The Role Of Efflux Pump Inhibitor In Enhancing Antimicrobial Efficiency Of Silver Nanoparticles And Methylene Blue As An Effective Photodynamic Therapy Agent, Yaran Allamyradov

Masters Theses & Specialist Projects

Efflux pumps are critical active transport systems utilized by cells to expel toxic substances, including antibiotics and photosensitizer complexes, thereby contributing to antimicrobial resistance. Efflux pump inhibitors (EPIs), which are compounds that obstruct the transport of molecules through these pumps, play a pivotal role in enhancing the effectiveness of antimicrobial therapies against pathogens. This study investigates the effects of the EPI reserpine on the photodeactivation rate of pathogens when used in conjunction with silver nanoparticles (Ag NPs) and methylene blue (MB), a common photosensitizer.

Our research reveals that the application of reserpine, in combination with Ag NPs and MB, leads …

Functional Characterization Of A Lncrna Afu-254 In Stress Response And Pathogenesis Of Aspergillus Fumigatus, Ritu Devkota

All Theses

Aspergillus fumigatus is a saprophytic fungus that can cause a collection of diseases termed aspergillosis; the most severe is invasive pulmonary aspergillosis (IPA). Azole is a major class of antifungal drugs used to treat invasive pulmonary aspergillosis. However, in recent years, there has been an increase in fungal resistance to azole drugs, making the treatment of IPA even more challenging. It is becoming increasingly clear that long non-coding RNAs (lncRNAs), i.e., the RNAs that do not translate into proteins, mediated regulation is vital in stress response and pathogenesis; however, the mechanisms of how lncRNA contribute to fungal stress resistance and …

Establishment Of A Novel Prairie Vole (Microtus Ochrogaster) Sars-Cov-2 Infection And Transmission Model, Stephanie Rebecca Kehl

Open Access Theses & Dissertations

Considering that the number of SARS-CoV-2 cases and deaths continues to increase three years after the onset of the pandemic, the need for animal models to study disease pathology and test antiviral effectiveness remains paramount. Prairie voles offer unique advantages as an infection model, such as mirroring human social behavior, including pair bonding and biparental offspring rearing, having inducible estrus and ovulation cycles, and not being overly domesticated. Based on the sequence homology of the vole ACE2 receptor to that of other species that are susceptible to SARS-CoV-2, such as the ferret and hamster, we hypothesized that the vole ACE2 …

Manipulation Of Cellular Proliferating Cell Nuclear Antigen (Pcna) During Herpes Simplex Virus Type 1 Infection, Jessica Packard, Jill A. Dembowski

Electronic Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a double stranded DNA virus that replicates within the nucleus of host cells. Using accelerated native isolation of proteins on nascent DNA (aniPOND), cellular proteins were found to associate with HSV-1 replication forks. One host factor of interest is proliferating cell nuclear antigen (PCNA), the DNA sliding clamp that tethers DNA polymerases and DNA damage response proteins to replicating cellular DNA. Although HSV-1 encodes its own DNA polymerase processivity factor (UL42), PCNA plays a key role in HSV-1 infection. We used commercially available PCNA inhibitors and short hairpin RNAs (shRNA) to investigate how …

Elucidating The Roles Of Septin Proteins In Thermotolerance And Cell Wall Integrity In Cryptococcus Neoformans, Stephani S. Martinez Barrera

All Dissertations

Cryptococcus neoformans is a globally distributed fungal pathogen responsible for causing cryptococcal meningitis in immunocompromised individuals. This pathogenic yeast must adapt to changes in temperature upon entering the human host. Septin proteins are conserved filament-forming GTPases that assemble as higher-order complexes at the cell cortex to support cytokinesis and morphogenesis in fungal and animal cells. In C. neoformans, four septin homologs (Cdc3, Cdc10, Cdc11, and Cdc12) assemble at the mother-bud neck, contributing to cytokinesis through poorly understood mechanisms. C. neoformans strains lacking the septins Cdc3 or Cdc12 are viable at 25°C, but fail to proliferate at 37°C, and are …

Assessment Of Tce And Chiral Pcb Dechlorination Rate, Congener Diversity, And Enantioselectivity In Town Creek, Sc, Usa Sediment Microcosms, Catherine P. Sumner

All Dissertations

Polychlorinated biphenyls (PCBs) and trichloroethene (TCE) are ubiquitous contaminants and are recognized as persistent organic pollutants due to their extreme chemical stability. PCBs were manufactured by chlorinating biphenyls that created 209 congeners with various structures, of which 19 are chiral and can exist as a pair of stable atropisomers. PCBs have been known to cause developmental and neurological toxicity in humans and wildlife; they can act as endocrine disrupters, carcinogens, and teratogens. Sangamo Weston Inc. was an industrial plant located near Town Creek in Pickens Country, South Carolina, that manufactured capacitors and used Aroclors 1016 and 1254 as dialectic fluids …

Investigation Of The Microbiome Of A Recirculating Aquaculture System (Ras) For Crassostrea Virginica Larvae, Isabelle Townsend

Master's Theses

Recirculating Aquaculture Systems (RAS) offer control over physicochemical and biological factors impacting aquaculture success. One understudied facet of RASs is the water microbiome. Oyster larval microbiomes are shaped by their aquatic microbiomes. Understanding the dynamics of and the factors shaping RAS microbiome may provide insights to how the microbiome can be a tool for optimizing larval production. This study’s goals were to investigate the microbiome stability of a RAS rearing oyster larvae across time and space, determine impacts of larval presence on the microbiome, and examine connections between larvae production outcomes and microbiome stability. Water samples were collected weekly from …

Synergistic Effects Of Novel Penicillin-Binding Protein 1a Amino Acid Substitutions Contribute To High-Level Amoxicillin Resistance Of Helicobacter Pylori, Alain Cimuanga-Mukanya, Evariste Tshibangu-Kabamba, Patrick De Jesus Ngoma Kisoko, Fabien Mbaya Tshibangu, Antoine Tshimpi Wola, Pascal Tshiamala Kashala, Dieudonné Mumba Ngoyi, Steve Ahuka-Mundeke, Gunturu Revathi, Ghislain Disashi-Tumba

Pathology, East Africa

The growing resistance to amoxicillin (AMX)—one of the main antibiotics used in Helicobacter pylori eradication therapy—is an increasing health concern. Several mutations of penicillin-binding protein 1A (PBP1A) are suspected of causing AMX resistance; however, only a limited set of these mutations have been experimentally explored. This study aimed to investigate four PBP1A mutations (i.e., T558S, N562H, T593A, and G595S) carried by strain KIN76, a high-level AMX-resistant clinical H. pylori isolate with an AMX minimal inhibition concentration (MIC) of 2 µg/mL. We transformed a recipient strain 26695 with the DNA containing one to four mutation allele combinations of the pbp1 gene …

Evaluating The Impact Of The Poultrystar®Bro Probiotic On The Incidence Of Bacterial Chondronecrosis With Osteomyelitis Using The Aerosol Transmission Challenge Model, Ruvindu Perera, Khawla Alharbi, Amer Hasan, Andi Asnayanti, Anh Dang Trieu Do, Abdulkarim Shwani, Raj Murugesan, Shelby Ramirez, Michael Kidd, Adnan A. Alrubaye

Poultry Science Faculty Publications and Presentations

Bacterial chondronecrosis with osteomyelitis (BCO) lameness is a major welfare issue for broiler production worldwide affecting approximately 1.5% of broilers over 42 days old. Excessive body weight gain causes mechanical stress on long bones, leading to micro-fractures. This condition induces a bacterial infection of fractures, resulting in bone necrosis and eventual BCO lameness. Increasing gut integrity and supporting Calcium metabolism contribute to the optimal bone structure and subsequently reduce BCO lameness. Probiotics thus provide an excellent strategy for alleviating BCO due to the improvement of intestinal integrity and barrier function. Accordingly, the present study investigated the lameness reduction through the …

Phylogenomic Analyses Of Three Distinct Lineages Uniting Staphylococcus Cohnii Snd Staphylococcus Urealyticus From Diverse Hosts, L. Caroline House, Amer Hasan, Andi Asnayanti, Adnan A. Alrubaye, Jeff Pummill, Douglas Rhoads

Poultry Science Faculty Publications and Presentations

We sequenced and assembled genomes for 17 isolates of Staphylococcus cohnii isolated from osteomyelitis lesions in young broilers from two separate experiments where we induced lameness using a hybrid wire-litter flooring system. Whole genome comparisons using three different methods support a close relationship of genomes from both S. cohnii and Staphylococcus urealyticus. The data support three different lineages, which we designated as Lineage 1, Lineage 2, and Lineage 3, uniting these two species within an evolving complex. We present evidence for horizontal transfer between lineages of genomic regions from 50–440 kbp. The transfer of a 186 kbp region from …

The Impact Of Reactive Oxygen Species On Bactericidal Activity And Drug Resistance In Salmonella Typhimurium Upon Chlorine And Eugenol Exposure, Mohammed Aljuwayd

Graduate Theses and Dissertations

Salmonella Typhimurium (S.T) is a foodborne pathogenic bacterium which causes salmonellosis in human beings. Chicken is the most common source of S.T contamination. In chapter I, I discuss the growth of the poultry industry, the role chickens play as Salmonella reservoirs, the spread of drug-resistant strains caused by chicken husbandry and antibiotic use, and how eugenol can be used in poultry feed to decrease Salmonella infections and improve intestinal health. In chapter Ⅱ, I summarize the role of reactive oxygen species (ROS) in bactericidal activity. In chapter Ⅲ, I describe the killing mechanism of sodium hypochlorite (NaOCl) and identify the …

Pilz Domain-Containing Proteins Regulate Motility In Acinetobacter Baumannii, Gabriel Smith

Electronic Theses and Dissertations

Acinetobacter baumannii is an increasingly multidrug-resistant pathogen contributing to hospital-acquired infections, necessitating a greater understanding of how it interacts with its surroundings. Many bacteria utilize different methods of bacterial motility to move about and interact with these surroundings. A bacterial second messenger, cyclic diguanosine monophosphate (c-di-GMP), can regulate various motility factors that are potentially advantageous for survival in and adaptation to their environment. Concentrations of c-di-GMP are regulated by specific synthesizing and degrading enzymes. Controlled levels of c-di-GMP allow interaction between the c-di-GMP and its binding effectors that induce changes in bacterial phenotypes such as biofilm formation and motility. A …

Mechanisms Of Neurodevelopmental Toxicity Of Topiramate, John W Steele, Vaishnav Krishnan, Richard H Finnell

Faculty, Staff and Students Publications

Prescriptions for antiseizure medications (ASMs) have been rapidly growing over the last several decades due, in part, to an expanding list of clinical indications for which they are now prescribed. This trend has raised concern for potential adverse neurodevelopmental outcomes in ASM-exposed pregnancies. Recent large scale population studies have suggested that the use of topiramate (TOPAMAX, Janssen-Cilag), when prescribed for seizure control, migraines, and/or weight management, is associated with an increased risk for autism spectrum disorder (ASD), intellectual disability, and attention-deficit/hyperactivity disorder (ADHD) in exposed offspring. Here, we critically review epidemiologic evidence demonstrating the neurobehavioral teratogenicity of topiramate and speculate …

Uvc And Planetary Habitability: Insights From Desert Lichens And Cyanobacteria, Tejinder Singh

UNLV Theses, Dissertations, Professional Papers, and Capstones

An important question in astrobiology is whether life can exist under the levels of UVC radiation found on Archean Earth, Mars, and exoplanets. We investigated this question by studying the UVC survival of colonial cyanobacterium and lichens that grow in harsh desert environments and possess natural sunscreens. We irradiated them nonstop in a desiccated state with a UVC flux closely representing the upper limit on those planets: 55-60 W/m². After irradiation, we rehydrated and assessed their survival using chlorophyll fluorometry and by counting the number of viable colonies that formed on agar plates. All three study organisms survived two to …

Comprehensive Investigation Into The Molecular Mechanisms Driving The Emergence Of Emm4 Group A Streptococcus, Chioma Odo, Samuel A Shelburne, Anthony R. Flores, Steven J Norris, Anna Konovalova, Blake Hanson

Dissertations and Theses (Open Access)

Abstract

Comprehensive Investigation into the Molecular Mechanisms Driving the Emergence of emm4 Group A Streptococcus

Chioma Modeline Odo, M.S.

Advisory Professor: Samuel A. Shelburne, MD, Ph.D.

The major gram-positive bacterium group A Streptococcus (GAS) is a model organism for studying microbial epidemics as it is well known to cause infections that occur in waves. GAS strains are grouped based on the composition of the N-terminal sequence of the M protein which is encoded by the emm gene. With the advent of large-scale whole genome sequencing, GAS clonal emergence events in emm1, emm3, and emm89 types have been identified …

Probing The Ecological Functions Of Thermophiles Using Cultivation-Dependent And Cultivation-Independent Techniques, Dengxun Lai

UNLV Theses, Dissertations, Professional Papers, and Capstones

High-temperature geothermal springs are ecosystems that resemble early Earth, offering insights into the origins and early evolution of life. In these unique ecosystems, thermophilic microorganisms thrive. However, our knowledge of thermophiles remains limited. A major challenge is that many thermophiles remain uncultivated. The primary goal of this dissertation was to explore the diversity, metabolism, and ecological functions of thermophiles using cultivation-dependent and cultivation-independent approaches. Chapter 1 provides a broad overview of geothermal spring ecosystems and thermophiles, along with a roadmap of the dissertation. Chapter 2 documents a study on the response of specific thermophiles from Gongxiaoshe (GXS) Hot Spring in …

Characterizing Enterobacter Cloacae Genetic Elements Responsible For Interactions With Candida Albicans, Abigail Suarez

Electronic Theses and Dissertations

Polymicrobial interactions are an important, yet understudied area of research. Candida albicans is the most common human fungal pathogen. The bacterial genus, Enterobacter, is a source of nosocomial acquired infections and increased drug resistance. Our lab has previously discovered that Enterobacter preferentially adheres to C. albicans hyphae. From an E. cloacae transposon library screen, six candidates displayed reduction in C. albicans attachment. These candidates were identified genetically and characterized for involvement in attachment to C. albicans. A fluorescent plasmid was introduced into E. cloacae to measure and observe adherence to C. albicans in planktonic and biofilm growth. In vivo …

Candida Albicans Farnesol Synthesis And Secretion, Daniel J. Gutzmann

School of Biological Sciences: Dissertations, Theses, and Student Research

Candida albicans is a polymorphic fungus and opportunistic commensal found primarily in the gastrointestinal and skin of healthy individuals. Several barriers prevent C. albicans from causing disease including a healthy immune system and microbiome. When these barriers become comprised, C. albicans can transition to a pathogen and disseminate through the intestinal mucosa leading to life-threatening bloodstream and invasive infections with mortality rates of up to 64%. Morphogenic plasticity is key to this transition and impacts virulence, adaptation to different host environments, and evasion of host immune responses. One regulator of morphogenesis is farnesol. Farnesol is a secondary metabolite …

Candida Albicans Farnesol Synthesis And Secretion, Daniel John Gutzmann

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Candida albicans is a polymorphic fungus and opportunistic commensal found primarily in the gastrointestinal and skin of healthy individuals. Several barriers prevent C. albicans from causing disease including a healthy immune system and microbiome. When these barriers become comprised, C. albicans can transition to a pathogen and disseminate through the intestinal mucosa leading to life-threatening bloodstream and invasive infections with mortality rates of up to 64%. Morphogenic plasticity is key to this transition and impacts virulence, adaptation to different host environments, and evasion of host immune responses. One regulator of morphogenesis is farnesol. Farnesol is a secondary metabolite …

The Interaction Of Endorepellin And Neurexin Triggers Neuroepithelial Autophagy And Maintains Neural Tube Development, Lei Lu, Meizhu Bai, Yufang Zheng, Xiukun Wang, Zhongzhong Chen, Rui Peng, Richard H Finnell, Tongjin Zhao, Chengtao Li, Bo Wu, Yunping Lei, Jinsong Li, Hongyan Wang

Faculty, Staff and Students Publications

Heparan sulfate proteoglycan 2 (HSPG2) gene encodes the matrix protein Perlecan, and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects (NTDs). We discovered rare genetic variants of HSPG2 in 10% cases compared to only 4% in controls among a cohort of 369 NTDs. Endorepellin, a peptide cleaved from the domain V of Perlecan, is known to promote angiogenesis and autophagy in endothelial cells. The roles of enderepellin in neurodevelopment remain unclear so far. Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the …