Life Sciences Commons^™

The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind

Graduate Theses and Dissertations

In this dissertation I examined the relationship between individual energetic status, hormone production, and life history trait expression in field-active Timber Rattlesnakes, Crotalus horridus. In chapter one I reviewed what is known regarding these relationships in snakes and defined major research goals. In chapter two I described the seasonal profile of testosterone (T) and corticosterone (CORT) in relation to the breeding season and to individual energetic status in males. Results showed that the seasonal pattern of T production in C. horridus was different than other pit viper species with similar mating patterns. Testosterone was elevated in the months leading up …

Intestinal Inflammation Model Inducing Gut Leakage By Different Methods In Broiler Chickens Using Fitc-D As A Marker, Eduardo Vicuna

Graduate Theses and Dissertations

Traditionally, antibiotic growth promoters (AGP) have been used in food animals to reduce enteric inflammation and maintain intestinal homeostasis, thus improving performance. Due to increasing restrictions regarding the use of AGP, precise and high throughput enteric inflammation models and markers to search for effective alternatives are urgently needed. Oral administration of fluorescein isothiocyanate dextran (FITC-d) and its passage into blood can be used as a marker for tight junction permeability. FITC-d is a large molecule (3-5 kDa) which does not usually leak through the intact gastrointestinal tract barrier. However, when conditions disrupt the tight junctions between epithelial cells, the FITC-d …

The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud

Graduate Theses and Dissertations

Outbreaks from the consumption of fresh produce are a concern in the United States. The consumptions of fresh produce have increased recently which expose a large segment of society to such outbreaks. Spinach and cantaloupe are minimally heated or processed before consumption which makes them a possible source of foodborne illness. The objective of this research was to investigate the effect of organic acids alone and in combination to reduce attached Salmonella Typhimurium (S.T) and Escherichia coli O157:H7 (E.coli) on spinach and cantaloupe, and to disintegrate biofilm formed by these pathogens by electrostatically spraying with two organic acids. To quantify …

Genetic Mapping Of Yield And Normalized Difference Vegetative Index In Soft Red Winter Wheat (Triticum Aestivum L.), Christopher Keith Addison

Graduate Theses and Dissertations

Wheat is the most widely cultivated cereal crop, being grown on 17% of the global crop land and as such must be adapted to an array of environmental stresses. In order to become a variety, wheat breeding lines must be tested across a range of environments for both high productivity and stability. Quantitative trait loci (QTL) mapping and indices are tools that can aid plant breeders in the selection of superior lines. Soft red winter wheat accounts for 20% of the total wheat production in the United States, being grown in the southeastern U.S. predominantly along the Mississippi River. However, …

Monitoring Abundance Of Ips Bark Beetles And Determining Related Tree Mortality In Arkansas And Texas, Chandler Stefan Barton

Graduate Theses and Dissertations

The abundance of the southern pine engraver beetles, Ips avulsus (Eichhoff), I. grandicollis (Eichhoff), and I. calligraphus (Germar), was monitored with pheromone-baited traps in 2012 and 2013 in Arkansas and eastern Texas. Additionally, vehicle-based and comprehensive ground-based surveys were used to estimate and confirm the amount of dead and fading trees in each trapping site. Pine engraver beetles have historically been recognized as secondary invaders of healthy trees, but observations of pine mortality in Texas and Arkansas appeared to correspond with high population densities of Ips spp. Forest sites exhibiting subjectively high or low incidence of Ips-associated mortality in Arkansas …

Distribution Of The Egyptian Goose (Alopochen Aegyptiacus) In Northwestern Arkansas And In The United States Of America, Cameron Chesbro

Graduate Theses and Dissertations

The Egyptian Goose (Alopochen aegyptiacus) is an exotic member of the Anatidae that has been residing in northwestern Arkansas since the 1980s (Smith and James 2012). Following the discovery of Egyptian Geese in the area, not much attention has been given to the consequences of population increase. The Egyptian Goose has shown many diverse population growth patterns in areas where it has been introduced and started feral populations. The purpose of this study was to assess the current population size of the Egyptian Goose in northwestern Arkansas,and confirm successful breeding. The methods used in this study included conducting road surveys …

Improving Production Efficiency Of Beef Cow-Calf Operations, Amanda Jo Davis

Graduate Theses and Dissertations

Three studies were conducted to improve and incorporate reproductive management practices into beef cow-calf production. First study evaluated serial use of Estrotect estrous detection patches as a simple, cost-effective reproductive management tool to identify cyclic animals before breeding, distinguish between females conceiving to AI versus natural service, and determine seasonal pregnancy rate after bull removal. Also determined, was effectiveness of altered timing of GnRH treatment (1 d ± CIDR removal) in a modified 14-d CIDR-Select Synch protocol. When evaluated over a 4-wk period, estrous detection patches correctly (P < 0.01) identified 79% of cyclic and 86% of non-cyclic heifers. Patches were 96 and 98% accurate in identifying heifers and cows pregnant by AI, respectively, and were 76 and 87% accurate in identifying pregnant heifers and cows at the end of the breeding season (P < 0.01). Treatment with GnRH at CIDR removal reduced labor costs and animal handling without compromising estrous response (both ~63.0%) and AI pregnancy rates (~76 and 77%; P > 0.1). Second study determined if addition of PGF2alpha treatment on d 7 …

Phylogeny And Diversity Of Entamoeba In Cockroaches, With An Emphasis On Periplaneta Americana, Mustafa Husain Fakhri

Graduate Theses and Dissertations

While the parasitic Amoebozoan Entamoeba histolytica has been well-studied for its role in human pathogenesis, the biodiversity of invertebrate-inhabiting Entamoeba has scarcely been investigated. Using molecular methods, I searched for Entamoeba in the guts of cockroaches from four of the six Blattodean families. Entamoeba small-subunit rRNA genes were recovered from all eight species of cockroaches tested, five of which represent newly discovered hosts. Phylogenetic analysis of over 190 sequences revealed a novel and highly diverse clade of cockroach-inhabiting Entamoeba, separate from the clade predominated by vertebrate-inhabitants. These results double the known genetic diversity of Entamoeba and suggest that they may …

Prediction Of Superovulatory Response In Beef Cows Based On Serum Anti-Mullerian Hormone And Antral Follicle Number, Keith Center

Graduate Theses and Dissertations

A study investigated the use of Anti-Mullerian hormone (AMH) and/or follicle counts as a predictor of subsequent superovulatory response and embryo production in 79 beef cows. Before initiation of superovulation, ultrasonography was used to scan the ovaries of each donor cow to record the number of 3 to 5 mm follicles present, and a blood sample was collected for measure of serum AMH. At the time of embryo collection, the ovaries of donor cows were palpated to estimate the number of corpora lutea (CL) present on each ovary. Recovered embryos were evaluated for stage of development and morphological quality. Across …

Effects Of Chemical And Enzymatic Modifications On The Starch-Inclusion Complex Formation, Emily Arijaje

Graduate Theses and Dissertations

Starch-inclusion complexes have been proposed as delivery tools for bioactive molecules; however complexation yield is generally low with low solubility, which may limit the bioavailability of the included molecule. It was proposed that chemical (acetylation) and/or enzymatic (isoamylase and beta-amylase) modifications of starches prior to complex formation with fatty acids of different structures, including stearic, oleic and linoleic acid, may help increase complexation yield and solubility of the resulting starch complexes. Potato starch had a significantly higher complexation yield than common corn and high amylose (~70%) corn starches after debranching combined with a beta-amylase treatment. Debranched waxy maize starch and …

Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour

Graduate Theses and Dissertations

Filamentous fungi are responsible for numerous plant and animal diseases. The filamentous ascomycete Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. Also of substantial concern is the contamination of infected kernels with fumonisins, toxic secondary metabolites linked to toxicoses in humans and livestock. The number of sequenced fungal genomes is rapidly increasing. However, functional characterization of fungal genes has not progressed at a comparable rate. In pathogenic fungi, uncharacterized genes represent a source for novel virulence factors or anti-fungal targets. Therefore, to fully understand the genetic mechanisms underlying fungal pathogenesis, …

Microbial Community Shifts Caused By Changes In The Primary Oxidant At A Drinking Water Treatment Plant, Connie Marie Moloney

Graduate Theses and Dissertations

Microbial communities resistant to common oxidants can cause concerns for water treatment plants (WTPs). If a bacterium is not fully oxidized during disinfection, these species can impede upon filtration processes or seed biofilms in the distribution system. In an effort to minimize disinfection by-products (DBP's) that result from the reaction of chlorine (Cl2) with natural organic matter, water treatment plants have the option to change their primary oxidant to chlorine dioxide (ClO2). The following study examines the change in microbial communities during the sedimentation process under differing oxidation regimes, specifically chlorine (Cl2) and ClO2 at the local water treatment plant …

Identification Of Root-Knot Nematodes (Meloidogyne Spp.) Of Arkansas Using Molecular Diagnostics, Churamani Khanal

Graduate Theses and Dissertations

Root-knot nematodes (Meloidogyne spp.) are highly-adaptable, obligate plant parasites distributed worldwide. In addition, root-knot nematodes are an economically important genus of plant-parasitic nematodes. Meloidogyne incognita, M. arenaria, M. javanica, M. hapla and M. graminis have been reported from Arkansas during 1964 to 1994. Previous identifications were based primarily on morphological characters and host differentials. In this study, identification using molecular diagnostics methods was performed to identify Meloidogyne species present in Arkansas. A total of 106 soil and root samples from 36 of the 75 counties were collected and processed to obtain root-knot nematodes. Polymerase chain reaction (PCR) was performed …

Dissection Of Gray Leaf Spot Of Maize Through Functional Genomics, Robert Louis Hirsch

Graduate Theses and Dissertations

Gray leaf spot, caused by Cercospora zeae-maydis, is a devastating disease of maize that reduces yields and increases management costs. C. zeae-maydis penetrates maize leaves through stomata, but the biological and molecular bases of this process are poorly understood. The goal of this research was to elucidate the biological parameters of stomatal infection in C. zeae-maydis, and to identify and characterize novel genetic pathways involved in stomatal sensing and pathogenesis. Histopathological observations of a GFP-expressing strain of C. zeae-maydis during infection of maize indicated that the fungus responded to host-derived stomatal cues during the infection process. C. zeae-maydis was observed …

Evaluation Of Medicago Truncatula Accessions For Triterpene Saponins And Their Potential Impacts On Plant Pests, Samantha Roberson

Graduate Theses and Dissertations

Plants have developed numerous ways to protect themselves from microbes and insects, including producing secondary metabolites that negatively impact an invading pathogen or pest. Saponins are specialized metabolites found in many plant species and may play a role in protecting the plant. Though saponins are found in many plant species, triterpene saponins are found primarily in dicotyledons, including legumes. Medicago truncatula is a model system for studying legume biology and some accessions accumulate high concentrations of saponins. Accessions of M. truncatula known to have differing levels of saponins in both foliar and root tissues were tested for their suitability as …

The Phenotypic Effects And Transcript Response Of Salt Stress, The Impact Of Viral Infection On Salt Stress Symptoms, And The Effect Of Salt Stress On Soybean Virus Vector Activity In Soybean Varieties That Vary In Chloride Uptake, Alma Glenn Laney

Graduate Theses and Dissertations

With the increase in saline soils worldwide, understanding the mechanisms for salt tolerance in plants is important to reduce yield loss due to salt stress. Soybean, Glycine max (L.) Merr., genotypes differ in chloride uptake with genotypes that take up chloride into foliar tissues tending to be salt-sensitive whereas those that partially exclude chloride from the leaves are more salt-tolerant. Transcriptional and physiological responses were measured in two soybean cultivars, Clark and Manokin, which differ in chloride uptake in response to salt stress and in combination with Soybean mosaic virus (SMV) and its aphid vector, Aphis glycines . The interaction …

Functional Characterization Of The Arginine Vasotocin 4 Receptor (Vt4r) In Sensory Circumventricular Organs Of The Chicken Gallus Gallus, Nguiessan Alphonse Aman

Graduate Theses and Dissertations

Past studies have shown that the avian vasotocin 4 receptor (VT4R), homologous to the mammalian arginine vasopressin receptor 1a (V1aR/AVPR1A) is involved in immobilization stress. It was not known, however, whether the receptor is also associated with osmotic stress, and if so, what brain regions may be involved. Four treatment groups of chicks were used for the study. One group was subjected to 1h immobilization stress and two groups were administered intraperitoneal injection of 3 M NaCl or 0.15 M NaCl. One additional group served as controls. After 1 h, blood samples were taken for the determination of plasma levels …

Investigation Of Nuclear And Cytoplasmic Functions Of The Dlipin Protein Of Drosophila Melanogaster, Qiuyu Chen

Graduate Theses and Dissertations

Lipin family proteins are highly conserved proteins present in species ranging from mammals to yeast. Lipin 1, the first Lipin gene identified in fatty liver dystrophy (fld) mutant mice, encodes the bifunctional protein Lipin 1, which can serve as an Mg2+-dependent phosphatidic acid phosphatase (PAP) and transcriptional co-regulator. dLipin, the single Lipin ortholog of Drosophila melanogaster, is required in triglyceride synthesis and fat body development. To study the transcriptional co-regulator activity of dLipin, nuclear receptors were screened to find receptors that interact with dLipin. The genetic interaction data indicated that Drosophila hepatic nuclear receptor 4 (HNF4) was a promising candidate …

The Elimination Of Listeria Monocytogenes Biofilms From Stainless Steel Deli Meat Slicer Components By The Use Of Hurdle Technologies, Alexandria Wynne Mertz

Graduate Theses and Dissertations

Listeria monocytogenes growth is of the greatest concern amongst ready-to-eat foods. The United States Department of Agriculture's Food Safety and Inspection Services determined that deli luncheon meats pose the greatest risk of contamination from L. monocytogenes Industrial meat slicers have many removable parts that are connected with sealers and gaskets, which can become worn over time. These spaces cannot be cleaned adequately, therefore are susceptible to bacterial growth. Planktonic cells form biofilms in order to protect the cell from adverse conditions, like during routine cleaning and sanitation. Once a biofilm is formed, the bacteria are much more difficult to eradicate …

Evaluation Of Betaine And Methionine Replacement For Improving Performance And Meat Quality For Broilers Reared Under Higher Temperature Conditions, Malea Graham Frank

Graduate Theses and Dissertations

4,096 broiler chicks were randomly allocated to 128 floor pens (32 birds/pen). 2,048 day-old male broilers were placed in the east end of a barn, and the following week 2,048 day-old male broilers were placed in the west end. At each placement day, half of the chicks were Cobb 500 and half were Ross 708, and each pen contained only one breed source. East end birds received coccidiostat in the feed, west end received coccidial vaccine, and each end was under separate environmental control. Eight diets contained two levels of coccidiostat (0, 1 lb./ton), methionine (deficient, adequate), and betaine (0, …

Short-Term Effects Of Poultry Litter Or Woodchip Biochar Amendment In A Temperate Zone Agronomic System, Katy Elizabeth Brantley

Graduate Theses and Dissertations

Biochar, a charcoal product produced by the anaerobic thermal decomposition of biomass, can provide agronomic benefits when soil applied. However, research is lacking in temperate region soils investigating specific biochar products and their effects on agronomically important crops. A greenhouse study utilizing poultry litter biochar and a field study utilizing pine woodchip biochar were conducted to observe the effects of biochar application to Northwest Arkansas soils on corn growth and nutrient availability. A third experiment investigated poultry litter and pine woodchip biochar influences on soil water retention. In all three experiments, biochar was applied at three rates (0, 5, and …

Identification And The Significance Of Selective Proteins In Bile And Plasma Of Normal And Health-Compromised Chickens, Balamurugan Packialakshmi

Graduate Theses and Dissertations

During the last 50 years, animal breeding programs in commercial poultry have made significant progress in the bodyweight gain of broilers but led to several metabolic and skeletal disorders. Lameness associated with proximal femur known as femoral head separation (FHS) or femoral head necrosis (FHN) is one of the major metabolic disorders in poultry industry. In order to select for healthy chickens, markers that can distinguish between healthy and affected birds are required. Biomarkers from blood represent an ideal and rich source of markers which can be obtained using minimally invasive methods. The biomarkers were explored in an experimental model …

Evaluation Of Porcine Ipec-J2 Cell Line Growth Rate And Immune Response To E. Coli (0111:B4) Lps, Xiaofan Wang

Graduate Theses and Dissertations

The objective of this study was to evaluate the intestinal porcine epithelial cell-jejunum 2 (IPEC-J2) cell line as a model to study the innate immune function of live pigs. Growth rates of IPEC-J2 cells in T-75 flasks and 96-well plates were evaluated using a hemocytometer and spectrophotometer for cell quantity measurements to determine growth rate and doubling time. Growth rates of IPEC-J2 cells in T-75 flasks and 96-well plates were 0.4016 and 0.2851 times of doubling/day respectively with a doubling time of 1.73 d and 2.43 d, respectively. Confluent IPEC-J2 monolayers were tested at five time intervals (0, 1, 2, …

Switchgrass Cultivar, Harvest Frequency, Fertilizer Source, And Irrigation Effects On Near-Surface Soil Properties In West-Central Arkansas, Alayna A. Jacobs

Graduate Theses and Dissertations

Switchgrass (Panicum virgatum L.) has been identified as a model bioenergy feedstock crop and is expected to become an important feedstock for future renewable fuel generation. Agronomic management combinations that maximize monoculture switchgrass yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management combinations on near-surface soil properties. The objective of this research was to determine the residual near-surface soil property effects of three years (2008 to 2011) of consistent management combinations to maximize switchgrass biomass production, including cultivar (‘Alamo’ and ‘Cave-in-Rock’), harvest frequency (1-cut and 2-cut systems per year), fertilizer source (poultry …

Development Of A Turkey Coccidiosis Vaccine Candidate: An Attenuated Line Of The Protozoan Parasite, Eimeria Meleagrimitis, Thilakar Rathinam

Graduate Theses and Dissertations

Coccidiosis is an economically important enteric disease of poultry caused by protozoan parasites belonging to the genus Eimeria. Drugs are most commonly used to control coccidiosis. Widespread usage of anticoccidial drugs in the field has resulted in development of drug resistant strains and consequently decreased drug efficacy. An alternative control strategy using attenuated vaccines is desired. A series of experiments was designed to identify, isolate and attenuate a strain of a common and pathogenic species of Eimeria of turkeys, E. meleagrimitis.

Sensitivity of field isolates of turkey coccidia to the anticoccidials drugs amprolium, clopidol, diclazuril, and monensin was investigated. A …

Antibacterial Activity Of Commercially Available Plant Extracts On Selected Campylobacter Jejuni Strains, Divya Oppath Sivasankaran

Graduate Theses and Dissertations

Campylobacter jejuni is recognized as a leading cause of foodborne illness worldwide with approximately 850,000 cases per year in the United Sates. A total of 18 species of Campylobacter have been identified worldwide to date. Foodborne transmission of C. jejuni is mainly through the consumption of unpasteurized milk, contaminated poultry meat and water. C. jejuni can survive in very diverse environments under stressful conditions in human and animals which is different from the specific conditions and media required in laboratory experiments. There has been increased research in recent years to identify naturally occurring antibacterial agents to control and eliminate C. …

Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz

Graduate Theses and Dissertations

Approximately 40,000 women will die from breast cancer in the United States in 2014. About 90% of these deaths will be due to metastases, rather than the primary tumor and majority of metastases are due to the recurrence and progression of non-metastatic disease. Current adjuvant treatments, such as chemotherapy and radiation, have severe side effects and may result in overtreatment and drug resistance.

Since greater than 90% of patients are diagnosed between stages I-III and have minimal residual disease after treatment, there is an opportunity to treat patients with an autologous breast cancer vaccine. Autologous vaccines under development have a …

Alkaline Hydrolyzable-Nitrogen, Seeding Date, And Clay-Fixed Ammonium As Potential Indicators Of Rice Response To Nitrogen Fertilization In Arkansas, Anthony Michael Fulford

Graduate Theses and Dissertations

Several potential indicators of rice (Oryza sativa L.) response to nitrogen (N) fertilization include the soils alkaline hydrolyzableN (AHN) concentration, seeding date, and the soils clayfixed NH₄N content. Three studies were conducted to: (1) correlate AHN, determined using Illinois Soil Nitrogen Test (ISNT) or Nitrogen Soil Test for Rice (NSTaR), to plant parameters of interest and develop a fertilizer N rate calibration curve capable of predicting the 95% relative grain yield (RGY) fertilizer N rate for rice grown on clayey soils; (2) evaluate the influence of seeding date and N fertilization on rice plant growth and grain …

Measuring The Role Of Inhibition In Auditory Discrimination In Mice, Tazima Nur

Graduate Theses and Dissertations

Understanding how inhibitory neurons affect sensory information processing in the cerebral cortex is an ongoing goal of both neuroscience and statistical physics research. In this master's thesis research project, an experimental system has been designed and built for studying how auditory dynamic range depends on inhibitory neurons, based on observations of mouse behavior. In this thesis, firstly, the topic of inhibition and information processing has been introduced. Then two papers related to inhibition and dynamic range has been reviewed in detail. One of the papers is an experimental work that analyzes the affect of inhibition on dynamic range. The other …

The Economic Viability Of Cocoa Crop Insurance In Ghana, Justin D. Mckinley

Graduate Theses and Dissertations

This study was motivated by the fact that Ghanaian cocoa producers face lower yields than other main cocoa producing counties which in turn increases food insecurity for smallholder producers. In addition, low yields experienced by Ghanaian producers is a driving factor for forest degradation and deforestation as cocoa producers encroach further into previously undisturbed forests in efforts to increase their incomes. There are currently production methods to achieve higher yields readily available in Ghana; however, many producers choose not to adopt these methods because they are seen as too risky, or simply cannot adopt them due to financial/credit constraints. A …