Microbiology Commons^™

Elucidating The Proteolytic Determinants Of Flavivirus Infection, Lochlain C. Corliss

All ETDs from UAB

Flaviviruses, recently renamed to orthoflaviviruses, are small, enveloped viruses with positive-sense, single-stranded RNA (ssRNA) genomes of about 11 kilobases. Upon cell entry and uncoating, the viral RNA (vRNA) is directly translated at the endoplasmic reticulum (ER) as a single polyprotein that is then processed by the viral and cellular proteases into 10 functional subunits, consisting of three structural proteins and seven nonstructural (NS) proteins. Among the NS proteins are NS2B and NS3, which form the viral protease complex. NS3 consists of a serine protease domain while NS2B is anchored to the ER and contains a cytoplasmic loop that serves as …

Molecular Interactions Between The Shellfish Pathogen Vibrio Coralliilyticus Re22 And The Probiont Phaeobacter Inhibens S4sm, Jessica Coppersmith

Open Access Dissertations

Oyster larvae aquaculture is an important industry, both economically and environmentally, helping to create sustainable food systems by supplying seed oysters to farms, and also to restoration projects aimed at building coastal resilience and improving water quality by rejuvenating wild populations. However, oyster larvae are highly susceptible to rapid mortality events, crashes, which can seriously impact the industry. One source of these crashes in hatchery systems is vibriosis, caused by pathogenic species of Vibrio bacteria that are ubiquitous in temperate coastal waters, and with rising surface water temperatures their prevalence and virulence are increasing. To prevent these larval crashes from …

Identification Of Host-Pathogen Protein Interactions: Yeast Two-Hybrid Analysis Of Sars-Cov-2 Nsp10 And Human Cellular Proteins, Antonios Argyriou

Selected Full-Text Master Theses 2021-

The ongoing COVID-19 pandemic, caused by SARS-CoV-2, has resulted in over 774 million cases and 7 million deaths worldwide, establishing it as one of the most devastating pandemics in recorded history. While current therapeutic approaches primarily target viral entry mechanisms and specific enzymes, the limited understanding of non-structural protein functions hinders the development of comprehensive antiviral strategies. This research focuses on Nsp10 (non-structural protein 10), a highly conserved 139-amino acid protein essential for viral mRNA capping and replication. Nsp10 serves as a critical cofactor in the formation of methyltransferase complexes with Nsp14 and Nsp16, playing a vital role in viral …

Insights Into Female Urinary Microbiota Through Long-Read 16s Rrna Sequencing, Jerrin John

Dissertations

The human urinary microbiome—once thought to be sterile—is now recognized as a dynamic, low-biomass microbial community with potential implications for urinary tract health. Conventional short-read 16S rRNA gene sequencing targeting individual variable regions often lacks the taxonomic resolution needed to distinguish closely related species, while culture-based methods may miss fastidious or low-abundance taxa. We applied full-length 16S rRNA gene sequencing across all nine variable regions to daily urine samples collected from asymptomatic premenopausal female participants. Sequence data were processed with a modified DADA2 pipeline optimized for long reads to generate exact sequence variants. We compared species-level community profiles against both …

Brachial Plexus Lesions: Uncommon Causes And Clinical Sequelae, Lucy Greenhagen

Biology and Microbiology Graduate Students Plan B Research Projects

The brachial plexus is a complex network of nerves that transmit motor and sensory information between the spinal cord and upper extremities. Brachial plexus lesions may be caused by a broad range of congential and traumatic conditions. These lesions present a challenge to healthcare providers both for diagnosis and treatment. While variations in the brachial plexus have been widely reported, resources outlining the prevenance and involvement of anatomical variation along with their possible clinical presentation are more limited. The objective of this review is to describe uncommon causes of brachial plexus lesions and the clinical challenges they present for providers. …

Alternative Treatments And Potential Cures For Type 1 Diabetes, Dillon Peterson

Biology and Microbiology Graduate Students Plan B Research Projects

Type 1 diabetes (T1D) is an autoimmune disease that affects multitudes of people without a cost-effective cure. T1D is caused by the immune system reaching a threshold where it then begins to attack the beta cells in the pancreas causing inflammation, which eventually leads to the death of beta cells. Once a large majority of the beta cells die off, the pancreas begins to inadequately supply insulin to the body, which is when the symptoms of T1D begin to emerge. To treat these symptoms, the person must utilize synthetic insulin. The utilization of synthetic insulin, along with the plethora of …

Microbial Mavericks: Turning Hazards Into Snacks, Alison G. Blanton

Biology Dissertations - Archive

Symbiotic associations with microbes are widespread across life and provide hosts with essential and beneficial functions. A growing concern in pest management is symbiont-mediated detoxification (SMD), a form of metabolic resistance to insecticides. The best-known example of SMD involves the bean bug Riptortus pedestris, where an environmentally acquired but obligate Caballeronia symbiont confers resistance to the organophosphorus insecticide fenitrothion. Motivated by this model, I began my work in another known bug-Caballeronia symbiosis: Leptoglossus phyllopus, native to the United States. I then expanded the study to include two additional U.S.-native hosts, Leptoglossus zonatus and Anasa tristis. Representative …

Bacterial Two-Hybrid Systems Evolved: Innovations For Protein-Protein Interaction Research, Rebecca M. Richardson, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Bacterial two-hybrid (B2H) systems offer a versatile platform for detecting protein-protein interactions (PPIs) in vivo. Originally developed to study bacterial transcriptional regulators, these systems have evolved to support a wide range of applications, including interaction mapping, domain analysis, and high-throughput screening. This review surveys the development and expansion of B2H systems across diverse biological contexts. We highlight technical considerations, platform-specific innovations, and recent adaptations that extend the utility of B2H systems in both prokaryotic and eukaryotic protein interaction research environments. By comparing different B2H variants and discussing their integration with complementary approaches, we provide a framework for leveraging these …

Nucleotide-Derived Bacterial Alarmones Attenuate The Induction Of Type-I Interferon Responses In A Murine Macrophage Reporter Cell Line, Ryan P. Kilduff, Erin B. Purcell, Lisa M. Shollenberger

Chemistry & Biochemistry Faculty Publications

The stringent response is a well-studied phenomenon in many bacterial systems and regulates resource-consuming activities such as transcription, translation, and replication. The stringent response is a well-conserved signaling framework, as are the nucleotide-derived signaling mediators, collectively referred to as (p)ppGpp or as alarmones. There is a wealth of research evaluating nucleotide-derived alarmone signaling in bacterial models, however, their potential to modulate innate immune signaling has not yet been evaluated. Several common pathogen-synthesized molecules, such as lipopolysaccharide (LPS) and cyclic-di-AMP (c-di-AMP), act as pathogen-associated molecular patterns (PAMPs), which are common patterns that alert the innate immune system of bacterial infection. The …

Impacts Of Tick Parasitism On The Rodent Gut Microbiome, Robert J. Brinkerhoff, Joshua Pandian, Meghan Leber, Isabella D. Hauser, Holly D. Gaff

Biological Sciences Faculty Publications

Host microbiota may impact disease vector behavior and pathogen transmission, but little is known about associations between ectoparasites and microbial communities in wildlife reservoir species. We used Illumina metagenomic sequencing to explore the impacts of tick parasitism on the rodent fecal microbiome in both a field and laboratory setting. We found that tick parasitism on wild hosts was associated with variation in the fecal microbiota of both the white-footed deermouse, Peromyscus leucopus, and the southern cotton rat, Sigmodon hispidus. In a lab experiment, we detected significant changes to the fecal microbiome after experimental exposure to immature ticks in …

Investigating Regulation And The Regulome Of The Nucleic Acid Binding Protein Spovg Within Borrelia Burgdorferi, Timothy C. Saylor

Theses and Dissertations--Medical Sciences

Prior studies indicated Borrelia burgdorferi SpoVG protein was regulated, SpoVG binds specifically to a number of nucleic acids, and SpoVG binds to the non-variable section of the major virulence factor vlsE. Although a direct transcriptional activator or inhibitor was not elucidated, it is shown that SpoVG is regulated based on cell culture density independent of the growth rate of B. burgdorferi, indicating that SpoVG regulation is outside the scope of the alternative sigma factor RpoS. Using a dCas9 CRISPRi construct to target SpoVG resulted in protein expression trending towards upregulation of the BosR-RpoS regulon, and a marked decrease …

Comparative Evaluation Of Fungal Strains For The Bioprocessing Of Soybean Hulls Using Cheese Whey As Fermentation Medium, Ruchita Bhattarai

Electronic Theses and Dissertations

Globally, soybean is the most widely cultivated oilseed crops, and serve as the primary source of cooking oil, contributing to around 50% of global oilseed production. During the industrial processing of soybean oil, a significant amount of soybean hull (SH) is produced, which makes up about 8% of the grain yield, resulting in approximately 18–20 million tons of hulls, one of the largest by-products in the soybean industry. The hulls have limited commercial value and are primarily used as fiber additives in dairy cattle feed, but a large portion is still discarded as agricultural waste. Similarly, cheese whey (CW), a …

Isolation And Characterization Of Rhizobia Bacteria From Midwest Soils, Jr Loya

Electronic Theses and Dissertations

Symbiotic bacteria, known as rhizobia, can colonize the roots of legume plants and then convert atmospheric nitrogen into a usable form by the host through the process called biological nitrogen fixation (BNF). Many of these bacteria produce other plant-growth-promoting benefits, such as nutrient acquisition, phytohormone production, and the modification of plant stress responses. Agricultural inoculants made from these bacteria have helped reduce the need for man-made nitrogenous fertilizers, known causes of pollution and eutrophication. There are additional benefits in developing bacteria inoculants local to regional soils. The ability to survive and compete in Midwest soil and climates present an opportunity …

Investigating Antimicrobial Efficacy Of Turmeric And Rosemary Oil Against Staphylococcus Aureus, Aishwarya Tripathi

Selected Full-Text Master Theses 2021-

This study investigates the antimicrobial efficacy of turmeric (Curcuma longa) and rosemary essential oil (Rosmarinus officinalis) against Streptococcus aureus, with a comparative analysis to phenoxyethanol, a widely used synthetic preservative. The growing consumer demand for natural cosmetic formulations have intensified the search for plant-derived alternatives to synthetic preservatives. Turmeric and rosemary oil were selected based on their documented antimicrobial, antioxidant, and anti-inflammatory properties. The objective of this research was to evaluate whether these natural agents can serve as effective preservatives in topical gel formulations, either individually or in combination, and how their efficacy compares to phenoxyethanol.

Eight gel-based formulations were …

Of Mice And Men: The Regulation Of Herpes Simplex Virus 1 Latency In Mouse And Human Neurons, Paige N. Canova

Dartmouth College Ph.D Dissertations

Herpes simplex virus 1 (HSV-1) establishes latent infections in sensory neurons, from which HSV sporadically reactivates, often due to external stress and other stimuli. Latency and reactivation are commonly studied using in vivo and ex vivo models in a variety of hosts, as well as in vitro models including primary mouse neurons and neurons derived from human pluripotent stem cells (iPSCs). The criteria for authentically modeling HSV latency include the ability to easily manipulate host genetics and biological pathways, as well as mimicking the immune response and viral pathogenesis in human infections. Presently, there remains a pressing need for …

Interactions Between Microplastics, Biofilms, And Antimicrobials In Freshwater Streams, Ryan Thomas Krantz

Dissertations

Microplastics (MPs) are ubiquitous contaminants in freshwater ecosystems that could be hotspots for the interaction of antimicrobial compounds and surface-attached microbial biofilm communities. MPs and antimicrobials are both common in wastewater and urban freshwaters and MPs can adsorb contaminants like antimicrobials to their surface. Within aquatic habitats, MPs also support colonization by microbial biofilms. Therefore, we hypothesized that the adsorption of antimicrobials to MP surfaces would affect microbial communities colonizing MPs, altering their diversity, composition, and antimicrobial resistance. We investigated the effects of these interactions across two studies. The first study, discussed in Chapter 2, used a microcosm approach to …

Valorizing Municipal Solid Waste For Sustainable Aviation Fuel And Polyhydroxyalkanoate Bioplastics: Pyrolysis And Microbial Pathways, Emon Das

Theses and Dissertations--Biosystems and Agricultural Engineering

The escalating global burden of municipal solid waste (MSW), projected to reach 3.88 billion tons annually by 2050, calls for innovative valorization strategies to mitigate environmental impacts and promote a circular bioeconomy. This thesis investigates the conversion of MSW into two high-value products: sustainable aviation fuel (SAF) and polyhydroxyalkanoate (PHA) bioplastics. Chapter one presents comprehensive physicochemical characterization and pyrolysis-GC/MS analysis of MSW feedstocks. The physicochemical results reveal that densification enhances handling and storage properties, while pyrolysis-GC/MS analysis indicates that plastic-rich MSW streams produce bio-oils with favorable hydrocarbon profiles suitable for SAF production, potentially contributing to decarbonization efforts in the aviation …

“What’S Supp” Developing An In Vitro Model For Healthy Oral Biofilms, Alex Labossiere

Open Access Dissertations

The study of oral plaque has largely been influenced by the study of pathogens. Here in Chapter 1, I will discuss how this pathogenic focus has been dominant until the onset of microbiome research and begin to explain microbiomes in the context of supragingival plaque in homeostatic communities. From there we will then discuss the possible roots where dysbiosis may arise from plaque to cause disease and ways in which we can study healthy supragingival plaque by in vitro models.

In chapter 2, I will discuss molecular commensalism and how it can be viewed as a tool to further understand …

Impact Of Submarine Groundwater Discharge On Microbial Communities In A Highly Anthropized Coastal Lagoon (Mar Menor, Se Spain), Daniel Romano-Gude, Júlia Dordal-Soriano, Júlia Rodriguez-Puig, Andrea G. Bravo, Irene Alorda-Montiel, Aaron Alorda-Kleinglass, Marc Diego-Feliu, Cristina Romera-Castillo, Rebeca Mallenco-Fornies, Javier Gilabert, Jordi Garcia-Orellana, Valentí Rodellas, Clara Ruiz-González

OES Faculty Publications

Submarine groundwater discharge (SGD) supplies large quantities of nutrients and other terrestrial elements to coastal ecosystems, impacting marine biota and ecosystem functioning. Despite the relevance of prokaryotes for marine biogeochemistry, little is known about their responses to groundwater inputs. Here we explored the impact of SGD on the spatiotemporal patterns of prokaryotic communities from the Mar Menor (Murcia, Spain), a highly anthropized hypersaline coastal lagoon that receives large amounts of nutrient-polluted SGD. Using 16S rRNA amplicon sequencing, activity assays, and flow cytometry, we investigated the dynamics of prokaryotic communities across the lagoon and its connected environments (freshwater streams, groundwater, soils, …

Deciphering Genetic Contributions To Antibiotic Persistence: Insights From Multi-Gene Knockout Studies, Elise K. Schweer

Electronic Theses and Dissertations

Antibiotic resistance is a critical global health challenge, complicating efforts to treat bacterial infections effectively. Antibiotic persistence plays a significant role in driving resistance. Persisters are a subpopulation of non-dividing bacterial cells that often evade lethal antibiotic treatment. Once antibiotics are removed, these cells "resurrect," resuming growth and may lead to relapsing infections. Notably, the progeny of persister cells exhibit a heightened tendency to acquire mutations or incorporate antibiotic resistance genes, further compounding the challenge of antibiotic resistance. In our recent study, we knocked out seven hypothetical genes and observed a significant reduction in persister levels. Compared to the wild …