Digital Commons Network^™

Evaluating The Impacts Of The Invasive Macrophyte, Crassula Helmsii, On Macroinvertebrate Assemblages At Small Spatial Scales In Lentic Ecosystems, Keivan Rakhshani

The Plymouth Student Scientist

Freshwater ecosystems cover only three percent of the Earth’s surface yet support approximately ten percent of global biodiversity. These systems play a crucial role in maintaining native biodiversity across spatial and temporal scales but are increasingly threatened by anthropogenic stressors, including habitat modification, pollution, and biological invasions. The introduction of non-native macrophytes can fundamentally alter community structure by modifying habitat complexity, resource availability, and competitive interactions. This study assesses the impact of the invasive macrophyte Crassula helmsii on macroinvertebrate assemblages at small spatial scales within partially invaded ponds in Dartmoor National Park, southwest England. Three ponds with varying degrees of …

Assessing Jasmonic Acid Seed Priming In Brassica Napus: Impacts On Aphid Herbivory Resistance And Seedling Fitness Trade-Offs, Daisy Stradling

The Plymouth Student Scientist

Jasmonic acid (JA) is a key phytohormone involved in plant defence, offering a potential sustainable alternative to conventional chemical pesticides. While JA seed priming has been explored as a strategy to enhance herbivore resistance in certain plant families, its potential fitness trade-offs remain poorly understood. This study investigates the effects of JA seed priming on Brassica napus (oilseed rape), a key agricultural crop, focusing on seedling fitness and resistance to Brevicoryne brassicae (mealy cabbage aphid), a major agricultural pest. To assess potential fitness trade-offs, seeds were primed with 75 µM JA, and multiple seedling fitness parameters were measured. Germination monitoring …

Microinjection, Gene Knockdown, And Crispr-Mediated Gene Knock-In In The Hard Coral, Astrangia Poculata, Jacob F. Warner, Ryan Besemer, Alicia Schickle, Erin Borbee, Isabella V. Changsut, Koty H. Sharp, Leslie S. Babonis

Arts & Sciences Faculty Publications

Cnidarians have become valuable models for understanding many aspects of developmental biology including the evolution of body plan diversity, novel cell type specification, and regeneration. Most of our understanding of gene function during early development in cnidarians comes from a small number of experimental systems including Hydra and the sea anemone, Nematostella vectensis. Few molecular tools have been developed for use in hard corals, limiting our understanding of this diverse and ecologically important clade. Here, we report the development of a suite of tools for manipulating and analyzing gene expression during early development in the northern star coral, Astrangia poculata. …

Characterizing The Germination Process And Establishing Best Practices For Seed Propagation Of Tamaulipan Thornscrub Species For Habitat Restoration, Saroj Dhakal

Theses and Dissertations

Tamaulipan thornscrub is an imperiled plant community of southern Texas and northeastern Mexico. Given its importance for biodiversity conservation, stakeholders have been involved in restoration programs using seedlings grown from wild seeds. However, stakeholders often report that insufficient seedling supply is a challenge. To address knowledge gaps in seed germination behavior limiting seedling production, this study was conducted on 18 Tamaulipan thornscrub species, identified by growers as difficult to germinate. Seeds of all studied species are orthodox except Amyris texana, which have recalcitrant properties. Nine species have physical dormancy that was successfully addressed with mechanical and/or chemical scarification. Other species …

Arthropod Communities Associated With Endangered Physaria Thamnophila (Zapata Bladderpod) And Its Nurse Plants, Cesar Adrian Hinojosa

Theses and Dissertations

Physaria thamnophila is a federally endangered plant whose associated arthropods are understudied and poorly understood. This study surveyed environmental conditions and the arthropod community within the Arroyo Ramirez Tract of the Lower Rio Grande Valley National Wildlife Refuge, assessed which environmental factors influenced the arthropod community, and sought arthropod taxa statistically associated with Physaria thamnophila. Sticky cards and pitfall traps were deployed for a 7 day period, and vacuum samplings occurred quarterly over the span of a year to collect arthropods that were identified to order and family level for Coleoptera, Hymenoptera, and Lepidoptera. Biotic and abiotic surveys were performed …

Determination Of An Effective Natural Boxelder Bug (Boisea Trivittata) Repellent, Reyna Chavez

Theses and Dissertations

This study investigates the use of ecofriendly repellant alternatives to pest management to control boxelder bugs (Boisea trivittata). This bug gathers by the thousands on warm surfaces of exterior suburban homes during early fall and late spring. I determined bug repellency to turmeric oil (Curcuma longa), catnip (Nepeta cataria), citronella (Cymbopogon nardus), and lavender (Lavandula angustifolia). The treatments consisted of essential oils containing 20% methanol. All treatments demonstrated repellency of Boxelder bugs. Citronella was the most effective and had the highest level of repellency range of 90-99%. Catnip was the least effective with a repellency range of 63-82%.

Clustering 24-Hour Ambulatory Blood Pressure Time Series With Dynamic Time Warping And Time Warp Edit Distance, John Knight

Theses and Dissertations

Ambulatory blood pressure monitoring (ABPM) captures dynamic circadian changes in blood pressure (BP) that are not reflected in static clinic readings. This study applied time-series clustering with two elastic distance measures—Dynamic Time Warping (DTW) and Time Warp Edit Distance (TWED)—to identify distinct phenotypes in 2,155 24-hour ABPM time series from participants in the Maracaibo Aging Study. DTW and TWED both yielded three clusters corresponding to non-dipping, moderate-dipping, and strong-dipping patterns. The non-dipping group showed elevated nighttime BP, associated with greater cardiovascular and cognitive risk, while the strong-dipping group was associated with higher education and younger age in baseline clinic measurements. …

Seagrass Preference Among Pinfish In The Lower Laguna Madre, Nathaniel Garza

Theses and Dissertations

Pinfish (Lagodon rhomboides) is a common estuarine fish species found from Massachusetts to the Yucatan, Mexico. As juveniles, pinfish spend a significant portion of their life in coastal seagrasses which provide both shelter from predators and food. Along the Texas coast, there are three major species of seagrass- turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme) and shoal grass (Halodule wrightii) that differ in structural complexity. The goal of this study was to determine if pinfish associate more with one seagrass species than the others. A year-long field study was completed using twelve sample sites in the Lower Laguna Madre, …

Bacillus Subtilis: A Bacterium That Can Potentially Degrade Low-Density Polyethylene (Ldpe) And Polyethylene Terephthalate (Pet), Migdalia Flores

Theses and Dissertations

The widespread application and disposal of plastics, such as low-density polyethylene (LDPE) and polyethylene terephthalate (PET), have raised significant environmental health concerns. Because of each plastic’s stability and durability, these plastics exhibit limited natural degradation in the environment. Recently, the environmentally friendly biodegradation of plastics by living microorganisms has attracted more attention, as they can assist in the natural degradation process. In this study, the bacterial strain Bacillus subtilis ATCC6051 was used to degrade LDPE and PET for 60 days. To measure the degradation of low-density (LDPE) and polyethylene terephthalate (PET), the dry weight was taken, and physical characteristics were …

Probing Prebiotic Rna Oligonucleotide Polymerization On A Mg-Fes Catalyst Using Microfluidics, Gabriella Garza

Theses and Dissertations

Non-enzymatic polymerization under aqueous conditions has long been viewed as unfavorable, due to product (H2O) inhibition in abiotic settings (Damer & Deamer, 2015); despite its efficiency in biology through ATP monomer activation. Geochemically sustained pH gradients may provide free energy for condensation of organic monomers (Martin & Russell, 2003). Here, we investigated a biologically analogous non-enzymatic mechanism for RNA oligomerization, by probing the catalytic properties of a Mg-rich FeS mineral under aqueous conditions. FeS minerals promote a diverse prebiotic reaction (Wächtershäuser, 1988) and would have precipitated at Hadean submarine hydrothermal systems (Sojo et al., 2016). Natural pH and redox gradients …

Population Structure Of Red Drum (Sciaenops Ocellatus (Linnaeus, 1766)) In Two Systems In The Northwestern Gulf Of Mexico, Sandra Antonia Leal

Theses and Dissertations

Red drum (Sciaenops ocellatus) are an economically significant species of fish inhabiting the Gulf of Mexico. There are limited studies assessing S. ocellatus population structure focused on the southern coast of Texas. A total of 1,008 fish were collected over one year on a quarterly basis at South Bay (SB) and Holly Beach (HB) in the Lower Laguna Madre (LLM) of Texas to assess population structure. Juvenile S. ocellatus utilize the water systems of the LLM as a nursery ground and were more abundant at SB (n = 718) than HB (n = 290). The most abundant age classes were …

Applicability Of Cementochronology To Estimate Season-Of-Death In Humans: Insights From Modern Documented Collections, Olga Ibarra-Sanchez

Theses and Dissertations

Dental cementum is characterized by lifelong deposition of alternating opaque annuli in fall/winter and translucent bands in spring/summer. This study aims to test the applicability of cementochronology to estimate season-of-death, by observing the properties of the last layer, with direct implications for forensic anthropology and bioarchaeology. The sample includes canine teeth from 146 adults (84 males, 62 females), age-at-death ranging from 20-97 years (mean=61.7 years, SD=18.6 years), from two contemporary skeletal collections. Of these individuals, 78 (53.4%) died in spring/summer and 68 (46.6%) died in fall/winter. Overall accuracy was low at 64.4% (94/146). Accuracy was higher for spring/summer deaths 100.0% …

Ontogenetic Analysis Of Parasaurolophus Braincases (Ornithischia, Hadrosauridae) From The Kaiparowits Formation (Upper Cretaceous) Of Utah, Usa: Comparing Juvenile And Adult Morphology, Amanda "Billie" C. Guerrero

Electronic Theses, Projects, and Dissertations

This study documents the ontogenetic development of the braincase in Parasaurolophus, a lambeosaurine hadrosaurid dinosaur known for its distinctive cranial crest. Whereas the crest has been extensively examined for its roles in communication and display, the braincase remains less understood, despite its structural and functional relationship with the crest. This research compares the braincase morphology of a juvenile specimen (RAM 14000, "Baby Joe"), a subadult specimen (RAM 17000), and an adult P. tubicen (NMMNH P-25100), to investigate how developmental changes influenced sensory systems, neurocranial architecture, and biomechanical adaptations across ontogeny.

Detailed morphological analysis reveals progressive changes from juvenile to …

Bricks, Bushes, And Bones: Urbanization Influence On Western Fence Lizard (Sceloporus Occidentalis) Morphology And Performance, Daisy P. Xiong

Electronic Theses, Projects, and Dissertations

With increasing urbanization due to rising human populations, organisms may be forced to adapt rapidly to changing environments. Urbanization is replacing natural surfaces with more impervious substrates which can result in morphological changes affecting organismal locomotion, then also impact fitness. This study compares urban and natural habitat impact on Western Fence Lizards (Sceloporus occidentalis) and their adaptations in such settings. We captured lizards from three locations in inland Southern California with both urbanized and natural habitats in order to compare the morphological differences between lizards, and then measured their performance to determine the possible impacts from their morphology. …

Lagomorphs, Ungulates, And Predation: Exploring Interactions And Quantifying The Effect Of Lagomorph Herbivory In Rangelands, Shantell Marie Garrett

All Graduate Theses and Dissertations, Fall 2023 to Present

Rangelands are expansive ecosystems that make up more than 30% of the total surface land area in the contiguous United States. In the west, they are typically categorized as shrublands, grasslands or deserts with low precipitation. The vegetation communities consist largely of grasses and forbs and are thus widely used for livestock grazing. Despite their barren appearance, rangelands are diverse ecosystems that are home to a wide breadth of species.

The Henry Mountains, located in south central Utah, is one example of this system type. With their inspiring red-rock mesas and towering plateaus, this public land, managed by the Bureau …

Reproduction And Larval Development Of The Invasive Asian Longhorned Beetle In South Carolina, Lindsey A. Stone

All Theses

The Asian longhorned beetle (Anoplophora glabripennis Motschulsky; ALB) is a major threat to forest health due to the damage done by larval feeding in host trees. In 2020, ALB was discovered in Charleston County, South Carolina, which presents a novel climate for this invasive pest in North America. I investigated the reproductive biology and larval development of ALB to support detection and management efforts. By exposing 19 host trees to mated pairs of adults, I was able to determine rates of oviposition success (55%), egg viability (55%), and early larval survival (56%). On average, females chewed nearly 1 egg …

Investigating The Impacts Of Azole Antifungals On Growth Of Cryptococcus Neoformans, Gnanambika Sindhe

All Theses

Cryptococcus neoformans, an opportunistic fungal pathogen is responsible for cryptococcosis, leading to approximately 181,000 deaths annually, predominantly in regions such as Sub-Saharan Africa. Fluconazole, a widely used fungistatic azole, is often administered due to its relative affordability and lower toxicity. However, resistance to fluconazole in C. neoformans can arise through aneuploidy, complicating treatment efforts. This study aims to deepen our understanding of resistance mechanisms to azole drugs by comparing fluconazole with other azoles, including both clinical and agricultural azole antifungals. Disk diffusion assays were performed to evaluate the ability of C. neoformans to develop resistance to these compounds, focusing …

The Development Of Tools For The Production Of Fusarium Oxysporum Race 4 Resistant Cotton Varieties, Thomas Rylands

All Theses

Fusarium oxysporum race 4 (FOV4) is a fungal pathogen that infects cotton (Gossypium spp.) plants, resulting in fusarium wilt (FW) disease that causes significant wilting, yield loss, and eventually death. Since cotton is such an important crop globally, with tens of millions of bales of fiber produced and sold worldwide each year, it is critical to develop effective strategies to combat this pathogen. This research aims to achieve that goal through two projects: (i) develop an efficient co-culture system to test fungal treatments in vitro, and (ii) develop a computer vision pipeline to more accurately assess plant resistance …

A Class Of Benzofuranoindoline-Bearing Heptacyclic Fungal Ripps With Anticancer Activities, Qiuyue Nie, Fanglong Zhao, Xuerong Yu, Mithun C Madhusudhanan, Caleb Chang, Siting Li, Sandipan Roy Chowdhury, Bryce Kille, Andy Xu, Rory Sharkey, Chunxiao Sun, Hongzhi Zeng, Shuai Liu, Dishu Zhou, Xin Yu, Kevin Yang, Sandra A C Figueiredo, Maria Zotova, Zichen Hu, Alan Y Du, Dongyin Guan, Rui Tang, Todd Treangen, Jin Wang, Pedro N Leão, Yang Gao, Junjie Chen, Peng Liu, Hans Renata, Xue Gao

Children’s Nutrition Research Center Staff Publications

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a promising source of new pharmaceuticals, yet the therapeutic potential of fungal RiPPs remains largely underexplored. Here, we report asperigimycins as a distinct class of fungal RiPPs, featuring a unique heptacyclic scaffold consisting of a benzofuranoindoline core and three additional macrocycles, primarily assembled by six distinct fungi-specific DUF3328 oxidases. Inspired by the enhancement of anticancer activity through the N-terminal pyroglutamate in naturally occurring asperigimycins C and D, we chemically modify the inactive asperigimycin B with a series of lipid substitutions at its N-terminus. A derivative with a C-11 linear fatty …

Reliability Analysis Of In-Person And Virtual Goniometric Measurements For Select Shoulder And Forearm Motions, Autumn Whitson, Tracy Cook, Lisa Middleton, Casey E. Humphrey, Aaron D. Sciascia

EKU Faculty and Staff Scholarship

Background Previous research on upper extremity range of motion has compared in-person to virtual measures for sagittal plane motions (flexion/extension) showing good-excellent reliability. Since upper extremity evaluation includes motion in all planes, it is important to assess whether transverse plane motion (rotation, supination, pronation) can be reliably measured during a virtual assessment. Purpose To evaluate the reliability (test/re-test inter-rater and intra-rater) of goniometric measurements of shoulder internal rotation and forearm pronation/supination obtained in-person and virtually. Study Design Observational cohort, Reliability study Methods Subjects 18-60 years of age with no upper extremity injuries were recruited for range of motion (ROM) testing …

Isolation Of The 2019 Bonnet Carré Spillway Effects On The Habitat Suitability Of Brown Shrimp (Farfantepenaeus Aztecus) And Blue Crab (Callinectes Sapidus) Using A Modeling Approach, Mallory Dyson

Master's Theses

In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27^th to April 11^th, and May 10^th through July 27^th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) …

Life History And Distribution Of Two Species Of Cownose Ray, Rhinoptera Bonasus And Rhinoptera Brasiliensis, In Mississippi Coastal Waters, Anna Millender

Master's Theses

Historically, the American Cownose Ray (Rhinoptera bonasus) was considered the only rhinopterid residing in the northern Gulf of Mexico (GOM); however, recent studies have confirmed the presence of the Brazilian Cownose Ray (Rhinoptera brasiliensis) throughout this region. The current study investigated the life history and distribution of both species within Mississippi waters, an area that previously represented a data gap for both species. From April 2016 – July 2025, 193 R. bonasus and 94 R. brasiliensis were analyzed to describe the reproductive biology. Reproductive timing, mating, gestation length, and parturition were similar among species. Although more …

Discovery Of Insecticidal Cyclotides From The African Plants Allexis Batangae And Allexis Obanensis, Negin Khatibi, Olivier Ndogo Eteme, Conan K. Wang, Edward K. Gilding, Ernestine Nkwengoua Zondegoumba, Michelle L. Colgrave, Yen Hua Huang, David J. Craik

Research outputs 2022 to 2026

Cyclotides are plant-derived cyclic peptides recognized for their crucial role in host defense against insects and fungal pathogens. They are characterized by an ultra-stable head-to-tail cyclic backbone and a cystine knot formed by three conserved disulfide bonds, and are considered to be a promising group of molecules for a diverse array of agricultural and pharmaceutical applications. Cyclotides have been identified in five major plant families, with the Violaceae being a particularly rich source. Although cyclotides are ubiquitous in the Violaceae, many genera within this family remain unexplored. In the current study, the presence of cyclotides in Allexis batangae and Allexis …

Benthic Infaunal Responses To Shoreline Restoration, Jessica Lauren Cline

Theses and Dissertations

In the age of increasing urban coastal sprawl, natural shorelines are being replaced by hard armoring structures, which result in the loss of valuable ecosystem services. Hybrid living shorelines, areas that include limited and less intensive armoring strategies paired with the integration of plants and other natural materials, present an opportunity to marry the need for more aggressive stabilization with the continued preservation of ecosystem functions and biological communities. This project uses benthic infauna to evaluate the success of a living shoreline installation in Palm Bay, Florida. The deployment features experimental treatments of breakwaters and red mangroves to explore how …

Phenology And Seed Treatment Impacts Surface Defenses And Fall Armyworm (Spodoptera Frugiperda) Growth In Rice (Oryza Sativa), Devi Balakrishnan, Jessica Ayala, Alejandro Vasquez, Nick Bateman, Rupesh Kariyat

Entomology and Plant Pathology Faculty Publications and Presentations

Rice (Oryza sativa L.) is considered as the most important staple food crop in the world, feeding half of the global population. One of the emerging concerns in rice is the fall armyworm (Spodoptera frugiperda, FAW), a highly polyphagous insect herbivore. Although FAW has been well studied across many host systems, rice-FAW interactions-including the effects of phenology and seed treatment-are less understood. In this study, we examined the response of FAW to rice under a thiamethoxam seed treatment across three different phenological stages (V5: tillering; V11: maximum tillering; R3: panicle exsertion). We used four commonly grown cultivars in USA, exposed …

Context Dependent Regulation Of Dicer Function During Oocyte-To-Embryo Transition, Nick A. Newkirk

Dissertations and Theses (Open Access)

Over two decades ago, Dicer was discovered as the primary enzyme responsible for the generation of small RNAs known as the microRNAs (miRNAs) and short interfering RNAs (siRNAs). Spatiotemporal regulation of Dicer-dependent small-RNA biogenesis affects many aspects of biology, including aging, disease progression, fertility, and cancer. Interestingly, a distinct population of Dicer-dependent small RNAs, known as the endogenous siRNAs (endo-siRNAs), are uniquely abundant in the germ cells and gametes, and are critical for normal fertility. Despite their function regulating new life, the mechanisms controlling their biogenesis and subsequent germ cell functions remain poorly defined. Work to parse these mechanisms in …

Capsinoids, Non-Pungent Trpv1 Agonists, Induce A Mild Hypothermia That Provides Short- And Long-Term Neuroprotection After Ischemic Stroke, Alexander Andersohn, Alexander Andersohn

Dissertations and Theses (Open Access)

Therapeutic hypothermia (TH) has demonstrated neuroprotection in instances of cardiac arrest and neonatal hypoxia/ischemia but faces different challenges in application to stroke due to the activation of cold defense mechanisms in conscious patients. This dissertation examines the efficacy and specificity of capsinoids (a purified mixture of capsiate and dihydrocapsiate) to induce a sustained mild hypothermia in conscious mice that is neuroprotective after stroke. Capsinoids function as TRPV1 agonists. However, unlike capsaicin, capsinoids are vulnerable to esterase-mediated breakdown, thus significantly restricting their action to the site of delivery. We showed that capsinoids delivered intraperitoneally (IP) to mice induced a TRPV1-dependent drop …

Functional Analysis Of Ftsa-Mediated Recruitment Of Ftsk In Escherichia Coli, Abbigale Perkins

Dissertations and Theses (Open Access)

Bacterial cytokinesis requires precise coordination between cytoplasmic and periplasmic components of the divisome to ensure that membrane constriction and chromosome segregation occur in synchrony. The actin-like protein FtsA plays a central role in this process by tethering FtsZ to the membrane and recruiting downstream division proteins. Despite its essential function, the mechanisms by which FtsA coordinates divisome activation and the recruitment of late-acting proteins remain incompletely defined. To address this, the role of FtsA in activating septal synthesis and recruiting the DNA translocase FtsK was examined using mutational analysis in Escherichia coli.

The FtsA^{M96E R153D} variant, which has …

Orthogonal Comparison Of Nuclear And Mitochondrial Clonal Architectures In Hematologic Malignancies, Nehali Shah

Dissertations and Theses (Open Access)

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by accumulation of mutations that disrupt hematopoietic differentiation and promote clonal expansion. Understanding how these mutations arise and evolve is essential for improving diagnosis, prognosis, and treatment stratification. Current methods are limited by either restricted genomic coverage (targeted panels) or low throughput and high cost (in single-cell whole genome sequencing, scWGS). An emerging alternative is the use of mitochondrial DNA (mtDNA) mutations as clonal markers.

This study aims to determine whether mitochondrial-derived clonal architectures correlate with nuclear-derived clonal architectures in AML, thereby evaluating mtDNA as a scalable orthogonal tool for lineage …

Assessing Response Diversity Of Spawning Conditions For Native Trout Among Streams To Interannual Changes In Snowpack, Autumn Kaye Zierenberg

Undergraduate Honors Capstone Projects

Stream habitat suitability for fish is controlled by physical, chemical and biological conditions impacted by interannual changes in climate. Intermittent streams are particularly sensitive to climatic variation and have long been overlooked as potential spawning habitats for fish and other riverine species. Spawning suitability in stream habitats is strongly influenced by connectivity to perennial habitats, the duration of surface flows and water temperatures, each of which are driven by annual snowpack and discharge conditions. Here, we examine how the spawning habitat suitability in different tributaries within a single river basin respond to changes in annual snowpack conditions. Specifically, we examined …