Life Sciences Commons^™

The Effects Of Nutrient Limitation On Toxin Production For The Harmful Algal Bloom Species, Pseudo-Nitzschia, In The Gulf Of Maine, Julia M. Park

Honors Theses

Pseudo-nitzschia is a pennate marine diatom that produces the neurotoxin domoic acid (DA). Domoic acid accumulates in the digestive tract of filter feeders and becomes concentrated at higher trophic levels. When DA concentrations reach critical levels, consumption of toxic shellfish can induce a condition known as Amnesic Shellfish Poisoning (ASP), which has been responsible for the deaths of marine mammals, seabirds and humans. This study worked to respond to a toxic Pseudo-nitzschia bloom in the Gulf of Maine during the fall of 2016, with the goal of quantifying and identifying Pseudo-nitzschia spp. in the bloom region and to determine the …

Crops And Controversy: Industry’S Role In The Gmo Debate, Carina Wallack

Honors Theses

The use of genetically modified crops (also called GM crops, genetically modified organisms, or GMOs for short) has become a highly contested issue. New genetic modification technologies offer a variety of advantages for improving agricultural efficiency. However, some scientists argue that the safety testing conducted thus far does not provide enough information and worry about possible health and ecological risks. Private industry sponsors a great deal of research on genetically modified crops. As the international controversy regarding the use of GMOs has unfolded, the very companies responsible for commercializing genetically modified crops have gained substantial influence in the resulting scientific …

Examining Interactions Between Opsins And Carotenoid Biosynthetic Proteins In Halophilic Archaea, Alexandru M. Plesa

Honors Theses

Organisms have evolved numerous specialized molecules for constantly responding to environmental changes. Examples of such molecules are the light-driven proton-pump rhodopsins, such as bacteriorhodopsin (BR) and cruxrhodopsin (cR), and the carotenoid pigments, such as retinal and bacterioruberin. In halophilic Archaea, retinal can covalently bind bacterioopsin (BO) and cruxopsin (CO) to form the corresponding protein complexes, and its biosynthesis is indirectly controlled by the activity of the lycopene elongase (Lye) enzyme, which converts lycopene, a retinal precursor, to a form of bacterioruberin. Interestingly, opsins were shown to inhibit the activity of Lye, thereby promoting retinal biosynthesis and indirectly regulating the apoprotein-cofactor …

Protein Kinase Activity Toward Taabf1 In Imbibing Grains, Taylor P. Enrico

Honors Theses

The hormones gibberellin and abscisic acid are essential for plant responses to changing environmental conditions, and can send opposing signals. In wheat, the transcription factor TaABF1 plays an important role at the intersection of a gibberellin-induced/abscisic acid-suppressed pathway. When gibberellin dominates, the GA-induced gene, Amy32b, is transcribed. When abscisic acid is dominant, TaABF1 is active and it downregulates GA-induction of Amy32b, while promoting ABA-induced transcription of the gene HVA1. The activity of TaABF1 is thought to be regulated by post-translational phosphorylation at key serine residues. In this study, to determine TaABF1 phosphorylation by wheat kinases, we purified recombinant …

Vein Patterning During Juvenile Wing Development In Oncopeltus Fasciatus And Jadera Haematoloma, William R. Simmons

Honors Theses

Wings are a defining characteristic of all pterygote insects and are agreed to originate from a single common winged ancestor. However, essentially nothing is known about the molecular mechanisms that regulate wing development and patterning outside of Endopterygota, and the vast majority of this knowledge comes solely from Drosophila melanogaster. There is reason to suspect that the drastic developmental differences that exist between Endopterygota and Exopterygota have resulted in changes in the mechanisms, timings, or even genes that govern wing development. This study examined the roles of several genes known to be involved in D. melanogaster wing development and patterning …

Temporal Changes In The Larval Placopecten Magellanicus Population In A Small-Scale Fishery Closure Area In Coastal Maine, Usa, Jessica P. Batchelder

Honors Theses

The Midcoast Maine Collaborative Scallop Project was established in 2013 by fishers, scientists, and policy makers to determine if a small-scale closure area could restore the local Atlantic sea scallop (Placopecten magellanicus) population to an area in coastal Maine that previously supported high scallop densities. These stakeholders established a three by one mile closure area in the Lower Muscle Ridge Channel to assess the response of the adult and larval scallop populations. Understanding the larval dynamics in a closure area is key to evaluating the recovery potential of the population and for future population stock levels. This study …

Environmental Contingency Of Seed-Fungi Interactions In Coexisting Invasive Purple Loosestrife And Native Cattail, Shayla R. Williams

Honors Theses

Purple loosestrife (Lythrum salicaria) is a highly invasive species able to quickly take over entire wetlands, especially after disturbances. Bountiful seed production and a persistent and prolific seed bank play a key role in loosestrife’s ability to invade. However, some competing native species, such as cattails (Typha spp.) have comparable seed production rates but less abundant seed banks, suggesting that there may be a difference in belowground seed survival. I investigated the abundance of loosestrife and cattail seeds in soils at roadside sites relative to above-ground stem densities. Given the importance of fungal pathogens to seed …

Development Of A Chemical Genetic Screen To Determine Synergistic Compounds With Laromustine In Treating Glioblastoma Multiforme Cultured Cells, Ryan Weeks

Honors Theses

Laromustine is a chemotherapeutic sulfonylhydrazine prodrug used in clinical trials to treat acute myeloid leukemia (AML) and glioblastoma multiforme (GBM). While treatment of AML with laromustine has more demonstrative clinical success, there are enough promising data against GBM to pursue additional pre-clinical and clinical experiments. To determine the synergistic effects caused by treating cultured GBM cells with laromustine and a library of FDA-approved compounds, a chemical genetic screen was developed. To optimize the screen, optimal cultured GBM cell seed density, growth period and maximum well capacity were determined. The treatment period for a lethal dose of laromustine in cultured GBM …

Ecological Predictors And Consequences Of Non-Native Earthworms In Kennebec County, Maine, Julia Rogers

Honors Theses

Non-native earthworms are found throughout much of the United States and southern Canada in areas that were glaciated during the most recent glaciation. These earthworms are changing nutrient cycling, modifying soil structure, and influencing diversity in forests throughout the Northern United States, and their invasion northward is facilitated by human activities. Although worms are present in compost piles and gardens of all Maine counties, there are no comprehensive studies of earthworms distributions in forested areas of Maine. I documented the presence and absence of earthworms in forested recreation areas in Kennebec County, Maine, and investigated ecological and landscape level variables …

The Effect Of Cyanobacterium Gloeotrichia Echinulata In The Belgrade Lakes, Maine, Harriet T. Rothschild

Honors Theses

Gloeotrichia echinulata is a cyanobacteria species that has been increasingly forming blooms in oligotrophic lakes in the Northeastern United States. The Belgrade Lakes in central Maine have experienced increasing blooms over the past decades. Long Pond and Great Pond in the Belgrade Lakes region are popular locations for summer tourism and year-round residents. Research into G. echinulata is important to the Belgrade community because of potential effects to water quality, public health, and recreation. Studying G. echinulata bloom density throughout the summer and how it may affect the phosphorous cycle, the nitrogen cycle, and the plankton community will help scientists …

Spatial And Temporal Patterns In Irruptive Fringillid Movements, Paul J. Dougherty

Honors Theses

Historic Christmas Bird Count and eBird data indicate that during winter invasions, North American irruptive fringillid species occur in relatively even numbers across latitudes east of the Rocky Mountains. Most boreal breeding species show large southward invasions every other winter, with this pattern typically being strongest across the northern and mid United States. eBird data confirms that many northern fringillids irrupt synchronously, and both datasets also show positive correlations between the winter movements of southern breeding species in many areas. Winter abundance records show negative correlations between northern breeding species and southern breeding species in nearly all monitored areas of …

The Impact Of Endocrine-Disrupting Chemicals On Wildlife Conservation, Eda Reed

Honors Theses

Endocrine-disrupting chemicals (EDCs), such as those from plastics and pesticides, have been hypothesized to affect wildlife populations. According to the U.S. National Institute of Environmental Health Sciences, EDCs ‘are chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife.’ A growing number of studies suggest wildlife are being exposed to EDCs, but how EDCs affect wildlife health and wildlife conservation is less well-understood. Through scientific literature analysis and a survey of wildlife conservationists and practitioners, this study aims to determine the current state of knowledge and data …

Global Reach, Local Markets: The Challenges Of Leading Global Innovation, Sarah Higgins

Honors Theses

This Global Studies honors thesis addresses how managers and leaders of global firms manage innovation across multiple markets. Current research on multinational corporations provides an understanding of different kinds of innovation and the ways to attend to multiple markets. However, there is less documentation of how these innovation strategies are actually implemented on the ground and the tensions that these efforts might produce. Therefore, my research focuses in particular on the challenges and tensions faced by leaders of global firms as they implement transnational innovation strategies. This study is based upon in-depth interviews with 20 participants who held positions in …

An Investigation Of Bag3 Knockdown And Its Effects On The Cytotoxicity Of Laromustine, Colin Sheehan

Honors Theses

Laromustine is a sulfonylhydrazine anticancer prodrug whose main cytotoxic arises from its ability to interfere with DNA replication of dividing cells. Multiple studies have suggested that Laromustine induces a form of cell death known as apoptosis. In a previous study investigating the mechanism of apoptosis, bcl2-associated athanogene 3 (BAG3) demonstrated significant upregulation in the presence of Laromustine. Given its anticancer ability, we selected BAG3 as a target for further investigation. BAG3 knockdown through transient shRNA transfections was performed in U138 glioblastoma multiforme cells and verified using qRT-PCR analysis. Finally, cell death assays were used to assess Laromustine’s cytotoxic effect on …

Mathematical Modeling Of Emiliania Huxleyi And A Host-Specific Virus, Julia Middleton

Honors Theses

The world’s oceans provide the basis for life on the planet. One microscopic algae, the coccolithophores, and Emiliania huxleyi in particular, is a major source of carbon drawdown in the context of the global carbon cycle and account for a significant amount of the primary production in oceanic ecosystems. We know that the oceans are packed with marine viruses and they have an important role in the rise and fall of plankton populations but current mathematical models do not accurately account for virus-host interactions when predicting plankton blooms. Therefore I am using model optimization and comparison techniques to evaluate current …

School Gardens: Cultivating A Child’S Nutritional Habits, Environmental Knowledge, And Sustainability Practices, Jeffrey Meltzer

Honors Theses

School gardens have existed since the late nineteenth century and today are becoming increasingly popular in many parts of the world, including where I studied in Maine and Australia (AUS). Multiple organizations support school gardens in Maine, including the Maine School Garden Network, which has over 125 registered school gardens. In AUS, the Stephanie Alexander Kitchen Garden Foundation primarily supports the school garden movement and has over 800 registered school gardens. While many researchers have studied school gardens, few have compared two countries, focused on environmental sustainability, or investigated Maine in particular. This thesis combines information from literature reviews, and …

The Impact Of Dams On Nitrogen Cycling In The Messalonskee Stream, Rebecca K. Forgrave

Honors Theses

The Messalonskee Stream in central Maine has five hydroelectric dams on 16.6km. Each dam drastically changes the flow regime of the stream, dividing it into segments with different patterns of sediment settling and organic matter retention. I investigated how these disruptions impact nitrogen cycling, specifically nitrification rates above and below each dam. I expected higher nitrification rates above the dams, where levels of organic matter are higher, and lower rates below the dam where scouring removes organic matter and fine sediment from the streambed. I measured sediment nitrification rates with a nitrapyrin-inhibition assay and potential drivers of nitrification including sediment …

The Role Of Underutilized Fish In New England's Seafood System, Taylor Witkin

Honors Theses

The global fisheries crisis has led to an increasing recognition for the need to relieve pressure on overfished, popular food fish stocks. Opportunities exist to shift consumer demand toward more sustainable choices, including fish that may be locally abundant. Attempts have been made to market underused fish (sometimes termed “trash fish”) that represent more sustainable alternatives; however, it is unclear whether consumers will choose to purchase these more sustainable options, particularly if underused fish are also unfamiliar. Chapter 1 reviews existing research and current issues surrounding sustainable seafood and the recent shift toward local, abundant, undervalued species in New England’s …

Optimization Of A Chemical Genetic Screen To Identify Druggable Targets In U138 Cells Treated With Laromustine, Kathryn Coe

Honors Theses

Laromustine is an experimental sulfonylhydrazine prodrug used in late-stage clinical studies against acute myeloid leukemia (AML) and glioblastoma multiforme (GBM). Despite initial promise for both indications, clinical trials for GBM have not been as successful as those for AML. To investigate methods for improving the effectiveness of laromustine in GBM and to learn more about the mechanism of action of laromustine, a chemical genetic screen will be conducted to identify agents that sensitize GBM cells to the anti-proliferative effects of laromustine. The library, which will include approximately 450 FDA-approved drugs, will be screened using a newly optimized high throughput assay …

Variations In Intra- And Interspecific Response To Mobbing Calls By The Black-Capped Chickadee (Poecile Atricapillus), Katerina M. Faust

Honors Theses

Mobbing calls are produced by a variety of bird species in response to predator sightings. These mobbing calls often function in intraspecific recruitment, but have recently been shown to have an interspecific response component as well. The mobbing calls produced by the Black-capped Chickadee (Poecile atricapillus) are distinct and encode information about the threat level of the predator. Conservation biologists often use playbacks of chickadee mobbing calls to detect species of birds and numbers of individuals in an area with higher accuracy than counts conducted without the use of playbacks. In this study, the factors that could potentially …

Investigating The Effects Of Bag3 Knockdown On The Cytotoxicity Of The Anticancer Drug Laromustine, Kayla Gross

Honors Theses

Laromustine is a sulfonylhydrazine anticancer prodrug whose cytotoxicity results from the formation of interstrand cross-links caused by the synergistic action of co- generated 2-chloroethylating and carbamoylating species. The cytotoxic activities of Laromustine involve the induction of apoptosis. Described herein is an investigation into this drug’s effects on apoptotic gene expression in HL-60 cells using qRT-PCR. Significant changes in the expression levels of 13 genes were observed, most dramatically in the upregulation of the bcl2-associated athanogene 3 (BAG3) gene. Given the pro-survival role of BAG3 in the cell, this investigation sought to decrease BAG3 mRNA levels in HL-60 cells using transient …

Prenatal Choline Supplementation And Mk-801 Toxicity: Protecting Memory And Preventing Neurodegeneration, Chelsea Nickerson

Honors Theses

Choline is essential to the development and function of the central nervous system. Supplemental choline is neuroprotective against a variety of insults, including neurotoxins like dizocilpine (MK-801). MK-801 is an NMDA receptor antagonist that is frequently used in rodent models of psychological disorders. At low doses, it causes cognitive impairments, and at higher doses it induces motor deficits, anhedonia, and neuronal degeneration. The primary goals of the present study were to investigate whether prenatal choline supplementation protects against the cognitive impairments, motor deficits, and neuropathologies that are precipitated by MK-801 administration in adulthood. Adult male Sprague Dawley rats were fed …

Investigating The Role Of Epibiotic Bacteria In Defense Against Chytridiomycosis In The Green Frog, Lithobates Clamitans, Sarah Nalven

Honors Theses

Amphibian populations have been declining for several decades, in part due to the emerging fungal skin disease, chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Chytridiomycosis has caused extinctions and extirpations in many parts of the world, but its influence varies across species, populations, and individuals. The Green Frog (Lithobates clamitans), which inhabits the eastern half of the United States, seems capable of sustaining Bd infections without experiencing die-offs. It is possible that the Green Frog's epibiotic bacteria are contributing to its defense against Bd as the epibiotic bacteria of several amphibian species are known to play …

Relationship Of Cross-Linking Potential To Mechanism Of Cell Death, Adam N. Spierer

Honors Theses

Mechlorethamine (HN2), a nitrogen derivative of mustard gas, was the first synthetic anti-tumor chemotherapeutic because it forms covalent cross-links between strands of duplex DNA. HN2 represents a class of bifunctional alkylating agents that are both chemotherapeutic and carcinogenic: diepoxybutane (DEB), the active form of the pro-drug treosulfan, and epichlorohydrin (ECH), a structural hybrid of HN2 and DEB, also form covalent cross-links between DNA. While HN2 and DEB are clinically used as anti-tumor chemotherapeutics, ECH is a structural hybrid of these two compounds not used in a clinical setting. Accordingly, we aimed to understand the relationship between the cross-linking potential of …

The Development And Morphology Of Zebrafish After Embryonic Ethanol Exposure, Frances Lee

Honors Theses

Maternal consumption of alcohol may subject the fetus to fetal alcohol syndrome or fetal alcohol spectrum disorders (FAS or FASD). FAS/D is a public health problem, and affected children are defined by varying degrees of irreversible mental retardation, physical defects, behavioral issues, and vision problems from prenatal alcohol exposure (Riley et al. 2011). Recent studies on FAS have looked towards animal models, such as zebrafish, Danio rerio, that exhibit homologous physical and behavioral effects of alcohol (Bilotta et al. 2004). I exposed zebrafish embryos to low doses of ethanol (0.5% v/v or 1% v/v) in either chronic (at least 8 …

Biomass Energy At Colby College, Rachel E. Baron

Honors Theses

In light of growing concern regarding the effects of global climate change, Colby College signed the American College and University Presidents’ Climate Commitment (ACUPCC) in 2008. Through this pledge, Colby has committed to reducing carbon emissions in its Climate Action Plan (IPCC 2007; CCAP 2010). The College seeks to be carbon neutral by 2015 (CCAP 2010). This will be accomplished through a variety of mechanisms, one of which includes the construction of a biomass facility to replace most of the oil currently used for heating (CCAP 2010).

Anthropogenic global climate change has been documented by many scientists, but was widely …

The Impact Of Tricaine Methanesulfonate, 2-Phenoxyethanol, And Carvone-Methyl Salicylate On The Innate Immune Response Of Zebrafish (Danio Rerio), Charles R. Wulff

Honors Theses

Anesthesia plays a vital role in the maintenance of aquaculture species, where it is used to minimize stress during complex handling tasks such as transport, assessment, and harvesting. However, anesthetics have been shown to suppress the innate immune response, which could impact immunity and increase risk of infection. Tricaine methanesulfonate (MS-222) and 2-Phenoxyethanol (2-PE) represent two of the most commonly used anesthetics in aquaculture, with R-(+)-carvone, in the form of carvone-methyl salicylate (CMS) has recently been proposed as an alternative anesthetic for food fish. These three anesthetics were used to assess the influence of anesthetics on the immune system of …

Do Male Physiological Condition And Territory Quality Affect Female Choice In The Brown Anole, Anolis Sagrei?, Sarah P. Flanagan

Honors Theses

Female mate choice is an important component of sexual selection because traits that influence male mate preference, such as physiology, and proficiency in acquiring resources, are favored. In lizards, the importance of mate choice remains unclear as reported results from experiments are contradictory. In this study, I investigated whether male physiology and territory quality are important to female mate choice for male Brown Anoles, Anolis sagrei. I tested the hypotheses that female A. sagrei prefer males with greater physiological capacities, and prefer higher quality territories, regardless of male phenotype. To test these, male A. sagrei were first rated for …

Zooplankton Of The Belgrade Lakes: The Influence Of Top-Down And Bottom-Up Forces In Family Abundance, Kimberly M. Bittler

Honors Theses

The purpose of this study was to assess the abundance and family diversity of zooplankton communities in the Belgrade Lakes, and to identify the broad scale and local variables that structure zooplankton communities in this region. The local effects of shoreline development and the presence of macrophyte patches were compared to larger scale variables, such as watershed wide residential development. Zooplankton are an intermediate link in the freshwater food web, and communities respond both to predation pressures as well as nutrient inputs. Shoreline development was expected to influence zooplankton densities by the increased nutrient inputs via erosion off developed sites …

Buffernomics: Assessing Willingness To Pay For Lake Conservation On North Pond And East Pond, Sophie D. Sarkar

Honors Theses

Hedonic property valuations in Maine have estimated that a one-meter decrease in water clarity can reduce shoreline property values by 4 to 16%. To avoid a loss on their lakefront investment, shoreline property owners have a particularly large incentive to conserve lake water quality. Nevertheless, while some shoreline residents voluntarily install vegetated buffers and actively participate in lake stewardship, others continue to ignore shoreline zoning laws at the expense of lake health. In this thesis, I examine the dichotomy of active and indifferent shoreline residents by analyzing the motivations that distinguish residents who are willing to pay (WTP) for and …