Life Sciences Commons^™

Locomotion And Life History In A Leaping Primate: Mechanics And Energetics Of Movement Throughout The Propithecus Lifespan, Nicholas Heslep

Masters Theses, 2020-current

Arboreal primates are typically altricial, exhibit long juvenile periods, and use dynamic locomotor behaviors that can be challenging and risky. Sifaka (Propithecus verreauxi) have particularly slow life histories for their size, with long juvenile periods, protracted reproductive careers, and long life spans. Slow somatic growth poses potential mechanical challenges for juvenile sifaka who use thigh-powered vertical clinging and leaping to follow group members during travel. I examined mechanical and energetic costs of movement in developing sifaka. I instrumented 8 wild sifaka (3 yearlings, 3 subadults, 2 adults) in 4 social groups with inertial sensors measuring tri-axial acceleration for …

Understanding Context Dependent Responses To Climate Change In Arizona Tiger Salamanders (Ambystoma Mavortium Nebulosum), Kentrell Richardson

Masters Theses, 2020-current

Future emissions scenarios project climate change to increase average global temperatures by at least two ℃ in the next 50 years resulting in changes in local climate and causing increased variability within microclimates. Ectotherms are especially sensitive to climate change due to their dependence on environmental temperatures to regulate physiological functions. Changes in temperature are likely to impact thermally cued processes within amphibians and result in changes in variable magnitudes and directions within local populations.

Salamanders were placed in cups and partially submerged in a water bath and heated at a rate of ~0.27℃/ minute. Once salamanders were unable to …

The Response Of Microcystis And The Microbiome To Exogenous Hydrogen Peroxide, Bryan A. Puma

Masters Theses, 2020-current

Microcystis spp. produce prolific annual blooms in freshwater systems worldwide. The success of these blooms depends heavily on the Microcystis spp. overcoming environmental factors such as oxidative stress caused by reactive oxygen species (ROS) like hydrogen peroxide. Most Microcystis genomes do not contain many genes for responding to oxidative stress, including those that encode the enzyme catalase. Other cyanobacteria such as Prochlorococcus that also lack hydrogen peroxide degrading enzymes have been shown to benefit from partnerships with heterotrophic bacteria. Microcystis spp. may also receive similar benefits from heterotrophic bacteria in the phycosphere. To test this hypothesis, we examined the …

Pre-Pulse Inhibition In Mutated Mice: Studying Compromised Microglial Cells To Discover New Genetic Connections To Autism, Bailey R. Kramarik

Senior Honors Projects, 2020-current

Microglial cells “play a pivotal role in refining neural networks during early critical periods” (Gabriele & Gray, 2020, p. 1). A disturbance in the functioning of these microglial cells contribute to specific characteristics of some neurodevelopmental disorders- including autism spectrum disorder. In this study, we used a mouse model to study disruptions in cell activity, as understanding the biological and genetic background of autism spectrum disorder could help us provide better treatment and therapy options to those diagnosed.

The mutated mice in this experiment have microglial cells with “compromised fractalkine signaling” (Gabriele & Gray, 2020, p. 4-5). We studied multimodal …

Pilfering Passerines? Inter-Class Competition: A New Direction In Foraging Ecology, Shannon Gillen

Masters Theses, 2020-current

Life in the epigeal layer below leaf litterfall often goes unexplored. Shrews (Soricidae, 1910) have foraged in this microhabitat for millions of years, carving out an existence in harsh habitats around the world, ranging from the tropics to subarctic boreal tundra. Two shrew species that inhabit the Shenandoah Valley of Virginia, the least shrew (Cryptotis parva) and northern short-tailed shrew (Blarina brevicauda), were the focus of this study. Shrews make epigeal foraging trails while they continually forage for food, and caching is a way to save this food for times of low and sporadic food availability. …

Is Immediate Flexibility Present In A Vocal Mimic, The Gray Catbird (Dumetella Carolinensis), Across An Urban Gradient?, Shannon K. Eppert

Masters Theses, 2020-current

Increasing urbanization has increased anthropogenic noise levels near developed areas. Urban noise is high amplitude and low-frequency, and these frequencies can overlap with the signals animals use to communicate, including bird songs. Many urban birds sing higher minimum frequencies in urban areas, which avoids some masking by noise, but the mechanism behind this difference is not well understood. Immediate flexibility is the ability to alter song in real-time in the presence of sudden noise, allowing for avoidance of masking and better signal transmission. I investigated if male catbirds increased signal transmission in the presence of anthropogenic versus high-frequency noise playback …

A Stable-Isotope Probing Approach To Modeling Bidirectional Nutrient Exchange In The Microcystis Phycosphere, Malia Gardner

Masters Theses, 2020-current

Cyanobacterial harmful algal blooms (cHABs) plague freshwater systems worldwide and are projected to increase in intensity in the coming decades. cHABs damage aquatic ecosystems by blocking light penetration into the water column, creating hypoxic conditions, and releasing toxins. One of the most prolific cHAB formers is the cosmopolitan genus of cyanobacteria Microcystis. Global climate change and anthropogenic loading of nutrients such as nitrogen (N) and phosphorus (P) fuel Microcystis bloom formation. Increasing global temperatures favor Microcystis because of its high optimal growth temperature. N input is of particular importance for Microcystis because it is unable to fix atmospheric N, …

Ecophysiology Of Toxic Bloom-Forming Cyanobacteria And Their Symbionts, Dominique J. Lockwood

Masters Theses, 2020-current

Currently, there is a pernicious microbe in the genus Microcystis that is putting the world’s freshwater resources at risk. A member of the phylum Cyanobacteria, otherwise referred to as blue-green algae, Microcystis forms massive algal blooms in lakes and has the potential to produce a toxin, which does not only harm humans, but also pets, livestock, and aquatic life. As recently as 2016, in the city of Toledo, Ohio, nearly 1 million residents went without clean drinking water for an entire weekend due to one of these Microcystis blooms. However, Microcystis does not only bloom in Ohio. In fact, …

Comparing The Effect Of Four Propagation Techniques On Hybrid Chestnut Seedling Quality, Taylor Evans

Masters Theses, 2020-current

Extensive resources have been used to breed hybrid chestnuts for reintroduction into the historical range of the American chestnut (Castanea dentata). Improving seedling quality is an efficacious method to improving restoration outcomes and nursery propagation methods can be selected to improve seedling quality, increasing the likelihood of survival. Four production methods (bed grown, air prune beds, container grown, and the Root Production Method®) and three media types (field soil, peat-perlite-vermiculite mix, and pine bark-rice hulls-sand mix) were compared across four measures of seedling quality (height, root collar diameter, root volume, and number of first order lateral roots) to …

Influence Of Testosterone On Male-Male Competition In The Red-Sided Garter Snake, Thamnophis Sirtalis Parietalis, Isabella M. G. Bukovich

Senior Honors Projects, 2020-current

Female mimicry in the red-sided garter snake, Thamnophis sirtalis parietalis, is described in several well-studied evolutionary advantages, but an aspect that remains elusive is how reproductive traits are linked to the 3-fold higher circulating androgens in males with this phenotype. In this study, we implanted male garter snakes (n=15 per group) with either a blank implant (SHAM; control) or a T implant, the latter simulating the female mimic phenotype. Following simulated low-temperature dormancy, males were scored for courtship intensity over three days of behavioral trials with females housed in the same facility. Males were sacrificed, and sperm were collected …

Characterizing The Role Of Β-Amylase3 In Cold Stress Response And Recovery In Arabidopsis Thaliana, Isabelle G. Houston

Senior Honors Projects, 2020-current

Starch is a polymer of glucose that is used as an energy store in plants. Mobilization of starch has implications in abiotic stress survival and recovery. While the importance of carbon and energy allocation in plant survival has been explored, the specific roles of starch degrading enzymes in plant responses to stress are still unclear. β-Amylase3, or BAM3, is the principle starch degrading enzyme at night and is transcriptionally upregulated in response to cold stress in the plant Arabidopsis thaliana. Using single and quadruple knockout mutant plants, I aimed to clarify the role of BAM3 in the response to …

Novel Method To Determine Paleodiet Of Extinct Equid Merychippus Sp. Using Dental Calculus, Ranjit Z. S. Virk

Senior Honors Projects, 2020-current

Within the Miocene Epoch, the emergence of grasslands within North America coincided with the incidence of higher-crowned teeth (hypsodonty) within the proto-horse Merychippus that allowed for the inclusion of these expanding grasslands as a food source. As herbivorous paleofauna consume plant matter, microscopic remains become incorporated within dental calculus and, due to their diagnostic morphology, can be used to identify dietary components. In Merychippus, the recovery of plant microfossils holds the potential to provide greater clarity on the paleodiet of these equids. In the present study, the purpose was to quantify and compare Merychippus paleodiet constituents among sample groups. …

Antibacterial Properties Of Novel Amphiphiles, Ariana Simeone

Masters Theses, 2020-current

Hospital acquired infections, particularly antibiotic resistant infections, are a growing concern due to their infection and mortality rate, as well as their growing economic burden, and it has been estimated that by the year 2050 the associated mortality rate will be around 10 million deaths per year. A solution to this is better means of prevention, and amphiphiles, compounds with at least one hydrophilic head group and at least one hydrophobic tail, are promising candidates for stopping the spread of infectious bacteria. Novel amphiphiles with two bipyridinium head groups, separated by a hydrophobic carbon spacer of varying lengths, and each …

Research And Development Of A Computational Simulation Of A Rat Tail, Abed Adawi

Masters Theses, 2020-current

To better understand the potential use of synergies in the neural control of muscle in the rat tail during the NWR, a new computational biomechanical model of the tail was created in Matlab/Simulink based on experimentally measured parameters – length, mass, stiffness, and damping - of the tail. The tail was simplified from 28 coccygeal vertebrae to 12 equal length segments. The model was validated by applying known forces to the tail and comparing the observed and predicted movements. Using forward dynamics assisted data tracking (FDADT), we determined that while a single tendon synergy was adequate for small and proximal …

Quantification Of Neuronal Specific Responses To Depletion Of The Nascent Polypeptide-Associated Complex In Caenorhabditis Elegans, Harrison Hall

Senior Honors Projects, 2010-2019

Cells experiencing misfolded protein stress can become debilitated and die, consistent with this stress being linked to numerous diseases. When misfolded proteins accumulate in the endoplasmic reticulum (ER), the unfolded protein response (UPR) initiates mechanisms that resolve this stress or trigger apoptosis, dependent on the severity and/or duration of the stress. The nascent polypeptide-associated complex (NAC) is a heterodimeric chaperone that mediates proper protein folding and localization during translation; depletion of the NAC promotes misfolded protein stress in the ER, resulting in the initiation of the UPR in affected cells. The relationship between the NAC and the UPR is not …

Detecting The Cold: Do Innexins Function In Cold Nociception?, Rachel Barborek

Senior Honors Projects, 2010-2019

Nociception is the perception of and response to harmful stimuli. Nociception is essential for minimizing tissue damage, but aberrant nociceptive pathways can result in chronic pain. Chronic pain in the U.S. is commonly managed with wide-acting opioids, and precisely defining the components of nociceptive pathways could uncover novel targets for pain therapies. I hypothesize that the vitally quick process of nociception would utilize electrical synapses because they transmit signals between neurons more quickly than chemical synapses do. This study, therefore, aims to uncover the potential role of the eight Drosophila melanogaster gap junction proteins, the Innexins, in cold nociception. Wild …

The Microcystis Microbiome: Interactions With Heterotrophic Bacteria In The Microcystis Phycosphere, Alexa Hoke

Masters Theses, 2010-2019

Harmful algal blooms are a growing problem globally in both freshwater and marine systems. Cyanobacterial harmful algal blooms (cHABs) can have numerous environmental and economic impacts. cHABs can reduce oxygen levels in the water column, ultimately leading to the death of larger organisms, and reduce light penetration, impacting aquatic vegetation. cHABs can also release toxins into the water and efforts to prevent toxins from entering drinking water can cost cities millions of dollars in added filtration. Microcystis is a freshwater cyanobacterium that is globally distributed. While many of the abiotic factors that can impact bloom formation are known, biotic factors, …

Reproductive Character Displacement In Calopteryx Aequabilis And C. Maculata: Improving Species Recognition Through The Divergence Of Male Mating Preferences, Melissa Encinias

Masters Theses, 2010-2019

An ongoing evolutionary question is how co-occurring species maintain reproductive barriers when they are morphologically, behaviorally, and ecologically similar. Without geographic isolation, traits involved in species recognition may be under selection to enhance reproductive barriers. Exaggerated trait differences between species in sympatric populations may reflect selection to reduce misdirected mating between species, or reproductive character displacement. While this phenomenon is widely recognized as an important stage in the speciation process, there is little direct evidence of this process in nature. In two North American damselfly species, Calopteryx aequabilis and C. maculata, wing pigmentation is sexually dimorphic and also shows …

Assessing The Prevalence Of Multidrug Resistant Salmonella Enterica From Stream Sediment And Poultry Litter In The Shenandoah Valley Of Virginia, Noah Greenman

Masters Theses, 2010-2019

Multidrug resistant Salmonella enterica present in stream sediment and poultry litter represent a critical health concern. A small number of S. enterica serotypes are responsible for most lab-confirmed infections in the US each year. To assess the prevalence of these significant strains, we isolated 88 S. enterica from stream sediment and poultry litter. Sequence data for all isolates were generated using an Illumina® sequencing platform, with long-reads for some isolates from the Oxford Nanopore MinION™ used in a hybrid genome assembly approach. Isolates were typed according to their serotype and multi-locus sequence type using SeqSero/SISTR and Enterobase respectively. Antibiotic resistance …

The One Health Initiative: The Intersection Of Human, Animal, And Environmental Health, Mary Evelyn Pearsall

Senior Honors Projects, 2010-2019

The One Health concept is a global strategy for strengthening interdisciplinary collaborations among health care for humans, animals, and the environment. The purpose of this honors capstone project is to study the One Health Initiative and create a comprehensive thesis on what the initiative is and how it is relevant to different sectors of health. An overview of prevalent zoonotic diseases will be provided including how they are transmitted and their global relevance. Case studies on zoonotic diseases will be used in which the effectivity of a One Health approach can be analyzed. In addition, relevant sections on One Health …

Biosemiotics As An Argument For The Recontextualization Of Biological Discoveries: A Critical Analysis Of The Biosemiotic Model Of Marcello Barbieri., Augustus Morrissey Snyder

Senior Honors Projects, 2010-2019

The primary purpose of this project was to investigate and explain the philosophical approach of biosemiotics to understanding living systems in contrast to the current scientific paradigm. Secondary goals were to evaluate the potential merits and relevance of this approach to biology and to introduce such a topic for discussion to biologists in a formal academic setting. My method consisted of critical textual analysis supplemented by analogy and biological examples where appropriate. In general, contemporary biosemiotics argues for a teleologic recontextualization of biological discoveries in practice and education. This is accomplished in a sophisticated fashion through the application and modification …

Antimicrobial Activity Of Novel Cationic Amphiphiles, Melanie Kusakavitch

Senior Honors Projects, 2010-2019

This project focused on the development of amphiphiles in order to prevent hospital-acquired infections before they have a chance to enter the host, thereby reducing the need for antibiotics. The antibiotic resistance crisis of the 21st century is a dangerous epidemic with global consequences. Therefore, there is a desperate need for novel approaches in antimicrobial research. This would decrease the overall length of stay in hospitals and costs associated with such a stay. In this study, tetracationic amphiphiles with two 12-carbon chains and an aliphatic linker were studied. The MIC value of each amphiphile and strain pair was determined and …

Muscle Synergies And How They Contribute To The Movement Of The Tail During The Nociceptive Withdrawal Response In The Rat’S Tail, Hasti Izadpanah

Senior Honors Projects, 2010-2019

Noxious stimuli can evoke the nociceptive withdrawal response (NWR), which protects the affected part of the body from injury. The rat’s tail, because of the large number of joint (n=84) and muscle (n=300) degrees of freedom, may present a computational challenge to the central nervous system. Previous studies have revealed that synergies act to reduce the number of degrees of freedom across diverse movements in a variety of animals; however, there is little information in mammals on synergistic control of the tail. The long-term specific aim of this project is to test the hypothesis that during the NWR muscle synergies …

Reconstruction Of The Tail Nociceptive Withdrawal Response From Combinations Of Movement Primitives Associated With Individual Muscles In The Rat, Justin Nguyen

Senior Honors Projects, 2010-2019

Abstract

One type of involuntary movement is the nociceptive withdrawal response (NWR), in which mammals move a part of their body away from noxious, or tissue damaging, stimuli. Previous studies have evoked the limb NWR in diverse animals such as cats, frogs, and humans. However, there is minimal information on how complex movement arising from numerous muscles and joints, such as in the tail of the rat, is effectively coordinated.

The specific aim was to identify the contribution of movement from individual extrinsic muscles to the tail NWR utilizing a new technique. From previous studies, extrinsic muscles in the pelvis …

Morpho: Expectations & Mutations, Lynda Bostrom

Masters Theses, 2010-2019

Morpho: Expectations & Mutations is a written document accompanying the culmination of my three years painting at a graduate level. The result of which is an autobiographical body of work navigating the tension of being a human with an invisible disease, while straining to understand Western societal constructs of women. I simultaneously reject these fairy tales as a standard recipe for happiness, yet identify with its visual language that is rooted in the vernacular of my generation. Redefining the elements I reject or embrace helps me to look beyond the boundaries of these constructs, and adopt an attitude of curiosity …

Tetrameric Structure Of Beta-Amylase 2 (Bam2) In Arabidopsis Thaliana, Lauren Elizabeth Pope

Senior Honors Projects, 2010-2019

Plants store starch during the day for use at night. This process of transitory starch degradation is mostly attributable to the β-Amylase (BAM) family, which are starch exohydrolases that cleave the penultimate α-1,4 glycosidic bonds of starch to release maltose. BAM2 was recently characterized as a catalytically active, K⁺-requiring tetramer with sigmoidal kinetics and cooperativity. All other catalytically active BAMs display Michaelis-Menten kinetics, no cooperativity, and do not require salt, making BAM2’s characteristics intriguing. Due to a lack of a crystal structure, a monomeric homology model of BAM2 was generated using I-TASSER based on a BAM5 from soybean. …

The Role Of Brain Stem 5-Ht1a And Gaba-A Receptors In The Thermoregulatory Response To Hypoxic Stress, Alexander Schmidt

Senior Honors Projects, 2010-2019

Sudden Infant Death Syndrome (SIDS) is a leading cause of infant mortality. Alterations in brainstem development of Serotonin (5HT) and γ-aminobutyric acid (GABA) are linked to its cause. The sympathetic premotor neurons located in the Nucleus of the Raphe Pallidus (NRP) in the brainstem have both 5-HT1A and GABA-A receptor subtypes that mediate protective cardiovascular responses to environmental stress. It is hypothesized that alteration in these receptors at the NRP will also modify protective thermoregulatory responses to hypoxic stress such as hypothermia. Using aseptic techniques, male and female Sprague-Dawley rats (230-385g) were instrumented with radiotelemetry probes to non-invasively measure core …

Rat Hind Limb Nociceptive Withdrawal Response To Heat And Mechanical Stimuli Depends On Initial Position Of The Paw But Not Stimulus Location, Giavanna Verdi

Senior Honors Projects, 2010-2019

Mammals rapidly withdraw their hind limb in response to noxious stimulation, which is a protective movement known as the nociceptive withdrawal response (NWR). The NWR has been previously studied in spinalized, decerebrated and anesthetized non-human and human mammals; however, there is minimal information on the NWR in intact, unanesthetized non-human mammals.

The first specific aim was to identify the factors that determine the direction and magnitude of the NWR in intact, unanesthetized rats. Based on previous studies, we hypothesized that the location of stimulation and the initial position of the paw preceding the NWR will influence the direction and magnitude …

Searching For Sex Differences In Snake Skin, Sydney E. Ashton

Senior Honors Projects, 2010-2019

The production of many secondary sexual signals, including pheromones, is controlled by sex hormone action at the sites of signal synthesis. The red-garter snake (Thamnophis sirtalis parietalis) is an ideal vertebrate for studying the interaction between steroids and sexual signals: males exclusively rely on skin-based female pheromones during courtship, and pheromone composition is augmented by treatment with sex steroids (e.g., males produce female pheromone if implanted with estrogen). But how do steroid hormones promote pheromone expression at the molecular level in snake skin? Feminizing effects of estrogens on sexual signals are known to result from activation of estrogen …

Reverse Genetic Screening Of Innexin Gap Junction Proteins In Drosophila Neurons, Shannon P. Fox

Senior Honors Projects, 2010-2019

The reflexive response and perception of pain (nociception) is an evolutionarily conserved process in animals. Pain can be a major health concern and current treatments often prove insufficient, especially in regards to chronic pain. Greater understanding of the molecular processes underlying pain sensation could lead to new and more effective treatments. The aim of this study is to investigate the molecular mechanisms of cold nociception in Drosophila melanogaster. A specific subset of peripheral sensory neurons (Class III dendritic arborization (da) neurons), are implicated in Drosophila larvae’s response to noxious cold.

Previous literature has associated a family of gap junction protein, …