Life Sciences Commons^™

The Effects Of Moderate And High Temperatures On Growth, Metabolism, And Blood-Oxygen Affinity In Ictalurus Spp., Brandon Gerhart

Theses and Dissertations

Despite the growing use of hybrid catfish (Ictalurus furcatus × I. punctatus) in aquaculture, few studies have investigated the comparative effects of temperature on physiological performance with other cultured catfish. Therefore, growth, metabolism, and blood-oxygen affinity of blue (I. furcatus), channel (I. punctatus), and hybrid catfish were compared at moderate (23°C) and high (33°C) water temperatures. Channel catfish had the greatest growth and were in better condition compared to blue and hybrid catfish. Hybrid catfish standard metabolic rates did not differ from blue or channel catfish, while hybrid catfish had higher maximum metabolic rates, …

Quantifying The Effects Of Abiotic Stress On Early Season Growth, Development, And Physiological Characteristics In Corn, Charles Hunt Walne

Theses and Dissertations

Corn is one of American agriculture's greatest success stories, where we have witnessed incredible increases in yield potential over the last half-century. However, abiotic stress is still the primary limiting factor preventing plants from reaching their true yield potential. In addition, agriculture is not exempt from the deleterious effects of changing weather patterns and the altered climate our world will face as time progresses. Thus, increasing our understanding of how crops interact with their environment both above and below the soil will be crucial to increasing production on a global scale while maximizing profitability at a local level. Five studies …

An Analysis Of The Effects Of Temperature And Other Environmental Factors On Microorganismal Productivity Within Aquatic Ecosystems Using Long-Term Data From Various Lter And Ilter Sites, Andrew Dorbu

Theses and Dissertations

Global climate change is a phenomenon resulting in more extreme weather patterns and species diversity loss. In this study, I explore the impacts of climate change on regional patterns of microbial productivity. Variation in microbial productivity was explained using temperature, salinity, and dissolved oxygen as predictors in regression models with data from the LTER and iLTER network of sites that ranged from the poles to the equator. I found a positive relationship between temperature and productivity. Antarctica and Arctic sites exhibited the strongest positive relationships supporting prior research demonstrating temperature as one of the driving forces of productivity change in …

Growth Kinetics Of Salmonella Spp. During Post-Harvest Storage Of Fresh And Fresh-Cut Papaya, Amandeep Singh

Theses and Dissertations

Fresh produce safety is major concern in United States. Fresh produce has been associated with numerous food-borne outbreaks each year. Salmonella has been a recurring issue in the papaya industry. Since 2010, imported papayas have been implicated in 8 multistate outbreaks associated with Salmonella spp. causing 480 illnesses, 113 hospitalization and 3 deaths. The main reason behind this problem is as fresh papaya is grown on fields where they are constantly exposed to preharvest microbial contamination through contaminated irrigation water, agricultural soil, raw manure and/or feces deposited by intruding domestic or wild animals. Moreover, majority fresh papaya is also consumed …

Sensitivity Of Aquatic Organic Matter Degradation To Changing Temperature And Nutrient Conditions In A Coastal Watershed, Curtis John Szewczyk

Theses and Dissertations

The degradation of organic matter (OM) within inland waters plays a pivotal role in the global carbon cycle and quantifying carbon budgets. Here, measurements of dissolved oxygen (DO) decay rates were used to infer the extent and kinetics of OM degradation under variable conditions. The goal of the investigation was to quantify how OM samples within the Waccamaw River watershed, South Carolina, respond to changes in temperature and nutrient availability as a function of their source location and lability. Samples were collected from urbanized stormwater detention ponds and undeveloped upland forested wetland drainages to provide contrasting and distinct OM sources …

Physiological Consequences Of Neuromodulation And The Cellular Properties That Underlie Them, Margaret Louise Demaegd

Theses and Dissertations

Neuronal activity is a product of more than the underlying neuronal connections. Modulatory influences like changes in the animal’s environment, the animals physiological state, or the release of neuromodulators can dramatically alter neuronal activity. Modulatory influences can be beneficial for the animal because they are a source of neuronal and behavioral plasticity, and they can provide neuronal circuits with the robustness needed to continue to function in new conditions, states, or tasks.However, malfunctions of the modulatory system can disrupt neuronal activity and lead to pathologies. Predicting how modulatory influences will alter neuronal activity is challenging because the underlying cellular and …

Examining Various Aspects Of Zika Virus Dissemination In Aedes Aegypti, Ileana C. Lozano

Theses and Dissertations

South Texas is one of the few locations where Zika virus has been locally transmitted in the U.S. It has a climate which is distinct to other areas with autochthonous transmission, with extremely hot, dry summers and moderate winter temperatures. Studying mosquito transmission of Zika in a range of temperatures conditions replicating where virus transmission is occurring is essential in order to have a better understanding of transmission patterns. These factors were examined by infecting mosquitoes and monitoring the dissemination status through real-time PCR analysis.

To further characterize dissemination of Zika virus within south Texas mosquitoes a time series immunohistochemical …

Evidence Of Local Adaptation To Climate In An Invasive Ectotherm: A Study On The Eurasian Gypsy Moth (Lymantria Dispar) In North America, Phillip M. Gibbs

Theses and Dissertations

Invasive species exist in nearly every ecosystem both terrestrial and aquatic. Improving our understanding of the mechanisms that shape the ability of these organisms to physiologically cope with their surroundings will be crucial to preparing for future impacts of climate change. The Gypsy Moth (Lymantria dispar) has been expanding its range across North America over the last 100+ years since its arrival in Medford, Massachusetts. This study quantifies upper thermal limits (UTL) across 8 different populations of L. dispar in North America and seeks to determine if signals of local adaptation to climate across a latitudinal gradient may …

Linking Physiology, Temperature, And Recruitment: A Classic Competitive Story Rewritten By Climate, Maeve Kerrigan Snyder

Theses and Dissertations

Climatic changes have the potential to alter population and community dynamics, ultimately influencing the biogeographic distributions of species. For many organisms, reproduction is physiologically tied to temperature. We tested the hypothesis that a physiological mechanism for reproductive failure in the acorn barnacle, Semibalanus balanoides, would result in predictable patterns of larval recruitment over broad geographic scales. Recruitment density was predicted to be dependent on the duration of permissive temperatures (< 10oC). for successful reproduction in adult populations of S. balanoides. We found that temperature was a reliable predictive variable for recruitment densities throughout our study region. Post-recruitment processes were also considered, specifically the competition between Semibalanus balanoides and Chthamalus montagui, described in Joseph Connell’s 1961 experiment. The competitive hierarchy outlined in this experiment is not consistently observed throughout the range overlap of the two species. Growth and mortality were found to differ dependent on species and latitude, indicating that climate mediates this classic ecological system. Our results provide useful knowledge for refining models of biogeographic shifts. A consistent failure of larval supply and a breakdown of competitive advantage could accelerate the pace of predicted range contraction for S. balanoides. Further investigation of how environmental variables interact with physiology and ecological processes is necessary for accurate predictions of climate change effects

Temperature Effects On An Axon’S Ability To Maintain Phasing Of A Rhythmic Motor System, Marissa Elaine Cruz

Theses and Dissertations

The precise timing of action potentials generated in the nervous system is crucial for generating adequate behavior. Once generated, action potentials travel along axons towards the neurons or muscles they innervate. Axons are also responsible for preserving the temporal fidelity of the generated action potentials. One challenge axons face is that they can be of considerable length, and exposed to changes in internal and external conditions. Temperature fluctuations, for example, affect the ion channels that generate and propagate action potentials causing changes in action potential speed. It is unclear if, and how, the timing of action potentials can be preserved …

Effects Of The Developmental Environment On Oxidative Damage And Antioxidants In Red-Eared Slider Turtle ( Trachemys Scripta Elegans ) Hatchlings, Lisa Allison Treidel

Theses and Dissertations

Developmental environments influence many individual phenotypes. However, currently we have a limited understanding of how the developmental environment influences oxidative stress resistance phenotypes. Oxidative stress is defined as a physiological state during which the production of harmful free radicals exceeds the protective capabilities of antioxidants. Variations among adults in susceptibility to oxidative stress can have important consequences for life history strategies and fitness related traits. Our work was aimed at providing insight in to the role that the developmental environment plays on oxidative stress phenotypes in the model oviparous reptile the red-eared slider turtle (Trachemys scripta elegans). Here, we conducted …

Utah Red Raspberry Jam: The Effects Of Formulation, Heating, And Time On Color, Flavor, Texture, And Antioxidant Capacity, Jennifer Leigh Chase

Theses and Dissertations

The amount and type of antioxidants present in raspberries is dependent upon cultivar, ripeness, and growing conditions. Previous research on raspberry jam has reported some color, antioxidant, and flavor loss after processing and storage, though it is unknown to what extent similar changes will occur in raspberries grown in Utah. Sugar concentration and heating temperature as well as storage time were evaluated in an effort to maximize color retention, flavor, antioxidant content, shelf life, and consumer acceptance of Utah-grown raspberry jam. Four types of jams were processed in two batches each: low-sugar (40-42 Brix) and typical sugar (65-68 Brix) at …

Head-Start Juvenile And Adult Resident Eastern Box Turtles (Terrapene Carolina Carolina): Winter Ecology Including Microhabitat Selection, Temperature Tolerance And Philopatry, Amberly Moon

Theses and Dissertations

The Eastern box turtle (Terrapene carolina carolina) is one of the most common reptiles in North America, but is soon to be threatened due to increased urbanization, disease, and the pet and food trades. In order to assist resource managers in choosing suitable sites for relocation studies, more information on the winter ecology of this species is necessary. We examined the temperature tolerance, microhabitat and degree of philopatry to hibernacula for juvenile and adult E. box turtles for two consecutive winters in Charles City Co, VA. The turtles were tracked via radio telemetry to record point locations during the active …

Calorespirometric Evidence For Adaptation Of Blackbrush And Shadscale To Growth Season Temperatures In Cold Deserts, Heidi A. Summers

Theses and Dissertations

Coleogyne ramosissima Torr. (blackbrush) and Atriplex confertifolia [Torr. & Frem.] Wats. (shadscale) are cold desert shrubs from different families that often grow together in the Great Basin and the Colorado Plateau in the life zone between 800 and 2000 m elevation. Tissue and seeds from the two species were collected from several localities. Metabolic heat and carbon dioxide production rates were measured with calorespirometry on tissue from field-grown plants and on seedlings at temperatures from 5 to 35°C at 5°C intervals. Blackbrush adapts to higher temperatures earlier than does shadscale, and once it has adjusted to higher temperatures, anabolic rates …

Velocity And Temperature Characterization Of The First Vacuum Stage Expansion In An Inductively Coupled Plasma - Mass Spectrometer, William Neil Radicic

Theses and Dissertations

The inductively coupled plasma - mass spectrometer (ICP-MS) is the analytical instrument of choice for trace element detection and quantification. Despite the popularity of ICP-MS, significant degradation in sensitivity and precision occurs as the result of matrix and instrument-induced effects. The sources of these effects are not well understood, characterized, or correlated to particular plasma operating condition settings or matrix compositions and involve both neutral and charged species. The purpose of this study is to characterize the behavior of metastable Ar (I) atom and Ca (II) ion through the measurement of Doppler velocities and fluorescence line width "temperatures."

For the …

Epidemiology Of Ustilago Bullata Berk. On Bromus Tectorum L. And Implication For Biological Control, Toupta Boguena

Theses and Dissertations

The seedling-infecting pathogen Ustilago bullata Berk. is a naturally occurring biological control agent for cheatgrass (Bromus tectorum L.). The effects of temperature and nutrients on pathogen teliospore germination behavior and the effects of temperature on host seed germination were examined. The effects of temperature on sporidial proliferation, host infection in a temperature-controlled environment and in a field setting for eight populations were investigated. The infection success of Ustilago bullata on Bromus tectorum in cultivated fields as a function of seeding date, inoculation method, inoculum density, supplemental watering, and litter was also investigated. Teliospores germinated faster on potato dextrose agar than …