Life Sciences Commons^™

Management Of Katahdin Hair Sheep, Elizabeth Ann Backes

Graduate Theses and Dissertations

The objectives of this research were to determine the effects of different management practices on Katahdin hair sheep performance. For experiment 1, over 2 yr, 5, 0.4-ha pastures were allocated randomly to 1 of 2 grazing treatments: 1) Continuous; or 2) 4-cell rotation. Fifty yearling Katahdin ewes (53 ± 0.7 kg initial BW; 3.3 ± 0.09 initial BCS) were stratified by BW and BCS and allocated randomly to pastures in early May. Grazing d, basal cover, forage quantity or quality did not differ across treatments; however, sampling date effects were detected for forage quantity and quality. Beginning and end of …

Quantitative Trait Loci Associated With Waterlogging Tolerance In A Soft Red Winter Wheat Mapping Population, Diana Carolina Ballesteros Benavides

Graduate Theses and Dissertations

Waterlogging is caused when water stays superficially in the soil for an extended period of time, creating an anaerobic environment which decreases plant growth and grain yield at maturity. Despite the impact of waterlogging on wheat production both globally and in the southeastern U.S., very little is known about the genetic control of waterlogging tolerance in wheat. The objective of this study was to determine the amount of genetic variation for vegetative stage waterlogging tolerance present within a wheat recombinant inbred line (RIL) population and to identify quantitative trait loci (QTL) associated with tolerance and productivity. Experiments were carried out …

A Comparison Of Milled Rice Fissuring Kinetics Of Hybrid And Pureline Cultivars, Semehar Haile Tesfaye

Graduate Theses and Dissertations

Over the past decade, the use of hybrid rice cultivars has greatly increased, and this has led to questions about the processing behavior of hybrid cultivars. This study compares the milled rice fissuring kinetics of hybrid and pureline cultivars. Also, this study elucidates the effects of kernel type (long-grain vs. medium-grain rice cultivars), surface lipid content (SLC), and kernel thickness on fissuring rates.

Three hybrid (CL XL745, CL XL729 and XL753) and five pureline (Wells, CL151, Cheniere, Jupiter and CL261) cultivar lots were procured. Jupiter and CL261 are medium-grain cultivars, whereas the rest are long-grain cultivars. Two experiments were conducted. …

Evaluating Economic Impacts Of Switchgrass Harvest Time, Nathanial Elsworth Cahill

Graduate Theses and Dissertations

This thesis deals with cost of production for cellulosic energy crops of switchgrass, miscanthus, and energy sorghum. The first chapter explains the rationale for development of decision support software called Energy Crop Analysis & Planning (ENCAP) and Switchgrass Harvest Date, Yield, Nutrient Removal Estimator (SHYNE). The second chapter examines harvest date implications on yield, nutrient removal, opportunity cost of modified sale dates, and post-harvest storage losses. This harvest date analysis leads to a profit maximizing harvest date from the perspective of the producer. While this harvest date may be optimal for the producer, biorefineries may be interested in sourcing switchgrass …

The Role Of Histone H3 And H4 In Centromere Function And Genome Integrity, Payel Chaudhuri

Graduate Theses and Dissertations

Histone H2A plays an important role in chromosomal segregation among parent and daughter cells during mitosis. While it is established that this histone is important in maintaining chromosome number in cell, further work is carried out to explore the role of other histones like H3 and H4 for similar effects. A systematic study is initiated by screening a library based on mutation of different amino acid residues in these histones. This detailed screening identified specific regions within H3 and H4, which are critically important for centromeric function. These histones residing near the DNA entry/exit region of nucleosome effects the functionality …

Effect Of Prescribed Burning In The Forests Of Buffalo National River, Arkansas, Francis Ndar Onduso

Graduate Theses and Dissertations

Prescribed burning (also referred to as controlled or hazard reduction burning) refers to the use of fire under controlled conditions to achieve a desired end product or goal. However, the nature and magnitude of the changes that result from prescribed burning are still incompletely known, and this is especially true for the forests of the Ozarks of northern Arkansas. The overall objective of the research project described herein was to obtain the data necessary to develop a better understanding of these changes, particularly as they relate to the use of prescribed burning as a management technique in the Buffalo National …

Spatial Distributions Of Rhizoctonia Species In Soybean Fields Undergoing Annual Rotations With Rice, Terry Neil Spurlock

Graduate Theses and Dissertations

Aerial blight is caused by Rhizoctonia solani AG1-IA. This pathogen also causes sheath blight of rice. In Arkansas, many soybean and rice fields undergo an annual rotation of these two crops which facilitates a continuous source of inoculum from one year to the next. Aerial blight is a two stage disease in that R. solani AG1-IA colonizes the plant during the early vegetative growth stages and then aerial blight develops after the soybean canopy closes in the later reproductive stages of development. As a result of the upper portion of the canopy often being asymptomatic, significant yield loss can occur …

Evaluating Economic And Environmental Impacts Of Changing Herd Sire Genetics On Arkansas Cow-Calf Operations, Daniel Keeton

Graduate Theses and Dissertations

This research looks at impacts of changing sires, and thus bull genetics, on cow-calf operations of varying land and herd sizes in the state of Arkansas. A 2012 Across-Breed EPD table, adjusted to the Angus breed, was used to estimate breed sire effects on birth weight and weaning weight of the herd's offspring (Kuehn and Thallman 2012a). Together with modified animal performance, the use of 2012 and most recent five- and ten- year Arkansas state average prices, allowed the evaluation of changing herd sires by accounting for breed type and hide color differences in prices. Using a spreadsheet tool that …

Proteomic And Biochemical Studies Of Estrogen-Mediated Signaling And Novel Estrogen Receptor-Interacting Proteins In Breast Cancer Cells, Zhenqi Zhou

Graduate Theses and Dissertations

Estrogen plays essential roles in the growth, development, and homeostasis of a number of tissues, and can also be linked to the growth of breast cancer. The biological activities of estrogen are mediated by estrogen receptors (ERs) ERá and ERâ, and also orphan G-protein-coupled receptor 30 (GPR30). In order to identify novel proteins that are involved in ER-mediated actions of estrogen, we used mass spectrometry-based quantitative proteomic methods to systematically profile global protein expression in responses to E2 (17â-estradiol) stimulation in human breast cancer cell, and identify and characterize cellular novel proteins that are associated with ERs in breast cancer …

Soybean (Glycine Max) Response To Imazosulfuron Drift And Carryover From Rice (Oryza Sativa), Sandeep Singh Rana

Graduate Theses and Dissertations

In the Midsouth, soybean is often grown in close proximity to rice or in rotation with rice. Herbicides used in rice can injure soybean via drift or carryover. Consequently, field trials were conducted to determine the response of soybean (cv. AG 4703) to imazosulfuron drift and carryover (at Fayetteville, Marianna, Keiser and Pine Tree, AR) from rice. To assess the potential for carryover, soybean was planted into rice fields treated the previous year with imazosulfuron (rotation study). To evaluate in-season sensitivity of soybean to imazosulfuron (tolerance study) relative to halosulfuron, a common sulfonylurea herbicide applied to rice, both imazosulfuron and …

Selecting Drought Tolerant Soybean Genotypes Using Qtls Associated With Shoot Ureide And Nitrogen Concentrations, Alejandro Bolton

Graduate Theses and Dissertations

In soybean, nitrogen fixation is more sensitive to drought than other physiological processes like photosynthesis. The sensitivity of nitrogen fixation to drought has been associated with high shoot concentrations of ureide and nitrogen under well-watered conditions. Previous research by Hwang et al. (2013) detected quantitative trait loci (QTLs) in a KS4895 by Jackson population associated with shoot ureide and nitrogen concentrations. The present research evaluated the use of these QTLs in selecting genotypes with drought tolerant nitrogen fixation. Our objectives were to compare actual versus expected phenotype of recombinant inbreed lines (RILs) selected using molecular markers, and to evaluate the …

Ecology And Structure Of Black Bear (Ursus Americanus) Populations In The Interior Highlands Of Arkansas, Thea Vandervelde Kristensen

Graduate Theses and Dissertations

In the Interior Highlands of Arkansas, Missouri, and Oklahoma, over-harvest, extensive logging, and reductions of habitat availability by other means contributed to the decline of black bears (Ursus americanus). Bears were extirpated from the majority of the region by the 1940's Oklahoma by 1915 and from Missouri by 1931. From 1958-1968, the Arkansas Game and Fish Commission undertook a reintroduction to the Ouachita and the Ozark National Forests in Arkansas. The successful growth and expansion of the released population caused these efforts to be considered one of the most successful reintroductions of carnivores. In this dissertation, I sought to examine …

Excretion Of Phenolic Compounds After Consumption Of Fresh Versus Aged Chokeberry Juice In Rats, Sarah Elizabeth Graves

Graduate Theses and Dissertations

Flavonoids, such as anthocyanins, may be responsible for the health benefits of chokeberries, as they are present in large quantities in chokeberries and are potent antioxidant and anti-inflammatory agents. Despite these health properties, previous investigations on the bioavailability of flavonoids illustrate that little of the ingested amount reaches the bloodstream. This study investigated two factors that may help to explain these inconsistencies. First, storage of berry fruits and berry fruit products leads to extensive polymerization of their anthocyanins with procyanidins. Additionally, after consumption flavonoids may undergo metabolism into phenolic acids and subsequent conjugation to an extent that may explain their …

A Roadmap To Mindful Consumption Through Informative Labeling Practices: The Effects Of Sustainability Disclosure Formats On Consumer Product Evaluations, Yoon-Na Cho

Graduate Theses and Dissertations

Despite the interest of consumers in sustainable and environmentally friendly products, only a limited number of studies have focused on sustainability level disclosures for consumer packaged goods. The general overarching purpose of this dissertation is to extend the internal reference point and information processing literatures to better understand how consumers will process sustainability disclosures. Applying the theoretical lens of assimilation bias in conjunction with self-enhancement offers an important extension to prior work. Across two retail lab studies and four online experiments, I demonstrate that the perceived sustainability utility (i.e., the difference between a specific brand's level of sustainability and category-level …

Turpentine Creek: Arkansas' Refuge, Jacob Paul Bain

Graduate Theses and Dissertations

The goal of this Master's thesis film project was twofold. First, I wanted to explore the problem, huge but relatively unknown, of the ownership of exotic pets in the United States of America. Second, in conjunction with that problem, I wanted to see how Turpentine Creek Wildlife Refuge (TCWR) approached it and what, as an organization, they do to help resolve this problem locally and nationally. In turn, the film also provides an in-depth look at a very unique refuge in the state of Arkansas. Using my own equipment, I shot and edited a short-form documentary about TCWR. The film …

The Interactive Effects Of Multiple Stressors On Lithobates Catesbeianus And Anaxyrus Americanus, Matthew Kyle Holden

Graduate Theses and Dissertations

Amphibian populations worldwide have experienced dramatic declines, and many species have already become locally, regionally, or globally extirpated with thousands more being threatened with extinction. These declines have occurred more rapidly in amphibians than any other group of vertebrates, which is especially concerning to scientists because amphibians serve as indicator species of overall environmental health. Major causes for amphibian declines are discussed in Chapter 1 and include: habitat modification and destruction, commercial over-exploitation, introduced species, environmental contaminants, global climate change, and infectious diseases.

Chapter 2 discusses the major research aspects of the thesis by examining the interactive effects of multiple …

Comparison Of Potential Salmonella Portals Of Entry And Tissue Distribution Following Challenge Of Poultry, Gopala Krishna Kallapura Sheshagiri

Graduate Theses and Dissertations

The following studies evaluated our hypothesis that transmission by the fecal-respiratory route may be a viable portal of entry for Salmonella and could explain some clinical impressions of relatively low-dose infectivity under field conditions in relation to the requisite high oral challenge dose that is typically required for infection of poultry through the oral route in laboratory studies. Initial field reports indicating tracheal sampling to be a sensitive tool for monitoring Salmonella infection in commercial flocks, suggested that tracheal contamination could be a good indicator of Salmonella infection under commercial conditions. Further, a usual assumption regarding airborne Salmonella reaching the …

Design, Development, And Characterization Of Novel Antimicrobial Peptides For Pharmaceutical Applications, Yazan H. Akkam

Graduate Theses and Dissertations

Candida species are the fourth leading cause of nosocomial infection. The increased incidence of drug-resistant Candida species has emphasized the need for new antifungal drugs. Histatin 5 is a naturally occurring human salivary antifungal peptide and the first line of defense against infections of the oral cavity. This research has focused on understanding the activity of histatin 5, and subsequently designing novel peptides that may serve as models for the further development of therapeutics to treat fungal infection.

This objective has been achieved in three steps: studying the structural requirement of histatin 5 involved in antifungal activity, the identification of …

Genome-Wide Association Mapping Identifies Qtls And Candidate Genes For Salt Tolerance In Soybean, Lei Huang

Graduate Theses and Dissertations

Salinity is a common abiotic stress causing soybean yield loss worldwide. Use of tolerant cultivars is an effective and economic approach to coping with this stress. Toward this, research is needed to identify salt-tolerant germplasm and better understand the genetic and molecular basis of salt tolerance in soybean. The objectives of this study were to identify salt-tolerant genotypes, to search for SNPs and QTLs associated with salt tolerance, and to identify candidate salt tolerance genes. A total of 192 diverse soybean lines and cultivars were screened for salt tolerance in the greenhouse based on visual leaf scorch scores after 15 …

Evaluation Of Water Sanitation Options For Poultry Production, Pramir Maharjan

Graduate Theses and Dissertations

An evaluation of poultry farm water supplies was conducted to determine the value and impact of water system sanitation practices in commercial broiler houses on microbial levels. Water line cleaning between flocks using concentrated disinfectant solution before placing chicks reduced biofilms retained in the lines to a safe level. Occasional microbial surges were noticed during different points of flock grow-out period even when daily water sanitation was present indicating water is highly susceptible to microbial contamination. However, the daily water sanitation practice controlled the occasional microbial surges in water from sustaining and kept drinking water to a microbiologically acceptable level. …

Abiotic And Biotic Factors Affecting The Japanese Beetle In Arkansas, Bryan Mathew Petty

Graduate Theses and Dissertations

Japanese beetles are a relatively new pest to Arkansas. During my Ph.D. research I investigated the pathogens and environmental factors influencing Japanese beetle populations in the state. The prevalence of various pathogens and parasitoids attacking Popillia japonica were recorded annually from wild populations. Of specific interest was the microsporidian pathogen Ovavesicula popilliae, which I introduced as a biological control agent in the state. Details of the relationship between this pathogen and the Japanese beetle were investigated, including dose response, host range, and spore production. Additionally, annual abundance of the beetle in the region was recorded and tracked over the course …

Identification And Confirmation Of Quantitative Trait Loci For Seed Protein And Oil Content Of Soybean, Jiao Wang

Graduate Theses and Dissertations

Protein and oil are the major chemical constituents of soybean seed that affect the quality of soyfood, feed, and oil products. Therefore, soybean cultivars with high protein and/or high oil are desirable for the soyfood and feed markets. Use of molecular-marker-assisted selection will facilitate the breeding process of such cultivar development. The objectives of this research were to identify new quantitative trait loci (QTL) and confirm previously reported QTL associated with seed protein and oil content by using simple sequence repeat (SSR) markers and single nucleotide polymorphism (SNP) markers. Two recombinant inbred line (RIL) populations consisting of 242 individuals from …

Distribution And Control Of Glyphosate-Resistant Johnsongrass (Sorghum Halepense) In Arkansas Soybean, Dennis Brent Johnson

Graduate Theses and Dissertations

Johnsongrass, once the most persistent and troublesome grass weed of row crops throughout the southern U.S., has previously been confirmed resistant to the acetolactate synthase (ALS) and acetyl-coenzyme A carboxylase-inhibiting herbicides in the Midsouth and has recently evolved resistance to glyphosate in Arkansas. The goal of this research was to establish the geographical distribution of herbicide-resistant johnsongrass in Arkansas and to develop herbicide programs for controlling glyphosate-resistant johnsongrass in Arkansas soybean. Johnsongrass accessions were collected from 14 counties in the Mississippi River Delta region of Arkansas and screened for resistance to four of the most commonly used postemergence herbicides for …

The Impact Of Parent Education On Parental Feeding Practices, Larra Kolby Brawley

Graduate Theses and Dissertations

This research looked at the potential impact that parent education may have on the feeding practices of parents of young children. Since eating behaviors are a national concern for both children and adults, it's important to examine how we can create not just healthier children but, as a result, healthier adults. This study utilized an intervention that was an adapted version of a healthy eating curriculum created by Sesame Workshop and the California WIC association with the intention of improving parental feeding practices through a behavior-based approach. Previous research with this curriculum has addressed only low-income populations, with a relatively …

Characterization Of Host Immune Responses To Eimeria Adenoeides Infection In Turkey Poults, Ujvala Deepthi Gadde

Graduate Theses and Dissertations

Coccidiosis is a common enteric disease of turkeys that is caused by protozoan parasites belonging to the genus Eimeria. There are about seven species of Eimeria that affect turkeys and of these E. adenoeides is the most pathogenic and commonly recognized. Infection with Eimeria is known to induce a long lasting protective immunity in chickens, but nothing is known regarding the acquisition of immunity to Eimeria in turkeys. The experiments reported here were aimed at investigating the biological and cellular immune response to E. adenoeides in turkey poults under different conditions of exposure. In experiment 1 (Chapter II), 20 …

Effects Of High-Velocity Versus Low-Velocity Resistance Training On Resting Metabolic Rate And Functional Performance In Older Adults, Laura Ashleigh Morgan

Graduate Theses and Dissertations

The purpose of this study was to compare the effects of a 12-week high-velocity resistance training (HVRT) protocol to a traditional low-velocity resistance training (LVRT) protocol on resting metabolic rate (RMR) and other selected measures of muscular and functional fitness in older adults. Nineteen adults between the ages of 65 and 82 participated: 8 HVRT, 7 LVRT, and 4 controls (CTRL). Initially, no differences existed between groups except for age (p = .016). HVRT (75.6 years) was older than LVRT (69.6 years) and CTRL (69.3 years). The exercise intervention consisted of 2 days/week sessions for 12 weeks at 3 sets …

The Relationship Among Ankle Function, Functional Capacity, And Body Composition To Balance In Geriatric Populations, Joseph Robert Chaney

Graduate Theses and Dissertations

The primary purpose of this research study was to identify significant relationships among measures of ankle strength, ankle range of motion, body composition, and functional capacity to balance ability in geriatric populations which may potentially assist in identifying older individuals with increased risk of falling. A battery of five test (ankle strength assessments, ankle range of motion , DXA, functional fitness, and balance) were administered to 20 participants (6 males, 14 females, mean age 69.78 ± 3.98) that had indicated to be at least 65 years of age or older and no history of falls within the previous 12 months. …

The Use Of Non-Traditional Technologies To Improve The Efficiency And Sustainability Of Modern Poultry Production, Christopher Pixley

Graduate Theses and Dissertations

Historically, major driving factors for the animal agriculture industry have been efficiency and profitability. As demand for efficient food production has increased, the industry has focused research efforts on ways to improve the rearing process. Current market demands are requiring the industry to abandon some of the traditional tools it has used to maximize productivity. However, developing alternative technologies are available which may fill the void. Unfortunately, these alternatives are less well-described and the beneficial impacts they can have are not fully understood. As the animal agriculture industry matures it is becoming evident that consumers will continue to demand methods …

Study Of Thermotolerance Mechanism In Gossypium Hirsutum Through Identification Of Heat Stress Genes, Jin Zhang

Graduate Theses and Dissertations

ABSTRACT

Heat stress causes major losses to cotton seed and lint yield. Introduction of heat stress tolerance to Arkansas cotton varieties is highly desirable. However, very little is known about the molecular basis of heat stress tolerance in cotton. The present study attempted to identify heat stress tolerance genes in two heat-tolerant cotton cultivars, VH260 and MNH456, originating from Pakistan. Towards this, the expression profile of the cotton orthologs of sevenArabidopsisheat stress tolerance genes was studied in these two cultivars, and compared with the two heat-susceptible cotton cultivars, ST213 and ST4288, originating from Mississippi Delta region. In addition, physiological parameters …

Algae To Propellants: Biosynthesis Of 1,2-Propanediol From Algal Derived Sugars, Lauren Rachelle Merriman

Graduate Theses and Dissertations

Propylene glycol dinitrate (PGDN) is an important component used in the formulation of energetic materials. A renewable, environmentally-friendly and effective production technique for the production of 1,2-propanediol, an important precursor to PGDN, is desired. While fermentation of 1,2-propanediol has been achieved, it suffers from major limitations such as expensive feed sugars and relatively low yields. It is hypothesized that algae sugars could serve as a feedstock for the microbial synthesis of 1,2-propanediol, thereby reducing production costs and enhancing sustainability.

Algal biomass produced from an Algal Turf Scrubber® has proven to have significant potential as a source of fermentable materials. However, …