Digital Commons Network^™

Mechanisms By Which Mechanotransduction Promotes Proliferation In Keratinocytes, Chhavi Chaudhary

Electronic Theses and Dissertations

Chronic wounds are wounds that do not heal within 30 days and often they can last over a year. Interference in any of the wound healing stages may hinder the process. Some of the local and systemic factors such as infection, old age, diabetes, AIDS, and the regular application of corticoids may also have negative effects on the healing process. Cell proliferation is an important phase in epidermal wound healing in which surviving epithelial cells replicate independently into daughter cells through mitosis and maintain a balance between cell growth and cell loss during the cell cycle. Physical and chemical stimuli …

The Evolution Of Peristenus (Hymenoptera: Braconidae): Taxonomy, Phylogenetics And Ecological Speciation, Yuanmeng Zhang

Electronic Theses and Dissertations

Parasitoid wasps are ecologically and economically important as biological control agents. However, little is known about the diversity, distribution and biology of most hymenopteran parasitoids due to their small size, morphological conservatism, and complex life styles. The focus of my PhD research was to investigate the evolution and speciation of euphorine braconid wasps, using a combination of multilocus phylogenetics and population genomic techniques combined with traditional taxonomy. The three data chapters of my dissertation are divided into different taxonomic ranks of euphorine braconids, focusing on genera, species, and populations. For chapter 2, I built a multilocus phylogeny of the tribe …

Identification Of Qtl Modifying The Activity Of The Tcb1-S Locus And Characterization And Sequencing Of Two Plutonium-Beryllium Induced Reduced Gametophyte Transmission Mutants In Maize, Merritt Bryer Burch

Electronic Theses and Dissertations

This thesis is split into two independent projects both involving the male gametophyte generation of maize. The first project looks at how pollen interacts with the female gametophyte to reduce its transmission in cross-incompatible reactions controlled by the unilateral cross-incompatibility system, teosinte crossing barrier 1. The second project explores two plutonium-beryllium induced male gametophyte mutants and attempts to uncover their genetic basis.

Identification of QTL Modifying the Activity of the Tcb1-s Locus
Teosinte crossing barrier 1 (Tcb1) is a unilateral cross-incompatibility system present in maize that provides a pre-zygotic pistil barrier to plants carrying Tcb1-s (strong allele) from pollen …

Regulation Of Local Auxin Metabolism During Soybean Nodule Development, Suresh Damodaran

Electronic Theses and Dissertations

Legume-rhizobia symbiosis leads to the development of secondary root organs called nodules. Rhizobia bacteria housed inside nodules assimilate atmospheric nitrogen and convert them into plant usable forms thereby reducing the need for fertilizer application in crop legumes like soybean. Nodule development is a coordinated process orchestrated by multiple plant hormones. In soybean, the auxin responsive gene expression was detected in nodule primordia and in the periphery of mature nodules, primarily in nodule vasculature. Auxin hypersensitivity reduces nodule formation in soybean and also polar auxin transport inhibition at the site of nodule development is not crucial for determinate nodule formation. Therefore, …

The Role Of Genomic Versatility In Multi-Niche Preferences Of Escherichia Coli, Gitanjali Nandakafle

Electronic Theses and Dissertations

Escherichia coli strains are naturally present as either commensals or pathogens in the gastrointestinal tract of mammals and some other vertebrates. Until recently, it was assumed that E. coli are solely associated with the gut and are unable to survive outside of a host for a long period of time, the basis of its use as an indicator organism. Recent reports suggest that E. coli can become naturalized to several tropical, subtropical or temperate soils and aquatic environments, where they have been isolated repeatedly. Several studies have shown that these strains are capable of surviving and proliferating in the environment …

The Ecology Of Land Managers In Riparian Restoration, Lisa Buie Clark

Electronic Theses and Dissertations

While previous studies in restoration ecology have focused on the efficacy of direct management actions, the driving forces on management decisions (e.g., managers' characteristics or attitudes, environmental conditions) and the indirect impacts on restoration outcomes from management decisions (such as whether to collaborate) are quantified here for the first time. As a case study, I used data from 244 sites across the riparian Southwest US where the invasive shrubby tree Tamarix sp. was removed using various different methods. I surveyed and interviewed the 45 land managers who were responsible for the removal projects to determine their characteristics, attitudes, and …

The Effects Of Acidic Conditions And Tannins On The Survival, Development, And Behavior Of Cope’S Gray Treefrog (Hyla Chrysoscelis), Caleb E. Dodd

Electronic Theses and Dissertations

As amphibians decline around the world, freshwater acidification resulting from pollutants and acid rain may be a contributor. The ability of organisms to cope with environmental changes is greatly mediated by behavior, and recent studies indicate that anthropogenic acidification impairs behavioral responses by impacting olfactory abilities of aquatic organisms. Responding appropriately to novel stimuli is important for individual performance and survival, and pollutants may cause organisms to behave maladaptively. In this study I sought to: a) determine whether the oviposition site choices of adult female frogs correspond with the pH and tannin conditions that maximize tadpole survival and performance in …

Biodiversity And Evolution In The Guiana Shield, South America, Andrew Michael Snyder

Electronic Theses and Dissertations

The neotropics are characterized as the most species rich region in the world. Unfortunately, the region's unparalleled biodiversity has not protected it from ongoing threats such as agriculture, mining, logging, oil extraction, and climate change. I studied the biodiversity and evolution of the herpetofauna of South America in order to investigate the influence of historical geological and climatological events in shaping extant neotropical diversity, particularly the Guiana shield. For my research, I set out to explore the processes involved in shaping the remarkable extant diversity using anuran amphibians as models. With my dissertation, I provide a comprehensive review of the …

Impact Of Human Disturbance On The Behavior And Physiology Of The Endangered Ringed Sawback Turtle (Graptemys Oculifera), Jessica Mary Heppard

Electronic Theses and Dissertations

Turtles are one of the most threatened taxa worldwide. In addition to direct anthropogenic impacts such as hunting and pollution, unintentional indirect human disturbance affects poikilothermic turtles by disrupting thermoregulatory basking behavior. In this thesis I assess the behavioral and physiologic impacts of high boat traffic, reductions of basking structures, and environmental factors on basking behavior, rates of disturbance, thermoregulation, parasite load, shell condition, and population recruitment in two populations of the endangered ringed sawback (Graptemys oculifera), also known at the ringed map turtle, on the Pearl River outside Jackson, MS. Basking behavior was influenced by availability of basking structures, …

Effects Of Hydrological Connectivity On The Benthos Of A Large River (Lower Mississippi River, Usa), Audrey B. Harrison

Electronic Theses and Dissertations

The effects of hydrological connectivity between the Mississippi River main channel and adjacent secondary channel and floodplain habitats on macroinvertebrate community structure, water chemistry, and sediment makeup and chemistry are analyzed. In river-floodplain systems, connectivity between the main channel and the surrounding floodplain is critical in maintaining ecosystem processes. Floodplains comprise a variety of aquatic habitat types, including frequently connected secondary channels and oxbows, as well as rarely connected backwater lakes and pools. Herein, the effects of connectivity on riverine and floodplain biota, as well as the impacts of connectivity on the physiochemical makeup of both the water and sediments …

Leaping Behavior In Silver Carp (Hypophthalmichthys Molitrix): Analysis Of Burst Swimming Speeds, Angle Of Escape, Height, And Distance Of Leaps, Ehlana Stell

Electronic Theses and Dissertations

Silver Carp have rapidly expanded their range exploiting vulnerable habitats, disrupting fisheries, and inflicting unknown ecological damage. These fish have continued to spread into the Middle Mississippi River and the Tennessee River Valley and great effort is being expended to prevent Silver Carp from entering the Great Lakes and expanding further into the Ohio, Illinois, Missouri, and Tennessee Rivers. Using boat-mounted cameras, we recorded in situ video of invasive Silver Carp, Hypopthalmichthys molitrix leaps to measure their horizontal distance, height, and angle of escape as well as their burst speed. Video tapes of fish leaps were obtained from populations of …

Morphological And Behavioral Traits Associated With Locomotion In Lizards, Chase T. Kinsey

Electronic Theses and Dissertations

Morphology, locomotion, and behavior are co-adapted to optimize performance and ultimately fitness. Successfully navigating a complex environment is dictated by an animal’s locomotor behavior, and for some behaviors, its locomotor performance. The locomotor performance of an organism is directly related to the form and function of the structures involved in locomotion such that movement is efficient – that is, minimal loss of energy. The first chapter of this thesis focuses on the effects of obstacle placement and forelimb position on facultative bipedalism. Placing an obstacle beyond a lizard’s acceleration threshold did not affect the frequency of bipedal posture. Furthermore, the …

Behavioral And Disease Ecology Of Gopher Tortoises (Gopherus Polyphemus) Post Exclusion And Relocation With A Novel Approach To Homing Determination, Johnathan Napier

Electronic Theses and Dissertations

In the wake of human expansion, relocations and the loss of habitat can be stressful to an organism, plausibly leading to population declines. The gopher tortoise (Gopherus polyphemus) is a keystone species that constructs burrows it shares with 362 commensal species. Frequent exclusions and relocations and long generation times have contributed to G. polyphemus being State-designated as Threatened in Florida. Prior studies have indicated that G. polyphemus may possess homing behavior and thus be able to counteract stressors due to relocation and exclusion. I radiotracked a cohort of G. polyphemus for 11 months following excavation, relocation, and exclusion due to …

Evolution And Distribution Of Phenotypic Diversity In The Venom Of Mojave Rattlesnakes (Crotalus Scutulatus), Jason Strickland

Electronic Theses and Dissertations

Intraspecific phenotype diversity allows for local adaption and the ability for species to respond to changing environmental conditions, enhancing survivability. Phenotypic variation could be stochastic, genetically based, and/or the result of different environmental conditions. Mojave Rattlesnakes, Crotalus scutulatus, are known to have high intraspecific venom variation, but the geographic extent of the variation and factors influencing venom evolution are poorly understood. Three primary venom types have been described in this species based on the presence (Type A) or absence (Type B) of a neurotoxic phospholipase A2 called Mojave toxin and an inverse relationship with the presence of snake venom metalloproteinases …

Evaluation Of Dietary Phytochemicals As Rumen Modifiers In Lactating Dairy Cows, Sonia Rodriguez Jimenez

Electronic Theses and Dissertations

Phytochemicals such as tannins included in dairy cow nutritional programs, as a natural feed additive, promise to improve rumen bypass protein and consequently reduce the feeding cost by decreasing the amount of CP needed in the ration. Additionally, if tannins are fed along with high quality protein sources, this could improve the AA profile reaching the small intestine and potentially improving health and performance of dairy cows. The black pepper, specifically its alkaloid piperine, is a nontoxic, natural dietary compound with a broad range of physiological activity. Lactating dairy cows ingesting these phytochemicals (tannin extracts and black pepper) will potentially …

A Review Of The Serica (Coleoptera: Scarabaeidae: Melolonthinae) Of Mexico, Canada, And The Western United States, Reese John Worthington

Electronic Theses and Dissertations

Twenty-two species and subspecies of Serica occur in Mexico. Serica ensenada Saylor, 1948 is recognized as a junior synonym of Serica pilifera Horn, 1894. Two new species, Serica ascia Lago & Worthington and Serica fenestra Lago & Worthington are described from Mexico. Three genera of Sericini are recorded from Canada, Maladera castanea (Arrow), Nipponoserica peregrina (Chapin), and twelve species of Serica. Seventy-seven species and subspecies of Serica occur in the contiguous United States west of the 100th meridian. Eleven new species, Serica berriani Lago & Worthington, Serica cuneiverpa Lago & Worthington, Serica desolaterra Lago & Worthington, Serica katelinae Lago & …

Predictors Of Fish Assemblage Structure And Dynamics In Atlantic Coastal Plain Streams, Rebecca Scott

Electronic Theses and Dissertations

Effective management of freshwater fishes requires a mechanistic understanding of the drivers of assemblage composition; in other words, what determines who is where and when. Stream fish assemblages are potentially influenced by environmental factors that act on multiple spatiotemporal scales, but the relative influence of these drivers may vary between geophysically distinct regions. This study sought to determine the patterns and drivers of fish taxonomic and functional assemblage composition in the coastal plain, a region possessing unique hydrologies, faunas, and physiochemical conditions. I addressed this goal using two complementary chapters, both of which utilized environmental and biotic data collected from …

Comparison Of Three Benthic Macroinvertebrate Passive Sampling Devices For Non-Wadeable Streams, Kelsey A. Laymon

Electronic Theses and Dissertations

Rivers and streams provide essential ecosystem services to the degree that the monitoring and maintenance of these systems becomes imperative. Biomonitoring provides managers and policymakers with the tools to make informed decisions, and macroinvertebrates are often the object of biomonitoring because they are ubiquitous in most systems and are known to be good indicators of water quality. However, methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) have not been standardized across states and regions and an established method for macroinvertebrate biomonitoring in large rivers of Georgia is not currently available. My study compared macroinvertebrates collected with three types …

Identification Of Macropinocytosis Regulating Proteins And Signaling From Macropinosomes, Louise Monga

Electronic Theses and Dissertations

Understanding macrophage cell biology is important due to macrophages key roles in human health and diseases including proper immune function, wound healing, atherosclerosis, and cancer. Despite their importance, relatively little is understood about macrophage activation, growth factor signaling, and cytoskeletal regulation. This thesis presents data from investigations into mechanisms of macrophage growth factor signaling and actin polymerization for ruffling and macropinocytosis. Alt-R CRISPR-Cas9 method and dextran uptake assay were used to knock out individual genes (SHP-1, Lyn, Syk, BTK, Vav1) and determine their role in macropinocytosis and CSF-1R signaling. Dextran uptake was disrupted in SHP-1 and Lyn targeted knockout cells, …

Transcriptome Analysis Of Root Development In Wheat Triticum Aestivum Using High Throughtput Sequencing Technologies, Ghana Challa

Electronic Theses and Dissertations

Root provides plant water, nutrients and anchorage from soil. Most our knowledge of molecular mechanisms of root development is from the dicot model plant Arabidopsis, but very few studies have done in monocot crop systems like rice, maize, and wheat. We are studying very short root (VSR) phenotype in wheat, and lack of a sequenced reference genome in wheat prompted us to sequence and assemble the root transcriptome of the reference cultivar Chinese Spring (CS). A root transcriptome was assembled from the sequenced reads generated from root tip and the mature root tissues of CS. Approximately 169 million reads were …

Expression Analyses And Identification Of Key Molecular Participants In Plant Responses To Environmental Cues, Praveena Kanchupati

Electronic Theses and Dissertations

Plants constantly engage and interact with the environment and respond to the changes in conditions like temperature, water, and photoperiod, by regulating expression of genes of multiple regulatory and signaling pathways. Insight into these pathways and their participants has provided and will provide candidates to improve various agronomically important traits in crops through marker-assisted breeding and genetic manipulation. With this aim in mind, in the present study, I attempted to identify key candidate genes that are involved in the regulation of; i) plant response to low temperature stress, ii) plant roots’ response to soil moisture content and iii) flowering time. …