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Characterizing The Role Of Pa5189 Of Pseudomonas Aeruginosa In Deletion And Overexpression Mutants, Seh Na Mellick

Theses/Capstones/Creative Projects

In the context of rising multidrug resistance in biofilm-forming pathogens like Pseudomonas aeruginosa, this study investigates the role of the understudied transcription factor PA5189 in antibiotic resistance and biofilm formation. PA5189 deletion and overexpression mutants were created in a parent P. aeruginosa strain using pEX18Tc-based recombinant suicide vectors, with genotypic verification of putative triparental conjugants achieved through restriction digestion and PCR. The study revealed that PA5189 overexpression significantly increases resistance to commonly used broad spectrum antibiotics such as ciprofloxacin and imipenem. Additionally, differential expression of PA5189 was found to notably affect biofilm formation, with variations contingent on the nutrient …

Associations Between Gut Microbiome Metabolomics And Endometriosis Risk, Progression, And Non-Invasive Diagnosis: A Review, Marlee Sanders

Honors Theses

Endometriosis is a gynecological condition that affects 1 in 10 women of reproductive age, is characterized by growth of endometrial tissue outside of the uterus, and encompasses metabolic, immunologic, and endocrine dysfunction. Despite its significant impact, endometriosis remains inadequately studied within the realm of women's health, emphasizing the crucial need for innovative approaches in the analysis and diagnosis of this complex condition. The cause of endometriosis is unknown however it could be influenced by genetics, environmental factors, diet, lifestyle, and notably composition of the gut microbiome. Recent scholarly interest has sparked inquiries into the correlations between endometriosis and the gut …

Antimicrobial Activity Of Cat Flea (Ctenocephalides Felis) Gut Proteins On Different Days After Blood Feeding, Dhruva K. Karnik

Honors College Theses

Cat fleas (Ctenocephalides felis) are a blood-feeding ectoparasitic insect and a common domestic pest found throughout the world. Because of their reliance on host blood, fleas are exposed to blood-borne pathogens; however, the flea gut lumen is a hostile environment for microbial colonization. For example, the gut epithelia differentially express immune genes in response to feeding. In the present study, we measured the antimicrobial activity of gut proteins from cat fleas at different days after feeding (2, 5, 7, and 14). Dissected flea guts were homogenized, passed through a syringe filter, and measured in a protein assay kit. …

Cultivating Excellence: A Literature Review On Harnessing The Power Of The Gut Microbiome For Athletic Performance, Maya Katharine Dean

Honors Projects

The interplay between our gut microbiome and health is immense. This literature review analyzes the current research assessing the interplay between gut microbiome and athletic performance. Knowing how to improve gut microbial diversity via nutrition and supplementation can take athletic performance to the next level; namely improvements in immune, mental, and physical health.

Ammonium Chemotaxis In Chlamydomonas Reinhardtii, Gabela Nelson

LSU Doctoral Dissertations

Analysis of ammonium chemotaxis in Chlamydomonas reinhardtii is largely hindered, compared to that of phototaxis, despite equal importance on flagellated microalgal physiology. A major contribution of this shortfall is the lack of proper assay method. We developed a simple Petri dish assay method in which light is homogenously exposed while patterns of the cellular migration are tracked with a function of time. Using the method, new findings were revealed. First, this research presented that a strain lacking the eyespot organelle required for light gradient-sensing exhibits similar chemotactic behavior compared to a wild-type strain, suggesting Chlamydomonas sense an ammonium gradient not …

Adherent-Invasive Escherichia Coli (Aiec) Promotes Mild Colitis In The C57bl/6 Il-10 Ko Mouse Model Of Crohn's Disease, Sarah Sm Zaw

Senior Theses

Crohn's disease (CD) is a chronic inflammatory bowel disease. Interleukin-10 knockout (IL-10 KO) mice are crucial in CD research. Adherent-invasive Escherichia coli (AIEC) is a subgroup of E. coli. In one study, IL-10 KO mice colonized with AIEC developed colitis in the distal colon compared to wild-type (WT) mice. I investigated how AIEC NC101 WT affects colitis severity in IL-10 KO mice of the C57BL/6 genetic background. Similar results in both genotypes would enhance mouse strain accessibility. Germ-free C57BL6 IL-10 KO mice were divided into groups: colonized with AIEC NC101 for 12, 15, or 18 weeks, or kept germ-free. Histopathological …

An Antiviral Response Unleashed: Deciphering The Relationship Between Shiftless And Rna Granules During Kshv Infection, David C. Hatfield

Masters Theses

Herpesviruses persist as a parasitic actor among many species. These viral agents can rapidly seize control over host cells by influencing global gene expression. Through a process known as host shutoff, herpesviruses cause a widespread degradation event of host transcripts within the cytoplasm. Specifically, Kaposi Sarcoma associated herpesvirus (KSHV) encodes for an endoribonuclease, termed SOX, that orchestrates this manipulation of gene expression. We and others have discovered certain transcripts that escape this fate; we suggest that this is an active escape, where transcripts have 3’ UTR elements that disallow SOX cleavage. One of the escapees that has been found is …

Investigating The Escape Mechanism Of Sre Bearing Mrna Transcripts During Viral Host Shutoff, Daniel Macveigh-Fierro

Doctoral Dissertations

During viral infection, the virus and host clash for control over gene expression in an evolutionarily arms race that has raged for thousands of years. During lytic replication, Kaposi’s sarcoma associated herpesvirus (KSHV) triggers a massive RNA decay event known as host shut off. This causes over 70% of all RNA to be degraded suppressing the host antiviral response while freeing resources for viral replication. Our lab focuses on a subset of transcripts that escape from this viral degradation event using a cis acting 3’ UTR element known as a “SOX resistant element” or SRE. Although we have identified a …

The Impacts Of Environment And Host Evolutionary Relationships On Lemur Microbiota, Rachel B. Burten

Doctoral Dissertations

Recent studies have shown that the mammal microbiome is modified by environmental conditions, and that reduced microbiome functionality is associated with host health issues. Microbiome data in wild and captive primate populations can therefore be used to assess their health as they encounter a variety of environments. Comparative studies of the microbiome can also inform disease ecology, conservation, and captive management strategies tailored to different primate species. Therefore, this study examines how the hair, oral, and gut microbiota of nine wild and captive lemur species are determined by host phylogenetic relationships and host environment. I found that host species identity …

Investigating The Mechanisms Of Surface Sensing Using Motility Appendages By Pseudomonas Aeruginosa Pa14, Christopher James Geiger

Dartmouth College Ph.D Dissertations

Biofilms are surfaced attached communities of cells encased in an extracellular matrix. The transition from free-swimming planktonic cells to a surface attached biofilm begins with cellular changes that occur after surface contact. This process is known as "surface sensing" and the opportunistic pathogen Pseudomonas aeruginosa PA14 uses its two motility appendages, type IV pili (T4P) and a single, polar flagellum to sense and traverse surfaces. The first cellular changes to occur within this organism upon surface contact is an increase in the second messengers cAMP and cdi- GMP. While the genes involved in surface sensing by P. aeruginosa are known, …

The Ecological Responses To Hydroperiod Of Wetland Plant Species Determined By Manipulated Soil Surface Elevation (Marsh Organs), Brandon Wolff

LSU Master's Theses

As sea level rise, subsidence, and abandonment of natural deltaic processes due to a highly engineered Mississippi River continue to threaten Louisiana’s coastal wetlands, the need for a system-wide understanding of natural wetland land-building and preservation processes has never been greater. A key component of any wetland is the ever-changing water environment that periodically floods and dries the marsh platforms. The flooding depth, duration, and frequency, known as the hydroperiod, along with salinity and soil fertility are key determining factors of vegetation and marsh types at a particular location. Different types of vegetation will have different growth characteristics such as …

Gut Dysbiosis Correlates With Covid-19 Severity, Ednita Escobar

CMC Senior Theses

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) impacts not only respiratory but also gut and oral microbiomes, influencing the manifestations of COVID-19. Each person’s unique microbiome consists of microorganisms such as bacteria, fungi, and viruses, some of which are symbiotic and others potentially harmful. Alterations in the gut microbiome, specifically, can affect the severity and symptoms of COVID-19. A review of studies indicate a pattern of gut dysbiosis in COVID-19 patients characterized by a decrease in beneficial microbiota and/or an increase in opportunistic pathogens. This gut imbalance correlates with disease severity, suggesting that the gut microbiome plays a significant role …

Assessing The Role Of The Microbiome, Parasite Infections, And Movement In Avian Health, Olivia N. Choi

Electronic Theses and Dissertations

Avian health encompasses the physical, physiological, and behavioral well-being of birds. Assessing avian health is not only important for the conservation and management of wild birds and the recreational economy, but also for the management of infectious diseases that threaten public health and agriculture. Birds, comprising approximately 10,000 species and an estimated 50 billion individuals worldwide, are known to be involved in the spread of pathogens, some of which are zoonotic (from animals to humans), such as avian influenza and West Nile viruses. Individual measures of avian health may include physical measurements (e.g., body mass, wing length), pathogen infection status, …

Interactions Between Streptococcus Agalactiae And Candida Albicans Affect Persistence And Virulence, Kathryn Patenaude

Electronic Theses and Dissertations

Streptococcus agalactiae (Group B Streptococcus or GBS), a Gram-positive bacterium, and Candida albicans, a polymorphic fungus, are commensal microbes in most of the population they colonize but are also capable of causing severe and sometimes fatal infections in certain patient groups. Both organisms share similarities including the colonization the same tissue environments and causing infections in specific patient groups including those who are newborn, pregnant, suffering from chronic conditions like diabetes and HIV, as well as elderly patients. Previous research discovered that GBS and C. albicans can synergize to enhance the colonization of GBS in the bladders of mice, but …

Pseudomonas Aeruginosa Enhances Fluconazole Activity Against Candida During Polymicrobial Infection, Siham Hattab

Electronic Theses and Dissertations

Polymicrobial infections pose a significant challenge in the field of medicine due to our incomplete understanding of how pathogens interact during infection and how these interactions impact the effectiveness of drug treatments. Among the opportunistic pathogens, Candida albicans and Pseudomonas aeruginosa stand out, as they are often found in similar infection sites, such as burn wounds, the lungs of patients with cystic fibrosis and those on mechanical ventilation. Candida albicans is an opportunistic fungus responsible for invasive candidiasis, a condition associated with a high mortality rate of 40% in hospitals. Pseudomonas aeruginosa, on the other hand, is the primary pathogen …

Pathogenicity Of Acinetobacter Calcoaceticus, Kaitlan A. Sullivan

MUSC Theses and Dissertations

Acinetobacter is a genus of gram-negative bacteria that have been appearing frequently in hospitals contributing to infections in the blood, lungs, urinary tract, and other parts of the body. It infects patients with weakened immune systems that are placed on ventilators, after the use of catheters, or have any other open wounds produced by prolonged hospital stays. This genus of bacteria is problematic due to its high probability of becoming resistant to multiple classes of antibiotics. Thus, we are determining the pathogenicity of clinical isolates of Acinetobacter calcoaceticus using the organism Caenorhabditis elegans as a model.

We are testing …

Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie

Doctoral Dissertations

Prescribed fires in Southern Appalachian forests are vital in ecosystem management and wildfire risk mitigation. However, understanding the intricate dynamics between these fires, soil microbial communities, and overall ecosystem health remains challenging. This dissertation addresses this knowledge gap by exploring selected aspects of this complex relationship across three interconnected chapters.

The first chapter investigates the immediate effects of prescribed fires on soil microbial communities. It reveals subtle shifts in porewater chemistry and significant increases in microbial species richness. These findings offer valuable insights into the interplay between soil properties and microbial responses during the early stages following a prescribed fire. …

The Identification Of Small Molecule Inhibitors To Candida Albicans Phosphatidylserine Synthase, Yue Zhou

Doctoral Dissertations

Candida albicans phosphatidylserine (PS) synthase, encoded by the CHO1 gene, has been identified as a potential drug target for new antifungals against systemic candidiasis due to its importance in virulence, absence in the host and conservation among fungal pathogens. This dissertation is focused on the identification of inhibitors for this membrane enzyme. Cho1 has two substrates: cytidyldiphosphate-diacylglycerol (CDP-DAG) and serine. Previous studies identified a conserved CDP-alcohol phosphotransferase (CAPT) binding motif present within Cho1, and here we revealed that mutations in all but one conserved amino acid within the CAPT motif resulted in decreased Cho1. For serine, we have predicted a …

Impact Of Cadmium Stress On Soil Virus Reproduction And The Persistence Of Viruses Under Abiotic Conditions, Zhibo Cheng

Doctoral Dissertations

Soil viruses are ubiquitous and greatly impact the structure and function of soil microbial communities, with their effects modulated by various environmental factors. This study investigates the inactivation of naturally occurring soil viruses in sterilized soil, as well as the effects of cadmium (Cd) exposure and carbon (C) and nitrogen (N) nutrient availability on the population dynamics of virus-host communities in agricultural soil.

Lab-scale slurry and unsaturated experiments were performed to examine virus inactivation in the absence of host bacteria in sterilized soil. In slurry experiments, virus abundance declined by over 90% after 10 days of incubation. The addition of …

Integration Of Raman Spectroscopy And Python-Based Data Analysis For Advancing Neurobiological Research, Natalie E. Dunn

Doctoral Dissertations

The field of Raman spectroscopy continues to expand into biological applications due to its usefulness as a non-invasive technique that can be utilized qualitatively and quantitatively. However, the inherent weakness of Raman scattering leads to the need for each collected spectra to undergo a preprocessing step to remove noise, background drift, and cosmic rays. Biological research in particular needs large datasets due to the increased variability in samples. As datasets grow, the need to perform preprocessing on each individual spectra becomes daunting. Often, these steps are done by hand with the help of specialized software programs. Preprocessing can be accelerated …

Exploring The Regulation Of A Bacillus Pumilus Bioplastic Degrading Protein, Elise Keara Phillips

Doctoral Dissertations

Biodegradable plastics are being adopted to reduce the environmental impacts associated with petroleum-based plastics, including long residence times, and reliance on fossil fuels as a feedstock. Microbial degradation of bioplastics is still poorly understood, which leads to inconsistent degradation outcomes and challenges for implementation. Bacillus pumilus B12 degrades the biodegradable bioplastic polylactic acid (PLA) via the protease AprE, but the regulatory mechanisms controlling aprE expression in B. pumilus B12 are largely unknown. To explore this question, we established developed a conjugation- based method to introduce DNA into B. pumilus B12 and diverse Bacillus species that is applicable to environmental and …

Development Of Novel Methods To Study Host-Microbe Interactions In The Larval Zebrafish Gastrointestinal Tract, Anh K. Trinh Nguyen

Dissertations & Theses (Open Access)

The dynamic nature and inaccessible location of the intestine pose significant challenges to the study of intestinal physiology and pathology. Zebrafish larvae, possessing optical transparency and genetic tractability, offer an accessible and clinically relevant model for investigating dynamic events in the intestine via time-lapse imaging. In the first part of this work, I discuss our efforts to optimize the parameters of a foodborne infection assay using paramecia as a vehicle. This method provides an effective, high-throughput alternative to infection via immersion or oral gavage, and replicates the most common route of transmission of gastrointestinal (GI) infection in humans. The foodborne …

Novel Microbial Guilds Implicated In N2o Reduction, Guang He

Doctoral Dissertations

N₂O is a long-recognized greenhouse gas (GHG) with potential in global warming and ozone depletion. Terrestrial ecosystems are a major source of N₂O due to imbalanced N₂O production and consumption. Soil pH is a chief modulating factor controlling net N₂O emissions, and N₂O consumption has been considered negligible under acidic conditions (pH <6). In this dissertation, we obtained solids-free cultures reducing N₂O at pH 4.5. Furthermore, a co-culture (designated culture EV) comprising two interacting bacterial population was acquired via consecutive transfer in mineral salt medium. Integrated phenotypic, metagenomic and metabolomic analysis dictated that the Serratia population excreted certain …

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …

The Impacts Of Tilled-In Biodegradable Plastic Mulch On Soil Microbial Communities, Corissa L. Martin

Masters Theses

Plastics mulch films are used in agriculture to help increase crop production by regulating soil water retention and soil temperature while also preventing weed growth. Despite these benefits, plastic mulches have led to higher levels of microplastic pollution as weathering occurs. In response to this issue, biodegradable plastic mulches (BDMs) have been introduced to help reduce plastic pollution as they are designed to be tilled into soil after each growing season to continue degradation. Degradation of these mulch films is dependent on climate and, in some areas, complete degradation can take years. Since some biodegradable plastic mulches are made of …

Developing Disinfection Strategies For Controlling Human Norovirus, Sars-Cov-2, And Clostridioides Difficile Endospores In Long-Term Care Facilities, Jinge Huang

All Dissertations

Long-term care facilities (LTCFs) provide an environment favorable for the transmission of three critical human pathogens: human norovirus (HuNoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and Clostridioides difficile. Given residents in LTCFs are susceptible to infections due to their advanced ages and compromised immune systems, effective environmental surface disinfection plays a crucial role in controlling the spread of human pathogens within these settings and, therefore, mitigates the risk of infections caused by these pathogens. This dissertation aimed to assess the efficacy of various types of disinfectants against two HuNoV surrogates [feline calicivirus (FCV) and Tulane virus (TuV)], two …

Detection And Control Of Environmentally Transmissible Viruses, Anand R. Soorneedi

Doctoral Dissertations

Viruses, owing to their ubiquitous nature and ability to infect almost every other species, have long been a subject of interest for scientists. Some of the virus species can be very deadly to humans and animals alike and can impose a huge economic and health burden across the world. The recent CoVID-19 pandemic underscores the importance of timely detection for developing effective intervention strategies. Unfortunately, some of the virus species that cause significant health and economic impacts do not have robust and reliable detection methods due to several reasons. In some cases, despite having gold standard methods for detection of …

A Biochemical Approach To Characterize A Divergent Trypanosoma Brucei Mitochondrial Dna Polymerase, Polib, Stephanie B. Delzell

Doctoral Dissertations

Trypanosoma brucei is a single-celled parasitic protist that causes African sleeping sickness in people and nagana in cattle in sub-Saharan Africa. T. brucei and related trypanosomatid parasites contain an unusual catenated mitochondrial genome known as kinetoplast DNA (kDNA) composed of dozens of 23 kb maxicircles and thousands of 1 kb minicircles. The kDNA structure and replication mechanism are divergent from other eukaryotes and essential for parasite survival. POLIB is one of three Family A DNA polymerases that are independently essential to maintain the kDNA network, and has been implicated in minicircle replication. However, the division of labor among the paralogs, …

The Discovery Of A Novel Bacteria From A Large Co-Assembly Of Metagenomes, Matthew Finkelberg

Masters Theses

In the summer of 2022, a co-assembly of metagenome was created using the microbes found at Barres Woods in Harvard Forest. 14 samples were taken, and sample was split into the organic and mineral layer, which totals 28 Bulk MAGs. Within this Co-assembly, 4 different genomes were found which were designated with the phylum of FCPU426. Three of which were considered medium quality and one being assigned high quality. The novel phyla first appeared in NCBI and GTDB databases in June 2018. The name FCPU426 dates to 2010 and was named based on the 16s amplicon sequencing.

The novel phylum …

Climate Change, Giant Viruses And Their Putative Hosts, Sarah K. Tucker

Masters Theses

Viruses hold our attention for the horrific impact they have on human health and welfare. However, viruses are a critical part of our ecosystem and facilitate the cycling of carbon and other important nutrients. The cycle of virus infection, followed by host resistance and the subsequent evolution of new strains enables adaptation to changing hosts and the environment. Giant viruses, some with particle sizes large enough to be visible in light microscopes and their bewildering array of accessory genes, have captivated scientists and the general public since their discovery two decades ago. Giant viruses are part of the Nucleocytoviricota (NCV) …