Microbiology Commons^™

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 …

Wasting Disease Of A Marine Foundation Species Links Community Interactions To Disease Dynamics, Lillian R. Aoki, Olivia J. Graham, Reyn M. Yoshioka, Rebecca Maher, Lindsay Alma, Eileen E. Hofmann, Colleen A. Burge, Drew Harvell, Maya L. Groner

CCPO Publications

Infectious disease plays a key role in shaping marine communities, including in seagrass meadows, which form biodiverse coastal habitats. Eelgrass (Zostera marina) is the most widespread seagrass species and is susceptible to seagrass wasting disease, caused by the protist Labyrinthula zosterae. As a foundation species, eelgrass strongly influences ecosystem structure, function and services; recent work has begun to explore the links between critical community interactions and seagrass wasting disease. Here, we highlight recent advances about how the eelgrass community regulates and responds to seagrass wasting disease, from the microbiome to herbivores and filter feeders. We further show …

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 …

Bio-Inspired Airfoil Design Based On The Aerodynamic Analysis Of A Bird Feather Microstructure, Jack C. Ihm

College of Graduate Studies: Theses & Dissertations

This study investigates the aerodynamic effects of a bio-inspired airfoil design based on the microstructure of a secondary feather from a female wood duck. The research hypothesized that incorporating barbs and barbules into an airfoil design would modify boundary layer behavior by introducing localized flow disturbances. To test this, a bio-inspired airfoil was developed by integrating the microstructure into a NACA 0012 airfoil and analyzed using computational fluid dynamics (CFD) simulations at angles of attack of 0°, 5°, 10°, and 15°. The results showed that the bio-inspired airfoil influenced boundary layer behavior, producing localized flow disturbances near x/c = 0.7 …

Backyard Chimeric Microbiomes: K-12 Participatory Science, Abigail Saucier

Honors Theses and Capstones

The US education system has seen a recent push for more secondary school curriculum to include STEM (Science, Technology, Engineering, and Mathematics) materials and activities. Middle and high school is a pivotal time when academic and personal experiences affect the development of student attitudes towards STEM (Christensen et al., 2015; Moreno et al., 2016). Teachers often utilize hands-on activities to promote student engagement with science curriculum (Brooks & Poles, 2021; Christensen et al., 2015). Hands-on activities improve student learning, but impacts vary by type of activity. When students work towards a known outcome they can feel disconnected from the work …

Effects Of Liraglutide On The Gut Bacterial Community, Jami Anne Bull

Graduate Theses/Dissertations

Overweight and obesity are major health concerns associated with metabolic disorders and gut dysbiosis. Treatment options such as GLP-1 receptor agonists, like liraglutide, promote weight loss and improve insulin sensitivity; however, their impact on the gut bacterial community remains unclear. This study investigated the effects of liraglutide on the gut bacterial community of diet-induced obese (DIO) mice using Illumina DNA sequencing of the bacterial 16S rRNA gene. My study used twelve-week-old male C57BL/6J DIO mice. They were placed on a high-fat diet and treated with liraglutide (0.2 mg/kg) via daily subcutaneous injection for 14 Days. High-fat and low-fat diets control …

The Influence Of Flower-Microbe Interactions On Bumble Bee Behavior And Gut Microbiome Composition, Success Chiamaka Ekemezie

Graduate Theses/Dissertations

This thesis examines how microbial interactions in floral nectar and environmental variation influence bumble bee (Bombus spp.) foraging behavior and gut microbiome composition. Pollen germination experiments and behavioral assays in the lab tested whether Metschnikowia reukaufii (yeast) and Acinetobacter nectaris (bacteria) induce pollen germination and bursting in nectar and affect bee behavior subsequently. Both microbes reduced intact pollen, but bees did not alter flower preference. Furthermore, the study also assessed how floral and bee community composition shaped gut microbiome composition across six Missouri prairies. Using amplicon-sequenced fungal ITS and bacterial 16S rRNA genes, I found that fungal microbiome composition varied …

Spatial And Temporal Shifts In Bacterial Communities And Nutrient Removal In Two Springfield Wastewater Facilities, Rubina Sherchan

Graduate Theses/Dissertations

Bacterial communities play a central role in the biological nutrient removal and overall performance of wastewater treatment plants (WWTPs). However, very few is known about the spatial and seasonal dynamics of these communities. This study explores the spatial and seasonal variations in bacterial community composition across multiple treatment stages in two municipal WWTPs—Southwest (SWTP) and Northwest (NWTP)—in Springfield, Missouri. Using 16S rRNA gene amplicon sequencing, I analyzed 87 samples collected during summer and winter of 2024 from influent, sludge, aeration basins, clarifiers, and final effluent stages. I retrieved 16.4 million (summer) and 3.2 million (winter) sequences. Proteobacteria dominated both seasons …

Inoculating Soybean Plants At Different Growth Stages: Selecting Bradyrhizobium, Sinorhizobium, Or Both, Matthew R. Knoll

Graduate Theses/Dissertations

Soybean plants rely on nitrogen for growth, however atmospheric nitrogen (N2) is not a usable form and needs to be converted into different forms that are available to the plant. Nitrogen fixing bacteria such as rhizobia form symbiotic relationships with Soybeans in exchange for shelter and excess plant sugars. As a result, the plant can get the nitrogen it needs. There are four main genera of rhizobia that can form root nodules on Soybean including Bradyrhizobium, Sinorhizobium, Mesorhizobium, and Rhizobium. At this point, the effect that age of the host plant has on the selection of …

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 …

Biotransformation Of Camelina Meal Via Pretreatment And Fermentation For Functional And Nutritional Upgrading, Ram Kumar Bhattarai

Electronic Theses and Dissertations

Camelina sativa, an oilseed crop of the Brassicaceae family, has seen increased cultivation in North America in response to the rising demand for biofuels over the past two decades. With this growth, camelina meal, a byproduct of oil extraction, has emerged as a promising yet underutilized resource, particularly for applications in animal nutrition. This study aimed to evaluate the potential of camelina meal as a substrate for submerged fungal fermentation and to examine how this bioconversion affects its physicochemical and nutritional properties. The influence of mild pretreatments (unwashed, washed only, and washed/dried and ground) on fermentation outcomes was also assessed. …

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 …

The Antibiofilm Efficacy Of Copper And Zinc-Enhanced Borate Bioactive Glasses On Polymicrobial Biofilms, Sarah Fakher, David J. Westenberg

Biological Sciences Faculty Research & Creative Works

Healthcare-acquired infections (HAIs) are a significant global challenge driven by biofilm-forming pathogens. Polymicrobial biofilms, involving interactions between multiple microbial species, exacerbate treatment difficulties due to their enhanced resistance to antimicrobial therapies. Borate bioactive glasses (BBGs) are an emerging class of biomaterials that have attracted significant interest in infection control. The incorporation of copper and zinc into the BBG matrix can effectively disrupt biofilm formation and bacterial colonization. This study investigates the antibiofilm efficacy of copper and zinc-doped BBGs against polymicrobial biofilms formed by S. epidermidis, E. coli, and P. aeruginosa. Using static and dynamic biofilm models, BBGs were applied through …

Ribomoe: An Application Of Mixture Of Experts On Artificial Riboswitch Classification, Hainian Audrey Long

Master's Projects

Urban water sewage is a potential health concern due to its possibility to spread contagious RNA viruses such as Coxsackievirus B3. However, detection of viral particles remains challenging because of low viral concentrations in wastewater and high mutation rates of the RNA virus. To address this, this study proposes a novel viral detection method using synthetic riboswitches that bind to the target virus and trigger a reporter gene, amplifying the detection signals. To support the design of effective riboswitches, we present a machine learning model for classifying riboswitch performance, integrating RNA sequence data with secondary structural features. This model used …

The Role Of Fruiting Bodies In Protecting A Community Of Myxococcus Xanthus Spores From The Environment, Dave Lall

Wayne State University Dissertations

Environmental microorganisms have evolved a variety of strategies to survive fluctuations in environmental conditions, including the production of biofilms and differentiation into spores. Myxococcus xanthus are ubiquitous soil bacteria that produce starvation-induced multicellular fruiting bodies filled with environmentally resistant spores (a specialized biofilm). Isolated spores have been shown to be more resistant than vegetative cells to heat, ultraviolet radiation, and desiccation. The evolutionary advantage of producing spores inside of fruiting bodies is not clear. Here, we examine a hypothesis that the fruiting body provides additional protection from environmental insults. We developed a high-throughput method to compare the recovery (outgrowth) of …

Optimization Of L-Citrulline Production In Corynebacterium Glutamicum, And The Effect Of The Human Small Intestine Environment, Simran S. Ghulldu

Honors Undergraduate Theses

L-citrulline is a crucial amino acid involved in nitric oxide production, which supports cardiovascular health, physical performance, and intestinal well-being. Nitric oxide deficiency is linked to conditions like hypertension, highlighting the need for efficient L-citrulline production. This study attempts to enhance L-citrulline synthesis in Corynebacterium glutamicum, a bacterium widely used in industrial amino acid production, as well as test a The hypothesis is that overexpressing carAB, which encodes carbamoyl phosphate synthetase, will increase carbamoyl phosphate levels and boost L-citrulline production. Two C. glutamicum strains were used: a wild type and the CRBG strain, which has mutations that promote …

Optimizing Crispri Gene Silencing Of Putative Drug Targets In Mycobacterium Abscessus, Max Ivanov

Honors Undergraduate Theses

Among nontuberculous mycobacteria (NTM), Mycobacterium abscessus (Mab) poses a particular threat to patients with cystic fibrosis and chronic obstructive pulmonary disease due to the lung damage and higher mortality rate it causes. Current treatments involve prolonged multi-antibiotic regimens that are often ineffective, highlighting the need for new drug targets.

The CRISPR Interference (CRISPRi) system uses a deactivated Cas9 protein (dCas9) to enable inducible gene silencing, offering a potential approach to identifying new targets. Genes that lead to a loss of Mab viability when silenced are considered essential, an important attribute of potential drug targets. While CRISPRi has shown …

Unravelling The Role Of Two-Component Systems In Mycobacterium Abscessus, Andrea C. Molero Perez

Honors Undergraduate Theses

Mycobacterium abscessus (Mab) is an emerging pathogen within the nontuberculous bacteria (NTM) which poses a threat due to its complex multi-drug resistance and opportunistic nature. It is predicted that only 45.6% of patients will have successful treatment, with immunocompromised and cystic fibrosis patients being the most threatened. Moreover, investigating new treatment approaches is key to responding to this public health issue. Two-component systems (TCS) are regulatory pathways that play a pivotal role in bacterial survival and virulence. These systems are composed of a sensor histidine kinase (HK) and cognate response regulator (RR) protein that senses environmental cues and triggers specific …

Genomic And Metabolic Network Properties In Thermophiles And Psychrophiles Compared To Mesophiles, Amal Saeed Alblooshi

Theses

Thermophiles and psychrophiles are extremophilic microorganisms that thrive in harsh conditions. Thermophiles are mostly located in hot springs, prosper in high temperatures. Psychrophiles thrive in extremely cold environments, including polar regions and deep-sea habitats. Although they play a crucial role in biotechnology and environmental research, their mechanisms of adaptation are still not well understood. The main objective of this thesis is to understand the genomic characteristics and metabolic network features in thermophiles and psychrophiles compared to mesophiles. The genomes of 59 species among thermophiles, psychrophiles, and mesophiles were collected from the NCBI database. These genomes were used to analyze their …

Elucidation Of The Post-Transcriptional Regulation And Role In Iron Homeostasis Of The Outer Membrane Vesicle Protein Ynce In Salmonella, Mira J. Schmidt

Honors Undergraduate Theses

Iron is an essential element for most bacteria as it is a crucial cofactor for enzymes involved in fundamental reactions such as DNA synthesis. Despite being the fourth most abundant element on Earth, bacteria face challenges acquiring iron under aerobic conditions due to the poor solubility of its oxidized form (Fe³⁺). To overcome this, bacteria have developed various strategies of iron acquisition, such as the production of siderophores. Siderophores are small molecules that scavenge free Fe³⁺ in iron-deprived environments. Iron acquisition is tightly regulated due to its capability of promoting hydrogen peroxide formation via the Fenton reaction. In Salmonella Typhimurium, …