Biology Commons^™

The Role Of Semaphorins In Response To Injury In C. Elegans Neurons, Maria Belen Harreguy Alfonso

Dissertations

When neural tissue is injured by trauma, delicate neuronal processes such as axons and dendrites are prone to lesion damage and often disconnect. The molecular, cellular, and circuit mechanisms that underlie the regrowth and reconnection of these processes and the recovery of behavior are major challenges in the fields of neuroscience, regeneration, and resilience. At the molecular and cellular levels, signaling pathways that mediate neuronal growth cone guidance during development can play a role in neuronal regeneration and recovery from injury. One family of signaling proteins involved in this process comprises the highly conserved semaphorins and their receptors, the plexins. …

Visual Circuitry In Adaptive Behavior: Extraction Of Complex Visual Image Information By Arrays Of Non-Image Forming Eyes, Thomas Kipp Halladay Groves

Dissertations

A complete understanding of how neural circuitry underlies the detection and integration of visual cues continues to elude researchers in the 21st century. Since the dawn of life on earth, light has exerted enormous selective pressure on all living organisms. Visual systems represent one of the most common sensory systems in existence, with significant homologies among elements of these systems, such as photopigments and developmental genes. Offering nearly unmatched single cell access at all levels of its nervous system, the European medicinal leech (Hirudo spp.) is an excellent system in which to identify behaviorally relevant neuronal circuits. Hirudo evolved discrete …

Characterization And Genomic Analysis Of Two Escherichia Coli O157:H7 Bacteriophages Isolated From Pigeons, Mohamad I. Alolama

Dissertations

Enterohemorrhagic Escherichia coli, also known as EHEC, is a subset of Shiga toxin-producing E. coli (STEC), and it has recently been identified as one of the principal foodborne pathogens. E. coli O157:H7 is the most important serotype of STEC for its role in causing foodborne illnesses. E. coli O157:H7 could cause various gastroenteritis symptoms such as diarrhea, hemolytic uremic syndrome, hemorrhagic colitis, and thrombotic thrombocytopenic purpura and may cause death. Elimination of E. coli O157:H7 during food processing and storage is a possible solution. Bacteriophages have a significant impact on bacterial populations in nature due to their ability to …

Policy Implications Of Managing Biodiversity And Natural Resources Across International Boundaries, Dillon Brown

Dissertations

Fisheries Management under the best of scenarios is a complex action. It requires thoughtful consideration of resources that tend to be out of sight, widely distributed, highly variable both spatially and temporally, and present dramatic variation in life history and ecology. No one management approach has been developed which can effectively incorporate all these variables. Add to this the issue of transnational boundary movements of these resources, and one discovers that this complex issue needs to be addressed by multiple entities, agencies, and nations to have any chance of success.

This research set out to discover ways in which fisheries …

Sources And Distribution Of Microplastics In The United Arab Emirates, Rana Zeeshan Habib

Dissertations

Microplastics (plastic pieces size) are an emerging environmental contaminant that is ubiquitously present in terrestrial, aquatic and aerial environments. United Arab Emirates (UAE) is categorized among the highest domestic waste producing countries (on per capita basis) in the world. A large portion of waste ends up in the environment and contains macro-, meso- and microplastics. No comprehensive study has been carried out in the UAE to investigate the abundance, sources, distribution and impact of microplastics on its environment. Therefore, a comprehensive study to analyze the sources and distribution of microplastics in the UAE was urgently needed. The objective of the …

Brainless But Smart: Investigating Cognitive-Like Behaviors In The Acellular Slime Mold Physarum Polycephalum, Subash Kusum Ray

Dissertations

Evolutionary pressures to improve fitness, have enabled living systems to make adaptive decisions when faced with heterogeneous and changing environmental and physiological conditions. This dissertation investigated the mechanisms of how environmental and physiological factors affect the behaviors of non-neuronal organisms. The acellular slime mold Physarum polycephalum was used as the model organism, which is a macroscopic, unicellular organism, that self-organizes into a network of intersecting tubules. Without using neurons, P. polycephalum can solve labyrinth mazes, build efficient tubule networks, and make adaptive decisions when faced with complicated trade-offs, such as between food quality and risk, speed and accuracy, and exploration …

Flexibility Vs Consistency: Quantifying Differences In Neuromodulatory Elicited Patterns Of Activity, Elizabeth M. Cronin

Dissertations

Central pattern generating circuits underly fundamental behaviors such as respiration or locomotion and are under the influence of neuromodulators. The presence of neuromodulators is thought to confer flexibility to these circuits to generate distinct patterns of activity to meet distinct behavioral needs. Network output flexibility can be achieved by distinct classes of neuromodulators, those which have convergent cellular actions but divergent circuit actions or by those which have divergent cellular actions but convergent circuit actions.

Both classes of neuromodulator exist in the stomatogastric nervous system of the crab Cancer borealis and influence the activity of a central pattern generating circuit …

The Effects Of Prescribed Fire On Ant-Mediated Seed Dispersal In Missouri, Eva M. Colberg

Dissertations

Many aspects of animal-mediated seed dispersal are vulnerable to disturbance, including partner identity and dispersal quantity and quality. This dissertation explores ant-mediated seed dispersal of the herb Sanguinaria canadensis in Missouri Ozark oak forests, where prescribed fire is a common land management tool. In Chapter 1, I test the definition of a keystone seed disperser using absolute and relative contributions of different ant species to the quantity and distance of seed dispersal, based on field observations of S. canadensis seed dispersal. I demonstrate that the ant Aphaenogaster rudis is better described as a numerically dominant rather than keystone seed disperser, …

From Young To Old: The Effects Of Sedentary-Aging And Exercise Interventions On Structural Plasticity Of Lumbar Motor Neurons, Nmj, And Glial Cell Line-Derived Neurotrophic Factor Expression, Alberto Felipe Cintron-Colon

Dissertations

Neuromuscular weakness has been associated with age progression. A possible reason is a disconnection between muscle and neuron, causing components from both the central and peripheral nervous systems to deteriorate. Exercise, however, has beneficial effects for both muscle and nervous tissue, inducing neuroprotection. Neurotrophic factors are powerful regulators of neuronal maintenance and synaptic strength. Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor that has been shown to be a potent survival factor for somatic motor neurons that innervate skeletal muscle.

This study aims to evaluate changes in structural plasticity of motor neurons in the lumbar spinal cord and …

Repeated Low-Level Blast Induces Chronic Neuroinflammation And Neurobehavioral Changes In Rat Models, Arun Reddy Ravula

Dissertations

Blast-induced neurotrauma (bTBI) is a signature medical concern for military personnel when they are exposed to explosions in active combat zones. However, soldiers as well as law enforcement personnel are also repeatedly exposed to low-level blasts during training sessions with heavy weaponries as part of combat readiness. Service personnel who sustain brain injuries from repeated low-level blasts (rLLBs) do not display overt pathological symptoms immediately but rather develop cognitive impairments, attention deficits, anxiety, and sleep disturbances over time. An improved rat model of rLLB was developed in this thesis by applying controlled low-level blast pressures (10 psi) repeated five times …

Ocean Quahog (Arctica Islandica) Population Dynamics: Sex-Based Demographics And Regional Comparisons In The Northwest Atlantic, Kathleen M. Hemeon

Dissertations

Arctica islandica (ocean quahog) is the longest-lived bivalve on Earth. Individuals on the deep continental shelf of the Mid-Atlantic (US) can survive for centuries, and when found in the colder, boreal waters of Iceland, ages over 500 years can be reached. The ocean quahog is important in the US, yet very little is known about the resiliency of the ocean quahog stock to fishing activity, and ocean quahog recruitment patterns over time. To quantify and constrain age-reader error prior to age analysis, a triple-method error protocol was developed for A. islandica that included age-reader bias, precision, and error frequency. The …

Investigating The Bactericidal Activity Of Lactobacillus Crispatus Cell-Free-Supernatant, Omar Majed Abdul-Rahim

Dissertations

Antimicrobial-resistant (AMR) microorganisms are an increasingly seriousproblem worldwide, accounting for thousands of fatalities annually. The current literature on combating AMR pathogens often centers on commensal microbes such as Lactobacillus species, which are most frequently found in asymptomatic ‘healthy’ patients and are believed to elicit protective effects. In this dissertation, I sought to investigate the protective effect of Lactobacillus crispatus, utilizing our vast collection of clinical isolates. Previous work from our lab had found that cell-free-supernatant (CFS) of L. crispatus is robustly bactericidal, and that this killing activity does not depend on hydrogen peroxide or lactic acid. We identified phenyl-lactic acid …

Cognitive Ecology Of Color Vision In Orchid Bees, Andreia Queiroz Santos A Figueiredo

Dissertations

Animals interact with their environment and acquire information from it. Information can be processed by their sensory systems and influence behavior, often mediated through mechanisms of decision-making and learning. Animal pollinators acquire information from flowers and use this information to make decisions about the flowers they visit. My research aimed to understand the role of color vision in a tropical pollinator, the orchid bee Euglossa dilemma. Chapter 1 is a review exploring pollination through the lens of prepared learning. Prepared learning proposes that animals learn some associations better than others due to an evolved match with the environment. I …

Impact Of Date-Pit Activated Carbon In Different Applications: Biomedical And Environment, Betty Titus Mathew

Dissertations

Activated carbon (AC) or activated charcoal are black carbonaceous porous solid material with prominent physico-chemical properties such as low volume pore size distribution, high specific surface area, and high-degree of surface reactivity for adsorption and other chemicals reactions. AC as strong and reliable adsorbent have been reported to be employed in diverse applications stretching from water/air purification, medical, sewage treatment, energy storage devices, catalyst, supercapacitor electrodes fabrication, and as biosensors component. In this current work, AC was produced from date pits, which is a common biological waste product in UAE, and used for biomedical and environmental applications instead of using …

The Interplay Of The Physical Landscape And Social Dynamics In Shaping Movement Of African Savanna Elephants (Loxodonta Africana), Maggie Wisniewska

Dissertations

Free ranging African savanna elephants (Loxodonta africana) are increasingly impacted by human-induced habitat loss and poaching for ivory. Because elephants live in tightly knit groups, this combination of threats not only reduces the size of their populations but also degrades their social interactions. Long-term relationships with socially competent individuals, such as experienced seniors, benefit the ability of other group members to access limiting resources and avoid danger. Understanding how anthropogenic pressure may affect persistence of elephant populations is important, because elephants are an economically important keystone species. This doctoral thesis characterizes how individual elephants influence the movement of their social …

The Impacts Of Aging, Sedentarism, And Exercise On Neurotrophic Factor Expression And Innervation In The Heart And The Effects Of Treatment With Α-Cgrp On Heart Function, Gabriel Almeida Alves

Dissertations

Neurotrophic factors (NFs) are important molecules responsible for development, differentiation, regeneration, and maintenance of new and mature neurons. Neurotrophic factors act as neurocytokines and may assist with the regulation of axonal and dendritic arrangements and synaptic plasticity between neurons themselves or with other non-neural target tissues. In this study, we analyze the levels of two NFs: glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF). Cardiomyocytes produce these neurotrophic factors which assist with the innervation pattern of the heart. The heart is innervated by the two branches of the autonomic nervous system; namely the sympathetic nervous system and …

Chemical And Biological Control Of Canker Disease Of Delonix Regia Caused By The Fungus Neoscytalidium Dimidiatum, Seham Mohammed Al Raish

Dissertations

In the United Arab Emirates (UAE), royal poinciana (Delonix regia) trees suffer from stem canker disease. Symptoms of stem canker can be characterized by branch and leaf dryness, bark lesions, discoloration of xylem tissues, longitudinal wood necrosis and extensive gumming. General dieback signs were also observed leading to complete defoliation of leaves and ultimately death of trees in advanced stages. The fungus, Neoscytalidium dimidiatum DSM 109897, was consistently recovered from diseased royal poinciana tissues; this was confirmed by the molecular, structural and morphological studies. Phylogenetic analyses of the translation elongation factor 1-a (TEF1-α) of N. dimidiatum from the …

These Fish Were Made For Walking: Morphology And Walking Kinematics In Balitorid Loaches, Callie Hendricks Crawford

Dissertations

Terrestrial excursions have been observed in multiple lineages of marine and freshwater fishes. These ventures into the terrestrial environment may be used when fish are searching out new habitat during drought, escaping predation, laying eggs, or seeking food sources. The physiological demands for life under water and on land are vastly different and require different functional adaptations. Fish with terrestrial excursions must be capable of dealing with the stresses of both aquatic and terrestrial environments for varying periods of time. To deal with these stresses, amphibious fishes exhibit many morphological and behavioral adaptations. These adaptations have led to a range …

Development Of Deep Learning Neural Network For Ecological And Medical Images, Shaobo Liu

Dissertations

Deep learning in computer vision and image processing has attracted attentions from various fields including ecology and medical image. Ecologists are interested in finding an effective model structure to classify different species. Tradition deep learning model use a convolutional neural network, such as LeNet, AlexNet, VGG models, residual neural network, and inception models, are first used on classifying bee wing and butterfly datasets. However, insufficient data sample and unbalanced samples in each class have caused a poor accuracy. To make improvement the test accuracy, data augmentation and transfer learning are applied. Recently developed deep learning framework based on mathematical morphology …

Il-27 Signaling In The Maintenance Of Intestinal Barrier Following Ethanol Intoxication And Burn Injury, Marisa Luck

Dissertations

Roughly half of burn patients that are hospitalized in the United States each year have detectable blood alcohol levels. Alcohol intoxication at the time of burn injury leads to worse outcomes, including longer hospital stays, increased rates of infection, and death. One of the severe consequences of intoxication and burn injury is the disruption of the gastrointestinal (GI) tract, which houses the largest reservoir of bacteria in the human body. Leakiness of the gut barrier can contribute to inflammation, infection, or sepsis from gut-derived microbes. Interleukin-27 (IL-27) is a cytokine that has shown some beneficial effects in other models of …

Identification And Characterization Of Novel Genes And Genetic Interactions That Influence Iba Metabolism, Vanessica Jawahir

Dissertations

Indole-3-butyric acid (IBA) is an endogenous storage auxin important for maintaining appropriate indole-3-acetic acid (IAA) levels that influences primary root elongation and lateral root development. IBA is metabolized into free IAA in the peroxisome in a multistep process similar to fatty acid β-oxidation. Although many components specific to IBA metabolism and peroxisome function have been identified, our understanding is incomplete. I sought to identify novel components of IBA metabolism or peroxisome function by conducting a forward genetic screen for Arabidopsis thaliana plants with enhanced resistance to IBA. I identified Long chain acyl-CoA synthetase 4 (LACS4) as a novel gene functioning …

Efficient Approximations For Stationary Single-Channel Calcium Nanodomains, Yinbo Chen

Dissertations

Mathematical and computational modeling plays an important role in the study of local Ca2+ signals underlying many fundamental physiological processes such as synaptic neurotransmitter release and myocyte contraction. Closed-form approximations describing steady-state distribution of Ca2+ in the vicinity of an open Ca2+ channel have proved particularly useful for the qualitative modeling of local Ca2+ signals. This dissertation presents several simple and efficient approximants for the equilibrium Ca2+ concentration near a point source in the presence of a mobile Ca2+ buffer, which achieve great accuracy over a wide range of model parameters. Such approximations provide an efficient method for estimating Ca2+ …

Genetic Population Structure And Microbiome Of German Cockroaches In Urban Environments, Xueyang Fan

Dissertations

Pests of human habitats may harbor and disperse pathogens that cause human disease. One such pest is the German cockroach (Blattella germanica), which is known to harbor numerous pathogens, including Klebsiella and Pseudomonas. The aim of this study is to reveal the importance of the German cockroach as a potential vector of human medically important diseases. To do so, this study investigates German cockroach population structure and their associated bacterial microbiome in urban residential environments. Ninety German cockroaches are collected from three residential apartment buildings in three New Jersey cities. Samples are caught by glue traps and stored at -20°C. …

Comparison Of Retention Rates Between Traditional On-Ground And Online Biology Laboratory Courses In The Community College Setting, Megan Davis Winborne

Dissertations

Community colleges provide vital educational resources to students across the nation. Online learning has become an integral part of the course offerings for community colleges. With regards to online learning, there is a lack of empirical evidence and research focused on community college offered biology laboratories, particularly concerning retention rates of these students. Means, Toyama, Murphy, and Bakia. (2013) found that even though there are copious amounts of studies dedicated to evaluation of evidence-based practices in online learning formats, many of them neglected to review retention rates associated with online educational courses.

The purpose of this study was to determine …

Plant Evolution And Urbanization: Quantifying The Effects Of Natural Selection In Shaping Shepherd’S Purse (Capsella Bursa-Pastoris) Populations In New York City, Rebecca Panko

Dissertations

The aim of this study is to quantify the effects of natural selection in shaping Capsella bursa-pastoris populations along an urban-rural gradient in New York City.

A reciprocal transplant experiment with 168 lab-germinated C. bursa-pastoris seedlings from both urban and rural populations are grown in eight paired home and away sites distributed throughout the New York metropolitan area. Sites are visited approximately thirteen times to record plant fitness. There is evidence for local adaptation of urban populations: urban plants have longer reproductive durations and produce more seed pods in urban environments. These findings suggest that urban plants are better adapted …

The Roles Of Inhibition In C. Elegans Locomotion, Lan Deng

Dissertations

Inhibition plays important roles in modulating neural activities at different levels from small synapses to brain regions, and different systems from sensory to motor. To achieve translocation, locomotor systems produce alternation of antagonist muscles, including axial posture and limb movement and alternation. In the nematode C. elegans, a cross-inhibition circuit, involving excitatory cholinergic and inhibitory GABAergic motoneurons, is believed to generate the dorsoventral alternation of body-wall muscles that supports backward undulatory locomotion. This dissertation challenges this prevalent hypothesis, delves into studying different roles of inhibition, and depicts the expression pattern and functional role of ionotropic GABAA receptor, UNC-49, in motoneurons …

An Investigation Of The Impacts Of Traditional, Virtual, And Hybrid Biological Laboratories On College Students’ Achievement And Motivation To Learn Biology, Shavonda Jackson

Dissertations

Virtual courses function in a different manner than traditional courses, therefore they require teaching methods and assessment techniques geared specifically to maximize this learning experience. Internet-based learning and distance-education are no longer new concepts in the science field. Because of this, many collegiate biology programs have created courses that can be taken virtual or hybrid. A number of experimental studies have had great influence in terms of the effects and impacts of educational technology in relation to virtual laboratories.

However, not many studies emphasize the impact of hybrid laboratories on student achievement or assess students’ motivation to learn in a …

Regional Differences In Wild North American River Otter (Lontra Canadensis) Behavior And Communication, Sarah Walkley

Dissertations

This study focuses on the vocalization repertoires of wild North American river otters (Lontra canadensis) in New York and California. Although they are the same species, these two established populations of river otters are separated by a significant distance and are distinct from one another. River otters are semi-aquatic social predators that can be found throughout North America. This is the first study to examine the vocalizations of wild river otters, and results are compared across field sites in the different regions. River otter vocalizations and behaviors in New York were recorded using Bushnell Aggressor trail cameras that …

Cellular And Molecular Mechanism Underlying Alcohol Inhibition Of Bone Fracture Healing, Jonathan Michael Eby

Dissertations

Alcohol consumption is associated with increased risk taking and injuries leading to bone fracture. During bone fracture repair mesenchymal stem cells (MSCs) located at the site of injury differentiate into chondrocytes and osteoblasts to form a fracture callus. While most fractures heal without complication, studies show that alcohol abuse can lead to delayed fracture healing and fracture callus formation in both people and animals. Despite what is known about alcohol consumption in pre-injury pathologies like osteopenia and osteoporosis, the cellular and molecular mechanisms by which alcohol consumption inhibits fracture callus formation following orthopaedic injury remain to be elucidated. Here, we …

Mitochondria Imaging And Targeted Cancer Treatment, Tinghan Zhao

Dissertations

Mitochondria are essential organelles as the site of respiration in eukaryotic cells and are involved in many crucial functions in cell life. Dysfunction of mitochondrial metabolism and irregular morphology have been frequently found in human cancers. The capability of imaging mitochondria as well as regulating their microenvironment is important both scientifically and clinically. Mitochondria penetrating peptides (MPPs), certain peptides that are composed of cationic and hydrophobic amino acids, are good candidates for mitochondria targeting. Herein, a novel MPP, D-argine-phenylalanine-D-argine-phenylalanine-D-argine-phenylalanine-NH₂ (rFrFrF), is conjugated with a rhodamine-based fluorescent chromophore (TAMRA). The TAMRA-rFrFrF probe exhibits advantageous properties for long-term mitochondria tracking of …