Life Sciences Commons^™

Diversity, Identification, Mapping And Pyramiding Of Genes For Resistance To Soybean Mosaic Virus [Glycine Max (L.) Merr.], Innan Gloria Cervantes Martinez

Graduate Theses and Dissertations

Soybean Mosaic Virus (SMV) is a prevalent viral pathogen transmitted by aphids and via seed, causing significant yield loss and quality reduction. There are seven SMV strain groups (G1 to G7) and three resistance loci( Rsv1, Rsv3, and Rsv4) reported in soybean. New sources of SMV resistance would be valuable for breeding cultivars with durable resistance to multiple strains. The objectives of this research were to analyze genetic diversity of SMV-resistant soybean germplasm at the molecular level; to pyramid three genes from different sources for durable SMV resistance; and to identify and map new genes/alleles for differential reactions to SMV …

A 1,461-Year Growing Season Precipitation Reconstruction For The Carolina Coastal Plain, Kathryn Perkins Wolff

Graduate Theses and Dissertations

A recollection and dating of ancient cypress trees and subfossil logs was performed at Black River, North Carolina, and the separate Black River, South Carolina. The new updated and expanded chronologies date from AD 365 to 2010 and 549 to 2010, respectively. Baldcypress ring-width chronologies are dominated by high inter-annual to decadal variability and do not tend to capture century scale fluctuations in tree-ring growth that could be associated with centennial scale change in climate. The tree-ring chronologies were standardized with a technique designed to preserve low frequency variance known as regional curve standardization. The two chronologies were averaged into …

Herbicide Resistance Mechanism(S) In Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Populations In The Southern United States, Reiofeli Algodon Salas

Graduate Theses and Dissertations

Italian ryegrass is a principal weed problem in wheat production fields in the Southern US. Resistance to herbicides diclofop, mesosulfuron, and pinoxaden among ryegrass populations has been reported. Glyphosate-resistant Italian ryegrass populations were identified in Desha County, Arkansas. This research aimed to 1) determine resistance patterns to ACCase (diclofop and pinoxaden) and ALS (imazamox, mesosulfuron, and pyroxsulam) herbicides among Italian ryegrass populations from the southern US; 2) determine if cytochrome P450-mediated enhanced herbicide metabolism contributed to resistance; and 3) elucidate the resistance mechanism to glyphosate in four Arkansas populations (Des03, Des05, Des14, and D8). For objective 1, 30 accessions from …

Cotton Response To High Temperature Stress During Reproductive Development, Justin B. Phillips

Graduate Theses and Dissertations

Temperature is a primary controller of the rate of plant growth, developmental events, and fruit maturation. Increased temperatures from global climate change are projected to cause substantial losses in crop productivity by the end of the twenty-first century. Elevated temperatures affect all stages of cotton development, but the crop seems to be particularly sensitive to adverse temperatures during reproductive development. In Arkansas, temperature stress is considered to be one of the main factors affecting cotton yield. Environmental stress during floral development is a major reason for the disparity between actual and potential yields. Field and growth chamber studies were conducted …

Growth Promoting Implants And Nutrient Restriction Prior To Feeding: Effect On Carcass Composition, Carcass Quality, And Consumer Acceptability Of Beef, Jessica Ann Robinette

Graduate Theses and Dissertations

Implant strategy and nutrient restriction prior to finishing may alter feedlot performance, as well as carcass characteristics and consumer acceptability of beef. The objectives of these studies were to determine the effect of prefinishing implant strategy and plane of nutrition on prefinishing and feedlot performance, carcass characteristics and quality, and consumer acceptability of beef. In 2 experiments, spring-born calves were weaned in the fall (Exp. 1, n =120; and Exp. 2, n = 96) and were either finished as calves (CALF-FED) or placed on a growing program with a target ADG of 0.45 kg/d (RSTR) or 0.91 kg/d (UNRSTR) before …

Effects Of Management Strategies And Molecular Breeding Values On Cattle Performance And Carcass Traits, Benjamin Collins Williamson

Graduate Theses and Dissertations

Forty-eight Gelbvieh x Angus steers (265 ¡À 40 kg) were utilized to determine the relationships among molecular breeding values (MBV), steer performance, and carcass traits. Body weight (BW), hip height (HH), hip width (HW), exit velocity (EV; rate at which steers exited the squeeze chute and traversed 1.8 m) and body ultrasound measurements of steers were recorded at d 0, 93 and 154 of grazing mixed stockpiled endophyte-infected and -free tall fescue. Tissue samples were collected for genomic profiling (Igenity, Merial Limited, Duluth, GA). Steers were transported to the Oklahoma State U fed for 159 d, harvested and carcass parameters …

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Graduate Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber …

Effect Of Water-Deficit Stress On Cotton During Reproductive Development, Dimitra Loka

Graduate Theses and Dissertations

Water deficit is a major abiotic factor limiting plant growth and crop productivity around the world. Cotton (Gossypium hirsutum L.) is considered to be relatively tolerant to drought and the effects of water stress on leaf physiology and metabolism have been extensively documented. However, information is lacking on the effect of water-deficit stress on the cotton flower. It was hypothesized that water-deficit stress would impair gas exchange functions which consequently would result in perturbation of carbohydrates of cotton reproductive units. To investigate this hypothesis growth room studies and field studies were conducted with the objectives being to document the physiological …

Early Season Population Dynamics And Residual Insecticide Effects On Bird Cherry-Oat Aphid, Rhopalosiphum Padi In Arkansas Winter Wheat, Beven Mcwilliams

Graduate Theses and Dissertations

Bird cherry-oat aphid is a common pest of Arkansas winter wheat. This aphid vectors barley yellow dwarf virus which may cause extensive crop damage and yield loss when wheat is infested by virulent aphids in the fall. Some suggest this damage may be avoided using insecticide seed treatments if growers are unable to delay planting, as is recommended. Field population dynamics of bird cherry-oat aphid during fall 2009 and 2010 was assessed through random sampling of whole plants and pan trapping methods to evaluate aphid immigration. The field plots were divided into four subplots treated with a systemic insecticide seed …

Lameness Associated With A Possible Neural Problem In The Lower Spinal Cord Of Chickens, Gallus Gallus, Gurueswar Nagarajan

Graduate Theses and Dissertations

Since the second half of the twentieth century lameness in broiler chickens has been known to be caused by different types of disorders, however the etiology of several type of lameness remain unknown. Because of the intense selection of broilers for rapid growth, some birds are more prone to physiological insults resulting in lameness. This study focuses on possible neural problems in the lower spinal cord associated with lameness in broilers. Broilers were raised in pens with wire floors and provided with food and water ad libitum. Three groups of birds 1) birds displaying a normal gait (Controls), 2) lame …

The Role Of Ascorbic Acid In The Plant-Herbivore Interaction, Kelly Ann Carruthers

Graduate Theses and Dissertations

Ascorbic acid (AsA), vitamin C, is an important molecule that is vital for both human and plant health, because it aids in the detoxification of reactive oxygen species (ROS) caused by various abiotic and biotic stresses including UV, salinity, ozone, and attack from pathogens In order to understand the role of AsA in the plant-herbivore interaction, we looked at the effects of the wound-responsive hormones, jasmonate, wounding, and herbivory on AsA content. Our study is the first to directly compare the effects of wounding and jasmonates on AsA levels in plants. We looked at the effects of wounding and methyl …

Effect Of Enzymatic Treatments On The Physiochemical Properties Of Different Corn Starches, Curtis Robert Luckett

Graduate Theses and Dissertations

Amylose readily reassociates to form films and crystalline structures that are resistant to digestion by amylolytic enzymes and known as resistant starch type III (RS3). This study investigated the RS3 formation and cereal coating properties from enzyme-modified corn starches with varying amylose contents, including Hylon VII (70% amylose), Hylon V (50% amylose), and common corn (25% amylose). For RS3 formation, corn starches were first gelatinized and then hydrolyzed using β-amylase to varying degrees. The resultant hydrolyzed starch was debranched with isoamylase and then exposed to 3 times of temperature cycling at 135/133/133°C for 30 min and 95°C for 24 hr …

Territories,Territoriality, And Conservation Of The Louisiana Waterthrush And Its Habitat, The Watershed Of The Upper Buffalo National River, Leesia Cheryl Marshall

Graduate Theses and Dissertations

The Louisiana Waterthrush, Parkesia motacilla, is a migratory wood-warbler and breeding season resident of the eastern United States. Males defend breeding territories that extend linearly along clear, fast-flowing, gravel-bottomed, forest streams. Defense includes two song types, primary and extended song. As riverine specialists, birds rely upon aquatic invertebrates as prey and riparian habitat features for nesting. They use a unique foraging maneuver, leaf-pulling, that involves picking up or pulling a leaf from water, and turning it over to search for prey. Their relationship with riparian habitat introduces potential for Louisiana Waterthrushes to serve as indicators of stream health. The …

The Relationship Between Chronic Ankle Instability And Functional Movement Impairment In Division I Female Athletes, Akihito Tajima

Graduate Theses and Dissertations

Lateral ankle sprains are the most common injury in athletics (Denegar & Miller, 2002; Ekstrand & Tropp, 1990). In addition, the recurrent rate of ankle sprains is as high as 80% (Smith & Reischl, 1986). Repetitive ankle sprains may lead to a phenomenon known as chronic ankle instability (Hertel, 2002). It has been theorized that there are two main attributions to chronic ankle instability: mechanical and functional instability (Monaghan, Delahunt, & Caulfield, 2006). The exact mechanism of chronic ankle instability is still unclear; however, recent studies focus on multiple factors rather than single measurements, in addition to functional testing. A …

Genetic Analysis Of Chromosomal Regions Affecting Sperm Mobility In The Chicken (Gallus Gallus Domesticus), Sharath Chandra Munnaluri

Graduate Theses and Dissertations

This project is focused on determining the contributions of particular genetic loci to low sperm mobility in the chicken. Sperm mobility has been shown to be a major determinant of male fertility in broiler breeders. A whole genome SNP scan identified chromosomal regions (QTLs) that control sperm mobility. I used microsatellites from 4 chromosomal regions ( 15.151 on chromosome 6, 12.435 on chromosome Z, 12.341 on chromosome Z, and 17.214 on chromosome Z) to determine the association of these regions with sperm mobility in experimental lines divergently selected for mobility phenotype. Determination of the genetics underlying sperm mobility will identify …

Biological Strategies And Mathematical Approaches For Limiting Bacterial Contaminants And Chemical Pollutants In Bioethanol Fermentations, Alia Chahed Ep Limayem

Graduate Theses and Dissertations

During the most recent decades increased interest in fuel from biomass in the United States and worldwide has emerged each time petroleum derived-gasoline registered well publicized spikes in price. The willingness of the U.S. government to face the issues of more heavily high-priced foreign oil and climate change has led to more investment on plant-derived sustainable biofuel sources. Biomass derived from corn has become one of the primary feedstocks for bioethanol production for the past several years in the U.S. However, the argument of whether to use food as biofuel has led to a search for alternative non-food sources. Consequently, …

Stable Isotope Analysis (Delta Nitrogen-15 And Delta Carbon-13) And Bioenergetic Modeling Of Spatial-Temporal Foraging Patterns And Consumption Dynamics In Brown And Rainbow Trout Populations Within Catch-And-Release Areas Of Arkansas Tailwaters, Jon M. Flinders

Graduate Theses and Dissertations

I examined spatial and temporal consumption dynamics using an energy intake model and a bioenergetics model of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta, within three catch-and-release (C-R) areas in Bull Shoals and Norfork tailwaters to determine whether trout populations were limited by food supply. I also examined the seasonal and ontogenetic shifts in the foraging patterns of brown and rainbow trout within these areas using gut content analysis (GCA) and stable isotope analysis (SIA) of C and N. I examined 605 brown trout and 768 rainbow trout for GCA and SIA at Bull Shoals, Norfork, …

Utilization Of Natural Green Tea And Grape Seed Extracts And Nisin To Reduce Conventional Chemical Preservatives And To Inhibit The The Growth Of Listeria Monocytogenes In Ready To Eat Low And High Fat Chicken And Turkey Hotdogs, Amara Venkata Sunil Perumalla

Graduate Theses and Dissertations

Ready-to-eat meat (RTE) products such as hotdogs represent a popular segment in convenience food purchases. Increased demand has led the processors to extend the shelf life by minimizing lipid oxidation and post-processing contaminants such as Listeria monocytogenes. There is a growing interest in the food processors and consumers regarding the use of natural alternatives in place of synthetic food additives to control the growth of foodborne pathogens and (or) lipid oxidation. In recent years, green tea (GTE) and grape seed extracts (GSE) are increasing choices as they have demonstrated antioxidant as well as antimicrobial properties in various food applications. …

Feed Supplementation With Natural Extracts Of Cranberry And Its Efficacy On Campylobacter Colonization In Poultry, Ann Woo-Ming

Graduate Theses and Dissertations

Campylobacter spp. has been identified as one of the leading causative agents of food borne diarrheal illness. Epidemiological evidence has shown that poultry is the main source for human infection. Poultry are asymptomatic carriers of Campylobacter within their gastrointestinal tract, with colonization levels reaching 106-108 cfu/g cecal content. Surveys of domestic poultry flocks have estimated that approximately 90% of flocks are positive for Campylobacter colonization. Risk assessment studies have determined that by reducing levels of Campylobacter colonization during rearing, incidences of human infection will be significantly reduced. Currently there are no consistently effective treatments to eliminate Campylobacter from poultry flocks. …

Systematic Observation Of Coach Feedback In Elite Youth Volleyball, Mark David Mann

Graduate Theses and Dissertations

The purpose of the study was to understand the relationship of coach feedback during time-outs to the performance of 16-18 year old volleyball players in competitive match play situations. The systematic observation of coach feedback during 89 time-outs was recorded using the Coach Time-Out Observation Instrument (CTOOI). Out of the 879 feedback statements that were made during the 89 time-outs, the CTOOI categorized coach feedback for technical feedback (with an internal or an external focus), tactical feedback (referring to our team or the opponent), and psychological feedback (as either encouraging or discouraging remarks). Data from the Game Performance Assessment Instrument …

Role Of Lactic Acid Bacteria As A Bio-Sanitizer To Prevent Attachment Of Listeria Monocytogenes On Deli Slicer Contact Surfaces, And The Influence Of Listeria Innocua On The Attachment Of L. Monocytogenes On Selected Materials Located In The Food-Processing Environment, Jean Baptiste Ndahetuye

Graduate Theses and Dissertations

Listeria monocytogenes an important foodborne pathogen that continues to be a serious problem for the food industry. This pathogen contaminates food primarily during post-harvest in the food-processing environment. Its ecology in the food-processing environment is not well understood but previous research has demonstrated the ability of L. monocytogenes to survive on food contact surfaces after cleaning and disinfection. The current study explored the attachment of three lactic acid bacteria (LAB) strains, Lactobacillus animalis , Lb. amylovorus and Pediococcus acidilactici , their combination in a cocktail, and their influence to prevent the attachment of L. monocytogenes at room temperature by examining …

Intake, Digestibility, Insitu Disappearance And Ruminal Fermentation Of Bermuda Grass Hay By Lactating Beef Cows Offered Corn Or Hominy Feed As Supplements, Zibani Madzonga

Graduate Theses and Dissertations

Hominy feed, a co-product of dry corn milling, has been evaluated to a limited extent in feedlot and dairy rations, but has not been evaluated as a supplemental energy source for lactating beef cows. The objective of this study was to determine the effect of level of hominy feed supplementation on intake, digestibility, in situ DM disappearance, and ruminal fermentation characteristics of medium quality bermudagrass hay. Five ruminally cannulated lactating beef cows (BW = 596 kg, SE = 13.9) were used in an experiment with a 5 × 5 Latin square design. Treatments were low hominy (LH; 0.25% …

Sanitation Assessment Of Food Contact Surfaces And Lethality Of Moist Heat And A Disinfectant Against Listeria Strains Inoculated On Deli Slicer Components, Sabelo Muzikayise Masuku

Graduate Theses and Dissertations

The overall objectives of this study were to: evaluate the efficacy of different cleaning cloth types and cloth-disinfectant combinations in reducing food contact surface contamination to acceptable levels; determine the optimum moist heat and moist heat + sanitizer treatments that can significantly reduce the number of Listeria strains on deli slicer components; and investigate if the moist heat treatment used in this study induced the viable-but-non-culturable (VBNC) state in Listeria cells. The efficacy of wiping cloths was measured using ATP-bioluminescence and total plate count methods using four different wiping cloths and silver dihydrogen citrate sanitizer on food contact surfaces. The …

Gene Expression And Physiological Analyses To Study Metabolic Shifts In Medicago Truncatula Subjected To Biotic Stresses, Michelle Ryan Martin

Graduate Theses and Dissertations

Plants are frequently under attack from pests and deploy various defense mechanisms to fight off predators. Many plant defenses are induced following herbivory or pathogen infection. An investment in defense could potentially lead to a diversion of metabolic resources away from primary metabolism, including reduction in plant commitment to photosynthesis. In this thesis, changes in expression levels of representative genes for primary and secondary metabolism were studied using real-time polymerase chain reaction (PCR) in Medicago truncatula Gaertner subjected to beet armyworm (Spodoptera exigua H¨¹bner) damage or Phoma medicaginis Malbr. & Roum. infection. Photosynthetic yield was also measured using chlorophyll fluorescence …

Foliar Symptoms Of Acute Ozone Injury And Exposure Response Characteristics Of Select Native Perennials, Susan Denise Frey

Graduate Theses and Dissertations

Twenty seven perennial species native to the Eastern Temperate Forests Level I Ecoregion were exposed to an acute ozone (O3) treatment consisting of a target peak O3 concentration of 2.0 ppm for 30 minutes in a closed chamber environment, during the summer of 2010. Plants were evaluated for visible foliar injury symptoms and symptoms were described and photographically documented. Ten of the 27 species developed visible foliar injury in which interspecific and intraspecific response to O3 was observed. A severity index was used to compare response to acute ozone exposure for the ten species displaying visible foliar injury. Species showing …

Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick

Graduate Theses and Dissertations

Because of their simple fruiting bodies consisting of one to a few spores atop a finely tapering stalk, protosteloid amoebae, previously called protostelids, were thought of as primitive members of the Eumycetozoa sensu Olive 1975. The studies presented here have precipitated a change in the way protosteloid amoebae are perceived in two ways: (1) by expanding their known habitat range and (2) by forcing us to think of them as amoebae that occasionally form fruiting bodies rather than as primitive fungus-like organisms. Prior to this work protosteloid amoebae were thought of as terrestrial organisms. Collection of substrates from aquatic habitats …

Crisis Communication Needs Assessment: A Delphi Study To Enhance Instruction For Agricultural Communicators And Other Stakeholders, Allyson Ceary Mcguire

Graduate Theses and Dissertations

Agricultural communicators and industry stakeholders need to be able to develop, prepare and implement crisis communication plans to help assure the sustainability of the agriculture industry should a crisis event occur. A thorough exploration of possible options and needs for training crisis communicators is a needed study in the agriculture industry. Students learning to prepare for managing crises in real life situations are rarely taught in a hands-on, experiential manner. Students can read and analyze case studies pertaining to crises, but without having an actual crisis; little means exist for preparing students for real world situations. There is a need …

Factors Determining Media Coverage Of Meat And Poultry Recalls: Evidence From The Ap Newswire, Thais Fregonesi Carvalho

Graduate Theses and Dissertations

Food safety is an important public health issue. Product recalls are an important part of the overall food safety system and occur when potentially unsafe products enter the marketplace. However, it is important that information about the recall ultimately reaches the public. This research assesses the publicity that recalls receive by the popular media. The focus is specifically on recalls of meat and poultry products. Publicity is measured by coverage in the AP Newswire. Data were gathered from the United States Department of Agriculture's Food Safety and Inspection Service (FSIS) and cover meat and poultry recalls from 1982 to 2009. …

Host-Virus Interactions Of Infectious Laryngotracheitis Virus Infection In Cultured Cells, Jeong Yoon Lee

Graduate Theses and Dissertations

Infectious laryngotracheitis virus (ILTV; Gallid herpesvirus 1) causes upper respiratory diseases in mainly chickens and exhibits 90-100% of high morbidity and up to 70% of mortality, resulting in huge economic losses in the poultry industry worldwide.

To study host-ILTV interactions, the changes in genome-wide gene expressions in response to wild-type and vaccine ILTV infections in primary chicken embryo lung cells were investigated using microarray analysis. Results provide crucial insights into host cell pathogenic and immunogenic responses against wild-type and vaccine ILTV infections. Using microarray method and Ingenuity Pathway Analysis (IPA) bioinformatics tool, 273 and 306 differentially expressed genes were identified …

Characterization And Molecular Analysis Of University Of Arkansas Peach, Prunus Persica (L.) Batsch, Flesh Types And Development Of A Post-Harvest Evaluation Protocol For Arkansas Peach And Nectarine Genotypes, Paul James Sandefur

Graduate Theses and Dissertations

This study determined the effect of pre-cold storage treatment on P. persica genotypes, developed a protocol for the evaluation of breeding selection and cultivar storage performance, and provided information on post-harvest performance of these individuals. Additionally, characterization of the peach and nectarine flesh types, validation of endopolygalacturonase (endoPG) DNA markers, and investigation of endoPG marker allele combinations associated with the slow-melting-flesh (SMF) trait were done.

Fruit from 30 individuals were harvested at minimum- and well-mature states. After conditioning for 24 h at 20 ◦C, all 2010 fruit were exposed to 2 min of 1 ◦C 100 ppm chlorinated hydro-cooling, a …