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Full-Text Articles in Life Sciences

Testing Evolutionary Conservation Of Sex Determination In Lepidoptera Using Crispr/Cas9 Gene Editing, Sophia Schroeder Jan 2023

Testing Evolutionary Conservation Of Sex Determination In Lepidoptera Using Crispr/Cas9 Gene Editing, Sophia Schroeder

Honors Theses

The mechanism of sex determination in Lepidoptera is largely unexplored, and limited to knowledge of only a few genes. Adult Lepidoptera have obvious sexually dimorphic qualities, such as their genitalia. However, significant sex determination genes are not imperative for the adult developmental stage. Knockouts of some sex determination genes (doublesex isoforms) are shown to be lethal in the embryonic and larval stages of development in several animals. However, it is unclear whether this is due to their respective impact on sex determination and sexual dimorphism, or the existence of another function, such as pleiotropy, within a particular gene. Moreover, …


Biomechanics Of Mantis Prey Capture, Danielle S. Taylor Jan 2023

Biomechanics Of Mantis Prey Capture, Danielle S. Taylor

Honors Theses

Mantis species have a variety of different morphologies, so do the extreme forms of mantis limbs trade prey catching capability for camouflage? We hypothesize that some extreme forms of mantis limbs that are associated with cryptic species may be associated with a tradeoff of the capability of those limbs. Previous research has developed 2D morphologies of several hundred species of mantises. We are creating a 3D morphology by using micro dissection, micro CT imaging to construct our 3D biomechanical model. We found the attachment points of the ligaments and muscles from a Tenodera forearm and have constructed a 2D biomechanical …


Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa Jan 2023

Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa

Honors Theses

Elevation gradients have been used to understand how climate change impacts various ecosystems processes by substituting distance across elevation with time, reflecting a previous, colder climate. To monitor the changes in soil organic carbon (SOC), plant community, and functional traits across time in the face of climate change, this study used space-for-time substitution to emulate a long-term study with elevational gradients and revisited the same gradient for nearly two decades to monitor elevational effects across time. With this research, I aim to answer the following questions: (1) How does elevation impact ecosystem processes and alpine plant traits? (2) How does …


Modeling Jadera Haematoloma’S Phenotypic Variation In The Context Of Its Developmental Plasticity, Michael C. Yorsz Jan 2022

Modeling Jadera Haematoloma’S Phenotypic Variation In The Context Of Its Developmental Plasticity, Michael C. Yorsz

Honors Theses

Phenotypic plasticity is the ability of an organism to integrate information from environmental cues to inform the development of its phenotype and remains understudied in biology. Models of plasticity are needed because evolution in the presence of plasticity is poorly understood. Jadera haematoloma, a hemimetabolous true bug, is an excellent animal model of plasticity, exhibiting a non-linear plastic response to juvenile nutrition that biases adult development into groups with differences in flight capability, wing shape, and fecundity. However, there is a lack of literature consensus regarding the range of developmental outcomes in the species. Some publications report the presence …


Pfas Environmental Contamination In Central Maine, Megan H. Andersen Jan 2022

Pfas Environmental Contamination In Central Maine, Megan H. Andersen

Honors Theses

PFAS (per- and polyfluoroalkyl substances) are toxic, persistent, and bioaccumulative chemicals that are used in a variety of consumer products and industrial applications. Paper mills across the state of Maine have used PFAS in their industrial paper making processes, and their wastes often flow for treatment into municipal sewage treatment facilities. PFAS contaminated municipal wastewater from the general use of PFAS consumer products are also processed by these plants. Liquid waste is condensed into solid waste septage and sludge, and in what was thought to be an environmentally friendly repurposing practice, municipal sludge and septage has been spread on plots …


Community Interventions To The Food Insecurity Crisis Inuit Currently Face In Nunangat, Alyssia R. Getschow Jan 2022

Community Interventions To The Food Insecurity Crisis Inuit Currently Face In Nunangat, Alyssia R. Getschow

Honors Theses

Inuit living in Nunangat, a northern territory in Canada, are facing unprecedented rates of food insecurity. The increasing impacts of anthropogenic climate change are rapidly changing the Arctic landscape in Nunangat, posing challenges to Inuit hunters who hunt and live completely self-sufficient off of the land. This lack of access to country foods and the impacts these conditions are having on Inuit communities are forcing Inuit to consider aid propositions from the Canadian government. Due to a long history of conflict with white settlers during the colonization of Canada, there is a feeling of distrust and cultural distaste between Canada …


Challenges Of Constructing Entrainment Map For Arbitrary Circadian Models, Yuxuan (Nelson) Wu Jan 2022

Challenges Of Constructing Entrainment Map For Arbitrary Circadian Models, Yuxuan (Nelson) Wu

Honors Theses

The entrainment map, developed by Dr.Diekman and Dr.Bose, is claimed to be a 1-dimensional map that produces a better prediction for phase-locking than methods than the phase response curve for circadian models. In his paper, he constructs the entrainment map for the two-dimensional circadian model, the Novak-Tyson model, and the other two higher-dimensional circadian models. For this thesis, we concentrate on exploring if it is viable to construct the entrainment map for other circadian models that are not included in his paper: the Becker-Weimann model and the Relogio model. In addition, we discuss the challenges of constructing the entrainment map …


Impact Of The North American Monsoon On Molt Migrant Passerines, Liuqingqing Yang Jan 2021

Impact Of The North American Monsoon On Molt Migrant Passerines, Liuqingqing Yang

Honors Theses

Breeding, molt, and migration place considerable yearly demands on migrating passerines in North America. Due to conflicts in energy allocation, many species have evolved migration strategies that prevent temporal overlap in these processes. However, there is recent evidence that some passerines which breed in western North America migrate to intermediate stopover sites to carry out molt, conflating molt and migration. Factors influencing the evolution of such a strategy are believed to include both aridity on breeding grounds and dependable flushes of late-summer productivity in the southwestern United States and northwestern Mexico. This productivity occurs due to the brisk rainfall of …


Contrasting Patterns Of Nutrient Limitation In The Littoral And Pelagic Zones Of Mesotrophic Maine Lakes, Grace C. Neumiller Jan 2021

Contrasting Patterns Of Nutrient Limitation In The Littoral And Pelagic Zones Of Mesotrophic Maine Lakes, Grace C. Neumiller

Honors Theses

Intense nutrient loading of nitrogen (N) and phosphorus (P) causes sudden regime shifts in freshwater ecosystems from clearwater to turbid conditions with frequent cyanobacterial blooms. Characterization of nutrient limitation patterns of primary productivity in these ecosystems is necessary for effective management of algal blooms. However, much of this research has focused on pelagic habitats. The influence of lake habitat (i.e. benthic littoral versus pelagic zones) on nutrient limitation of primary production in mesotrophic lakes is largely unknown, particularly in contrast to research on pelagic nutrient limitation in eutrophic systems. Using paired nutrient diffusing substrata and mesocosm experiments, we measured chlorophyll- …


Microbiome Community And Parasitic Infections In Wild Bees, Mark G. Young Jan 2021

Microbiome Community And Parasitic Infections In Wild Bees, Mark G. Young

Honors Theses

The microbiome is increasingly recognized for its complex relationship with host fitness. Akin to primates and other social animals, bumblebees harbor a specific microbiome derived from social contact. The bumblebee microbiome is characteristically species poor, with just a few “core” phylotypes accounting for the majority of total abundance. Genomic analyses reveal phylogenetic congruence and adaptation of the core endosymbionts to the bumblebee gut, indicating a shared evolutionary history. Prior investigations reveal that the relative abundance of core microbes is negatively associated with infection by a trypanosome, Crithidia bombi, and that the microbiome has a mechanistic role in immunity. As …


The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes Jan 2021

The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes

Honors Theses

The internal recycling phosphorus in freshwater lake bottom sediments represents a significant source of hypolimnetic phosphorus (P) release for many of Maine’s lakes. In summer months, Maine lakes often thermally stratify and the lake hypolimnion develops anoxia, leading to a reduction in redox potential at the sediment-water interface. These reducing conditions facilitate the reductive dissolution of ferric iron, and, since phosphorus is often present in freshwater lake sediments as solid FeOOH-PO4 complexes, results in release of soluble phosphorus into the water column. Our current study presents field and laboratory data from sediment fractionation extractions designed to quantify concentrations of …


Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee Jan 2021

Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee

Honors Theses

Bumblebees (Hymenoptera: Apidae: Bombus) show an incredible degree of size variation within and between species. Individuals from the same hive may vary up to 10-fold in mass. This variation allows individuals to specialize in foraging on different flowers suited to their morphology. However, as different species have different foraging behaviors, their variation in mouthparts and scaling of mouthparts to body size may have been under different kinds of stabilizing selection as they adapted to collect nectar from flowering plants over evolutionary time. Here, we examined the scaling relationships between body size and mouthpart structures, and the variation in mouthpart shape …


Artificial Reefs: A History, A Science, A Technology, Mairead D. Farrell Jan 2021

Artificial Reefs: A History, A Science, A Technology, Mairead D. Farrell

Honors Theses

Over the past 60 years, artificial reefs have expanded beyond the definition of a technology, and in turn have developed into a unique branch of marine science. To better emphasize this growth and separation, a brief history of artificial reef development and usage in chapter two shows some of the key shifts over time in this technology’s purpose and the materials used to achieve that goal. Likewise, to indicate the scientific development of artificial reefs as a branch of marine science, their usage for discovery and research is recorded in chapter three, along with the exponential increase in published scientific …


Use Of Small Molecule Fanconi Anemia Pathway Inhibitors As Sensitizing Agents To Laromustine., Sam W. Marchant Jan 2021

Use Of Small Molecule Fanconi Anemia Pathway Inhibitors As Sensitizing Agents To Laromustine., Sam W. Marchant

Honors Theses

Laromustine is an experimental chemotherapeutic sulfonyl hydrazine prodrug shown in clinical trials to be effective against acute myeloid leukemia. The mechanism of action of laromustine involves interstrand crosslinking, via chloroethylation, and enzyme inhibition, caused by carbamoylation. The work described herein aims to investigate whether inhibition of the replication-dependent interstrand crosslink repair Fanconi Anemia pathway further sensitizes cells to laromustine. By measuring metabolic activity immediately after drug exposure, we find laromustine to be equally as cytotoxic towards Fanconi Anemia deficient and wild type cells. However, through clonogenic assays we show Fanconi Anemia mutations sensitize cells to laromustine’s anti-proliferative effect. Furthermore, we …


Identifying Metabolites As Markers Of Fatigue In Athletes, Christopher D. George Jan 2020

Identifying Metabolites As Markers Of Fatigue In Athletes, Christopher D. George

Honors Theses

Fatigue in athletes caused by inadequate rest and other stressors can be severely detrimental to their health, and yet there is no reliable way to measure and track fatigue. Many classical measures of fatigue like body mass and resting heart rate are not reliable ways to track the physical fatigue of an athlete because they can change with many factors. In addition, it is not known how academic stress on top of physical stress affects fatigue. Metabolomics is a relatively new area of study and tracking metabolites offers the possibility to produce biomarkers to assess fatigue. This study collected saliva …


The Impact Of Climate Change On The Migration Phenology Of New England’S Anadromous River Herring And American Shad, Charles K. Cobb Jan 2020

The Impact Of Climate Change On The Migration Phenology Of New England’S Anadromous River Herring And American Shad, Charles K. Cobb

Honors Theses

Anadromous fish play important roles in food webs and nutrient cycling in both aquatic and marine ecosystems. As a result of climate change however, anadromous fish’s migration timing has begun to change, with potentially deleterious consequences to both anadromous fish, and the species that depend on them. Western coastal US studies have linked earlier anadromous fish returns to warming marine temperatures and changes in river flow regimes, but the exact temperatures thresholds that anadromous fish respond to, and the relative importance of temperatures and river flows, remain somewhat unknown. Additionally, there has been relatively little research on anadromous fish phenology …


Development And Validation Of Gene Delivery Methods For ​Crassostrea Virginica, Adrienne N. Tracy Jan 2020

Development And Validation Of Gene Delivery Methods For ​Crassostrea Virginica, Adrienne N. Tracy

Honors Theses

The Eastern oyster (Crassostrea virginica) is an important part of the East Coastal USA economy because aquaculture creates jobs. Sadly, the oysters are under constant threat due to increasing pollution, red tides, and diseases. Bivalves, and oysters in particular, are also becoming potential model organisms in medical research. With the sequencing of the oyster genome, scientists are focusing on deciphering the function of the predicted genes. However, the limited number of molecular and cellular tools available makes functional annotation of the genome challenging. A consistent, replicable gene delivery system needs to be developed to assess gene function and understand the …


Assessing A Two-Hit Model Of Schizophrenia: Prenatal Choline Deficiency And Induced Hypofunction Of Nmda Receptors In Male And Female Long Evans Rats, Samuel Gray, Samuel W. Gray Jan 2020

Assessing A Two-Hit Model Of Schizophrenia: Prenatal Choline Deficiency And Induced Hypofunction Of Nmda Receptors In Male And Female Long Evans Rats, Samuel Gray, Samuel W. Gray

Honors Theses

Choline is an essential dietary nutrient essential to the development and function of the central nervous system. Prenatal choline deficiency alters hippocampal development as well as acetylcholine metabolism, leading to cognitive impairments and attentional and sensory processing deficits into adulthood. MK-801 is an NMDA receptor antagonist frequently used in rodent models of neuropsychiatric conditions, particularly schizophrenia. Acutely and sub- chronically, it causes hyperlocomotion and social withdrawal. One primary goal of the present study were to investigate prenatal choline deficiency induces a biological vulnerability to the motor deficits, anhedonia, and social impairment precipitated by low-dose sub-chronic MK-801 administration in adulthood. Another …


Executive Function Deficit As A Precursor To Memory Impairments In Hapoe4 Transgenic Rats, Kaitlin Mcmanus Jan 2020

Executive Function Deficit As A Precursor To Memory Impairments In Hapoe4 Transgenic Rats, Kaitlin Mcmanus

Honors Theses

The hApoE4 allele is one of the strongest genetic risk factors for Alzheimer’s disease (AD). It underlies amyloid-bdeposits and neurofibrillary tangles, the two hallmarks associated with AD pathology, and is subsequently associated with AD symptomology. Despite its importance, no rat animal studies to date use hApoE4 knock-ins. In addition to this deficit in the field of AD literature, the vast majority of AD studies focus on memory, even though executive function deficits may precede memory impairments in AD, and may be a predictor of AD development. Thus, the present study addressed these gaps in AD research by investigating the behavioral …


Tracking The Endangered Northern Black Racer, Coluber Constrictor Constrictor, In Maine To Determine Areas Of Conservation Importance, Josiah Johnson Jan 2019

Tracking The Endangered Northern Black Racer, Coluber Constrictor Constrictor, In Maine To Determine Areas Of Conservation Importance, Josiah Johnson

Honors Theses

The Black Racer (Coluber constrictor) is a large-bodied snake species found across North America. One subspecies, the Northern Black Racer (C. constrictor constrictor) is listed as endangered in Maine because of its restricted range in York County. Racers have generally been found to prefer open habitats and ecotones, but the specific habitat preferences of racers in Maine is unknown, hindering efforts to preserve habitat for racer conservation. To address this knowledge gap, the Maine Department of Inland Fisheries and Wildlife (MDIFW) has an ongoing project tracking black racer movements in Sanford and Kennebunk, Maine, and I had the opportunity to …


Insects And The Evolution Of Developmental Pathways: Functional Analysis Of Genetic Sex Determination Mechanisms In Oncopeltus Fasciatus, Josefine Just Jan 2019

Insects And The Evolution Of Developmental Pathways: Functional Analysis Of Genetic Sex Determination Mechanisms In Oncopeltus Fasciatus, Josefine Just

Honors Theses

Natural selection alters genetic pathways over evolutionary time. However, different pathways have been shown to maintain mutations at varying rates, leading to different levels of conservation across developmental pathways. Sex determination pathways, in particular, show vast diversity across animals despite the fundamental conservation of biological sex itself. Here, I investigated the sex determination pathway of the hemimetabolous insect, Oncopeltus fasciatus. The large milkweed bug, O. fasciatus, is part of the order Hemiptera, which provides a relevant outgroup study to other insects in which sex determination has been studied to date. I studied three sex determination genes, intersex, fruitless …


African Savannah Elephant Group Size And Behavior In The Makgadikgadi Pans National Park, Botswana, Katherine S. King Jan 2019

African Savannah Elephant Group Size And Behavior In The Makgadikgadi Pans National Park, Botswana, Katherine S. King

Honors Theses

African savannah elephants (Loxodonta africana), the largest elephant species, influence the structure of the environment they inhabit. Elephants exhibit complex patterns of social behavior between individuals within a population. Many behavioral studies focus on interactions among individuals within a population rather than broader trends related to group size. My study seeks to understand how male African savannah elephant group size is influenced by seasonality, age, physical condition and distance to permanent water resources. I examined the interaction of these variables in two ways: (1) a literature review of elephant behavior and conservation, and (2) an analysis of male …


Disc1 Knockout Rats Reveal Sexually Dimorphic Patterns Of Impairment Across Development, Stephanie S. Desrochers Jan 2018

Disc1 Knockout Rats Reveal Sexually Dimorphic Patterns Of Impairment Across Development, Stephanie S. Desrochers

Honors Theses

Schizophrenia is a chronic disorder characterized by three symptom categories: positive (hallucinations, delusions), negative (anhedonia, anxiety), and cognitive (sensory processing and memory deficits). We worked with a biallelic deletion of the Disrupted-in-schizophrenia-1 (DISC1) gene in Sprague-Dawley rats to facilitate our understanding of the biological bases of schizophrenia. Mutations of DISC1 are associated with a higher prevalence of schizophrenia. Adult DISC1 knockout, compared to wildtype, rats display features of schizophrenia-like outcomes in rodent models. The present study investigated the progression of the cognitive symptom deficits in prepulse inhibition (PPI), assessing animals at postnatal days 17 (pre-weaning), 26 (post-weaning), 39 (adolescent), and …


Investigating Phosphorylation Patterns And Their Effect On The Activity Of Transcription Factor Taabf1 In Imbibing Cereal Grains, Grace Uwase Jan 2018

Investigating Phosphorylation Patterns And Their Effect On The Activity Of Transcription Factor Taabf1 In Imbibing Cereal Grains, Grace Uwase

Honors Theses

The wheat transcription factor TaABF1 plays an important role in hormone-mediated regulation of seed dormancy and germination of cereal grains. Evidence shows that TaABF1 activity is regulated by phosphorylation, and previous work in our lab showed that when serine residues in its conserved regions; S36, S37, S113, S115 were altered to phosphomimetic aspartate, the 4xD TaABF1 mutant had increased activity as a transcription factor. However, when only S113 was altered, TaABF1’s activity was greatly reduced. The work presented here explored whether the S36D/S37D/S115D mutant would have stronger activity than the 4xD mutant. Using the particle bombardment technique to introduce the …


Haloferax Volcanii For Carotenoid Production, Erika Smith Jan 2018

Haloferax Volcanii For Carotenoid Production, Erika Smith

Honors Theses

Carotenoids are used as natural colorants and have been shown to have numerous health benefits, making these molecules highly desirable in the aquaculture, pharmaceutical, and nutraceutical markets. There is increasing consumer demand for the natural synthesis of carotenoids, but current methods are limited by the cost and difficulty of extraction from organisms. The halophilic archaeon Haloferax volcanii is amenable to extraction and has an endogenous carotenoid biosynthetic pathway that culminates in the accumulation of the carotenoid bacterioruberin; however, H. volcanii also synthesizes important precursors that can be converted into more highly-desired carotenoids, such as β-carotene and astaxanthin, in the presence …


The Effects Of Nutrient Limitation On Toxin Production For The Harmful Algal Bloom Species, Pseudo-Nitzschia, In The Gulf Of Maine, Julia M. Park Jan 2018

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 …


Examining Interactions Between Opsins And Carotenoid Biosynthetic Proteins In Halophilic Archaea, Alexandru M. Plesa Jan 2017

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 Jan 2017

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 Jan 2017

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 …


Crops And Controversy: Industry’S Role In The Gmo Debate, Carina Wallack Jan 2017

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 …