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Eavesdropping On Gulf Of Maine Cetaceans In The Vicinity Of Mount Desert Rock, Christopher James Tremblay

Electronic Theses and Dissertations

Passive acoustic monitoring, the recording and analysis of biological sound, is a standard method of research into the distribution and behavior of cetaceans worldwide. Acoustic monitoring is reliant upon a thorough reference catalog of species vocalizations and an understanding of the temporal and geographic parameters in which vocalizations occur. This study combined a standard cetacean passive acoustic monitoring survey with a concurrent visual survey at a known baleen whale summer feeding ground to determine the annual species and vocal composition, compare species detection rates using each method, and identify and attribute novel vocalizations to species. The survey took place at …

Assessing The Upper Critical Limit Of The Thermoneutral Zone In Laboratory Mice, Teumbo Ngunte

Electronic Theses and Dissertations

Endothermic organisms such as mammals and birds rely on high energy budgets to regulate body temperature. Many studies have previously investigated the thermo-regulation of mammals under the lower critical temperature of the thermoneutral zone, yet our knowledge in determining the upper critical limits is still scarce. As an endotherm, lab mice (Mus musculus) are perfect models to determine the cost to maintain constant body temperature as ambient temperature increases. The upper critical temperature of the thermoneutral zone of this species has been estimated to be above 32°C and below 34°C. By utilizing different genetic backgrounds of lab mice in this …

Providing Experimental Evidence For Mouse Telomerase Reverse Transcriptase As A Novel And Unique Adult Neural Stem Cell Marker, Caroline Dean Curtis

Electronic Theses and Dissertations

With the prevalence of neurodegenerative pathologies in our society today it is imperative that we begin to look at novel approaches to the underlying problem of dying neurons that are not replaced. Adult neural stem cells exist naturally and could potentially be manipulated into targeted repair of damaged brains, given substantial research. The first step in this process is to find a way to specifically mark the earliest subset of these cells, the quiescent adult neural stem cells. Here we provide evidence for the existence of a novel and unique qANSC marker in mouse telomerase reverse transcriptase (mTERT). mTERT has …

Characterization And Functional Rescue Of Congenital Muscular Dystrophy With Megaconial Myopathy In A Mouse Model Of The Disease, Ambreen A. Sayed

Electronic Theses and Dissertations

Congenital muscular dystrophy with megaconial myopathy (MDCMC) is an autosomal recessive disorder characterized by progressive muscle weakness and wasting. Megamitochondria in skeletal muscle biopsies and cognitive impairments in MDCMC patients are observations exclusive to this type of muscular dystrophy. The disease is caused by loss of function mutations in the choline kinase beta (CHKB) gene which results in dysfunction of the Kennedy pathway for the synthesis of phosphatidylcholine (PC). A rostro-caudal muscular dystrophy (rmd) mouse with a deletion in the Chkb gene resulting in MDCMC-like symptoms has been reported by our lab. In order to test if the rmd mice …

Effects Of Increasing Temperature And Acidification On The Growth And Competitive Success Of Alexandrium Catenella From The Gulf Of Maine, Drajad Seto

Electronic Theses and Dissertations

The increases in ocean temperature and pCO2 due to climate change are projected to affect the growth and future prevalence of Harmful Algal Blooms (HABs) in nearshore waters, but systematic studies on the effects these climate drivers have on harmful algal species are lacking. In particular, little is known about how future climate scenarios will affect the growth of the toxic dinoflagellate Alexandrium catenella, which produces the toxins responsible for paralytic shellfish poisoning (PSP) that threaten the health and economy of coastal communities in the Gulf of Maine. I examined growth responses of A. catenella and two other naturally co-occurring …

Developing Animal Feed Preservatives From Paper Mill Byproducts, Diana Carolina Reyes Gomez

Electronic Theses and Dissertations

Our objectives were to evaluate the antifungal properties of technical lignins against 3 molds and 1 yeast causing hay spoilage, and for their ability to preserve alfalfa hay nutritive value. In experiment 1, 8 technical lignins and propionic acid (PRP; positive control) were tested at a dose of 40 mg/mL. The experiment had a randomized complete block design (RCBD, 4 runs) and a factorial arrangement of 3 molds × 10 additives (ADV). The effects of ADV on the yeast were also evaluated with a RCBD. Across fungi, sodium lignosulfonate (NaL) and PRP were the only treatments with a 100 ± …

The Infection Dynamics Of Sea Lice On Atlantic Salmon (Salmo Salar) In Cobscook Bay, Maine, Usa, Catherine Anne Frederick

Electronic Theses and Dissertations

Sea lice (Lepeophtheirus and Caligus spp) are parasitic copepods that infect the external surfaces of fish hosts. Salmon lice (L. salmonis) outbreaks are commonly reported by operations in Canada, Norway, Scotland, Ireland, and the United States and are a primary concern in aquaculture because of their fish health and economic impacts. When farmed fish mortalities and treatments are accounted for, annual losses from sea louse infestations exceed $300,000,000 (Costello 2009). Farms experiencing sea lice infections risk on-site re-infection and transmission to wild populations and other farms that are hydrographically connected. In Maine, Atlantic salmon farms are located in the northeast, …

Modeling Human Cancer Therapy Response In Patient Derived Xenografts, Joan Malcolm

Electronic Theses and Dissertations

Patient‐derived xenografts (PDXs) generated by implanting human tumor tissue into a transplant compliant mouse host have been of increasingly importance to preclinical development and have been demonstrated to have advantages compared to cancer cell lines and cell‐line xenografts (CLX) for modeling therapeutic responses in cancer. Nevertheless, many open questions remain regarding the relationship between study design factors and classification of treatment response and the molecular fidelity of tumors passaged in PDXs relative to the original patient tumor(s). The research described in this dissertation addresses both of these significant issues related to the use of PDXs as a tool for modeling …

Multi-Tactic Ecological Weed Management In A Changing Climate, Sonja K. Birthisel

Electronic Theses and Dissertations

Climate change is expected to impact weed communities in Maine, and the efficacy of tools and tactics farmers use to manage them. Through seedbank sampling and surveys of Maine organic farms, we identified currently rare weeds that are known to be especially abundant or problematic in warmer areas of the USA and might therefore represent an emerging agronomic risk. Many ecological weed management strategies that focus on depleting the weed seedbank are expected to remain effective in a changing climate, and become increasingly important as efficacy of cultivation and some herbicide applications diminish or become more variable. Through field experiments, …

Pyrrolo[2,3-D]Pyrimidine Classical Antifolates For Targeted Cancer Chemotherapy- Applications Of Bioisosteric And Regioisomeric Substitutions For Improved Tumor-Selectivity And Potency, Manasa Punaha Ravindra

Electronic Theses and Dissertations

In 2018, it is estimated that 1,735,350 new cases of cancer and 609,640 deaths from the disease will be diagnosed in the United States alone. Conventional chemotherapy is by far the most successful category of clinical oncology, having cured (complete remission (CR), without return) or provided clinical benefit to millions of people. However, since its earliest discovery, the major causes of failure of conventional cancer chemotherapy have been dose-limiting toxicities and development of resistance. There is a desperate ongoing search for new cancer therapies as tumor-targeted agents (without harming normal cells or tissues) with low propensity for the development of …

Characterization Of G-Protein Coupled Receptors In Pain, Depression And Anxiety, Neil Lax

Electronic Theses and Dissertations

Chronic pain and major depressive disorder are widespread conditions in the world. Interestingly, these conditions often occur comorbidly, with each individual disease amplifying the symptoms of the other. A significant amount of preclinical research in pain and depression focuses on G-protein coupled receptors (GPCRs), implying that GPCRs may be useful in treating this comorbidity. Our efforts have sought to characterize several poorly understood GPCRs, including the serotonin receptor subtypes 2C and 7 (5-HT2CR and 5-HT7R) and metabotropic glutamate receptor 5 (mGluR5), along with more well-known GPCRs such as the mu opioid receptor (MOR), and the role that they play in …

Harnessing The Anopheles Microbiome To Conditionally Express Anti-Plasmodial Effectors During The Blood Meal, Jackie Shane

Electronic Theses and Dissertations

The control of vector-borne diseases such as malaria has been an extremely important research subject for hundreds of years. Because of the complex lifecycles of the pathogens that cause these diseases, finding a comprehensive treatment or preventative strategy has proven extremely difficult. Malaria alone is responsible for almost half a million deaths annually, most of them children under 5 years old. This disease is caused by parasitic protists in the genus Plasmodium that are transmitted to humans from Anopheles sp. mosquitoes. Most preventative strategies that are in use today revolve around controlling the vectors, including bed nets, insecticides, and larval …

Associations Between Avian Spruce-Fir Species, Harvest Treatments, Vegetation, And Edges, Brian W. Rolek

Electronic Theses and Dissertations

Habitat loss is the primary cause of species loss and declines of global biodiversity. Several birds associated with the spruce-fir forest type (hereafter spruce-fir birds) have declining populations across the continent in the Atlantic Northern Forest, and the extent of coniferous forest has declined in some areas. This region is extensively and intensively managed for timber products.

To investigate the influence from harvest treatments on the spruce-fir bird assemblage during the breeding and post-breeding period in lowland conifer and mixed-wood forests, we used avian point count detection data to test for associations between avian assemblages and seven common harvest treatments. …

Ecological Consequences Of Personality In A Guild Of Terrestrial Small Mammals: From Trappability To Seed Dispersal, Allison M. Brehm

Electronic Theses and Dissertations

Individual animals exhibit consistent behavioral tendencies over time and across contexts that have been termed personalities. Personality encapsulates an individual’s unique way of behaving and responding to life’s challenges, and since individuals vary in both personality type and their ability to exhibit behavioural plasticity, there are important links between an individual’s personality and its response to a changing environment; resulting in the study of animal personalities becoming increasingly popular in recent years. Previous research suggests that personality traits measured through standardized behavioural tests predict trappability (i.e. ‘trap happiness’ versus ‘trap shyness’). This relationship has been explored only within single …

Establishment Of Turfgrass From Seed And Sod In Sand Based Systems Combining Sprinkler And Subsurface Drip Irrigation Systems, Roshaan Ahmed Khan Niazi

Electronic Theses and Dissertations

The establishment of turfgrass using subsurface drip irrigation (SDI) in sand based media has limited success. However, it is unknown if starting with overhead (sprinkler) irrigation and transitioning to SDI can enhance turfgrass establishment. Two experiments were conducted at Stephen F. Austin State University (SFASU) to investigate the establishment of “L-93” creeping bentgrass (Agrostis stolonifera) from seed and “TifEagle” ultra dwarf hybrid bermudagrass (Cynodon dactylon x Cynodon transvaalensis) from sod using sand based media. Each experiment consisted of two trials conducted in summer 2017 and spring 2018. Both creeping bentgrass trials and the spring ultra dwarf …

Climatic Range Filling Of North American Trees, Benjamin Seliger

Electronic Theses and Dissertations

Understanding the degree to which species distributions are controlled by climate is crucial for forecasting biodiversity responses to climate change. Climatic equilibrium, when species are found in all places which are climatically suitable, is a fundamental assumption of species distribution models, but there is evidence in support of climate disequilibria in species ranges. Long-lived, sessile organisms such as trees may be especially vulnerable to being outpaced by climate change, and thus prone to disequilibrium. In this dissertation, I tested the degree to which North American trees are in equilibrium with their potential climatic ranges using the ‘range filling’ metric, which …

Black Soldier Fly Larvae As Value-Added Feed For Aquaculture In Maine, Joshua Villazana

Electronic Theses and Dissertations

Black soldier flies (BSF), Hermetia illucens (Linnaeus) (Diptera: Stratiomyidae) consume decaying organic waste as larvae (BSFL) and can be used for recycling a variety of biogenic wastes. BSFL can also be processed into value-added animal feeds, including those used in aquaculture. An overarching goal of this project was to obtain additional insights into BSF biology to improve their rearing and handling in future mass-production facilities serving Maine aquaculture.

We tested BSFL growth in the laboratory on seven seafood wastes from Maine fish processing facilities. Substrates potentially suitable for BSFL rearing included finfish trimmings, wet sea cucumber, dry quahog, and sea …

Direct And Indirect Effects Of Invasive Cirsium Arvense On Pollination In Southern Appalachian Floral Communities, Jesse Daniels

Electronic Theses and Dissertations

Invasive plants can alter pollination dynamics in invaded communities by disrupting patterns of pollinator visitation, pollen transfer dynamics (conspecific [CP] and heterospecific [HP]), and reproductive success. The direction of invasive effects (competitive, neutral, and facilitative) may be partially determined by spatial scale and species’ floral traits. Here, we investigated pollinator visitation, CP and HP receipt, and pollen tube growth for species in a C. arvense present community and non-present community at two scales. At the community-level, the effect of C. arvense on pollinator visitation varied among species. Floral symmetry seemed to explain this variation. At the floral neighborhood-level, we found …

The Role Of Non-Neuronal Acetylcholine In Urogenital Chlamydial Infection, Jessica R. Lockhart

Electronic Theses and Dissertations

Chlamydia trachomatiscauses a bacterial sexually transmitted infection, Chlamydia, that is often chronic and casues reproductive complications in women. We hypothesized that Chlamydia infection increases local acetylcholine (ACh) production, which regulates the host’s inflammatory response to the infection. Female mice infected with C. muridarumwere sacrificed at days 3, 9, 15, and 21 post-infection, genital tract tissues harvested, and immunohistochemistry performed to enumerate ACh-producing cells. Infection increased the number of ACh-producing cells in cervical tissue at days 3,15, and 21 post-infection (pi), uterine tissue at day 3 and 9 pi, and ovarian tissue day 3, 15, and 21 pi. These …

Comparisons Between Movement Onset Identification Methods Used In Isometric Mid-Thigh Pull Test, Junshi Liu

Electronic Theses and Dissertations

This dissertation aimed to explore the usefulness of using force derivatives for onset detection in the isometric mid-thigh pull test. First, we examined applications of three differential calculus principles, first and second derivative, and curvature using visual detection as a reference under different baseline conditions. Second, we compared the best derivative method to a threshold-based method using visual detection as a reference. Results of our first investigation showed trivial differences between many differential calculus methods and visual detection. However, statistical differences exceeding a trivial effect was observed when instantaneous force and rate of force develop were examined. Through the first …

The Role Of Cyp2a5 In Cadmium-Induced Liver Injury, Julia Salamat

Electronic Theses and Dissertations

Cadmium is present in food and groundwater. Tobacco smoking and occupational exposure are also major sources for cadmium. Cadmium is primarily accumulated in liver, a major organ metabolizing exogenous chemicals. Chemical metabolism may cause detoxification, but it can also cause bio-activation resulting in liver damage. Cytochrome P450s (CYP) are major liver metabolism enzymes, and cadmium chloride (CdCl2) can induce CYP2A5 in mice. We examined the effect of CYP2A5 on CdCl2-induced liver injury using CYP2A5-knockout (cyp2a5-/-) mice. The cyp2a5-/- mice and their control WT mice were injected CdCl2 intraperitoneally at 5 mg/kg body weight, respectively, to induce liver injury. …

Localization Of Sip470, A Plant Lipid Transfer Protein In Nicotiana Tabacum, Shantaya Andrews

Electronic Theses and Dissertations

SABP2-interacting protein 470 (SIP470), a non-specific lipid transfer protein (nsLTP), was discovered in a yeast two-hybrid screening using SABP2 as bait and tobacco leaf proteins as prey. SABP2 is an important enzyme in systemic acquired resistance that converts salicylic acid to methyl salicylate. Localization studies are an important aspect to understanding the biological function of proteins. nsLTPs are generally considered apoplastic proteins and has been localized intracellularly and extracellularly. Transient expression shows highest expression of SIP470-eGFP at 2 days post infiltration into Nicotiana benthamiana. Confocal microscopy showed localization near the periphery of the cell. Subcellular localization using differential centrifugation showed …

Sip-428, A Sir2 Deacetylase Enzyme And Its Role In Biotic Stress Signaling Pathway, Bal Krishna Chand Thakuri

Electronic Theses and Dissertations

SABP2 (Salicylic Acid Binding Protein 2) plays a vital role in the salicylic acid signaling pathway of plants both regarding basal resistance and systemic acquired resistance against pathogen infection. SIP-428 (SABP2 Interacting Protein-428) is a Silent information regulator 2 (SIR2) like deacetylase enzyme that physically interacts with SABP2 in a yeast two-hybrid interaction and confirmed independently by a GST pull-down assay. We demonstrated that SIP- 428 is an NAD+ dependent SIR2 deacetylase enzyme. Transgenic tobacco plants silenced in SIP- 428 expression via RNAi showed enhanced basal resistance to microbial pathogens. Moreover, these SIP-428-silenced lines also exhibited a robust induction of …

The Study Of Alcoholic Liver Diseases, Seun Emmanuel Owoseni

Electronic Theses and Dissertations

Excessive alcohol consumption is the primary contributing factor in the development of alcoholic liver diseases (ALD). Nicotine contained in tobacco is a major addictive alkaloid, which enhances the effects of ALDs. The major enzyme involved in nicotine metabolism is cytochrome P450 2A5 (CYP2A5) which is produced in the liver. Alcohol can stimulate the CYP2A5 enzyme. We utilized cyp2a5-/- knockout mice in this research to examine the effects of CYP2A5.

The cyp2a5-/- mice and wild-type (WT) mice were fed liquid ethanol diet with or without nicotine to induce ALD. Nicotine enhancing effects on ALD were observed in WT mice but not …

Cd11b Regulation Of B Cell Receptor Signaling In Health And Systemic Lupus Erythematosus., Paul Lorenzo Dascani

Electronic Theses and Dissertations

Loss of function mutation in CD11b has been associated with incidence of systemic lupus erythematosus (SLE), a disease driven by B cell production of pathogenic autoimmune antibody. Our previous work has revealed the ability of CD11b to regulate B cell receptor (BCR) signaling and control autoimmune disease in mice. However, how CD11b regulates the immune response under normal conditions remains unknown. Through the use of a CD11b knockout model, we demonstrated that CD11b-deficient mice have an elevated antigen-specific humoral response in a Th2 type immunization. Deletion of CD11b resulted in elevated serum IgM and IgG antibody, increases in antigen-specific germinal …

Identification And Functional Characterization Of Effectors From An Anther Smut Fungus, Microbotryum Lychnidis-Dioicae., Venkata Swathi Kuppireddy

Electronic Theses and Dissertations

Microbotryum lychnidis-dioicae causes anther smut fungus in its host plant, Silene latifolia. The goal of this work is to identify and characterize the virulence determinants of this pathogen to better understand the molecular basis behind this host-pathogen interaction. This work studied for the first time the key effectors in the mechanism of infection by this fungal species. Using, yeast two-hybrid screens, I have identified the host plant interaction partners for the effector, MVLG_01732. A second effector MVLG_05720, interacts with other fungal proteins that appear to facilitate the fungal establishment and colonization during the infection. Our findings indicate that a …

Functional Consequence Of Psat1 Association On Pkm2'S Inherent Enzymatic Activity., Alexis Avidan Vega

Electronic Theses and Dissertations

Pyruvate kinase M2 (PKM2) is predominantly found in tumors, where it allows the cancer cell to adapt to metabolic conditions through allosteric regulation of its activity. We recently discovered that phosphoserine aminotransferase 1 (PSAT1) associates with and activates PKM2. Here, I sought to affirm PSAT1's ability to increase PKM2 activity through kinetic and association studies of wild-type or mutant PKM2 enzymes. I demonstrate that His-tagged WT and mutant PKM2 enzymes are active, exhibit different kinetics, yet cannot be activated by PSAT1. Comparison studies using untagged WT PKM2 suggest that inclusion of the His-tag disrupts PSAT1 association. In support, pull-down strategies …

Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush

Electronic Theses and Dissertations

There are thirteen known endogenous EGF-like ligands. We previously reported that Betacellulin (BTC) increases ligand-mediated corneal wound healing more than Epidermal Growth Factor (EGF) [Peterson et al. (2014) IOVS 55(5):2870-80], although the molecular reason for this is unknown. Despite being better at promoting wound healing via enhanced cell migration, BTC has reduced receptor affinity and weaker induction of EGFR phosphorylation. These data indicate that BTC’s response is not due to enhanced affinity or EGFR-kinase activity. Receptor phosphorylation and proximity ligation assays indicate that BTC treatment significantly increases ErbB3 phosphorylation and EGFR:ErbB3 heterodimers. BTC traffics EGFR at a faster rate than …

Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan

Electronic Theses and Dissertations

Periodontal disease is one of the most prevalent infectious diseases worldwide. Between 30-50% of the global adult population suffers from periodontal disease. Some form of periodontitis is present in 46% of American adults, corresponding to annual expenditures in excess of 14 billion dollars for treatment and prevention. Current treatments for periodontal diseases involve mechanical removal of plaque, correction of risk factors, gingival surgery and/or antibiotic therapy. To our knowledge there is no effective therapeutic approach that aims to limit pathogen colonization of the oral biofilm or re-colonization after treatment. Interaction of the pathogen Porphyromonas gingivalis with oral streptococci is critical …

Role Of Trkb-Signaling In Taste Development And Function., Jennifer Rios-Pilier

Electronic Theses and Dissertations

In the geniculate ganglion, taste neurons likely differentiate into subtypes during development, but very little is known about how these neurons are defined molecularly or how they differentiate. Embryonically, geniculate neuron development is regulated by the growth factor, brain ­derived neurotrophic factor (BDNF). Postnatally, BDNF becomes restricted to subpopulations of taste receptor cells with specific functions, primarily sour responding. I hypothesized that during development, the receptor for BDNF, tropomyosin kinase B receptor (TrkB), also becomes restricted to a neuronal subset. I used transgenic mouse models to label and quantify both geniculate sensory neurons (Phox2b+), and those expressing TrkB (GFP) across …