Life Sciences Commons^™

Heat Stress Response And Excystation In Entamoeba Histolytica, Irem Bastuzel

All Dissertations

Entamoeba histolytica is a water- and food-borne intestinal protozoan parasite that causes amoebiasis and liver abscess and is responsible for symptomatic disease in approximately 100 million people each year leading to ~ 100,000 deaths. The most common disease transmission follows the oral-fecal route, but it can also be transmitted by mechanical vectors such as animals carrying the amoeba from contaminated sources to water systems. In rare cases, disease transmission has been recorded in some patients in which men-to-men sexual practices were preferred.

The life cycle of E. histolytica starts through ingestion of infectious cysts, which are non-dividing, quadri-nucleated structures surrounded …

Crosscutting Understandings Of Fusarium Resistance In Sorghum And Wheat For Development Of Breeding Strategies And Novel Opportunities In Germplasm Improvement, Arlyn Ackerman

All Dissertations

Fusarium causes widespread disease in crops resulting in yield and quality loss across a range of host taxa that results in global incidence of carcinogenic mycotoxins contaminating the world’s food systems. This research sought to crosscut frameworks developed across the Fusarium host crop species of wheat (Triticum aesitivum) and sorghum (Sorghum bicolor [L] Moench) to further understand mycotoxin suppression and resistance. A deeper understanding of the biochemical resistances available in sorghum grain mold (SGM) was built by following research of wheat based upon deoxynivalenol resistance to Fusarium head blight (FHB). Through this research, phenotyping methods for Fusarium damaged kernels …

Genetics And Genomics Education Among Physician Assistants, Wesley Patterson

All Dissertations

This dissertation comprises five chapters to describe genetics and genomics education among physician assistant/associate (PA) students and practicing PAs. Chapter I introduces the gap in supply and demand of genetic services, the need for non-genetics healthcare providers to fill the gap, and the PA profession as a solution.

Chapter II is a rapid literature review that summarizes the available literature regarding genetics and genomics education for PAs. A paucity of literature exists to describe the current state of PA genetics-genomics education. The few studies retrieved describe content being taught in PA programs, the number of genetics-genomics contact hours PA students …

Microbial, Chemical, And Functional Components In Kefir, Natto, And Feed Ingredients, Dana Mccurdy

All Dissertations

Kefir grains were purchased from online, home kitchen vendors in the United States (n = 22), inoculated into UHT milk, and incubated at 25°C for 22 hours. Results indicated lactobacilli, lactococci and yeast in all samples. Six out of 11 samples contained coliform, and all samples contained pseudomonal and staphylococcal species. Using targeted genome sequencing (16S) of kefir grain samples 1, 2, and 3 revealed that lactobacilli were the predominant genera of bacteria. ITS sequencing revealed different fungal species in each grain. Results indicated potential presence of menaquinone-4 and menaquinone-7 by UPLC-MS/MS analysis.

The fermentation of whole and ground soybeans, …

Subchronic Dermal Toxicity Study Of Tithonia Diversifolia (Hemsley) A. Gray Gel Formulation In Wistar Rats, Muflihah Rizkawati, Mae Sri Hartati Wahyuningsih, Setyo Purwono, Dwi Aris Agung Nugrahaningsih, Abdul Karim Zulkarnain

The Thai Journal of Pharmaceutical Sciences

Background: Tithonia diversifolia has been widely developed as an anticancer therapy. Our previous study before showed that T. diversifolia was able to inhibit cell proliferation and collagen accumulation of keloid fibroblasts and decrease the index of rabbit scar hypertrophy. The acute dermal toxicity study of T. diversifolia gel formulation did not show toxic effect for 14 days and the LD50 was estimated more than 2%. However, toxicity data subchronic dermal toxicity study was not available for this T. diversifolia gel formulation. Objectives: Our study aimed to evaluate the subchronic dermal toxicity of T. diversifolia gel formulation in rats. Materials and …

Preparation And Stability Of Fluocinolone Acetonide Premicroemulsion Concentrates And Microemulsions For Oral Lichen Planus Treatment, W. Muangsiri, P. Chukaewrungroj, Pornpen Werawatganone

The Thai Journal of Pharmaceutical Sciences

Purpose: Fluocinolone acetonide (FA) preparations were developed in the forms of premicroemulsion concentrates and microemulsions and their stabilities were evaluated. Materials and Methods: A pseudoternary diagram of clove oil, surfactant mixture (containing polysorbate80: Polyethylene glycol 400 [PEG400] at the ratio of 2:1), and water was constructed for the formulation of FA premicroemulsion concentrates and microemulsions. Physical properties and chemical stabilities of the preparations were monitored in the absence and presence of three antioxidants. Their beyond-use dates were determined. Results and Discussion: The premicroemulsion concentrates and microemulsions containing polysorbate 80, PEG400, and clove oil successfully improved FA solubility. Average diameters of …

Infection And Transmission Determinants Of Flea-Borne Rickettsioses, Hanna J. Laukaitis

Graduate Theses and Dissertations (2019 - present)

The genus Rickettsia is comprised of Gram-negative, obligate intracellular bacteria that are spread by hematophagous arthropods. Elucidating the factors conferring rickettsial virulence has perplexed investigators for decades, complicated by the lack of efficient genetic tools necessary to uncover rickettsial- and vector-specific factors contributing to persistence. The advent of transposon mutagenesis has enabled the field to make vast developments in uncovering novel rickettsial mechanisms utilized in various host backgrounds. Thus, the aim of this study was to generate Rickettsia felis transposon mutants and characterize novel phenotypes associated with genetic disruption in an arthropod background. Distribution of rickettsiae is reliant on the …

Genomic Analysis And Characterization Of Surface Properties Of Naphthalene Degrading Acinetobacter Isolates, Gunn Emilie Berge

Graduate Theses and Dissertations (2019 - present)

No abstract provided.

An Examination Of Sex-Differences In Quadriceps Fatigability During High- And Low-Intensity Contractions, Katie G. Kennedy

Graduate Theses and Dissertations (2019 - present)

The purpose of the current study was to compare sex-differences in quadriceps fatigability following both high- and low-intensity repeated, isometric contractions. Twenty-four (12 males, 12 females) participants completed two experimental visits consisting of repeated, isometric contractions of the knee extensors at 30% (LT) and 70% (HT) of maximal voluntary force (MVIC) until failure. Prior to, and immediately following the fatiguing contractions, strength, voluntary activation (VA), and peak twitch torque (PTT) were assessed while measuring surface electromyographic amplitude of the vastus lateralis (VLAMP) and vastus medialis (VMAMP ). Fatiguing bouts were assessed via mean torque (TQMEAN), total repetitions completed, torque coefficient …

Determining The Full-Length Structure Of Collagenase H Using Small-Angle X-Ray Scattering, Josie Carson

Chemistry & Biochemistry Undergraduate Honors Theses

Known to cause gas gangrene, Hathewaya histolytica secretes two sister collagenases, collagenase G (Col G) and collagenase H (Col H), to degrade the triple helical structure of collagen to further infection in a host. Individual domains of Col H have been crystalized in previous studies, but methods in x-ray crystallization of full-length Col H have been unsuccessful. Using Small Angle X-Ray Scattering (SAXS) data, atomistic modeling was used to generate multiple conformations of Col H while accounting for flexibility between domains. Full-length Col H was found to adopt a two-state conformational model exhibiting a majority compact and a minority elongated …

Tools To Advance Environmental Monitoring, Wetland Restoration And Education In The Desert Southwest, Anna Elisa Pina

Open Access Theses & Dissertations

The relatively rare freshwater ecosystems in the southwestern United States serve as biodiversity hotspots, yet they are among the most threatened systems in the world due to human impacts and climate change. Despite their importance to this arid landscape, the aquatic communities of desert wetlands remain relatively understudied. To restore and create new wetland habitats, effluent is becoming a more commonly used water source for these habitats. However, the effects of byproducts within the treated wastewater on these unique systems have not been well studied. In this study, we aim to better understand the factors that drive water quality and …

Development Of A Ph-Triggered Cargo Delivery System With Esxa Mutants, Shuchen Chen

Open Access Theses & Dissertations

Tuberculosis (TB) is a communicable disease caused by Mycobacterium tuberculosis (Mtb). It was the leading cause of human death generated by a single infectious agent before the Coronavirus (COVID-19) pandemic. Mtb has a special mechanism to evade the hostâ??s immune system and utilize macrophages as reservoirs. Latent TB infections have been a threat to public health. Liposome has been widely used for drug delivery. Immunoliposomes are special liposome carriers coated with ligands, such as antigens, targeting certain cells or organs to regulate the uptake of liposome. By constructing the liposome components, or surface modification, cargo release of liposome can be …

Water Sourcing Strategies Of Desert Vegetation In Varying Soil Textures With Vegetation Competition: A Stable Isotope Analysis, Martha Elizabeth Gardea

Open Access Theses & Dissertations

Recent studies have suggested an ecohydrological separation of water exists in the northern Chihuahuan Desert, where vegetation types, rainfall regimes, and location in the terrain seem to determine the type of water (e.g. isotopically depleted or enriched in 18O and 2H) plants are able to source and use throughout their growing cycle. That work found evidence of creosote (Larrea tridentata) and mesquite (Prosopis glandulosa) using tightly bound soil water at both a site on an ephemeral channel and a site in higher elevated flat area because the isotopic signature of plant water at the beginning of the study did not …

Chihuahuan Desert Rock Pool Community Assemblages: Patterns Of Taxonomic Diversity, Joseph Lee Mcdaniel

Open Access Theses & Dissertations

As climate change continues to become more prevalent, increasing temperatures and altering precipitation patterns will disrupt the environmental balance of ecosystems and spark the imminent threat of a 6th mass extinction event. Many researchers believe this has already begun, as losses for numerous taxonomic clades have been well documented; however, the loss of invertebrates is still unknown and may be much more severe than those of other animal clades. A significant factor contributing to the shortfall of invertebrate biodiversity loss is rooted in the lack of understanding of the diversity and distribution of these animals. There is still much to …

Evaluation Of The Feeding Value Of Proso Millet In Growing-Finishing Diets For Pigs And Effects Of Feed Ingredients And Medium-Chain Fatty Acids On Porcine Reproductive And Respiratory Syndrome Virus (Prrsv) Survivability, Khang Nguyen

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of the project were to: 1) evaluate the feeding value of proso millet as a potential substitute for corn in corn-soybean meal-based diets for pigs; and 2) investigate the relationship between feed ingredients and virus survivability, followed by examining feed additive candidates that could mitigate the risk of transmission of viral pathogens.

In Exp. 1, 36 barrows were fed 1 of 4 dietary treatments, including: Diet 1, corn-soybean meal-based (control), and Diets 2, 3, and 4 had proso millet replacing 33%, 67%, and 100% of corn in the control diet, respectively. During Phase 3, pigs consuming the proso …

Impact Of Increasing Level Of Milk Production On Cow And Calf Behavior And Performance In The Nebraska Sandhills, Selby L. Boerman

Department of Animal Science: Dissertations, Theses, and Student Research

Selection for increased milk production across the United States has resulted in variable cow and calf production responses. Better understanding of calf nursing and grazing behaviors may provide opportunities to help estimate how milk and grazed forage intake influence variability in calf performance. In a 2-yr study, cow-calf pairs (n = 65) were equipped with neck collars containing global positioning system (GPS) units to validate the efficacy of high-frequency GPS data to accurately identify calf nursing events and grazing behavior. Data were collected during 3-wk tracking periods during early lactation (calf age 65.4 ± 10.0 d; EARLY) and late …

Using Strategic Supplementation To Enhance Cow/Calf Productivity In Summer Calving Herds In The Nebraska Sandhills, Nicole M. Woita

Department of Animal Science: Dissertations, Theses, and Student Research

Young range beef cows consuming low-quality forage may result in an imbalance of energy and metabolizable protein, which can negatively affect the nutrient status of the cow and reproductive performance. In a 2-yr study conducted at Gudmundsen Sandhills Laboratory near Whitman, NE, 2- and 3-yr-old May-calving range cows (n = 181) grazing native range were individually supplemented daily with one of four supplements: 1) mineral with a target intake of 113 g/d (MIN), 2) MIN with 200 mg per head of Rumensin to with a target intake of 113 g/d (RUM), 3) MIN with a 226 g/d of high …

Investigating Bacterial Community Composition And Antimicrobial Resistance Genes In Beef Cattle, Arena E. See

Department of Animal Science: Dissertations, Theses, and Student Research

While antibiotics have been critical over the last decade for curbing infectious diseases, they have contributed to the rise of antimicrobial resistance (AMR). Infections resulting from antimicrobial-resistant pathogens are correlated with severe morbidity, mortality, and healthcare costs. With the increasing concerns regarding AMR and its emergence, it is paramount to understand not only the effects of antibiotics on microbial community and diversity, but also to develop a novel tool that gives us a better understanding of the spread and functional traits of AMR genes.

To this end, rumen, fecal, and pen surface samples were collected from 72 animals at United …

Preclinical Development Of Novel Chemotherapeutic Agent Ac1lpszg: Formulation Optimization, In Vitro Characterization, And In Vivo Pharmacokinetics, Ritu Gupta

Dissertations (2016-Present)

Preclinical development of novel chemotherapeutic agent AC1LPSZG, a mammalian target of rapamycin (mTOR) inhibitor, involved development of sensitive reverse-phase ultra-performance liquid chromatography (UPLC) and LC-MS/MS methods for quantification of AC1LPSZG in in vitro study samples and rat plasma, respectively. Pharmacokinetic studies were done in SD rats after intravenous injection of cosolvent formulations. The resulting pharmacokinetic parameters were analyzed using non-compartmental analysis (NCA) and two-compartmental modeling. Poly (D, L-lactic-co-glycolic acid) (PLGA) is most used biodegradable synthetic polymer for nano drug delivery due to its non-toxic and biodegradable nature, and tunable release properties. PLGA nanoparticles (NPs) were prepared by ‘nanoprecipitation’ technique using …

Expression Of Claudins In Gill And Opercular Membranes In Relation To Osmoregulation In Euryhaline Atlantic Killifish, Fundulus Heteroclitus, Allison Mcfarland

Graduate Theses and Dissertations

Atlantic killifish (Fundulus heteroclitus) are euryhaline teleosts, which means they can thrive in environments with varying salinities, ranging from concentrated seawater (SW) to dilute fresh water (FW) and thus survive in estuaries. To be able to maintain ionic and osmotic homeostasis in these diverse salinities, osmoregulatory organs like gill and opercular membrane must be able to adjust the permeability and transport of water and ions. The surface epithelia in these organs need to prevent the passive flux of ions and water in a drastically changing environment, while being able to switch between active ion secretion or uptake dependent upon environmental …

Patterns Of Evolutionary Conservation And Divergence In The Short-Term Hyposalinity Stress Response Of A Euryhaline Diatom, Skeletonema Marinoi, Kathryn Judy

Graduate Theses and Dissertations

Survival under fluctuating environmental conditions, such as those increasing in frequency and magnitude under environmental change, requires a successful response to stress. Interspecific differences in stress responses may result in differential survival of species, even within a lineage. Diatoms may constitute one such lineage, as salinity tolerance among extant species is diverse, and the observation of frequent historic habitat transitions between marine and freshwater environments indicates that diatoms successfully mitigated (low) salinity stress in the past, followed by adaptation and diversification over evolutionary time scales. To understand to what extent the diatom hypoosmotic stress response consists of conserved and variable …

Determination Of The Functional Role Of Rab-Ggt In Physcomitrium Patens., Hyun Jin Jung

Electronic Theses and Dissertations

Protein prenylation, a common lipid post-translational modification, is required for growth and development in eukaryotes. Rab geranylgeranylation involves the addition of one or two 20-carbon geranylgeranyl moieties to Rab-GTPase target proteins, which regulate intracellular vesicle trafficking. The reaction is carried out by heterodimeric Rab geranylgeranyltransferase (Rab-GGT), which is composed of two associated α- and β-subunits, with the assistance of an additional protein called Rab escort protein (REP). Loss of function of the Rab-GGT α subunit RGTA1 has not been reported in any plant. While knockout of either of the two β subunits RGTB1 or RGTB2 results in …

Application Of Cannabidol To Ocular Pharmacokinetics And Pharmacodynamics., Alyssa Laun

Electronic Theses and Dissertations

Cannabidiol (CBD) is the most abundant non-psychotropic cannabinoid constituent of Cannabis sativa. CBD is potentially therapeutic for the eye through antioxidant, anti-inflammatory, and neuroprotective effects. However, the effect of CBD on intraocular pressure (IOP)- the major risk factor for glaucoma- is controversial and large variability exists in the literature. IOP is regulated through aqueous humor (AH) dynamics in trabecular meshwork (TM) tissues. Measurement of CBD in AH and correlation with effects on IOP would clarify what concentrations mediate changes to IOP. Therefore, the overall goal of this dissertation is to measure CBD in ocular tissues and correlate concentrations with …

Evaluation Of Factors That Contribute To Injury To Quizalofop-Resistant Rice From Quizalofop Applied Postemergence, Navdeep Godara

Graduate Theses and Dissertations

Quizalofop-resistant rice technology allows for over-the-top applications of quizalofop, an acetyl-coenzyme A carboxylase-inhibiting herbicide. However, quizalofop caused significant injury to quizalofop-resistant rice in some Arkansas fields during the first year of commercialization. Experiments evaluated the effect of early-season soil moisture and nitrogen availability; pre-exposure to low rates of glyphosate and imazethapyr; planting date; and environmental conditions including, soil moisture content, air temperature, and light intensity on quizalofop-resistant rice tolerance to quizalofop applications. All experiments assessed sequential quizalofop applications made to 2-leaf followed by 5-leaf stage of rice. Sequential quizalofop applications alone and with surface irrigation or nitrogen application at the …

Histomonosis In Turkeys – Factors Influencing Transmission, Pathogenesis, And The Search For Prophylactic Or Therapeutic Compounds, Thainá Landim De Barros

Graduate Theses and Dissertations

The incidence of histomonosis has been increasing in poultry since the ban of prophylactic and therapeutic compounds. Histomonosis is caused by the protozoa Histomonas meleagridis. The objective of this dissertation was to investigate factors impacting the pathogenesis and transmission of histomonosis and to evaluate compounds that could potentially prevent or reduce the severity of histomonosis in turkeys. In the first study, the effect of sodium chlorate and sodium nitrate on reducing histomonads growth was tested in vitro and added to a basal turkey diet. A decrease in the growth of histomonads in vitro was observed, but no in vivo effect …

Sex Differences In Cancer Cachexia And A Novel Mitochondrial Target For Cancer-Induced Muscle Wasting, Seongkyun Lim

Graduate Theses and Dissertations

Cancer cachexia (CC) is a devastating wasting syndrome characterized by marked weight loss including skeletal muscle atrophy that affects approximately 80% of cancer patients. Current therapeutic treatments including pharmacological and nutritional intervention are insufficient to prevent or reverse it. Prior studies demonstrated lower muscle mass, impaired muscle function, and mitochondrial health in the development of CC. Specifically, mitochondrial fusion protein, Optic atrophy 1 (OPA1) which plays a significant role in skeletal muscle health, is suppressed in the development of CC. Furthermore, most pre-clinical CC studies were mainly focused on males although there are distinct phenotypical differences in skeletal muscle between …

The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills

Graduate Theses and Dissertations

Alzheimer’s disease and related dementia (ADRD) rates are expected to triple by the year 2050. Early detection and specific mitigation efforts are warranted to blunt the alarming rate. Physical function (PF) declines with age, but higher physical function is associated with better cognitive functioning in middle-to- older age individuals. Moreover, greater physical activity (PA) is associated with better global cognition; however, Apoliporotein e4 carriers may not gain the same benefits with exercise. Additionally, plasma phosphorylated tau 217 (p-tau217) has been identified as a novel diagnostic ADRD biomarker which needs further research to examine associations with risk factors. Therefore, the aims …

The Role Of Temperature Variation On Macrophage Physiology And Function In Vitro In Mice, Chicken, And Fish, Intisar Abdullah Hassan

Graduate Theses and Dissertations

Fever is an essential component of the immune response. Baseline body temperatures vary in different species, and fever represents increased temperature over baseline. Fever initiates and enhances immune responses as well as creates an environment in which the body has advantages over pathogens. Macrophages are often the first line of cells that come in contact with pathogens, asthey reside in and traffic through tissues. They are important for their engulfment of pathogens that results in the digestion of the pathogen, and they also produce nitric oxide and cytokines that contribute to immune responses in a variety of ways, including initiating …

A Cross-Scale Nexus: Microbial Functional Genes In Tandem With Molecular-Level Nitrogen Fluxes And Implications For Field-Scale Biogeochemical Processes, Srusti Maddala

Graduate Theses and Dissertations

Nitrogen (N) biogeochemical cycling entails close networking between soil nutrients, plant species and resulting microbial communities, and abiotic factors such as temperature, moisture, and pH. To better understand transformations of N in soil microsites, which are known to be rich in N-cycling behavior, the microdialysis technique was employed to generate in situ data on temporal alterations of N during wetting-drying conditions in both the field and laboratory. The objectives were to 1) determine the lifespan of the microdialysis technique in field conditions, 2) evaluate the ability of the method to yield N fluxes that would be differential between the two …

Discrete Choice Experiments In Agricultural And Food Economics: Two Essays On Information Provision Modalities, Uncertainty Adjustment, And Hypothetical Bias, Monsoïa Arsène Juste Agossadou

Graduate Theses and Dissertations

Stated discrete choice experiments are extensively used in applied economics to study preferences and valuation for new products, as well as costs and benefits of new policies and programs. Moreover, information provision experiments widely use the method to examine information effects on different outcomes. This thesis explores two methodological issues in discrete choice experiments: (i) information provision modalities and (ii) hypothetical bias. The first study examines the effect of information modality by testing the effect of using combined text script and audio clip (treatment) versus only text script (control) to convey information in discrete choice experiments. Specifically, the study elicits …