on heart rate and rhythmicity in Drosophila melanogaster Canton-S (wild-type) pupae and pupae bearing a variety of heart mutations. Chapter 3 investigates further the possible mechanisms of melatonin’s ability to increase heart rhythmicity without significantly affecting heart rate. A melatonin antagonist, luzindole; a high-affinity melatonin agonist, 2-iodomelatonin and RNAi techniques are used to identify a possible melatonin receptor in Drosophila melanogaster.

An appendix contains a previously published manuscript detailing experiments performed at the …

Thinking Beyond The Fried Egg Model: How Accurately Do Students Perceive Cells In A Living Context?, Milissa Knox

Electronic Theses and Dissertations

This exploratory study investigated three aspects of introductory undergraduate biology students’ understanding about cells. The study, which took place at the University of Maine with voluntary students in Basic Biology (“BIO100”) in the summer and fall of 2009, examined (1) students’ pre-course perceptions of cells as they exist in a living context and (2) gains in students’ perception and knowledge about cells after completing the one-semester course (BIO100). Results are based on lecture exam scores, pre-post surveys developed as a part of this thesis, and interviews with two groups of biology students. A total of 498 students participated in the …

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe

Electronic Theses and Dissertations

Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while …

The Temporal Nature Of The Acute Stress Response And Its Impact On Explicit Learning, Steven B. Hutchinson

Electronic Theses and Dissertations

Acute stress is commonly experienced by many throughout their lives. Given the demanding lifestyle of many career paths, it's important to gauge the influence of these stressors upon cognitive performance. The present dissertation focus' upon explicit learning in attempts to explore one avenue of the stress-cognition relationship. The Trier Social Stress Test (TSST) was used as a lab stressor for Experiments 1 and 2, in which participants are asked to give a speech and complete a difficult math task in front of 2 evaluators trained to monitor non-verbal behavior. Experiment 1 investigates the dynamic stress response during the minutes following …

Breeding Bird Census To Compare Long-Term Changes In The Avifauna Of The Spruce-Fir Forest On Mount Guyot, Great Smoky Mountains National Park 1967-2015, Kevin C. Brooks

Electronic Theses and Dissertations

The high-elevation forests of the Southern Appalachian Mountains have been impacted and rearranged by a tiny introduced pest from Europe, known as the Balsam Woolly Adelgid (Adelges piceaea), creating a concern for conservation. Breeding bird censuses, along with botanical surveys, have been conducted periodically on an established 60-acre plot since 1967 on the virgin forested slopes of Mount Guyot, Great Smoky Mountains National Park, with the last census being completed in 2015. Breeding bird populations are shown to rise and fall in response to the forest’s changes over the last 48 years. Comparisons are made between all studies in order …

Characterization Of Sbip68: A Putative Tobacco Glucosyltransferase Protein And Its Role In Plant Defense Mechanisms, Abdulkareem O. Odesina

Electronic Theses and Dissertations

Plant secondary metabolites are essential for normal growth and development in plants ultimately affecting crop yield. They play roles ranging from appearance of the plants to defending against pathogen attack and herbivory. They have been used by humans for medicinal and recreational purposes amongst others. Glycosyltransferases catalyze the transfer of sugars from donor substrates to acceptors. Glucosyltransferases are a specific type of glycosyltransferases known to transfer glucose molecules from a glucose donor to a glucose acceptor (aglycone) producing the corresponding glucose secondary metabolite or glycone, in this case glucosides. It was hypothesized that SBIP68, a tobacco putative glucosyltransferase-like protein glucosylated …

Chemoattractant Receptors Blt1 And Cxcr3 Regulate Anti-Tumor Immunity By Facilitating Cd8+ T Cell Migration To Tumors., Zinal S. Chheda

Electronic Theses and Dissertations

Presence of increased numbers of CD8⁺ T cells in the tumors correspond to better overall survival in the patients. Variety of immuno-therapies have shown considerable efficacy in the clinic, however, a multitude of patients remain unresponsive. Most of these immunotherapies rely on effector T cell responses in the tumor. A major obstacle in the success of these immunotherapies is poor recruitment of CD8⁺ T cells into tumors despite intact effector responses in the periphery. Therefore understanding the mechanisms that regulate CTL infiltration into tumors becomes essential. Previous studies in our laboratory suggested an important role for BLT1 in …

Functional Characterization Of Aggregatibacter Actinomycetemcomitans Qsebc : A Bacterial Adrengeric Receptor And Global Regulator Of Virulence., Whitney Weigel

Electronic Theses and Dissertations

In order for a pathogen to successfully colonize the host, it must be able to acquire essential nutrients and regulate gene expression to respond to environmental fluctuations. One mechanism bacteria have evolved in order to detect these fluctuations and respond is the two component signal transduction systems (TCS). Aggregatibacter actinomycetemcomitans, a dental commensal associated with localized aggressive periodontitis, contains a TCS designated QseBC that was previously shown to regulate expression of several iron acquisition genes, biofilm formation and virulence, but the activating signal was unknown []. QseBC is a conserved TCS in the Enterobacteriaceae and Pasteurellaceae, but the activating signal …

Biogeography And Conservation Of Tidal Marsh Bird Communities Across A Changing Landscape, Maureen D. Correll

Electronic Theses and Dissertations

Given the current mass extinction crisis and continued fragmentation of resources worldwide, the outlook is dire for global biodiversity. Rising global temperature, sea levels, and storm frequency all create environmental conditions that can drive change in species abundance and distribution across a landscape. Those species reliant upon a single type of habitat and resource for survival, termed “specialists”, are particularly vulnerable to change due to their inability to utilize a variety of resources well. As a result, specialism is now considered one of the dominant factors determining extinction of species. In this dissertation I explore the effects of disturbance on …

Development Of Cerceis Fumipennis For Biosurveillance Of The Emerald Ash Borer In The Northeast, Jennifer Lund

Electronic Theses and Dissertations

One method being utilized for detection of the invasive emerald ash borer, Agrilus planipennis (EAB) involves monitoring aggregations of the wasp Cerceris fumipennis for the presence of EAB in their collected prey. Currently there is little information published on its nest structure, phenology, and prey fidelity. The objectives of this research were to: i) monitor C. fumipennis male and female emergence, female prey collection, and number of colonies relative to the accumulation of degree-days (DD) throughout the summer; ii) better understand nest structure, phenology, and prey requirements of C. fumipennis; and iii) investigate C. fumipennis prey selection and fidelity. …

Development Of A 3-Pronged Approach To Evaluation For The Icook-4h Project, Douglas R. Mathews

Electronic Theses and Dissertations

Most nutrition education programs are created without adequate forethought to planning evaluation strategies. The goal of this study was to develop and implement a comprehensive 3-pronged approach to evaluate iCook 4-H, a six- session, biweekly program for 9-10 year old youth and their adult main food preparer. It was used to evaluate the curriculum for the intervention of a 2-year childhood obesity prevention study. Forty iCook 4-H classes were implemented for 150 dyads by 16 leaders between September and December, 2013, in Maine, Nebraska, South Dakota, Tennessee, and West Virginia. The evaluation included measures of fidelity of implementation, process evaluation, …

Cardiovascular Regulation And Effects Of Respiratory Motor Training In Patients With Chronic Spinal Cord Injury., Bonnie Legg Ditterline

Electronic Theses and Dissertations

This dissertation attempts to discover the mechanisms between cardiovascular and respiratory motor control post spinal cord injury (SCI): in normal, non-injured (NI) persons, cardiovascular regulation is dependent upon respiration, but there is nothing that suggests the mechanism for this relationship post-SCI. Thus we hoped to evaluate various aspects of cardiovascular regulation to further illustrate how this relationship is changed or unchanged by SCI. Chapter I describes the anatomy and physiology of the spine, respiratory system, and cardiovascular system in a NI person, and then describes how the function of these systems is changed by SCI. In addition, we describe therapies …

Impact Of Urban Factors And Invasive Species On White-Footed Mouse (Peromyscus Leucopus) Habitat Use And Foraging Behavior In An Urban Forest Park., William Persons

Electronic Theses and Dissertations

White-footed mice (Peromyscus leucopus) select for areas of greater canopy cover at the macro scale, and for areas with more CWD at the micro-scale. White-footed mice potentially avoid habitats with higher invasive species richness. White-footed mice preferentially foraged under the honeysuckle canopy in response to changes in temperature and humidity. This study suggests that the interaction between P. leucopus and ground layer invasive species is complex, and that the effect of moonlight may be diminished in this urban park. Urban ecosystems demonstrate high levels of anthropogenic land-use change, modification of abiotic inputs, and altered disturbance regimes. These changes result …

Improving Extraction Of Allergenic Soy Proteins From Soy Products, Amma Konadu Amponsah

Electronic Theses and Dissertations

With recent increase in the utilization of soy proteins, there are mounting concerns of the escalation of soy allergies. It is, therefore, important to improve current methods of allergen detection to ensure accurate labeling of foods, produce more reliable and representative results in studies to create hypoallergenic food and establish allergen thresholds. The conditions used to extract proteins from foods are important determinants for appropriate detection and interpretation of the allergenicity of food materials. The extraction of soy proteins for soy allergen detections is conventionally performed with phosphate buffered saline (PBS) buffer for an extraction period of at least 2 …

Effects Of Complex Formation Of Dna With Positively Charged Polyamines And Polypeptides On The Products Of Oxidative Damage To Dna 2-Deoxyribose By Hydroxyl Radicals, Modeste N. Tegomoh

Electronic Theses and Dissertations

It is known that histones and other DNA-binding polycations protect DNA from radiation damage mediated by hydroxyl radicals. Until recently, this protection of DNA has mainly been attributed to compaction and aggregation. It was hypothesized that chemical repair of DNA sugar radicals by donation of hydrogen atom from polycations also significantly contributes to DNA protection. To test this hypothesis, the relative yields of low-molecular weight characteristic products of oxidation of DNA sugar were compared in X-irradiated samples of naked DNA and DNA complexes with a number of polycations by using an HPLC-based method of DNA damage product quantification. The variation …

Influence Of Lactobacillus Rhamnosus Isolated From “Amabere Amaruranu” Cultured Milk On Adipogenesis, Justin E. Kotala

Electronic Theses and Dissertations

This study was performed to test the in vitro effects of a Lactobacillus rhamnosus isolate from “amabere amaruranu”, a traditional Kenyan cultured milk, on 3T3-L1 and Caco-2 cell lines. Cultures of fully mature 3T3-L1 adipocytes were treated with bacterial isolate cell extract (CE), filtered spent broth (FSB) from overnight bacterial culture, or with a PBS control. Expression levels of PPAR³1 and 2, C/EBP±, and ATGL proteins in 3T3-L1 cells were upregulated by FSB treatment. CE treatment did not affect protein expression levels. Expression of MTTP and SREBP-1c proteins in Caco-2 cells showed no change with either treatment. Optical density measurements …

Atmospheric Nitrogen Assimilation In Ustilago Maydis., Michael Cooper

Electronic Theses and Dissertations

Nitrogen is an essential nutrient for all living creatures. Ammonium is one of the most efficiently used and thus preferred, sources of nitrogen. As with other dimorphic fungi, yeast-like cells of Ustilago maydis, a fungal pathogen of maize, switches to filamentous growth when starved for nitrogen/ammonium. U. maydis carries two genes, ump1 and ump2, encoding ammonium transporters that facilitate both uptake of ammonium and the filamentous response to its absence. While no obvious phenotype is observed when ump1 is deleted, cells without ump2 are unable to filament in response to low ammonium, although they can still grow. Surprisingly, …

A Plant-Made Cholera Toxin B Subunit Enhances Mucosal Wound Healing And Protects Against Ulcerative Colitis And Colon Cancer., Keegan J Baldauf

Electronic Theses and Dissertations

This dissertation describes the previously unidentified effects of a plant-produced recombinant cholera toxin B subunit (CTBp) on the gastrointestinal (GI) tract and its ability to protect against inflammation in a mouse model of colonic injury and ulcerative colitis (UC). To comprehensively analyze CTBp’s impacts on the GI tract, we employed global analysis methodologies based on multi-color flow cytometry to analyze immune cell populations in GI and systemic lymphatic compartments, gene expression microarray to decipher transcript-level changes in the colon and small intestine, and 16S rRNA sequencing to characterize fecal microbiota. Based on a drastic shift observed in the immune cell …

Co-Treatment With Conjugated Linoleic Acid And Nitrite Modulates Mitochondrial Respiration And Electron Transport Chain Activity In Vivo And Attenuates Mitochondrial Dysfunction During Cardiac Injury., Patrick Van Hoose

Electronic Theses and Dissertations

Cardiovascular disease and subsequent complications, such as myocardial infarction (MI), is the leading cause of death within the United States. Clinical intervention to reduce cardiac damage following myocardial ischemia is limited. Polyunsaturated fatty acids have been linked to an overall beneficial effect on cardiovascular health and function. Conjugated linoleic acid (cLA) is an 18:2 unsaturated fatty acid found within the diet in ruminant meat and dairy products. The cis-9 trans-11 isomer of cLA is the most prominent isomer within the diet and cLA has been linked to favorable outcomes in numerous disease states. The mechanism mediating the effects of cLA …

Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore

Electronic Theses and Dissertations

Counter to what some people think, urban areas can be biodiversity hotspots. Maintaining this biodiversity can be challenging, since exotic shrubs and vines block sunlight and threaten native plant regeneration. Since 2007, the Louisville Olmsted Parks Conservancy (LOPC) has spent $2 million on invasive plant management in Cherokee Park. Before the project began, long-term transects were established by the LOPC to collect baseline presence/absence data on 11 invasive plant species. In 2014, I revisited these transects and documented presence/absence data on the entire plant community. I found that four species (garlic mustard, winter creeper, Japanese honeysuckle, and English ivy) have …

Mechanisms And Intervention Strategies For Alcohol And Hiv-Antiretroviral Therapy-Induced Liver Injury., Hridgandh Donde

Electronic Theses and Dissertations

Chronic alcohol consumption is a leading cause of liver disease and liver-related death worldwide. Alcoholic liver disease includes, hepatic steatosis, steatohepatitis and ultimately fibrosis and cirrhosis. Emerging evidence has established the important role of the “gut-liver” axis in the development of alcoholic liver disease (ALD). Our recent work indicated that chronic alcohol induced perturbations in the gut microbiome and consequent changes in fatty acids have a major impact on the development of intestinal barrier dysfunction and ALD. The aim of this study was to investigate whether treatment with tributyrin - a butyrate prodrug results in protection against ALD in terms …

Regulation Of The Retinoblastoma Tumor Suppressor By The Novel Ras Effector Nore1a., Thibaut François Barnoud

Electronic Theses and Dissertations

Ras is the most frequently mutated oncogene in human cancers. It acts as a critical branch point in signal transduction, regulating numerous downstream effectors involved in cell growth and differentiation. While Ras can activate many growth promoting pathways, it can paradoxically regulate growth inhibitory pathways leading to apoptosis and cell cycle arrest. One of the ways Ras can inhibit the growth of cells is via a family of effectors called the RASSF proteins. RASSF5 (NORE1A) is a tumor suppressor that is frequently inactivated in human tumors by epigenetic mechanisms. NORE1A binds directly to Ras and promotes Ras-induced senescence. We have …

Dietary Carotenoids And The Complex Role Of Redness In The Behavior Of The Firemouth Cichlid Thorichthys Meeki., Sarah Anne Fauque

Electronic Theses and Dissertations

This dissertation takes a comprehensive approach to the role of dietary carotenoids on redness and the subsequent behaviors in the firemouth cichlid, Thorichthys meeki. I start with a brief introduction into signaling, the importance of carotenoids, and mate choice. The dissertation is then divided into three data chapters which are designed to stand as independent manuscripts. Chapter II documents how altering the availability of dietary carotenoids affects redness in the integument of male and female T. meeki. I tracked how redness changed in color and distribution in individuals over the course of 12 weeks. I confirm that a dichotomy …

The Ras Effector Nore1a Forms A Tumor Suppressor Complex With Brca1., Nicholas C Nelson

Electronic Theses and Dissertations

Ras proteins function as molecular signaling switches that can stimulate multiple mitogenic pathways in response to extracellular signaling. Oncogenic activation of Ras by structural mutation is a highly transforming event in ~1/3 of human cancers. However, aberrant Ras activation can also promote oncogene-induced senescence. This Ras-induced irreversible growth arrest is a physiological process that acts as a barrier to malignancy. The mechanisms by which Ras drives senescence and how this process is bypassed during Ras-driven transformation remains poorly understood.

Although mutations in the RAS gene are extremely rare in human breast cancer, the Ras signaling pathway is constitutively activated in …

Genomic And Transcriptomic Analyses Of Microbotryum Lychnidis-Dioicae Provide Insights Into The Biology Of A Fascinating Fungal Phytopathogen., Su San Toh

Electronic Theses and Dissertations

This study made use of the Silene latifolia/Microbotryum lychnidis-dioicae phytopathogen system as the focal system to establish the first reference genome for Microbotryum violaceum sensu lato. In silico analysis was performed on the genome assembly to identify various characteristics of the genome. Using RNA-Sequencing technologies on the Illumina platform, we collected transcriptomic data for both in vitro and in planta life stages of the fungus, providing the most comprehensive look at the gene expression and regulation of this fungus. Due to a lack of identifiable domains on the predicted genes, gene set enrichment analysis was done in …

Reproductive Ecology Of Black Bears In Maine: Maternal Effect, Philopatry, And Primiparity, Alyssa A. Vitale

Electronic Theses and Dissertations

The American black bear (Ursus americanus) relies upon dens in order to successfully reproduce and protect their offspring. Black bears utilize a variety of den types, each providing a different degree of protection. Black bears also exhibit an extended maternal care period in which offspring stay with their mother for 18 months. Maine’s black bear population is one of the largest in the U.S. (>30,000 bears) and since 1975, the Maine Department of Inland Fisheries and Wildlife has conducted research and monitoring to manage the population. This unique dataset allowed for examination of several generations of multiple …

Implementing Complex Partial Harvests In Central Maine: Is Tree Marking Necessary?, Sam Grimm

Electronic Theses and Dissertations

Recent trends in forest management regimes seek to strike a balance between a multitude of ecologic and economic values at multiple scales. Whether the objectives are traditional (timber production), or contemporary (ecological sustainability), the fundamental, practical question of “how” the forester implements a silvicultural prescription remains relatively unaddressed by research. Forest managers must consider: what good are carefully designed landscape plans and stand-level prescriptions if the treatments are not executed accurately? In northeastern North America, tree marking -- the simple designation of cut or leave trees to implement a given silvicultural prescription -- has declined, in favor of reliance on …

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also considered a complex …

Intra- And Interspecific Variation In Demographic Rates And Niche Across The Range Of A Species, The Saltmarsh Sparrow (Ammodramus Caudacutus), Katharine J. Ruskin

Electronic Theses and Dissertations

In this project, we examined various hypotheses that address one of the fundamental questions in ecology and evolution: what determines the range of a species? We used demographic data for saltmarsh sparrows (Ammodramus caudacutus) collected over the majority of the global breeding range. Saltmarsh sparrows are considered threatened by climate change, specifically sea level rise, which is predicted to result in loss of the tidal marsh habitat where saltmarsh sparrows live across their entire life cycle. For my dissertation, I investigated the reproductive biology of saltmarsh sparrows both to provide vital information for wildlife managers and to explore …

Forest Harvesting Productivity And Cost In Maine: New Tools And Processes, Patrick Hiesl

Electronic Theses and Dissertations

Computer simulations have been used in forestry and forest operations since around 1960. In many cases such simulations can be used to answer questions that would be time consuming and expensive to investigate in a real-life environment. This dissertation focuses on the use of computer simulation in forest operations to answer questions regarding the profitability of technological advancements, investments in precommercial thinning (PCT), and the use of different harvesting systems. To explore the benefits of decoupling a harvesting system, a new simulation method, called agent based modeling was used. Agent based modeling is primarily used in social sciences but now …