Life Sciences Commons^™

The Isolation And Characterization Of The Microbial Flora In The Alimentary Canal Of Gromphadorhina Portentosa Based On Rdna Sequences., Amy Renee Robertson

Electronic Theses and Dissertations

Multicellular organisms are not single individuals but carry a complex natural microflora with them. This complex's diversity and function can be considered a distinct ecosystem. Traditional methods of isolation and identification miss >90% of the actual diversity. This study uses the gut microflora of the Madagascar hissing roach, Gromphadorhina portentosa, as a model to examine this ecosystem. Isolated cultured bacteria were used to establish methods for identifying members of the microflora based on ribosomal RNA sequences. Universal primers for Eubacterial, Archaeal, and Eukaryotic 16s/18s rRNA were then used for PCR amplification of total DNA isolated from gut contents. Sequences …

1, Structural And Functional Studies Of Human Replication Protein A; 2 Dna Damage Responses And Dna Repair Defects In Laminopathy-Based Premature Aging., Yiyong Liu

Electronic Theses and Dissertations

The genome of mammalian cells is under constant attack from DNA-damaging agents. To maintain genomic integrity, cells activate an array of pathways primarily consisting of DNA repair and DNA damage checkpoints. Human replication protein A (RPA), a single-stranded DNA (ssDNA) binding protein, is essential for almost all DNA metabolic pathways. However, the role of RPA in nucleotide excision repair (NER), a DNA repair pathway for removing bulky DNA lesions, remains elusive. In this study, the binding of RPA to a battery of well-defined ssDNA substrates has been systematically examined using fluorescence spectroscopy. The results showed that RPA has a lower …

Evidence Of Ecological Speciation In Phacelia., Pamela Michele Glass

Electronic Theses and Dissertations

Phacelia purshii Buckley and P. fimbriata Micheaux are two species that are nearly morphologically indistinguishable. Seed germination experiments showed that the high elevation endemic, P. fimbriata requires lower temperatures to trigger germination. Following interspecific crosses, pollen tubes enter ovules and maternal tissue of the gynoecium matures but hybrid diploid and triploid organs fail to develop. DNA sequences from the ribosomal DNA internal transcribed region showed that P. fimbriata and P. purshii comprise a monophyletic clade but that P. fimbriata is more differentiated from related species. In contrast, P. purshii supported significantly higher levels of intraspecific polymorphism. Phacelia fimbriata and P. …

Mechanism Of Transcriptional Regulation Of C-Reactive Protein Gene Expression., Bhavya Voleti

Electronic Theses and Dissertations

C-reactive protein (CRP) is an acute phase protein produced by hepatocytes whose serum concentration increases in inflammatory conditions including cardiovascular complications. Statins that are used in the treatment of cardiovascular diseases to reduce cholesterol also lower serum CRP levels. In human hepatoma Hep3B cells, CRP is induced in response to cytokines IL-6 and IL-1β. The objective of the study was to determine the mechanism of regulation of CRP gene expression in Hep3B cells in response to cytokines and to determine the effect of statins on CRP expression. Key findings of our research were: 1. IL-1β-activated NF-κB p50/p65 acted synergistically with …

Crop/Livestock Integration Effects On Soil Quality, Crop Production, And Soil Nitrogen Dynamics, Ellen B. Mallory

Electronic Theses and Dissertations

Regional integration of potato and dairy farms has developed in Maine through arrangements where manure, feed, and sometimes land, are exchanged between neighboring farms. The effects of integration on soil quality, crop production, nitrogen (N) cycling, and N loss were investigated in field and laboratory studies of contrasting amended (manure, compost, green manure, and supplemental fertilizer) and nonamended (fertilizer only) soil management systems within 2-year potato (Solanum tuberosum L.) rotations in the Maine Potato Cropping Systems Project (MPEP). Additionally, soil quality of 48 integrated and nonintegrated Maine potato and dairy farm fields was assessed. The MPEP’s amended soil system enhanced …

Serum 25-Hydroxyvitamin D Response To Daily Oral Supplementation With 800 Iu Cholecalciferol In Premenopausal Women Living In Maine, Monica Nelson

Electronic Theses and Dissertations

The purpose of this research was to measure the serum 25-hydroxyvitamin D [25(OH)D] response to daily supplementation with 800 IU vitamin D3 during winter in premenopausal women living in Maine, and to examine the effects of body composition and hormonal contraceptive use on baseline serum 25(OH)D levels and the response to supplementation. One hundred twelve women (22.2±3.7 years old) received placebo from March 2005 until September 2005 when they were randomized to receive either placebo or 800 IU vitamin D3 through February 2006. Eighty-six women completed the study. Body composition was measured by dual-energy x-ray absorptiometry. Actual vitamin D3 content …

Mechanics Of Burrowing In Muddy Sediments, Kelly M. Dorgan

Electronic Theses and Dissertations

Marine muds are elastic solids through which animals move by propagating a crack-shaped burrow. Dilations previously considered anchors serve to exert dorsoventral compressive stresses on the burrow walls that, through elastic behavior of the medium, focus strongly at the tip of the burrow. This focused stress breaks adhesive or cohesive bonds, propagating a crack for the animal to follow. The force exerted by the polychaete, Nereis virens, to propagate a crack has been measured in gelatin, an analogue of muddy sediment, through photoelastic stress analysis. Finite element analysis was used to convert measured forces to those exerted in natural sediments …

Gene Therapy And Cellular Transplantation : Towards A Combination Strategy For Spinal Cord Injury Repair., Ahmed Abdelzaher Abdellatif

Electronic Theses and Dissertations

The combination of viral mediated gene delivery, tissue engineering, and Schwann cell (SC) transplantation offer a promising strategy to enhance axonal regeneration and functional recovery following spinal cord injury (SCI). The rationale and feasibility of using such combination has been extensively reviewed in Chapter 1. The study presented in Chapter 2 showed that lentiviral vectors are most suitable in situations where stable long term transgene expression is needed, while adenovirus and retrovirus are more suited for transient gene delivery. Tissue engineering combined with Schwann cell (SC) transplantation is a promising method to enhance regeneration and remyelination of axons following a …

Characterization Of The Group Ii Intron Gs. Int1 From The Thermophilic Bacterium Geobacillus Stearothermophilus., Huijing Sun

Electronic Theses and Dissertations

Group II Introns are small segments of DNA that reside in the chromosome of bacteria or the organelles of primitive eukaryotes. These elements have some very interesting properties. First, they are retrotransposons that can move from one location to a new location in DNA via a reverse transcription mechanism. Second, they form a large ribozyme that mediates self-splicing of the intron from pre-mRNA. A Group II Intron type protein with similarity to reverse transcriptase was discovered in the thermophilic bacterium Geobacillus stearothermophilus strain 10 (Vellore et al., 2004, Appl. Environ. Microbiol. 70: 7140-7147). Numerous copies of the intron, …

Nicotine Sensitization In Β-Arrestin 2 Knockout Adolescent Mice., Jennifer A. Correll

Electronic Theses and Dissertations

ß arrestin-2 is a protein involved in signaling of D2 receptors and plays a mediating role in sensitization to psychostimulants and the opiate morphine. In this study, 3-4 week old BA-2 KO and wild type C57/B6 mice received nicotine tartarate (s.c, 0.5 mg/kg free base) for 7 or 14 consecutive days followed by a drug-free period. An acute nicotine challenge followed the drugfree period. Results indicated that the absence of ß-arrestin-2 reduced sensitization to nicotine in Experiment 1. BA-2 KOs eventually demonstrated sensitization in Experiment 2. However, absence of ß-arrestin-2 blocked expression of sensitization on the challenge. After the challenge, …

The Effects Of Movement On Literacy., Kathy S. Luppe

Electronic Theses and Dissertations

The purpose of this study was to extend the knowledge of the relationship between movement and cognition by examining the impact of a sensory-motor program on the literacy skills of first grade learners from one elementary school in East Tennessee.

Literacy skills were evaluated using five subtests of the Dynamic Indicators of Basic Early Literacy Skills (DIBELS) assessment.

A 2 x 2 x 2 mixed factorial MANOVA was used to analyze group, gender, and test time effects on multiple dependent variables. The analysis yielded a statistically significant result (p < .05) in gains for the movement group and a …

Vitamin E (Tocotrienols) And Prostate Cancer: A Proteomics Approach., Christian Mbangha Muenyi

Electronic Theses and Dissertations

Proteomics is the large scale study of proteins in cells or organisms. The purpose of this study was to characterize the proteomic alterations occurring in a prostate cancer (LNCaP) cell line after treatment with delta-tocotrienol (a form of vitamin E not very prevalent from most dietary sources). We found that both gamma- and delta-tocotrienols induced time and concentration dependent growth inhibition and programmed cell dead (apoptosis) in LNCaP cells. Secondly, we used two-dimensional gel electrophoresis (2-DE) to characterize changes in protein expression levels associated with this treatment. Our results show that a specific set of proteins are regulated at both …

Development Of A Soy-Blueberry Burger And The Changes In Anthocyanins And Phenolics During Storage And Broiling, Pamela Beth Small

Electronic Theses and Dissertations

Blueberries are high in phenolic acids and flavonoids, which make them one of the leading sources of antioxidants. When added to foods, antioxidants can increase shelf life, maintain nutritional quality, and retard production of heterocyclic amines in meats during cooking thus having the potential to be of great significance to the food industry. Soy and soy-based foods have been gaining in popularity as a functional food for specific health conditions. Increased media coverage touting the health benefits of soy has generated a rise in consumer awareness. Two soy-blueberry burgers were prepared using 10 and 15% blueberry puree. A soy burger …

The Long-Term Effects Of A Group-Selection Timber Harvest On The Bird Community Of An Oak-Pine Forest In Maine, Stephen P. Campbell

Electronic Theses and Dissertations

Bird populations have been monitored at the Holt Research Forest in Arrowsic, Maine since 1983 as part of a long-term forest ecosystem study. In the winter of 1987-1988, 10 ha of the 40-ha study area were subjected to a group-selection timber harvest (i.e., a harvest that creates canopy gaps by removing small groups of trees). I analyzed the first 20 years of these data (5 years of pre-harvest data and 15 years of post-harvest data) for changes in abundance and spatial distribution of birds in response to the harvest. Although species’ responses to the group-selection harvest were idiosyncratic, two general …

Assessment Of The Flame Angelfish (Centropyge Loriculus) As A Model Species In Studies On Egg And Larval Quality In Marine Fishes, Chatham K. Callan

Electronic Theses and Dissertations

This project sought to determine if flame angelfish (Centropyge loriculus) could serve as models in examination of environmental and dietary effects on egg quality in marine fishes. Evaluation of 21 marine ornamental species identified flame angelfish as being amenable to egg quality research, due to their rapid conditioning and frequency of spawning. At the onset of this project, accidental copper introduction to broodstock systems required assays to determine the effects of copper exposure on survival and reproduction. Flame angelfish exhibited accute sensitivity to copper, as 60% of fish exposed to 0.25mg/L died within 12 hours of exposure. Likewise, fish exposed …

Assessing The Sustainability Of Agricultural Systems, Laura L. Kramar

Electronic Theses and Dissertations

This work constructs and tests a comparative technique that can be used to determine the ability of agricultural systems to meet multiple objectives of sustainability. Assessments are based on an agricultural system's ability to maintain five system stocks that represent environmental capital, social capital, human capital, physical capital, and financial capital. The capital stocks are measured as stock objectives, which are decomposed as indicators to calculate agricultural system scores. An examination of the complexity of agro-ecosystems and the multiple equilibria produced by balancing multiple objectives is used to explain the alternative criteria used in this comparative technique to evaluate agricultural …

T-Cell Dysfunction By Hcv Core Protein Involves Pd-1/Pd-L1 Signaling., Billy Ellis King

Electronic Theses and Dissertations

In 1989 the hepatitis C virus was identified as a significant cause of post-transfusion hepatitis. Nearly two decades later there is still no vaccine, inadequate treatment options, and limited understanding of how the virus establishes chronicity in the majority of the people it infects. Recent reports suggest that the interaction of a negative co-stimulatory pathway mediated by PD-1 and PDL-1 is associated with persistent viral infection. The role, if any, that PD-1/PDL-1 has in HCV infection is unknown. In this study we report that PD-1 is upregulated in T-cells from persons with chronic HCV infection when compared to healthy donors. …

Examination Of Microsporidia Spore Adherence And Host Cell Infection In Vitro., Timothy Robert Southern

Electronic Theses and Dissertations

Microsporidia are obligate intracellular pathogens that cause severe disease in immunocompromised humans. While albendazole is the treatment of choice, no therapy exists that effectively treats all forms or causes of human microsporidiosis. Recent studies show that the microsporidian Encephalitozoon intestinalis binds glycosaminoglycans (GAGs) associated with the host cell surface, and that the divalent cations manganese (Mn²⁺) and magnesium (Mg²⁺) augment spore adherence to host cells by activating a constituent on the spore surface. These studies also illustrate a direct relationship between spore adherence and host cell infection; inhibition of spore adherence leads to reduced host cell …

The Long Term Effect Of Time-Memory On Forager Honey Bee (Apis Mellifera) Recruitment., Matthew Walter Otto

Electronic Theses and Dissertations

Experiments were performed to determine the influence of the honey bee time-memory on a forager bee's sensitivity to recruitment. Two groups of foragers from one colony were trained to separate food stations at the same restricted time of day for several consecutive days. Feeding then was canceled at one station but continued for four more days at the other. Bees with more days of training at a non-productive source were significantly less likely than foragers with less training to be recruited to an alternative food source presented at the same time of day. Furthermore, the ability of a forager to …

Reversed-Phase Hplc Determination Of Cholesterol In Food Items., David Christian Essaka

Electronic Theses and Dissertations

Cholesterol is a fat-like molecule found among lipids in animal (including human) tissues. It is needed for maintaining good health. However, health issues have been raised because of the strong correlation between high levels of cholesterol in the body and cardiovascular disease. An HPLC method for quantitative determination of cholesterol in foods is presented. This involves a C-18 stationary phase using a 70:30 methanol: 2-propanol mobile phase with an UV detector set at 212 nm. The method showed linearity in the range 5.0 to 100.0 μg/mL and also good reproducibility with relative standard deviation of 4.22%, 2.71%, 4.8%, and 3.7% …

Evaluating Satisfaction And Benefit From Nutrition Counseling From A Registered Dietitian Among Head And Neck Cancer Patients Receiving Radiation Therapy., Lori E. Watson

Electronic Theses and Dissertations

The purpose of this study was to determine if patients with head or neck cancer receiving radiation were satisfied with the nutrition counseling they were receiving and if they obtained any benefit. Radiation to the head or neck region promotes side effects such as taste changes and chewing and swallowing difficultly that decrease food and fluid intake. A reduction in nutrients leads to weight loss, and weight loss in cancer patients increases the risk of morbidity and morality as well as decreases quality of life. Subjects were recruited from a local cancer treatment facility and a survey was administered. Subjects …

Myriophyllum Heterophyllum Michx. (Haloragaceae): Control And Vegetative Reproduction In Southwestern Maine, Jacolyn E. Bailey

Electronic Theses and Dissertations

Native to the southeastern United States, variable-leaf watermilfoil (Myriophyllum heterophyllum) is an invasive species in the Northeast and has been documented in Maine lakes for twenty years. Variable-leaf watermilfoil is targeted by the Maine Department of Environmental Protection as a species of grave concern as it has aggressively colonized twenty-six water bodies in Maine. This aquatic invasive plant grows in dense mats and outcompetes native vegetation. It is causing both ecological and economic disruption to Maine's lakes and ponds. The plants clog boat motors and deter people from swimming and other water related activities. Allofragmentation and autofragmentation occur …

The Effects Of Forest Practices On A Maine Amphibian Community, David A. Patrick

Electronic Theses and Dissertations

Changes in forest habitat have been linked to global declines in amphibian populations, but little research has been conducted into the mechanisms causing these declines. This study evaluated the effects of changes in forest habitat on the spatial distribution of a Maine amphibian community, focusing on juvenile wood frogs, Rana sylvatica. Juvenile wood frogs emerging from artificial ponds did not orient towards preferred habitat and a significant number of animals maintained the same directionality documented at the site from which larval individuals were collected. Abundance and habitat use differed among adults of 9 species of amphibians in a replicated …

The Effects Of Clearcutting And Glyphosate Herbicide Use On Parasitic Wasps In Maine Forests, Kristopher J. Abell

Electronic Theses and Dissertations

Parasitic wasps (parasitoids) play an important role as natural enemies of insects and contribute substantially to world biodiversity (May, 1988), yet they have received relatively little attention outside of agricultural settings. Clearcut harvesting and herbicide (glyphosate) application are frequent and widespread disturbances in Maine forests that drastically alter the local environment. Parasitoids are particularly susceptible to disturbance for several reasons: 1) they are vulnerable to small changes in environmental conditions, 2) they occupy a high trophic level, and 3) many are host specific. However, there may be potential benefits of disturbance such as increased food resources (floral nectaries) and increased …

Systematics Of The Lobulomycetales, A New Order Within The Chytridiomycota, David Rabern Simmons

Electronic Theses and Dissertations

Based on molecular phylogenetic analyses, the polyphyletic order Chytridiales, one of the four orders in the Chytridiomycota, contains several well-supported clades. One species, Chytriomyces angularis, however, does not group within the robust clades of the Chytridiales or any other chytrid order. The light-level morphology and zoospore ultrastructure of this aquatic species also differ from those of the type species of the genus Chytriomyces. I amassed nine additional pure culture isolates of soil-inhabiting chytrids with morphologies or rDNA sequences similar to C. angularis, including two isolates of C. poculatus, and studied the molecular phylogeny of these ten …

Gelation Of Previously Cooked Jonah Crab (Cancer Borealis) Minced Meat In New Food Product Development, Shari R. Baxter

Electronic Theses and Dissertations

Gelation of meat products plays an important role in utilization of by-products. Low-value muscle tissue that may go to waste can be reformed into new products that consumers find acceptable and want to purchase. In the crab industry, the need for byproduct utilization is great. Crab processing typically involves cooking whole crabs and picking the claw meat. A lower grade minced meat can then be extracted mechanically from the walking legs and carapace of the crab. Traditional protein chemistry indicates that only raw muscle proteins can form gels. However, by using a modified surimi processing technique, previously cooked Jonah crab …

Notch Regulation Of Human Breat Cancer Progression: Contrasting Roles For Notch Signaling, Christine F. O'Neill

Electronic Theses and Dissertations

Notch signaling is associated with activation of either oncogenic or tumor suppressor activities. The human mammary adenocarcinoma cell line, MDA-MB-231, was characterized in vitro and in xenografts in vivo to test the hypothesis that activation of Notch signaling regulates mammary tumor phenotype. Notch 1, Notch2, and Notch4 signaling was compared by stable expression of their constitutively active intracellular domains (ICD). Notch4 activation led to enhanced tumorigenicity, in addition to increased cell proliferation and survival in vitro, whereas the activation of Notch 1 or Notch2 decreased cell proliferation and survival, in which Notch2 increased apoptosis. Stably transfected cell lines were …

Effects Of Forest Management On Click Beetle (Coleoptera: Elateridae) Assemblages In The Acadian Forest Of Maine, Shelly L. Thomas

Electronic Theses and Dissertations

Click beetle (Coleoptera: Elateridae) assemblages were examined in three experiments in the Acadian forest of Maine. First, I used flight intercept traps to compare Elaterid assemblages in stands that developed after clearcut, shelterwood, and selection harvests. Click beetle richness was highest in stands managed under a selection system and lowest in stands regenerated using the clearcut method. The abundance of click beetle species was lower in stands managed by clearcutting than in stands managed using the shelterwood and selection methods. Hardwood basal area was the best environmental predictor for both species richness and species abundance. Second, I examined whether Elaterid …

Spatiotemporal Variation Of Avian Populations Within Geographically Isolated Freshwater Marshes, Brian Rodenbeck

Electronic Theses and Dissertations

Metacommunity connectivity, i.e., multi-species dispersal events, is vital to metapopulation persistence in patchy landscapes. Assessments of metacommunity connectivity are not trivial. However, a relationship between trophic rank and the species-area relationship has been found in previous studies, allowing for the use of the predator species-area relationship to act as a surrogate measure of actual metacommunity connectivity of prey species in some systems. For this study, avian species were selected as they are generalist top predators within the study system. Predator species richness within geographically isolated freshwater marshes is influenced by a number of factors. I explore the relative roles of …

Tree Calls Of Three Treefrogs (Hyla Femoralis, H. Gratiosa, And H. Squirella): Analysis Of Environmental, Behavioral, And Acoustic Characteristics, Kristine Schad

Electronic Theses and Dissertations

Male frogs typically call near water at dusk to attract females for breeding. During the breeding season, male treefrogs also emit diurnal "tree calls" or "rain calls" from the tops of trees. Very little is known about tree calls, although many treefrogs use them. Tree calls may be used to attract females, deter males or be triggered by weather conditions favorable for breeding: high temperature and relative humidity, and a drop in barometric pressure. As dusk approaches, male treefrogs continue tree calls from lower in the trees, and if conditions are favorable, jump to the ground and travel to a …