Life Sciences Commons^™

Characterization Of Histone Mutants Associated With Mitotic Defects In Saccharomyces Cerevisiae, Md Riajul Hossain

Graduate Theses and Dissertations

Nucleosomes, the basic unit and the building blocks of chromatin have an essential role in the tight packaging of DNA into higher order chromatin. Work from our lab and others have provided information on the contributions of different histone proteins and specific domains within the nucleosome made to create the centromeric chromatin structure required for normal chromosome segregation during mitosis. The DNA entry/exit site is a particular region of the nucleosome where histone H2A, H3 and H4 form critical interactions that appear to be essential for the association of Sgo1, a tension sensing protein that monitors kinetochore-microtubule attachment. In our …

High Throughput Phenotypic Evaluation Of Drought-Related Traits In Soybean, Hua Bai

Graduate Theses and Dissertations

Drought limits crop growth and yield in soybean. Rapid and effective methods of screening large numbers of soybean lines for drought tolerance are urgently needed. Two experiments were conducted to evaluate the effects of drought in soybean during reproductive stages. In the first experiment five genotypes from maturity groups 2 through 5 were tested under well-irrigated and drought conditions. Beginning at R5, leaf samples were taken for nitrogen concentration analysis. Pictures were taken across the top of each plot to determine the intensity of greenness using the Dark Green Color Index (DGCI). Aerial photographs were also taken to determine aerial …

Rice Consumption And Effects Of Rice Cake, Seolgitteok, On Human Health, Ellen Joy Pottgen

Graduate Theses and Dissertations

Within the United States type 2 diabetes is an ever growing health epidemic. The prevalence in the adult population has quadrupled over the past 30 years and is expected to continue on a similar path in the coming decades. While the cause of type 2 diabetes is multifactorial, it is considered to be an acquired condition related to environmental contributors including poor diet, obesity, and physical inactivity, which may be managed to alter the course or progression of the disease. Preventative or maintenance measures emphasize nutritional intervention strategies, including encouraging individuals to follow a nutrient-dense, high-fiber diet with ample whole-grains, …

Microbes In Rough Rice – Prevalence, Growth Kinetics And Links To Dry Matter Loss, Supriya Thote

Graduate Theses and Dissertations

The prevalence of microorganisms on freshly-harvested long-grain hybrid, long-grain pureline, and medium-grain rice has not been elucidated. The first objective of this two-part study was to determine the relative prevalence of microbes on freshly-harvested, high moisture content rice of different types and cultivars. The total and surface aerobic plate counts (APC) and mold counts were determined in terms of log10 colony forming units per gram of rice (log10 CFU/g) for six rice cultivars over two years. In 2013, among harvested samples of all the studied rice cultivars, the long-grain hybrid cultivars had the lowest APC levels (M = 8.10, SD …

Characterization Of Broiler Lines Divergently Selected For Breast Muscle Color, Sara Katherine Orlowski

Graduate Theses and Dissertations

An increase in the consumption of poultry has generated an increase in demand for higher yielding broilers. This has led to an increase in atypical meat and issues with appearance. Color is a direct result of a pH decline as meat goes through rigor mortis with meat generally becoming lighter. If the pH declines too rapidly or too slowly, meat quality can suffer. Physical properties of meat can be altered by pH. A fast pH decline results in pale meat with decreased tenderness. A slow pH decline can result in darker meat with a reduced shelf-life. With a known relationship …

In Vitro Fermentation Patterns Of Rice Bran Components By Human Gut Microbiota, Tung Minh Pham

Graduate Theses and Dissertations

The prevalence of colorectal cancer (CRC) has been increasing in recent years worldwide. In the United States, it is ranked the second leading cause of cancer death. Risks of CRC increase with age and are associated with several lifestyle factors such as diet, drinking and smoking habits, and levels of physical activity. There is an abundance of scientific literature demonstrating the protective roles of several dietary components including fibers and polyphenolic compounds. These compounds have been shown to be able to positively modulate gastrointestinal ecology by increasing the production of short-chain fatty acids (SCFA) and promoting the population of beneficial …

Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson

Graduate Theses and Dissertations

In the past decade, 29 shale basins have been actively developed across 20 states for extraction of natural gas (NG) via horizontal drilling/hydraulic fracturing (=fracking). This includes ~5000 wells within the Fayetteville shale of north-central Arkansas. Development often impacts both river- and landscapes, and management requires catchment-level evaluations over time, with organismal presence/absence as indicators. For this study next-generation sequencing was used to identify/characterize microbial communities within biofilm of eight Arkansas River tributaries, so as to gauge potential catchment influences. Streams spanned a gradient of landscape features and hydrological flows, with four serving as ‘potentially impacted catchment zones’ (PICZ) and …

Applications Of The Gst- Affinity Tag In The Purification And Characterization Of Proteins, Wibke Beatrice Kachel

Graduate Theses and Dissertations

With the latest innovations in biological sciences, large quantities of biologically active polypeptides as well as high throughput screening methods to quickly evaluate if these biomolecules potentially have therapeutic, diagnostic, or industrial purposes are required. The synthesis and purification of peptides and small proteins continue to be demanding as the production of high yields through chemical synthesis can involve large costs. On the other hand, there are only few examples of acquiring those biomolecules through cloning and expression in bacterial systems in form of recombinant fusion proteins. Glutathione S-Transferase (GST) is not only a very commonly used affinity tag to …

Innate Immunity In Chickens: In Vivo Responses To Different Pathogen Associated Molecular Patterns, Kristen Alicia Byrne

Graduate Theses and Dissertations

Pattern recognition receptors (PRRs) on host cells recognize motifs known as pathogen associated molecular patterns (PAMPs) that are common to groups of microbes. Examples include LPS on Gram-negative bacteria, the structural motif PGN common to all bacteria, MDP the smallest immunostimulatory unit of PGN, and poly I:C the dsRNA analog. PAMP recognition by and stimulation of the innate immune system is crucial to an individual’s ability to quickly limit microbial growth and stimulate the adaptive immune system. Characterization of the in vivo immune responses initiated by PAMPs has not been directly addressed. Using growing feathers (GF) as a novel intradermal …

Listeria Monocytogenes Strain Variation: Starvation, Metabolism, And Macrophage Survival, Nathan A. Jarvis

Graduate Theses and Dissertations

Listeria spp. are often isolated from raw and processed food products. Listeria monocytogenes is responsible for death rates of 10 to 30% in immune compromised people; it can also infect a vast range of animals. There are numerous reports of poultry harboring or becoming infected with L. monocytogenes. First, this research assessed the ability of L. monocytogenes to replicate within chicken macrophages. Using the gentamicin-killing assay, a cell culture of chicken macrophage-like cells (HD11) were infected with two strains of L. monocytogenes individually (EGD-e and Scott A). Results show that unlike data on mouse macrophages, intracellular L. monocytogenes do not …

Assessment Of The Level Of Protection Against Coccidiosis In Broiler Breeders Conferred By A Live Anticoccidial Vaccine, And Its Influence On Early Growth And Development., Muhammed Shameer Abdul Rasheed

Graduate Theses and Dissertations

Coccidiosis continues to be a great challenge to the poultry industry all over the world and in broiler breeders vaccination with live oocysts of Eimeria has been widely adopted as a control measure. Broiler breeders are usually subjected to feed restriction during their early growth however no studies have been undertaken on the effects of vaccination in birds whose feed has been restricted in this manner. The objective of this study was to assess the level of protection acquired by broiler breeder chickens when immunized at day-old with live eimerian oocysts and given a restricted diet. Effects upon growth and …

Long-Term Supplementation With Leucine Does Not Prevent Development Of Obesity In Rats Fed A High-Fat Diet, Dameon Smith

Graduate Theses and Dissertations

Excess dietary fat consumption has been implicated in the development of obesity and diabetes. Obesity can be characterized by a disproportionate increase in fat mass compared to lean body mass. However, if muscle mass can be increased or maintained in obesity, this may facilitate weight loss by increasing the body’s overall metabolic capacity. Historically, supplementation with the branched-chain amino acid leucine has been shown to increase muscle protein synthesis via the protein kinase mTORC1. Recent studies suggest that supplementation with leucine also has the potential to reduce weight gain and fat deposition in high-fat fed, obese mice. The objective of …

Genetic Basis Of Biosynthesis And Cytotoxic Activity Of Medicago Truncatula Triterpene Saponins, Brynn Kathleen Lawrence

Graduate Theses and Dissertations

Saponins are a large family of specialized metabolites produced in many plants. They can have negative effects on a number of plant pests and are thought to play a role in plant defense. With current and possible future uses in industry and agriculture, saponins have also been shown to be hypocholesterolemic, hypoglycemic, immunostimulatory, antioxidative, anti-inflammatory, and cytotoxic. In spite of their usefulness, our understanding of the genetic basis for saponin biosynthesis is still incomplete. We generated recombinant populations with parents from genetically distinct accessions of Medicago truncatula, with either high or low accumulation and varying profiles of saponins. Primers for …

Phenotypic And Gene Expression Analysis Of Diverse Rice Genotypes In Response To Drought, Miranti Rahmaningsih

Graduate Theses and Dissertations

Drought is one of the most limiting factors for rice (Oryza sativa L.) growth and development with vegetative and reproductive stages the most sensitive and distinct phases. During the vegetative stage, drought can cause reduction in growth and biomass accumulation. Moreover, water stress at reproductive stage can reduce yield significantly. Plants are protected against drought by three different mechanisms: drought avoidance, drought tolerance, and drought escape. An integrated approach combining physiology, breeding, and genomics could be an effective way to characterize and mitigate this problem. The objectives of this research were to (1) screen a diverse set of rice genotypes …

Determination Of Optimum Fall And Spring Nitrogen Fertilizer Rate For Maximizing Grain Yield Of Soft Red Winter Wheat Sown At Variable Planting Dates, Lucas Vasconcelos Vieira

Graduate Theses and Dissertations

An optimum planting date is important for winter wheat nitrogen (N) management as it dramatically changes the growing environment including temperature and moisture, ultimately affecting fertilizer efficiency and grain yield (GY). In Arkansas, high precipitation in the fall often forces farmers to delay planting and current Arkansas recommendations include the application of fall N when soft red winter wheat (SRWW) is sown later than optimum, despite the lack of data supporting this practice. This study evaluated the effect of rate and timing of N application on GY of SRWW sown at variable planting dates in Arkansas. Granular urea was split …

The Impact Of Crop Insurance On Indonesian Rice Production, Zaura Fadhliani

Graduate Theses and Dissertations

This study builds a theoretical model of the yield-based MPCI crop insurance policy for a risk averse rice farmer in Indonesia and presents the comparative statics analysis of policy variables on yield through the coupling, wealth, and insurance effects. Moreover, Using yield data from 1979 to 2014 for the Tuban Regency, this study applies numerical optimization to the model and simulates the effects of different policies on input use, certainty equivalents, indemnity payment, and premiums. The theoretical analysis shows that no coupling effect exists for change in the coverage level, while a coupling effect exists for change in the subsidy …

Characterization Of Echinochloa Spp. In Arkansas, Hussain Tahir

Graduate Theses and Dissertations

Echinochloa species are the most problematic grass weeds in rice and soybean production throughout the southern United States. The species under this genus has high intra- and interspecific variability, with many ecotypes, observed within a species. This study was conducted to: i) characterize the morphology and phenology of Echinochloa accessions from Arkansas in a common garden; ii) verify the species identity of these accessions based on their morphological traits, and iii) evaluate the dormancy characteristics of Echinochloa accessions. Junglerice (E. colona) was identified as the most common species, comprising about 78% of the accessions collected, with barnyardgrass (E. crus-galli) and …

Evaluation Of Long-Acting Eprinomectin Compared To Conventional Anthelmintics In Cow/Calf Production, Elizabeth Ann Backes

Graduate Theses and Dissertations

Experiment 1, 83, newly weaned, fall-born crossbred heifer calves were allocated randomly to 1 of 3 anthelmintic treatments: 1) control (CON); 2) combination pour-on moxidectin and oxfendazole (MO); and 3) long-acting eprinomectin (LAE). Two preplanned orthogonal contrast statements were used: 1) to compare CON to treated cattle; and 2) to compare OXF to LAE. Heifer BW and BCS were greater (P≤0.02) from MO and LAE on d 112, 140, 154, 168, 182 compared to CON. Heifer cyclicity, estrous detection, natural service and overall pregnancy rates were greater (P≤0.02) for MO and LAE compared to CON. Cattle fecal egg counts (FEC) …

Recognition Training For Faces Across Age Gaps, William Blake Erickson

Graduate Theses and Dissertations

Face recognition is a problem that has theoretical and applied value. However, the fact of facial aging is rarely addressed in research and unmentioned in the major theories of face recognition. Facial aging also has ramifications for missing persons and fugitive cases, confounding attempts by law enforcement to recover these people whose last known images are years or decades out of date. This dissertation reports three studies aimed at measuring baseline age-gap recognition ability and testing various training regimens designed to increase accuracy rates for this unique kind of recognition task.

Eucalyptus In Kenya; Impacts On Environment And Society, Brandy M. Garrett Kluthe

Graduate Theses and Dissertations

Eucalyptus trees were introduced to Kenya a little over a century ago. European colonization along with the development of a railway system increased the demand for a fast growing wood source. The expansion of the tree across the fertile lands in Kenya raises concerns about the environmental impact on ecosystems where it has been introduced. These concerns include degraded soils, loss of water resources, co-introduction of ectomycorrhizal species, and allelopathy. Economic benefits to local landowners were also explored as well as the potential for large Eucalyptus woodlots to maximize the sequestration of CO₂ from the atmosphere. This was examined through …

Comparisons Of Selected Household And Commercial Disinfectants Against Poultry Salmonella Isolates And A Survey Of Internal Parasites In Backyard Poultry In Arkansas, Kayleigh Moyle

Graduate Theses and Dissertations

Backyard and exhibition poultry have been gaining in popularity and as such there has been a large increase in the number of small flocks. As the interaction with poultry has increased, so has the opportunity for diseases and parasites, for both birds and people. One of the major zoonotic illnesses is caused by the bacteria Salmonella, which can be found in commercial and small flocks. Salmonella is the number 2 contributor of foodborne illnesses so its prevalence in commercial flocks is of high concern. Despite improved cleaning, disinfection, and biosecurity practices, there is still potential for disease outbreaks and infections …

Agro-Climatic Change, Crop Production And Mitigation Strategies-Case Studies In Arkansas, Usa And Kenya, John Westley Magugu

Graduate Theses and Dissertations

Although climate change impacts vary geographically and temporally, studies at local levels are not readily available for stakeholders to better understand how their local communities would be affected and what remedial measures could be more effective in their local contexts. This dissertation has examined climate change and its impacts in two different local contexts: eastern Arkansas in the USA and Nyando in Kenya. The first part of this dissertation develops agro-meteorological indicators and examines the relationship between agro-meteorological indicators and crop yields in eastern Arkansas between 1960 and 2014. Results reveal that temperature based indicators were more strongly correlated to …

Effect Of Hydration Status On Thermoregulatory Responses In Non-Obese And Obese Males, Matthew Tucker

Graduate Theses and Dissertations

During heat stress the human body thermoregulates via cutaneous vasodilation and sweating. Hypohydration can impair thermoregulatory responses that stem from the central nervous system (CNS), but it is unknown if impairments also occur post-synaptically in the microcirculation. Moreover, obese individuals may have impaired thermoregulation, possibly due to microvascular dysfunction. Purpose: The purpose of these studies was two-fold: 1) to determine if obese (OB) individuals exhibit impairments in thermoregulatory responses during exercise heat-stress (centrally-mediated) and intradermal infusion of vasoactive substances (peripherally-mediated) versus non-obese (N-OB), and 2) to determine if hypohydration subsequently affects these thermoregulatory responses differently between groups. Methods: Twenty-one healthy, …

Genetic Determinism Of Xanthomonas Arboricola Pv. Pruni (Xap) Resistance, Fruit Quality, And Phenological Traits In Peach And Incorporation Of Marker-Assisted Selection (Mas) In The University Of Arkansas Peach And Nectarine Breeding Program, Terrence James Frett

Graduate Theses and Dissertations

For over two decades the incorporation of marker-assisted selection (MAS) has been discussed as an innovative approach to increase peach breeding efficiency. Although hundreds of quantitative trait loci (QTLs) have been identified, only a few have been converted into usable MAS tools. This highlights a disconnect between genomic discoveries and practical application in breeding programs, which has delayed use of MAS.

In this dissertation, three sequential steps were performed with the objective to bridge this gap and develop breeding-relevant DNA tests for MAS of fruit bacterial spot resistance (Xap1 and Xap6), fruit quality [blush (Rf), acidity (D), and acidity and …

Design Of A Nutrient Reclamation System For The Cultivation Of Microalgae For Biofuel Production And Other Industrial Applications, Heather Sandefur

Graduate Theses and Dissertations

Microalgal biomass has been identified as a promising feedstock for a number of industrial applications, including the synthesis of new pharmaceutical and biofuel products. However, there are several economic limitations associated with the scale up of existing algal production processes. Critical economic studies of algae-based industrial processes highlight the high cost of supplying essential nutrients to microalgae cultures. With microalgae cells having relatively high nitrogen contents (4 to 8%), the N fertilizer cost in industrial-scale production is significant. In addition, the disposal of the large volumes of cell residuals that are generated during product extraction stages can pose other economic …

A Molecular Approach To Understanding The Effects Of Original-Xpc On The Modulation Of The Cecal Microbiota And The Survival Of Salmonella In The Poultry Host, Stephanie Roto

Graduate Theses and Dissertations

Salmonella is a foodborne pathogen commonly associated with poultry products; the economic burden to the U.S. is estimated to be approximately $693 million (without factoring in contaminated eggs). Recently, there has been pressure to withdraw sub-therapeutic levels of antibiotics (also known as antibiotic growth promoters; AGP) from poultry due to concern over antibiotic-resistant bacteria spreading to the human population. Therefore, various feed additives have been researched for their ability in providing protection against harmful pathogens and their potential growth promoting effects, both of which were attributes of poultry treated with AGP. This thesis consists of a comprehensive literature review that …

Use Of A Blunt Version Of Meullenet-Owens Razor Shear To Analyze Meat Qualities Of Broilers With Woody Breast Myopathy And Reared To Various Ages, Famous Lue Yang

Graduate Theses and Dissertations

Broiler breast meat tenderness is an important meat quality attribute. There has been an increase in incidences of woody breast along with white striping as meat quality defects. These defects have been found to negatively impact meat qualities of broiler breast fillets. Woody breast can be classified by the degree of hardness into normal (NORM) and severe (SEV). The Meullenet-Owens Razor Shear (MORS) method was developed to assess broiler meat tenderness and a blunt version (BMORS) has been reported to be more sensitive at higher degrees of toughness. The present study was intended to determine the effect of age, debone …

Responses Of Semi-Aquatic Snakes To Drought, Philip Nicholas Vogrinc

Graduate Theses and Dissertations

Aquatic ecosystems and their associated wildlife are threatened by alteration in the frequency and intensity of precipitation events predicted to affect many regions as a consequence of global climate change. Semi-aquatic snakes serve important roles as predators and prey within aquatic ecosystems, yet little is known about the effects of drought on these species due to their secretive behavior. Long-term studies at an isolated wetland in South Carolina found that drought caused populations of banded watersnakes (Nerodia fasciata) and Florida green watersnakes (Nerodia floridana) to crash. Alternatively, black swamp snakes (Seminatrix pygaea) fared well, exhibiting a resistance strategy by aestivating …

Gene Expression And Physiological Analysis To Study Differences Between Oryza Sativa Cultivars Susceptible And Resistant To Chalky Grain Formation Subjected To High Nighttime Temperatures., Nicholas Lawson

Graduate Theses and Dissertations

Starch composition and grain quality of rice is greatly influenced by genotype and environmental factors. The detrimental effects of high nighttime temperatures on rice yield and quality has recently become apparent, with some of the warmest average nighttime temperatures being recorded in the past few years. One of the most notable effects of this stress, an increase in grain chalk formation, correlates with a decrease in quality. This effect varies greatly between cultivars as some show less temperature-sensitive quality reduction than others. The goal of this research is to elucidate fundamental changes that occur in developing plants and grains as …

Genetic Analysis Of Soybean Mosaic Virus (Smv) Resistance Genes In Soybean [Glycine Max (L.) Merr.], Mariola Klepadlo

Graduate Theses and Dissertations

Soybean mosaic virus (SMV) causes the most serious viral disease in soybean worldwide. Seven SMV strains, G1 - G7, and three independent multi-allelic loci for SMV resistance, Rsv1, Rsv3, and Rsv4, have been identified. In the initial study, 299 soybean germplasm lines were genotyped for Rsv4 region, inoculated with SMV-G1 and G7 strains, and classified into several resistance groups. The Glyma.02g121400 locus was sequenced from ten soybean accessions, and alignment of the sequences revealed three SNPs displaying 100% polymorphic consistency when a soybean genotype carrying the Rsv4 gene was present. A cross between V94-5152 × Lee 68 was made to …