Microbiology Commons^™

An In-Depth Investigation Into Yersinia Pestis Phages: Isolating A Yersinia Pestis Phage From Soil And Constructing A Comprehensive Phylogenetic Analysis Of Known Yersinia Pestis Phages, Jacqueline Chavez

All HCAS Student Capstones, Theses, and Dissertations

Yersinia pestis, the causative agent of the plague, has become increasingly resistant to many antibiotics; therefore, alternatives such as phage therapy are necessary. Phage therapy uses combinations of bacteriophages or phages, which are viruses that only infect bacteria. However, phages—especially Y. pestis phages —are severely understudied. Thus, this research has sought to specifically isolate a phage from soil that infects Y. pestis. There were 146 samples that were collected from across the US, focusing on those with reported cases of plague. These samples were enriched with Y. pestis to maximize the amount of potential phage that target Y. pestis. …

Elucidating The Mechanism Of Interleukin-17a Signaling In The Pathogenesis Of West Nile Virus, Farzana Nazneen

Dissertations

West Nile Virus (WNV), a neurotropic flavivirus transmitted by mosquitoes, is a leading cause of viral encephalitis in the United States and remains a significant public health concern. Unfortunately, no vaccine or therapeutic intervention is available against WNV infection. Previous studies, including ours, demonstrated that interleukin-17A (IL-17A) signaling increases the cytotoxic potential of CD8⁺ T cells to facilitate WNV and parasite clearance; however, the molecular mechanism is not understood. IL-17 receptor C (IL-17RC) is an obligatory co-receptor with IL-17 receptor A (IL-17RA) for signaling induced by IL-17A, IL-17A/F, and IL-17F. In this study, we found that IL-17RC deficient ( …

Bactericidal Mechanism Of Peracetic Acid Against Salmonella Mediated By Reactive Oxygen Species, Mohammed Khalid Wheib Al-Doury

Graduate Theses and Dissertations

Peracetic acid (PAA) is extensively used as a bactericidal agent in poultry processing to reduce foodborne pathogens, including Salmonella enterica serotype Typhimurium (S. Typhimurium). Despite its widespread application, the exact mechanisms underlying its bactericidal effects, particularly the role of reactive oxygen species (ROS), remain incompletely understood. This dissertation examines the role of ROS in PAA-mediated bacterial killing and explores both genetic and metabolic factors that influence bacterial susceptibility to PAA. Findings from these studies have implications for enhancing the efficacy of PAA, thereby improving food safety practices in the industry.

The first study investigates ROS as a central component …

Induced Systemic Resistance Against Nematodes By Plant Growth-Promoting Microbes In Potatoes, Cole Grannan

Master's Theses

Biofertilizers consist of plant growth-promoting microorganisms that establish symbiotic relationships with plant roots and stems. These beneficial microbes play a crucial role in enhancing plant defenses against various threats including insects, nematodes, and microbial pathogens. The purpose of this study was to investigate the effectiveness of two fungal biofertilizers (an endophytic strain of Beauveria bassiana (BA) and a mixture of arbuscular mycorrhizal (AM) fungi), specifically their ability to induce systemic resistance against plant- parasitic nematodes (PPNs) in potatoes (Solanum tuberosum cv. Masquerade) under controlled greenhouse conditions. The study utilized soil collected from Colorado State University’s San Luis Valley (SLV) Research …

Evaluating The Duckweeds Lemna Minor And Spirodela Polyrhiza As Alternative Aquatic Hosts For The Spread Of The Bacterial Wilt Pathogen, Ralstonia Solanacearum, Irelynn Smith

Honors Theses

Ralstonia solanacearum is a plant pathogen that causes bacterial wilt disease in major crops such as tomatoes and potatoes. Recently, this bacterium was discovered in floating pennywort (Hydrocotyle ranunculoides) and Pennsylvania smartweed (Polygonum pennysylvanicum), two previously unsuspected aquatic plants. Duckweed is an aquatic plant with a high level of resilience and short doubling time. Common duckweed (Lemna minor) has previously demonstrated its capability as a versatile high-yield infection model for other types of pathogenic bacteria. Given this newfound branch of aquatic hosts and the fact that duckweed is a common pond weed previously identified in several ponds located nearby infected …

Lack Of Inflammatory Response In Mouse Embryonic Cells To Listeria Infection, Damilola Oyebode

Master's Theses

Approximately 1 in 5 pregnancies in the United States results in miscarriage, with a significant percentage of these losses attributed to failed implantation due to immunological challenges encountered by the early embryo. Recent research has shown that key cell types within mouse blastocysts, including embryonic stem cells (ESCs) and trophoblast stem cells (TSCs), exhibit remarkable resilience against the cytotoxic effects associated with viral infections and embryotoxic cytokines, such as TNFα and IFNγ, both of which are known to hinder blastocyst development. However, the immune properties of the preimplantation stage embryo, specifically the blastocyst, remain poorly understood. Using mouse cell model, …

Bioindicators Of Mercury In Riverine Systems, Kathryn Mudica

All-Inclusive List of Electronic Theses and Dissertations

This study focuses on the bioaccumulation and biomagnification of mercury in freshwater food webs, with emphasis on bioindicators, such as macroinvertebrates, crayfish, and river otters. Despite regulatory efforts and advancements in monitoring, significant gaps remain in understanding mercury dynamics in freshwater systems—especially regarding its transport, methylation, and bioavailability across different ecosystems. To address these knowledge gaps, this study adopts a biocentric approach, emphasizing the role of living organisms in their environment. By utilizing macroinvertebrates, crayfish, and river otters as bioindicators, we aim to assess mercury bioavailability and distribution. These organisms provide varying temporal and spatial scales of mercury accumulation, offering …

From Resistance To Host Response: An Integrative Study Of C. Difficile Infections, Amber Consul

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridioides difficile infection (CDI) is a major healthcare challenge, causing severe gastrointestinal illness and significant mortality. Understanding the mechanisms of antibiotic resistance, epidemiology, and immune response in CDI is critical for developing effective treatments and prevention strategies.

This dissertation encompasses three complementary studies. The first study investigates the genetic mechanisms underlying cephalosporin resistance in C. difficile strain 630 through differential gene expression analysis. The second study provides a descriptive epidemiological analysis of C. difficile ribotypes in a Las Vegas patient population, highlighting differences between healthcare-associated (HA-CDI) and community-associated (CA-CDI) cases. The third study integrates serum analyte profiling and transcriptomic analysis …

Enhancement Of Zika Virus Infection By West Nile And Dengue Virus Antibody Positive Cord-Blood Samples From Mothers In El Paso-Texas, Jeanette Orbegozo

Open Access Theses & Dissertations

The recent Zika virus (ZIKV) outbreak and its association with microcephaly cases and other neurological syndromes are important public health concerns. A phenomenon known as antibody-dependent enhancement (ADE) involves preexisting flavivirus antibodies to a specific flavivirus that enhances the severity of a second infection with a different flavivirus. Since ZIKV is related to flaviviruses like West Nile virus (WNV) and dengue virus (DENV), prior exposure to these viruses could elicit cross-reactive antibodies that may enhance a subsequent ZIKV infection. Therefore, this study aimed to determine if WNV and DENV antibodies from cord blood enhanced ZIKV infection in vitro. Initially, a …

Analysis Of Microbiome In Various Human Medical Conditions Using Next-Generation Sequencing Of The 16s Rrna Gene, Pallavi Sharma

Electronic Theses and Dissertations

Studies of human microbiomics, spanning diverse anatomical sites, offer a unique perspective into the complex microbial communities within the body. Influenced by age, gender, and disease, it mirrors broader microbial ecosystems. This study specifically delves into the ocular and gastrointestinal tract microbiome, comparing its composition in 43 healthy and diseased patients using 16S rRNA gene sequencing. We identified a rich microbial landscape, identifying over 338 bacterial taxa. Notably, Acinetobacter, Cutibacterium, Acidovorax and Herbaspirillum were prevalent in the ocular samples and Akkermansia, Faecalibacterium, and Anaerostipes were mostly prevalent in gut samples. Moreover, dry eye disease conditions were characterized by …

The Relationship Between Salvinia Molesta Infestation And The Microbial Ecology Of Wetlands At Caddo Lake, Tx, Usa, Martin Hadsell

Electronic Theses and Dissertations

Wetlands are known to host many beneficial geochemical processes such as nutrient cycling and carbon sequestration. These processes are primarily driven by the microbial communities within a wetland. The establishment of non-native invasive species within wetlands has the potential to alter the once beneficial functionality of wetland microbial communities due to the sensitivity microbes have towards environmental changes. Because of this, several metagenomic studies have been conducted to assess microbial community response to aquatic plant invasion; however, there haven’t been any studies researching the influence of Salvinia molesta (D.S. Mitch.), commonly known as Giant Salvinia, on microbial communities. The goal …

Dehydrin Client Proteins Identified Using Phage Display Affinity Selected Libraries Processed With Paired-End Phage Sequencing, Sandra Helena Unêda-Trevisoli, Lynnette M.A. Dirk, Francisco Elder Carlos Bezerra Pereira, Manohar Chakrabarti, Guijie Hao, James M. Campbell, Sai Deepshikha Bassetti Nayakwadi, Ashley Morrison, Sanjay Joshi, Sharyn E. Perry

School of Integrative Biological & Chemical Sciences Faculty Publications

The late embryogenesis abundant proteins (LEAPs) are a class of noncatalytic, intrinsically disordered proteins with a malleable structure. Some LEAPs exhibit a protein and/or membrane binding capacity and LEAP binding to various targets has been positively correlated with abiotic stress tolerance. Regarding the LEAPs’ presumptive role in protein protection, identifying client proteins (CtPs) to which LEAPs bind is one practicable means of revealing the mechanism by which they exert their function. To this end, we used phage display affinity selection to screen libraries derived from Arabidopsis thaliana seed mRNA with recombinant orthologous LEAPs from Arabidopsis and soybean (Glycine max …

Differential Responses Of Human Neutrophils To Legionella Species., Hannah E. Hanford

Electronic Theses and Dissertations

Legionella species are Gram-negative facultative intracellular bacterial pathogens commonly found in freshwater or soil environments where they survive and replicate within their natural protozoan hosts. Humans serve as an accidental host for Legionella species after inhalation of contaminated aerosolized water droplets or soil particles enabling the bacteria to enter the lungs, infect alveolar macrophages, and result in severe pneumonia. Evasion of degradation and proliferation within alveolar macrophages by Legionella species and manifestation of “Legionnaires’ disease” is dependent on the Dot/Icm type IV secretion system (T4SS). The T4SS apparatus is a needle-like channel for translocation of over ~350 effector proteins, depending …

Implementing The Methodology To Generate Diagnostic And Therapeutic Antibodies, Andrea Mariana Carlin

Open Access Theses & Dissertations

This research aimed to establish the methodology for developing monoclonal antibodies at The University of Texas at El Paso. Monoclonal antibodies are indispensable across multiple fields, including diagnostics, therapeutics, and biotechnology, yet there is a shortage of commercially available antibodies targeting specific proteins or possessing specialized characteristics. To address this gap, three models were selected: a peptide derived from the intracellular protein Schlafen 8 and two cell surface protein receptors: mouse vascular endothelial growth factor receptor 2 (VEGFR2) and human melanocortin receptor 4 (MC4R). These proteins present unique challenges in antibody generation, including issues of accessibility, expression, and specificity.

Throughout …

The Regulation Of The Secreted Proteases In Usa300 Isolates Of Staphylococcus Aureus, Jessica K. Jackson

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a Gram-positive opportunistic pathogen capable of causing myriad diseases, ranging from skin infections to pneumonia, endocarditis, and sepsis. It does this via the production of an array of virulence factors including toxins, adhesins, immunoglobulin-binding proteins, and proteases. Towards these latter elements, S. aureus produces ten secreted proteases that play a dual role in infection: firstly, by modulating the stability and abundance of other virulence factors, and secondly, by cleaving host factors to facilitate infection. Given their importance, we set out to explore the natural variability of protease production in a collection of clinical isolates from Tampa General …

Investigating Arbuscular Mycorrhizal Fungi-Cover Crop Interactions To Improve Sustainable Agricultural Practices, Isabel M. Zanartu, Connor Morozumi, Natalie Christian

The Cardinal Edge

Arbuscular mycorrhizal fungi (AMF) are fungal species that form beneficial relationships with plants. AMFs are known to help crops acquire important nutrients like nitrogen and phosphorus in the soil, and in return the plants provide carbon to the fungi. At least 80% of all plants partner with AMFs including staple crops such as rice, corn, wheat and soybeans. With so many plants likely relying on AMFs, current farming practices such as planting in monocultures and fallow overwintering may limit these relationships. On top of this, climate change challenges the reliability of these practices in the future. One sustainable agricultural practice …

Disruption Of The Oswrky71 Transcription Factor Gene Results In Early Rice Seed Germination Under Normal And Cold Stress Conditions, Santiago Bataller, James A. Davis, Lingkun Gu, Sophia Baca, Gaelan Chen, Azeem Majid, Anne J. Villacastin, Dylan Barth, Mira V. Han, Paul J. Rushton, Qingxi J. Shen

Life Sciences Faculty Research

Background

Early seed germination in crops can confer a competitive advantage against weeds and reduce the time to maturation and harvest. WRKY transcription factors regulate many aspects of plant development including seed dormancy and germination. Both positive and negative regulators of seed germination have been reported in many plants such as rice and Arabidopsis. Using a transient expression system, we previously demonstrated that OsWRKY71 is a negative regulator of gibberellin (GA) signaling in aleurone cells and likely forms a “repressosome” complex with other transcriptional repressors. Hence, it has the potential to impact seed germination properties.

Results

In this study, we …

Bodine: An Agent-Based Modeling Approach To Studying Localized Coexistence Across Environmental Heterogeneity, Alexandra Campbell

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Nuclear Polyhedrosis Virus (Npv) Motivates Wandering Behavior In The Gulf Fritillary Caterpillar, \Emph{Dione Vanillae}, Kayla Lizaola, Tiffany Bresnan, Arietta Fleming-Davies

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Boosting The Power Performance Of Microbial Fuel Cells By Using Dual Nanomaterial-Modified Carbon Felt Electrodes, Krishna Thapa, Wenyan Liu, Yuwei Zhang, David J. Westenberg, Yishu Zhou, Risheng Wang

Chemistry Faculty Research & Creative Works

Innovative design enhancements to microbial fuel cells (MFCs) are pivotal for improving their viability as renewable energy sources. This study introduces a dual approach to electrode modification, integrating polyaniline (PANI) and gold nanoparticles (AuNPs) on carbon felt (CF) anodes coupled with a unique cathode composed of DNA origami and chitosan. The synergistic effect of PANI and AuNPs significantly increases the hydrophilicity and conductivity of the anode, leading to a considerable surge in power density. Concurrently, the biocompatible DNA origami and chitosan-functionalized cathode facilitates efficient electron transfer without relying on conventional catalysts. Together, these modifications yield a 52.42% increase in the …

Genome-Guided Isolation Of The Hyperthermophilic Aerobe Fervidibacter Sacchari Reveals Conserved Polysaccharide Metabolism In The Armatimonadota, Nancy O. Nou, Jonathan K. Covington, Dengxun Lai, Xavier Mayali, Cale O. Seymour, Juliet Johnston, Jian-Yu Jiao, Steffen Buessecker, Damon Mosier, Alise R. Muok, Nicole Torosian, Allison M. Cook, Ariane Briegel, Tanja Woyke, Emiley Eloe-Fadrosh, Nicole Shapiro, Scott G. Bryan, Savannah Sleezer, Joshua Dimapilis, Cristina Gonzalez, Lizett Gonzalez, Marlene Noriega, Matthias Hess, Ross P. Carlson, Lan Liu, Meng-Meng Li, Zheng-Han Lian, Siqii Zhu, Fan Liu, Xian Sun, Beile Gao, Ritesh Mewalal, Miranda Harmon-Smith, Ian K. Blaby, Jan-Fang Cheng, Peter K. Weber, Gabriela Grigorean, Wen-Jun Li, Anne E. Dekas, Jennifer E. Pett-Ridge, Jeremy A. Dodsworth, Marike Palmer, Brian P. Hedlund

Life Sciences Faculty Research

Few aerobic hyperthermophilic microorganisms degrade polysaccharides. Here, we describe the genome-enabled enrichment and optical tweezer-based isolation of an aerobic polysaccharide-degrading hyperthermophile, Fervidibacter sacchari, previously ascribed to candidate phylum Fervidibacteria. F. sacchari uses polysaccharides and monosaccharides for growth at 65–87.5 °C and expresses 191 carbohydrate-active enzymes (CAZymes) according to RNA-Seq and proteomics, including 31 with unusual glycoside hydrolase domains (GH109, GH177, GH179). Fluorescence in-situ hybridization and nanoscale secondary ion mass spectrometry confirmed rapid assimilation of 13C-starch in spring sediments. Purified GHs were optimally active at 80–100 °C on ten different polysaccharides. Finally, we propose reassigning Fervidibacteria as a class …

Multiomics Of Yaks Reveals Significant Contribution Of Microbiome Into Host Metabolism, Shuli Yang, Jeiyi Zheng, Huaming Mao, Paramintra Vinitchaikul, Dongwang Wu, Jianmin Chai

Animal Science Faculty Publications and Presentations

An intensive feeding system might improve the production cycle of yaks. However, how intensive feeding system contributes to yak growth is unclear. Here, multi-omics, including rumen metagenomics, rumen and plasma metabolomics, were performed to classify the regulatory mechanisms of intensive feeding system on yaks. Increased growth performance were observed. Rumen metagenomics revealed that Clostridium, Methanobrevibacter, Piromyces and Anaeromyces increased in the intensively fed yaks, contributing to amino acid and carbohydrate metabolism. The grazing yaks had more cellulolytic microbes. These microbiomes were correlated with the pathways of "Alanine aspartate and glutamate metabolism" and "Pyruvate metabolism". Intensive feeding increased methane degradation functions, …

What Drives Gut Microbial Diversity And Community Structure Among Closely-Related Host Species?, Rylee Jensen

All NMU Master's Theses

The gut microbiome (GMB) of mammals hosts an important community of microbes that perform countless micro-ecosystem services for the host and are influenced by numerous factors including host physiology, environment, and phylogeny. Phylogeny may have a unique effect on GMB diversity and community structure (i.e., a GMB profile) via phylosymbiosis, a theory in which the evolution of hosts matches the evolution of their associated microbiota. Elucidating phylosymbiosis in mammals is difficult because multiple intrinsic and extrinsic factors collectively drive individual GMB variation. Thus, there is a need to simultaneously analyze the role of physiology, environment, and phylogeny on shaping host …

Natural Panola Mountain Ehrlichia Infections In Cattle In A Longitudinal Study Of Angus Beef Calves, Cierra Briggs, Drew Casey, Anna Grace Deakins, Jeremy G. Powell, Kelly Loftin, Emily G. Mcdermott

Entomology and Plant Pathology Faculty Publications and Presentations

Panola Mountain Ehrlichia (PME) is an emerging zoonotic pathogen, transmitted by Amblyomma americanum ticks in the southeastern United States. It is closely related to Ehrlichia ruminantium, the causative agent of heartwater disease. Heartwater disease is an often-fatal illness of ruminant livestock present in Africa and the Caribbean. The taxonomic relationship between PME and E. ruminantium has raised concerns about the pathogenicity of PME in livestock. To determine whether cattle could be naturally infected with PME in an endemic area, we conducted a one-year longitudinal study of Angus-breed beef calves in Fayetteville, Arkansas. One hundred seventy-seven calves born between September …

Enterococcus Faecium: Evolution, Adaptation, Pathogenesis And Emerging Therapeutics, Yahan Wei, Dennise Palacios Araya, Kelli L. Palmer

School of Podiatric Medicine Publications

The opportunistic pathogen Enterococcus faecium colonizes humans and a wide range of animals, endures numerous stresses, resists antibiotic treatment and stubbornly persists in clinical environments. The widespread application of antibiotics in hospitals and agriculture has contributed to the emergence of vancomycin-resistant E. faecium, which causes many hospital-acquired infections. In this Review, we explore recent discoveries about the evolutionary history, the environmental adaptation and the colonization and dissemination mechanisms of E. faecium and vancomycin-resistant E. faecium. These studies provide critical insights necessary for developing novel preventive and therapeutic approaches against vancomycin-resistant E. faecium and also reveal the intricate interrelationships …

Specialized Contact Sites Regulate The Fusion Of Chlamydial Inclusion Membranes, Christine Linton, Jordan Wesolowski, Anna Lobley, Toshiyuki Yamaji, Kentaro Hanada, Fabienne Paumet

Department of Microbiology and Immunology Faculty Papers

The intracellular bacterial pathogen Chlamydia trachomatis replicates within a membrane-bound compartment called the inclusion. Upon infection with several chlamydiae, each bacterium creates its own inclusion, resulting in multiple inclusions within each host cell. Ultimately, these inclusions fuse together in a process that requires the chlamydial protein IncA. Here, we show that inclusions form unique contact sites (inclusion contact sites, ICSs) prior to fusion, that serve as fusogenic platforms in which specific lipids and chlamydial proteins concentrate. Fusion depends on IncA clustering within ICSs and is regulated by PI(3,4)P₂ and sphingolipids. As IncA concentrates within ICSs, its C-terminus likely interacts …

The Association Between Oral Microbiome, Oral Inflammation, Periodontal Disease, And Systemic Metabolism In Individuals With/Without Type 1 Diabetes, Mianli Xiao

USF Tampa Graduate Theses and Dissertations

This study explores the associations between oral microbiomes, periodontal disease (PD), and systemic metabolism in individuals with and without Type 1 diabetes (T1D). Data were obtained from 208 participants (99 with T1D, 109 non-diabetic) in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) pilot study and 283 participants from the Oral Microbiome ancillary cohort study. Both studies included the collection of saliva or subgingival plaque samples. Microbial DNA was extracted, and the V4 region of the 16S rRNA gene was sequenced using the Illumina MiSeq platform. Machine learning models, including Random Forest (RF) and Multi-layer Perceptron (MLP), were applied …

Water Quality Of Silver Creek, A Buried Urban Stream, Nick Bultje, Valerie Krause, Rebecca Nulty

Student Papers and Reports

There are many sources of pollution that can affect a watershed. These pollutants can impact the water's pH, temperature, conductivity, and dissolved solids. Escherichia coli is a specific pollutant that comes from waste products of humans and animals. High levels of E. coli cause serious health problems. This study examines Silver Creek, a tributary within the Plaster Creek watershed. Silver Creek runs mostly underground and has storm drainage systems that flow into the creek. The goal was to explore the effects of the underground section of Silver Creek on water quality and E. coli levels. The water quality and levels …

Limits Of Longwood's Electron Microscope: A Study In Biological Imaging, Rachel Danzitz, Bjoern Ch. Ludwar

Fall Showcase for Research and Creative Inquiry

This study evaluates the imaging capabilities and limitations of the Hitachi TM4000II Plus Scanning Electron Microscope (SEM) and its Scanning Transmission adapter in biological imaging. A variety of specimens, including protozoans (e.g., Volvox and nematodes), bacteria (e.g., Magnetospirillum gryphiswaldense, Bacillus cereus, and Escherichia coli), tissue samples, and blood, were analyzed. While the SEM effectively imaged protozoans and bacteria, its ability to visualize viruses was deemed impractical. Despite claims of magnification up to 100,000x, clarity significantly decreased beyond 5,000x. The transmission adapter proved functional but challenging to operate consistently. The study highlights the microscope's limitations in producing high-clarity, …

Ophidiomyces Ophidiicola And Texas Snakes: A Field To Bench Study Of Ophidiomycosis, Kenlynn L. Volz

Biology Theses

Ophidiomyces ophidiicola (Oo), the primary cause of Ophidiomycosis, is a fungal pathogen recently detected in Texas snakes. Prior to this study, there were major knowledge gaps regarding Oo growth, spread, and suitable environmental conditions. This study filled those gaps using a field to bench approach involving sampling snakes across Texas, in vitro fungal growth, and ecological niche modeling. 103 snakes were sampled across Texas in 2023 and 2024 and six cases of Oo infection were detected. Results of the growth experiment suggest that Oo prefers more stable temperatures and high humidity to a point and that there is a …