Microbiology Commons^™

Functions Of The Trna Splicing Endonuclease And Other Adventures In Rna Processing, Jennifer Hurtig, Ambro Van Hoof

Dissertations and Theses (Open Access)

The tRNA splicing endonuclease (TSEN), has been studied for over three decades for its function in tRNA splicing. However, this enzyme has other functions that are just beginning to be characterized. Mutations in TSEN cause the neuronal disease pontocerebellar hypoplasia (PCH) that is characterized by atrophy of the cerebellum and pons, overall developmental failure, and usually results in death before adolescence. How mutations in TSEN cause these neuronal defects and disease is not understood. In yeast, TSEN has another essential function that is independent of tRNA splicing and is still unknown. In this thesis I strived to understand the other …

Development Of A Novel Fluorescent Reporter Baculovirus Vector For Testing Promoters In Lepidopterans, Daniel Howard

All Theses

Testing gene expression patterns is an important process in learning more about an organism. The standard methods of rtPCR and RNASeq provide highly detailed data on specific expression patterns, but can be resource consuming if many different samples including genes or organisms must be tested. A potential alternative for studying expression is the use of a reporter system carried by a vector system that encodes fluorescent proteins under the control of promoters of interest. Many lepidopterans (moths) are pestiferous and better understanding of gene expression levels in lepidopterans, both endogenous and exogenous including from their viruses, would be beneficial. Baculoviruses …

Generation And Characterization Of A Multi-Functional Panel Of Monoclonal Antibodies For Sars-Cov-2 Research And Treatment, Lila D. Patterson

All Theses

The Coronavirus disease 2019 (COVID19) pandemic caused by SARS-CoV-2 is an ongoing threat to global public health. To this end, intense efforts are underway to develop reagents to aid in diagnostics, enhance preventative measures, and provide therapeutics for managing COVID-19. The recent emergence of SARS-CoV-2 Omicron strains with enhanced transmissibility, altered antigenicity, and significant escape of existing monoclonal antibodies and vaccines underlines the importance of the continued development of such agents. The SARS-CoV-2 spike protein and its receptor binding domain (RBD) are critical to viral attachment and host cell entry and are primary targets for antibodies elicited from both vaccination …

Cyclic-Di-Gmp Regulates Salmonella Typhimurium Infection Of Epithelial Cells And Macrophages, Abdulafiz Musa

Electronic Theses and Dissertations

Regulation of the bacterial second messenger cyclic-di-GMP in Salmonella Typhimurium allows it to delicately alter phenotypes to optimize invasion and survive intracellularly in epithelial cells and macrophages to become virulent and cause infection. Cyclic-di-GMP concentration is regulated by the presence of external stimuli, sensory diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), and cyclic-di-GMP binding effectors. Previous studies established that maintenance of low cyclic-di-GMP concentrations is required for survival in macrophages, and that deletion of 3 active PDEs reduces this survival. Here I showed that these 3 PDEs also influenced the infection of epithelial cells. Further studies re-established the decreased survival in …

Fulfilling Koch’S Postulates And Evaluation Of Different Administration Routes In Poults Challenged With Streptococcus Gallolyticus, Latasha Gray

Graduate Theses and Dissertations

Streptococcus gallolyticus (SG) is a Gram-positive found as commensal gut flora in animals and humans. SG has been associated with acute mortality in poults 2 to 3 weeks of age, with lesions mainly consisting of splenomegaly, hepatomegaly, and pericarditis. The objective of this thesis was to reproduce disease in poults caused by SG recovered from clinical field isolates and evaluate different routes of administration. Three field isolates from geographically disparate areas in Arkansas and Missouri were used for the experiments contained in this thesis. Antibiotic sensitives of the three field isolates revealed sensitivity to penicillin as well as a wide …

Determining The Effects Of Maternal Adiposity On Preterm Neonatal Microbiome And Short Chain Fatty Acid Profiles, Dalton James, William A. Clark Phd, Kristy L. Thomas

Undergraduate Honors Theses

The gut microbiota and its metabolites have vast impacts on the human digestive system, immune system, and health outcomes. Short chain volatile fatty acids (SCVFAs) present in feces can be representative of the interactions of the microbiota present in the gut. Low microbiota diversity in the human gut is highly associated with obesity and adverse health outcomes. Furthermore, the maternal microbiome has a direct impact on neonatal microbiota through various pathways such as environment, skin flora, breast milk composition, and vaginal secretions. This study is aimed to further understand the associations between various factors (maternal adiposity, gestational time, length of …

Diagnosis Of Urinary Tract Infections And Rapid Molecular Characterization Of Antibiotic Resistance, Mohammed Harris

All Dissertations

Urinary tract infections (UTIs) are one of the most common infectious clinical entities in both community and hospital settings. They have a broad range of clinical severity yet inflict large epidemiological burden of morbidity and mortality on patients and the healthcare system with billions of dollars in cost of treatment. Understanding what methods are optimal for diagnosing UTIs are critical to mitigate the marked impact and cost of these infections.

Chapter 1 and 2 in this work surveys the broad array of diagnostic modalities for UTIs and highlights their advantages and limitations in the context of the current standard of …

“Pinkalicious": Outer Membrane Vesicles Isolated From Pseudoalteromonas Rubra Carry Prodigiosin Antibiotics As Cargo, Margaret Hill

Senior Honors Projects

Astrangia poculata, the state coral of Rhode Island, is susceptible to infection by Vibrio coralliilyticus RE22, which is a common marine pathogen affecting various invertebrate species. The settlement of coral larvae prior to the establishment of colonies is mediated by crustose coralline algae (CCA). This process may be induced by CCA-associated protective bacteria that colonize corals in early metamorphosis; furthermore, such bacteria potentially have downstream effects in the susceptibility of corals to pathogens. Strains of Pseudoalteromonas rubra isolated from CCA have been shown to induce larval settlement of tropical corals. We hypothesize that P. rubra induces the settlement of …

Oral Prevalence Of Akkermancia Muciniphila Among Pediatric And Adult Orthodontic And Non-Orthodontic Patients, Ching Shen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Akkermansia muciniphila (AM) is one of many highly abundant intestinal microbes that influences homeostasis and metabolic disorders and may also play a role in oral disorders. However, there is little evidence regarding the oral prevalence of this organism. Based upon this lack of evidence, the primary goal of this project is to survey an existing saliva repository to determine the overall prevalence of this organism and any associations with demographic or patient characteristics (age, sex, body mass index, race/ethnicity, orthodontic therapy). Using an approved protocol, a total n = 141 pediatric samples from an existing saliva repository were screened using …

Effects Of Cations And Dipicolinic Acid On B. Anthracis Spore Physiology And Cytotoxicity, Chandler P. Hassan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Inhalation of Bacillus anthracis spores leads to the most severe form of anthrax. Following phagocytosis by alveolar macrophages, spores germinate inside the phagolysosome. The mechanism used by the newly germinated B. anthracis cells to survive within macrophages is not completely understood.B. anthracis spores contain large concentrations of calcium in complex with dipicolinic acid (Ca-DPA). Upon germination, the cell excretes the large depot of Ca-DPA. DPA is an amphipathic molecule that could act as a buffer and modulate phagolysosome acidification. Intracellular calcium overload can disrupt signaling pathways required for normal macrophage function and trigger cell death. We hypothesized the release of …

Biochemical Characterization Of Fsa1572 From Fervidibacter Sacchari, The First Hyperthermophilic Gh50 With Β-1, 4-Glucanase Activity, Jonathan Covington

UNLV Theses, Dissertations, Professional Papers, and Capstones

The bacterium Fervidibacter sacchari is an aerobic hyperthermophile that catabolizes various polysaccharides and is the only cultivated member of the class Fervidibacteria within the phylum Armatimonadota. Among its glycoside hydrolase (GH) cache is an enzyme from GH family 50 (GH50), an understudied family with only 25 characterized representatives and two known activities from 1,518 predicted members in the Carbohydrate-Active EnZyme (CAZy) Database. Here, we expressed, purified, and functionally characterized an extracellular GH50 from F. sacchari called Fsa1572. Using colorimetric assays, we show it has novel β-1,4-glucanase activity and only weak agarose activity that is typical for GH50 enzymes. The purified …

Long-Range Regulation By The Shigella Virulence Gene Regulator, Virb, Cody Cris

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nucleoid-structuring proteins (NSPs) in bacterial cells can exert gene regulatory effects over great distances on DNA. This contrasts with the traditional view of bacterial transcriptional regulation, where transcription factors bind cis-acting regulatory sites proximal (<250 bp) to promoters to influence gene expression. In Shigella species, the histone-like nucleoid-structuring protein (H-NS) transcriptionally silences many genes on the large (~220 kb) virulence plasmid. During host colonization, however, silencing by H-NS is alleviated by the anti-silencer protein, VirB, which remodels the H-NS:DNA complex. This transcriptional anti-silencing is mediated by VirB:DNA interactions and the modulation of DNA supercoiling, which lead to the up-regulation of virulence genes. VirB is a central regulator of Shigella virulence, but the mechanistic basis for transcriptional regulation is incompletely characterized. Here, I focus on the potential for VirB to regulate transcription from remotely located DNA binding sites. Employing complementary in vivo approaches, I assessed the spatial stringency of the VirB binding site and elucidated how varying cellular VirB levels impacts regulation over different distances. I also evaluated how a molecular roadblock on DNA influences remote regulation by VirB. Additionally, I developed control tools to validate the ability of VirB to spread along DNA, an activity of VirB that putatively drives transcriptional regulation. These data are consistent with transcriptional anti-silencing being driven by VirB spreading along DNA. Overall, these findings highlight how VirB is not a conventional transcriptional regulator and broaden our perspective on transcriptional control in bacteria. Furthermore, this work contributes to our understanding of long-range gene regulatory effects, which are frequently overlooked and poorly characterized in bacteria.

Desert Spring Prokaryotes And Benthic Macroinvertebrates: Geological And Ecological Controls, Ariel D. Friel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Desert springs are aquatic oases, being considered among the most diverse and imperiled ecosystems on Earth. Despite the ecological significance and threatened status of desert springs, few studies have surveyed the microorganisms in these systems or their interactions with other community members. The primary goal of this dissertation was to describe the major controls influencing the community ecology of prokaryotic and BMI communities in cold- and moderate-temperature desert springs of the southern hydrographic Great Basin. Chapter 1 provides a broad overview of spring ecosystems and of each chapter included in this dissertation. Chapter 2 documents the first-ever, regional-scale survey of …

Poop! There It Is! Anti-Germinants And Biological Variables As Modulators Of Clostridioides Difficile Infection (Cdi), Jacqueline Renee Phan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridioides difficile infection (CDI) is a major cause of antibiotic-associated diarrhea. Due to its insidious nature, the Centers for Disease Control and Prevention (CDC) has declared CDI an urgent threat. A key characteristic of C. difficile is its ability to form dormant spores that act as the infectious vehicles for disease. In the gut, spores recognize bile salts to germinate into toxin-producing cells.Dysbiosis of the gut microbiome is a key factor in allowing the C. difficile spores to germinate. Normal gut microbiota naturally protects from CDI. However, biological variables such as diet and sex have been found to modulate to …

Cultivating Algae To Generate Pufas, And Macromolecules Using Struvite And Stress Factors, Alejandro Torres

Boise State University Theses and Dissertations

Agricultural and municipal wastewaters contain vital elements necessary for algal growth (i.e., N, P, Mg, K). One way to capture these elements, in an environmentally friendly way, is through struvite production (NH4MgPO4·6H2O), however, this process is costly to implement. High-value secondary commodities coupled to struvite production can enable implementation of this nutrient capture strategy for agricultural and municipal wastewater systems. In this study, struvite was tested as a nutrient source for cultivation of high-value algal biomass with the main focus on high-value lipids such as Eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). We compared the growth of microalgal strains C. …

The Effects Of Salt And Temperature On Three Methanogen Species: Implications For Mars, Katy Dunlap

Biological Sciences Undergraduate Honors Theses

The question of whether life has ever existed on Mars – either in the past or currently – has been pursued for decades. This debate has been prompted by a variety of discoveries regarding similarities between Mars and Earth and more recently concerns over human extinction. Mars, like Earth, once had large amounts of water, a key ingredient for life. H₂O exists on Mars in various forms now, and it is theorized that there is liquid water beneath the surface as well. Mars also contains salt and is very cold at its surface, pointing researchers towards the idea …

Understanding The Role Of Heterodisulfide Reductase During Nitrogen Fixation By Methanosarcina Acetivorans, Grant Shelnut

Biological Sciences Undergraduate Honors Theses

Methanosarcina acetivorans is a methanogenic archaeon (methanogen) that is important for several processes in our biosphere. A feature of interest within this methanogen is the enzyme nitrogenase which catalyzes the reduction of unusable dinitrogen gas (N₂) into a usable form of nitrogen, ammonia (NH₃). How electrons are transferred within M. acetivorans to nitrogenase during N₂ reduction is unknown. Heterodisulfide reductase (Hdr) is a key enzyme known to reduce the electron carrier protein ferredoxin, which is a direct electron donor to nitrogenase in bacteria. I hypothesized that cytoplasmic HdrA2B2C2 functions in electron transfer to nitrogenase and …

The Impact Of The American Association For Thoracic Surgery On National Institutes Of Health Grant Funding For Cardiothoracic Surgeons, J Hunter Mehaffey, Hanjay Wang, Adishesh K Narahari, Simar S Bajaj, Anirudha S Chandrabhatla, Alexander S Krupnick, Frank W Sellke, Todd K Rosengart, Y Joseph Woo

Faculty, Staff and Students Publications

Objectives: The American Association for Thoracic Surgery, through its annual meeting, pilot grant funding, Scientific Affairs and Government Relations Committee activity, and academic development programs (Grant Writing Workshop, Clinical Trials Course, Innovation Summit), has aimed to develop the research careers of cardiothoracic surgeons. We hypothesized that American Association for Thoracic Surgery activities have helped increase National Institutes of Health grants awarded to cardiothoracic surgeons.

Methods: A database of 1869 academic cardiothoracic surgeons in the United States was created in December 2020. National Institutes of Health grant records from 1985 to 2020 were obtained for each surgeon using National Institutes of …

Commentary: What’S On The Inside Counts, Paige E Brlecic, Todd K Rosengart

Faculty, Staff and Students Publications

No abstract provided.

Direct Cardiac Reprogramming: A New Technology For Cardiac Repair, Paige E Brlecic, Clark A Bonham, Todd K Rosengart, Megumi Mathison

Faculty, Staff and Students Publications

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with myocardial infarctions being amongst the deadliest manifestations. Reduced blood flow to the heart can result in the death of cardiac tissue, leaving affected patients susceptible to further complications and recurrent disease. Further, contemporary management typically involves a pharmacopeia to manage the metabolic conditions contributing to atherosclerotic and hypertensive heart disease, rather than regeneration of the damaged myocardium. With modern healthcare extending lifespan, a larger demographic will be at risk for heart disease, driving the need for novel therapeutics that surpass those currently available in efficacy. Transdifferentiation …