Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Graduate Theses and Dissertations

Discipline
Keyword
Publication Year

Articles 331 - 360 of 1741

Full-Text Articles in Life Sciences

Characterizing The Utility Of Atonik On Improving Rice Response To Herbicides, Srikanth Kumar Karaikal May 2023

Characterizing The Utility Of Atonik On Improving Rice Response To Herbicides, Srikanth Kumar Karaikal

Graduate Theses and Dissertations

Biostimulants can improve plant tolerance to abiotic stress by improving plant growth and development. Herbicides cause abiotic stress to crops shortly after application, which may affect yield. Preliminary tests showed that rice yield benefits from Atonik seed treatment or tank-mixture of Atonik with foliar herbicides. Experiments were conducted in the field and greenhouse to: (1) determine if seed treatment with Atonik improves rice tolerance to pre-plant herbicides; (2 and 3) evaluate the effect of Atonik seed treatment on rice response to pre-emergence and delayed pre-emergence herbicides; and (4) determine if Atonik improves crop safety of foliar-applied herbicides. Field studies were …

Go to article

Ecological, Evolutionary, And Temporal Dynamics Of Animal Mortality Events, Simon Patrick Tye May 2023

Ecological, Evolutionary, And Temporal Dynamics Of Animal Mortality Events, Simon Patrick Tye

Graduate Theses and Dissertations

Global declines of animal abundances are emblematic of the Anthropocene. Recent animal declines have increasingly involved more frequent and intense die-offs within populations, or mass mortality events (MMEs). These extreme demographic events can lead to rapid changes in biological communities, either by imperiling the affected population or influencing populations remaining within communities. To date, there is still limited information about the effects of predator MMEs on immediate ecological dynamics within communities and rapid evolutionary dynamics within remaining populations that may ensue. Moreover, few approaches exist to predict future occurrences of predator MMEs across broad spatial scales. To address these gaps, …

Go to article

An Ecological Perspective Of American Rodent-Borne Orthohantavirus Surveillance, Nathaniel Mull May 2023

An Ecological Perspective Of American Rodent-Borne Orthohantavirus Surveillance, Nathaniel Mull

Graduate Theses and Dissertations

Orthohantaviruses are a global group of viruses found primarily in rodents, though several viruses have also been found in shrews and moles. Many rodent-borne orthohantaviruses are capable of causing one of several diseases in humans, and the mortality associated with these diseases ranges from < 0.1% - 50% depending on the specific etiological virus. In North and South America, orthohantavirus research was ignited by an outbreak of severe disease in the Four Corners region of the United States in 1993. However, despite the discovery of over 20 orthohantaviruses in the Americas, our understanding of orthohantavirus ecology and virus-host dynamics in this region is still limited, and orthohantavirus surveillance is generally restricted in scope to select regions and small portions of host distributional ranges. In Chapter I, I present a literature review on the current understanding of American rodent-borne orthohantavirus ecology. This review focused on under-studied orthohantaviruses, addressing gaps in knowledge by extrapolating information from well-studied orthohantaviruses, general rodent ecology, and occassionally from Eurasian orthohantavirus-host ecology. There were several key conclusions generated from this review that warrant further research: 1) the large number of putative orthohantaviruses and gaps in orthohantavirus evolution necessitate further surveillance and characterization, 2) orthohantavirus traits differ and are more generalizable based on host taxonomy rather than geography, and 3) orthohantavirus host species are disproportionately found in grasslands and disturbed habitats. In Chapter II, I present a prioritized list of rodent species to target for orthohantavirus surveillance based on predictive modeling using machine learning. Probable orthohantavirus hosts were predicted based on traits of known orthohantavirus hosts using two different types of evidence: RT-PCR and virus isolation. Predicted host distributions were also mapped to identify geographic hotspots to spatially guide future surveillance efforts. In Chapter III, I present a framework for understanding and predicting orthohantavirus traits based on reservoir host phylogeny, as opposed to the traditional geographic dichotomy used to group orthohantaviruses. This framework establishes three distinct orthohantavirus groups: murid-borne orthohantaviruses, arvicoline-borne orthohantaviruses, and non-arvicoline cricetid-borne orthohantaviruses, which differ in several key traits, including the human disease they cause, transmission routes, and virus-host fidelity. In Chapter IV, I compare rodent communities and orthohantavirus prevalence among grassland management regimes. Sites that were periodically burned had high rodent diversity and a high proportion of grassland species. However, rodent seroprevalence for orthohantavirus was also highest in burned sites, representing a trade-off in habitat management outcomes. The high seroprevalence in burned sites is likely due to the robust populations supported by the high quality habitat resulting from prescribed burning. In Chapters V and VI, I describe Ozark virus and Sager Creek virus, two novel orthohantaviruses discovered from specimens collected during Chapter IV. Both chapters report full genome sequences of the respective viruses and compare both nucleotide and protein phylogenies with related orthohantaviruses. Additionally in Chapter VI, I support the genetic analyses with molecular and ecological characterizations, including seasonal fluctuations in host abundance, correlates of prevalence, evidence of virus shedding, and information on host cell susceptibility to Sager Creek virus.

Go to article

Factors That Affect Home Range Of Timber Rattlesnakes (Crotalus Horridus) In Northwest Arkansas, Bannon Gallaher May 2023

Factors That Affect Home Range Of Timber Rattlesnakes (Crotalus Horridus) In Northwest Arkansas, Bannon Gallaher

Graduate Theses and Dissertations

Conservation of animal populations requires knowledge of their habitat and spatial needs. Quantifying spatial requirements involves the analysis of home range. We examined the effects of sex, body size (SVL), body condition (log mass/log SVL), and year on home range in Timber Rattlesnakes (Crotalus horridus) in Northwest Arkansas. Individual locality data from an ongoing, 22+ year radio-telemetry study in Madison Co., Arkansas were analyzed using both minimum convex polygon (MCP) and Kernel Density Estimates (KDE). Plots of the number of sequential observations versus home range (MCP and KDE) determined that a minimum of 25 locations per individual per active season …

Go to article

Effects Of Landscape And Yard Features On Mammals In Residential Yards In Northwest Arkansas, Emily Johansson May 2023

Effects Of Landscape And Yard Features On Mammals In Residential Yards In Northwest Arkansas, Emily Johansson

Graduate Theses and Dissertations

The human footprint is rapidly expanding, and wildlife habitat is continuously being converted to human residential properties. Most wildlife residing in developing areas are displaced to nearby undeveloped areas. However, some animals can coexist with humans and acquire the necessary resources (food, water, shelter) within the human environment. This may be particularly true when development is low intensity, as in suburban yards. Due to the wide variety in how homeowners utilize their yards, they can be considered individually managed “greenspaces.” These yards can provide a range of food (e.g., bird feeders, compost, gardens), water (bird baths and garden ponds), and …

Go to article

Ecology, Evolution, And Gene Transfer Between Diatoms And Bacteria, Cory B. Gargas May 2023

Ecology, Evolution, And Gene Transfer Between Diatoms And Bacteria, Cory B. Gargas

Graduate Theses and Dissertations

Although photosynthetic macro-eukaryotes (i.e., plants) make up the majority of organic biomass on earth, bacteria are the second largest taxonomic group, by biomass. Bacteria are ubiquitous in our environment, living on, and within, man-made surfaces, natural environments, and eukaryotes themselves. The relationship between bacteria and eukaryotes has existed from the very beginning of eukaryotic life in the form of bacterial endosymbioses that resulted in mitochondria and plastids. Other eukaryote–bacteria relationships have evolved since then, ranging from the beneficial (e.g., mutualistic) to harmful (e.g., parasitic or pathogenic). Understanding these eukaryote–bacteria relationships is key to understanding both the evolution of important ecosystem …

Go to article

Biology, Monitoring, Sampling, And Management Of Rice Billbug, Sphenophorus Pertinax, In Furrow-Irrigated Rice, Chase Alan Floyd Dec 2022

Biology, Monitoring, Sampling, And Management Of Rice Billbug, Sphenophorus Pertinax, In Furrow-Irrigated Rice, Chase Alan Floyd

Graduate Theses and Dissertations

Furrow-irrigated rice hectares have increased annually for the last five years in the predominant long-grain rice producing states. Initial implementation of the system began in the 1980’s, but lack of rice blast (Magnaporthe grisea, Hebert) resistant cultivars made the system a nonviable option for rice producers. Hybridization of rice cultivars with less susceptibility has begun to increase the interest of producers to implement a furrow-irrigated rice production system due to the cost saving opportunities that it may provide. Elimination of the flood from large sections of the rice fields in a furrow-irrigated system alters management strategies and pest complexes compared …

Go to article

Evaluation Of Biological And Chemical Seed Treatments For Management Of Rice Diseases, Sherif Adam Sharfadine Dec 2022

Evaluation Of Biological And Chemical Seed Treatments For Management Of Rice Diseases, Sherif Adam Sharfadine

Graduate Theses and Dissertations

Rice is the primary staple for more than half of the global population and is the second most important cereal worldwide. In the US, rice is primarily grown in the southern states, with Arkansas leading production and responsible for 47% of the total rice production in the country. Diseases cause significant yield losses in rice. Sheath blight, rice blast and bacterial panicle blight are the main diseases in rice and cause significant yield losses. Sheath blight alone could cause up 50% yield loss in heavily damaged fields with highly susceptible cultivars. Additionally, rice seed and seedling diseases primarily caused by …

Go to article

Evaluation Of Chrysodeixis Includens Nucleopolyhedrovirus (Chinnpv) Formulations For Soybean Looper (Chrysodeixis Includens) Control In Soybean, Caleb Robert Rice Dec 2022

Evaluation Of Chrysodeixis Includens Nucleopolyhedrovirus (Chinnpv) Formulations For Soybean Looper (Chrysodeixis Includens) Control In Soybean, Caleb Robert Rice

Graduate Theses and Dissertations

Chrysodeixis includens Nucleopolyhedrovirus (ChinNPV) specifically Chrysogen, has been commercially available in South America since 2016 but is not current available in the U.S. Chrysogen targets soybean looper (Chrysodeixis includens) (SBL), the major defoliator of soybean (Glycine max (L.) Merrill) in the mid-southern region of the U.S. Experiments were conducted during the 2020 and 2021 growing seasons to evaluate effectiveness of three formulations of Chrysogen at multiple rates for control of SBL. Soybean looper larvae used for following experiments were kept in an insect incubator at the University of Arkansas Lonoke Research and Extension Center. The first objective was to evaluate …

Go to article

Loan Survival: Are Socially Disadvantaged Farmers More Likely To Default Or Pay In Full?, Marie-Cécile Vekemans Dec 2022

Loan Survival: Are Socially Disadvantaged Farmers More Likely To Default Or Pay In Full?, Marie-Cécile Vekemans

Graduate Theses and Dissertations

This study aims at identifying racial and gender discrimination in the usage of credit for Socially Disadvantaged Farmers and Ranchers (SDFR) in the United States. Usage of credit is considered successful when a loan has been paid in full and a failure is considered when the borrower defaults. Identifying such a pathway would provide useful information to the Federal government United States Department of Agriculture (USDA) Farm Service Agency (FSA) to evaluate the effectiveness and equity of loan programs. This study uses data from the USDA FSA farm loan programs that mainly target socially disadvantaged farmers and other underserved groups. …

Go to article

Isolation Of Drug-Sensitive Eimeria Species From Wild Turkey Feces And Development Of A Model Bioshuttle Program For Eimeria Meleagrimitis For Domestic Turkeys, Maria Carolina Trujillo Peralta Dec 2022

Isolation Of Drug-Sensitive Eimeria Species From Wild Turkey Feces And Development Of A Model Bioshuttle Program For Eimeria Meleagrimitis For Domestic Turkeys, Maria Carolina Trujillo Peralta

Graduate Theses and Dissertations

The objective of this thesis was to determine the anticoccidial profile of Eimeria spp. derived from wild turkeys. These drug-sensitive Eimeria spp. have potential to be used as vaccine candidates to control coccidiosis in commercial turkeys. Chapter two consists of a brief literature review focused on coccidiosis in turkeys. Chapter three addresses the methodologies utilized to isolate, recover, and speciate Eimeria recovered from wild turkey feces in the eastern two-thirds of the United States. From this, we successfully obtained single oocyst-derived stocks for E. meleagrimitis, E. dispersa, E. meleagridis, E. gallopavonis, and E. adenoeides. Chapter four describes the experiment conducted …

Go to article

Understanding The Potential Utility Of Tamarktm Grain Sorghum, Jacob Alan Fleming Dec 2022

Understanding The Potential Utility Of Tamarktm Grain Sorghum, Jacob Alan Fleming

Graduate Theses and Dissertations

Herbicide-resistant crops have been commonly used in corn, cotton, and soybean since the 1990s to control numerous different grass and broadleaf weeds. However, this technology has not been available for grain sorghum producers whom have faced challenges controlling grass weeds. Recently a collaboration between the University of Arkansas and Texas A&M University has resulted in a new bred line of grain sorghum, TamArkTM, which is resistant to ACCase inhibitor herbicides which have been previously used to control grass weeds in broadleaf crops. Multiple studies were conducted to determine the sensitivity of TamArkTM and problematic grass weeds to ACCase inhibitor herbicides, …

Go to article

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer Dec 2022

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer

Graduate Theses and Dissertations

The effect of Spirulina platensis inclusion in feed of commercial broilers was evaluated over one experiment. The study aimed to investigate the effects of Spirulina platensis freshwater algae inclusion on live performance and processing characteristics of commercial broilers subjected to daily cyclic heat stress. Day old Ross 708 male broilers were placed into 8 environmentally controlled chambers. At d 21, four chambers remained on a control diet containing no algae (CON) while 4 chambers received a diet that included algae at an inclusion rate of 2.5% (ALG). An 8 hour daily cyclic heat stress (24°C to 36°C) was applied to …

Go to article

Applying A Material Science Approach To Improve Rice Processing Performance, Michelle Oppong Siaw Dec 2022

Applying A Material Science Approach To Improve Rice Processing Performance, Michelle Oppong Siaw

Graduate Theses and Dissertations

Rice is typically consumed as whole kernel, which makes the economic value of whole kernels twice that of brokens. Macro-structural defects such as fissures and chalkiness have been recognized to weaken kernel mechanical strength, and thereby increase breakage during milling. However, high percentages of brokens are sometimes recorded even though these defects are controlled prior to milling. It was hypothesized that rice milling characteristics are influenced by endosperm porosity from the structural arrangement of chemical components and by bran thickness and composition. Thus, this study aimed to modify chemical components by applying treatments to alter rice porosity and its associated …

Go to article

The Antimicrobial Resistance Plasmid Mobilome Of Salmonella Enterica And Related Enteric Species And Factors That Influence The Transfer Efficiency., Suad Algarni Dec 2022

The Antimicrobial Resistance Plasmid Mobilome Of Salmonella Enterica And Related Enteric Species And Factors That Influence The Transfer Efficiency., Suad Algarni

Graduate Theses and Dissertations

The dynamic distribution of antimicrobial resistance genes in Salmonella enterica is considered a public health risk. S. enterica is one of the most important etiological agents of foodborne illness and has a critical impact on global human health. In S. enterica and related species, mobile genetic elements (MGEs) serve as primary vehicles for the dissemination of antibiotic resistance genes in the bacterial evolution. This dissemination can be impacted by different selective pressures that leads to diverse antibiotic response phenotypes. This project focusses on the dynamics of antimicrobial resistance genes, particularly exploring the transfer efficiency of multidrug resistance plasmids in S. …

Go to article

Optimization Of Clostridium Septicum Antigen Production And Evaluation Of Vaccine Administration Parameters For A Candidate Bacterin-Toxoid To Prevent Dermatitis In Commercial Turkeys, Aaron Forga Dec 2022

Optimization Of Clostridium Septicum Antigen Production And Evaluation Of Vaccine Administration Parameters For A Candidate Bacterin-Toxoid To Prevent Dermatitis In Commercial Turkeys, Aaron Forga

Graduate Theses and Dissertations

The objective of this thesis was to optimize the hemolytic activity of two isolates of Clostridium septicum to evaluate if hemolytic titer of C. septicum antigen at time of formalin inactivation corresponded to increased serum antibody titer to the C. septicum alpha-toxin of turkeys immunized with an experimental formalin inactivated bacterin-toxoid vaccine. Chapter 1 provides a brief overview of the thesis. Chapter 2 consists of a literature review focused on clostridial dermatitis, specifically C. septicum-associated dermatitis (cellulitis) that affects commercial turkeys. Chapter 3 outlines our attempts to optimize an experimental autogenous bacterin-toxoid vaccine as a potential strategy to mitigate clostridial …

Go to article

Differential Impacts Of Hhv-6a Versus Hhv-6b Infection In Differentiated Human Neural Stem Cells, Elham Bahramian Dec 2022

Differential Impacts Of Hhv-6a Versus Hhv-6b Infection In Differentiated Human Neural Stem Cells, Elham Bahramian

Graduate Theses and Dissertations

Within the family Herpesviridae, sub-family β-herpesvirinae, and genus Roseolovirus, there areonly three human herpesviruses that have been described: HHV-6A, HHV-6B, and HHV-7. Initially, HHV-6A and HHV-6B were considered as two variants of the same virus (i.e., HHV6). Despite high overall genetic sequence identity (~90%), HHV-6A and HHV-6B are now recognized as two distinct viruses. Sequence divergence (e.g., >30%) in key coding regions and significant differences in physiological and biochemical profiles (e.g., use of different receptors for viral entry) underscores the conclusion that HHV-6A and HHV-6B are distinct viruses of the β-herpesvirinae. Despite these viruses being implicated as causative agents in …

Go to article

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms Dec 2022

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Go to article

Thermal Inactivation Kinetics Of Salmonella In Milk Powder As Impacted By Water Activity And Powder Type, Erika Litta Kadas Dec 2022

Thermal Inactivation Kinetics Of Salmonella In Milk Powder As Impacted By Water Activity And Powder Type, Erika Litta Kadas

Graduate Theses and Dissertations

Historically, low-water activity (aw) foods (aw <0.65) were considered to be microbiologically safe for consumption. However, these foods have been implicated in outbreaks of pathogens such as Salmonella enterica, at a frequency that surely challenges this assumption of safety. Although usually implicated in outbreaks involving poultry and egg products, Salmonella spp. have frequently been the culprit in several outbreaks and recalls associated with low-water activity foods (LWAF) due to contamination resulting from the environment, animals, or even the employees during pre-or post-processing. One such LWAF that has been associated with Salmonella spp. outbreaks is milk powder. Milk powders are used in a variety of products ranging from infant formula to confectionary goods. With their widespread use, improving their safety is imperative. A key step in improving their safety is to thoroughly investigate preventive controls related to milk powder processing. The Food Safety Modernization Act (FSMA) established the Preventive Controls for Human Foods Rule, which mandates that processors design and establish a food safety plan outlining any potential hazards and the steps they will take to ensure those hazards do not compromise the safety of the product. Presently, the dairy industry does not have an established kill-step for milk powders post-spray drying. Spray drying may reduce some microbial populations, however, desiccation(e.g., spray drying) is not considered a kill-step. The work outlined in this thesis aims to assist our dairy industry partners in establishing their own thermal process for milk powders post-spray drying. Moisture sorption isotherms of two milk powders (nonfat dry milk: NFDM and a milk protein concentrate with 85% protein content: MPC-85) were determined and showcased that the temperatures at which the isotherms were determined (23, 40, or 60°C) significantly affected both the adsorption and desorption isotherms (p<0.0001) for each powder. Secondly, the thermal inactivation kinetics of Salmonella spp. in both powders were evaluated at two different water activities (0.20 and 0.30) and three temperatures (75, 80, and 85°C) to determine the effect of water activity on the thermal resistance of a cocktail of Salmonella spp. The D-values of Salmonella were heavily influenced by the thermal treatment temperature (p< 0.0001), but not the water activity (p >0.05). The overall findings contained within this thesis provide valuable information about the thermal inactivation kinetics of Salmonella spp. to our partners in the dairy industry so that they may implement an appropriate thermal process for their milk powders.

Go to article

Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa Dec 2022

Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa

Graduate Theses and Dissertations

Researchers in chemistry and biology often utilize computer simulations, in conjunction with experimental data, to model and predict the structures, energies, kinetics, processes, and functions of the systems that are their focus of study, ranging from single molecules to whole viruses. Here, we use molecular dynamics (MD) techniques to gain a deeper understanding of biomolecular processes in biology and biotechnology-oriented applications. Using a mixture of equilibrium and non-equilibrium MD simulations, this work describes the insertion process of YidC at the atomic level. In order to better comprehend the insertion process, several docking models of YidC-Pf3 in the lipid bilayer were …

Go to article

Cross-Modal Associations Between Hand-Feel Touch And Oral Irritation, Ragita Cantika Pramudya Dec 2022

Cross-Modal Associations Between Hand-Feel Touch And Oral Irritation, Ragita Cantika Pramudya

Graduate Theses and Dissertations

Hand-feel touch cues have been shown to influence the perception of other sensory modalities and can be used as means to create expectations toward food or beverage products presented concurrently with such cues. However, to date, there has been limited research on how these hand-feel touch cues could impact oral irritation elicited by capsaicin-containing products. Because oral irritation sensation is a dynamic perception lasting a period of time, temporal methodologies, such as Time-Intensity (TI) and Temporal-Check-All-That-Apply (TCATA), must be used when evaluating capsaicin-containing products. The use of temporal methodologies when examining the cross-modal effects of other cues on capsaicin irritation …

Go to article

Enhancing Amino Acid Utilization For Broiler Chickens Under Different Scenarios Of Dietary Protein Reduction And Subclinical Coccidiosis, Derrell Trevor Lee Dec 2022

Enhancing Amino Acid Utilization For Broiler Chickens Under Different Scenarios Of Dietary Protein Reduction And Subclinical Coccidiosis, Derrell Trevor Lee

Graduate Theses and Dissertations

Five experiments were conducted to evaluate responses of broiler chickens fed diets with different dietary amino acid (AA) levels when fed normal and reduced dietary crude protein (RCP) diets and reared under different coccidiosis control programs. In the studies with the use of RCP diets, the relationship between dietary Gly + Ser and the Met:Cys ratio was investigated. Experiment 1 evaluated broilers in 2 coccidiosis control programs (live vaccine or in-feed zoalene) and fed increased dietary AA derived from soybean meal or unbound sources from 0-40 d. Vaccination impaired young (0-26 d) broiler body weight gain (BWG) and feed conversion …

Go to article

In-Field And Greenhouse Assessments Of A Selection Of Preemergent Herbicides On Newly Planted Blackberries, Kayla Knepp Dec 2022

In-Field And Greenhouse Assessments Of A Selection Of Preemergent Herbicides On Newly Planted Blackberries, Kayla Knepp

Graduate Theses and Dissertations

This field trial assesses some of the preemergence herbicide options available to growers and their effect on newly transplanted blackberries (Rubus L. subgenus Rubus Watson). Weed control has recently been surveyed as a top priority for blackberry growers; however, limited preemergence herbicides are registered for new blackberry plantings. Weed control is an ongoing component of blackberry production and with few in-season postemergence herbicide options available, growers rely on preemergence herbicides to maintain clean fields. The preemergent herbicides assessed in this trial were chosen with the intention to broaden the chemical control options available to growers in new plantings. A two-year …

Go to article

The Role Of Microbiota-Biotransformed Bile Acid Metabolites On Campylobacter Jejuni- And Clostridium Perfringens-Infection, Ying Fu Dec 2022

The Role Of Microbiota-Biotransformed Bile Acid Metabolites On Campylobacter Jejuni- And Clostridium Perfringens-Infection, Ying Fu

Graduate Theses and Dissertations

Campylobacter jejuni (C. jejuni) and Clostridium perfringens (C. perfringens) are two leading pathogenic bacteria responsible for both human and animal diseases. In chapters Ⅱ to Ⅳ, I presented an overview of current knowledge on the role of immune response, microbiota, bile acids and their microbial metabolites on campylobacteriosis, and C. perfringens induced necrotic diseases.In chapter Ⅴ, I investigated effects of deoxycholic acid-modulated anaerobes (DCA-Anaero) on attenuating chicken transmission-exacerbated campylobacteriosis. SPF Il10-/- mice were gavaged with clindamycin for 7 days followed by infected with three C. jejuni strains, Cj-P0 (C. jejuni AR101), Cj-P1 (from chicken pre-infected with C. jejuni AR101), and …

Go to article

Amino Acid Nutrition In Broiler Breeders, Jordan Weil Dec 2022

Amino Acid Nutrition In Broiler Breeders, Jordan Weil

Graduate Theses and Dissertations

Amino acids (AA) are commonly referred to as the building blocks of protein due to their role in the synthesis of proteins. Considering these nutrients are involved in growth and metabolism, much emphasis is placed on determining the dietary requirements of amino acids. Therefore, an experiment was conducted to evaluate the amino acid requirements of performance parameters such as egg weights, egg production, egg mass, feed conversion ratios, and body weight gain in two age groups of broiler breeders. In this experiment, 648 Cobb 700 broiler breeder hens were placed in individual cages to determine the amino acid requirements of …

Go to article

A Study On Interactions Between Metal-Organic Frameworks And Biological Materials, Josh Phipps Dec 2022

A Study On Interactions Between Metal-Organic Frameworks And Biological Materials, Josh Phipps

Graduate Theses and Dissertations

Metal-organic frameworks or MOFs are an extremely useful tool in many areas of applications. Their popularity in recent years has arisen from their high efficiency in catalytic chemical reactions. This is made possible due to their porous interior and the ability of the MOFs components to be functionalized. These same traits make MOFs excellent for use in protein encapsulation or immobilization and have the potential to become excellent drug carriers. Their development in this utilization has been limited dramatically compared to MOFs chemical applications. This is due in part to the nature of biological processes taking longer to study, but …

Go to article

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban Dec 2022

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban

Graduate Theses and Dissertations

Nitrogenase is the metalloenzyme only found in bacteria and archaea that is essential for biological nitrogen fixation (diazotrophy), but it can also serve as a catalyst in biofuel production. All diazotrophs contain a molybdenum (Mo) nitrogenase, while some species contain additional alternative nitrogenases where either vanadium (V) or iron (Fe) replace Mo in the active site cofactor. Nitrogen fixation by bacteria has been extensively studied. The limited investigation of nitrogen fixation in methanogenic archaea (methanogens) indicates production of nitrogenase is simpler than in bacteria and methanogen nitrogenase has different biochemical properties. Thus, methanogen nitrogenases provide a promising alternative for genetic …

Go to article

Hypothesis Testing And Parameter Estimation In Mixture Cure Models For Cancer Survival Data, Mohammod Mahmudur Rahman Dec 2022

Hypothesis Testing And Parameter Estimation In Mixture Cure Models For Cancer Survival Data, Mohammod Mahmudur Rahman

Graduate Theses and Dissertations

In oncology clinical trials, when a treatment is administered to the patient population, a certain subset of patients may respond to the treatment while the other does not. The positive responders with long-term survival are considered “statistically cured” and can be referred to as cured patients or long-term survivors. When a proportion of patients achieve long-term survival, the hazard functions of two arms (control vs. treatment) are no longer proportional. As a result, the traditional log-rank test, which is the most popular test to evaluate the effectiveness of a treatment in clinical trials, tends to lose its power. In this …

Go to article

Identification Of Possible Vectors For Histomoniasis In Turkeys On Commercial Farms In Arkansas And Oklahoma, Treva Dillon Dec 2022

Identification Of Possible Vectors For Histomoniasis In Turkeys On Commercial Farms In Arkansas And Oklahoma, Treva Dillon

Graduate Theses and Dissertations

Histomonas meleagridis, is a parasitic protozoan, commonly found in the gallinaceous species of birds and is the causative agent of Blackhead disease. The cecal worm, known as Heteraskis gallinarum, acts as a vector in the spread of H. meleagridis in gallinaceous birds. H. meleagridis develops inside the cecal worm and in its eggs which allows H. meleagridis a method to survive in the environment. Blackhead disease causes high mortality rates in both chickens and turkeys; however, turkeys are noted to have a higher mortality rate compared to chickens. Molecular diagnostic testing such as PCR has been developed by creating primers …

Go to article

Comparative Analysis Of Conformational Transition Pathways In Homologous Proteins, Dylan Sebastien Ogden Dec 2022

Comparative Analysis Of Conformational Transition Pathways In Homologous Proteins, Dylan Sebastien Ogden

Graduate Theses and Dissertations

Molecular dynamics (MD) simulations are routinely used to study the dynamics of proteins. However, conventional MD limited to the sampling of local conformational changes as the functionally important conformational transitions of proteins often extend beyond the timescales of the simulations employed, for example, membrane transport proteins. We have determined the combination of multiple MD based techniques that allows for a rigorous characterization of energetics and kinetics of large-scale conformational changes in membrane proteins. The methodology is based on biased, nonequilibrium collective variable based simulations including nonequilibrium pulling, string method with swarms of trajectories, bias-exchange umbrella sampling, and rate estimation techniques. …

Go to article

First Prev Next Last