Microbiology Commons^™

Impact Of Achromobacter Xylosoxidans Infection On The Cf Lung In Single-Species And Polymicrobial Infection With Pseudomonas Aeruginosa, Caitlin E. Billiot

All ETDs from UAB

Achromobacter xylosoxidans is a Gram-negative bacillus that acts as an opportun- istic pathogen in those with cystic fibrosis (CF). Infection with A. xylosoxidans in these populations is associated with decreased lung function. Thus, this raises the question of the role of A. xylosoxidans in CF disease progression. CF is a polymicrobial disease and A. xylosoxidans is oftentimes isolated alongside Pseudomonas aeruginosa, a major CF colonizer. In the context of CF disease, it is important to understand the implications of polymicrobial infection as altered infection dynamics are observed when multiple microbes colonize together. In the first half of this work, we …

Understanding The Insecticidal Toxin Xpta2: A Shift In Toxin Complex Biology, Cole Lorenza Martin

All ETDs from UAB

Pore forming toxins (PFTs) belonging to the ABC toxin complex (Tc) family are responsible for targeting and translocating toxins into target cells. ABC toxins consist of three separate subunits, each subunit providing a vital role in the cytotoxic mechanism of the Tc. The A subunit or TcA is the largest subunit of the complex and contains the binding domains and the translocation channel that perforates the membrane. The B subunit or TcB functions as a gated linker that forms a cocoon with the TcC which houses the toxic peptide and subsequently gets translocated through the TcB and TcA into the …

Investigating Drivers In Phytoplankton Between Lentic And Lotic Ecosystems Within Twelvepole Creek Watershed, Devin Lee Farmer

Theses, Dissertations and Capstones

Harmful Algal Blooms (HABs) threaten aquatic ecosystems, local economies, and water quality. While extensively studied in lakes (lentic systems), their impact on flowing waters (lotic systems) remains underexplored. This study examined algal drivers in both ecosystems within the same watershed, focusing on Beech Fork Lake (lentic) and Twelve Pole Creek (lotic). Key environmental factors, including pH, turbidity, dissolved oxygen, and nutrient levels, were measured using in situ sensors and laboratory analysis. Water samples were analyzed for nitrogen, phosphorus, and algal biomass for comparison to environmental conditions. Phytoplankton was preserved for identification in future research. By comparing these environments, this study …

Engineering Chimeric Autoantibody Receptor T Cells (Caar): A Potential Cure For Graves' Disease, Kimbal Demars, Abigail Cheever, Chloe Kang, Hunter Lindsay, Mackenzie Hansen, Kim O'Neill, Scott Weber

Library/Life Sciences Undergraduate Poster Competition 2025

• Graves’ Disease (GD) is the 4th most common autoimmune disease in the United States.
• GD is characterized by autoreactive B cells releasing anti-thyroid stimulating hormone receptor (TSHR) Ab that bind to TSHR, causing an overexpression of hormones.
• Excessive hormonal release leads to hyperthyroidism, causing a variety of metabolic issues.
• No cure exists, only limited effectiveness of treatments, including chemotherapy, radiation, or thyroidectomy.
• Chimeric antigen receptors (CAR) T cell therapy has been effective in treating blood cancers.
• Modifying this therapy by engineering T cells that replace the antigen as the T cell receptor will selectively target autoreactive B cells, namely chimeric …

Effects Of Acute Injections Of Etoh In Cytokine Release In Mice, Alina Svitlana Rodriguez Bezruchko, Alka Gaur, Carlos M. Moreno, Jordan T. Yorgason, Scott Weber

Library/Life Sciences Undergraduate Poster Competition 2025

To learn the pathway by which the peripheral immune system interacts with dopaminergic neurons and triggers an addiction response, we compared cytokine and chemokine production levels before and after a 20-minute ethanol injection. Since some cytokines and chemokines can cross the blood-brain barrier, their peripheral production may influence neural activity. We had four groups: ethanol, saline, domperidone-ethanol, and domperidone-saline. As domperidone is a dopamine antagonist, we will use it as a control to verify that the change in cytokine production is due to ethanol rather than other factors.

Competitive Bacteria Inhibiting Yersinia Ruckeri Growth – A Strategy To Prevent Enteric Redmouth Disease (Erm) In Freshwater Fish, Kyler Linton, David Erickson

Library/Life Sciences Undergraduate Poster Competition 2025

Pacific freshwater fish are less likely than Atlantic freshwater fish to exhibit Enteric Redmouth Disease (ERM), or Yersiniosis as caused by Yersinia ruckeri. Based on the hypothesis that these fish may harbor commensal bacteria that inhibit Y. ruckeri growth, we isolated many kinds of commensal bacteria from fish intestines that we have collected from Alaska and local streams. Using co-culture experiments, we have conducted competitive assays to determine if the bacteria found in the gut biomes of these fish inhibit the growth of Y. ruckeri. These may be potential probiotic organisms that could provide resistance to ERM disease.

Acee And Pflb: Interference In Oxygen Independent Or Dependent Metabolic Pathways Affect Virulence Of P. Carotovorum, Ethan Shreeve, Foxx Naylor, Jeffrey Schachterle

Library/Life Sciences Undergraduate Poster Competition 2025

Pectobacterium carotovorum is a plant-pathogenic bacterium, causing soft rot diseases in vegetables such as potatoes and carrots. Mainly, this is achieved by the production of plant cell walldegrading enzymes, allowing for invasion of host cells. The general mechanisms underlying the pathogenicity of P. carotovorum are well characterized, but the phenotypic effects of some core metabolic processes are not. An important part of metabolism in bacteria is pyruvate production and utilization as a metabolic intermediate. P. carotovorum has two critical genes— pflB and aceE—that play roles in directing pyruvate metabolism. PflB encodes pyruvate formate-lyase, enabling the bacterium to convert pyruvate into …

Characterization Of Legionella Pneumophila Effector Protein Ceg10, Emmanuella Ofoka

Masters Theses & Specialist Projects

Legionella pneumophila, the causative agent of Legionnaires' disease, utilizes a Type IV secretion system (T4SS) to transport effector proteins into host cells. This bacterium is said to have over 300 effector proteins. Among these, the Ceg10 effector protein had remained uncharacterized, despite evidence suggesting the importance of bacterial effector proteins in the host-pathogen interaction. This study aimed to perform a structural and functional characterization of Ceg10 through transcriptomic, bioinformatics, and molecular analyses. Transcriptomic profiling of HEK 293T cells expressing Ceg10 revealed significant differential gene expression, with approximately 20 upregulated genes, including leucine-rich repeat, as well as other downregulated genes. …

"Dental Health For Mental Wealth": A Comprehensive Analysis Of The Underexplored Impact Of Oral Health And Behaviors On Neurobiology And Psychological Well-Being, Brooke C. Beck

Mahurin Honors College Capstone Experience/Thesis Projects

This thesis explores the link between oral health and psychological state, specifically, the effect of oral health on psychological state and how appropriate oral health impacts this relationship. A review of the literature was conducted and studies interpreted within the scope of oral health’s impact on psychological health and detailing some of the pathways proposed for such a link. The literature search was limited to the English language from well-known databases mainly from 2015 to 2025. A few outliers are present to include foundational information.

The effects of oral disease and oral self-care behaviors were dissected through a biochemical perspective, …

Propelling Whole-Cell Biosensor Creation By Leveraging Gene Fusion To Assemble Synthetic Functional Transcription Factors For The Detection Of Biomarkers, Samuel J. Verzino

Theses and Dissertations

Biosensors are analytical devices that leverage biological modules for the detection of molecules of interest. As customizable tools designed to aid in a wide array of diagnostics, these instruments are rapidly advancing the field of synthetic biology. While varied in their construction and purpose, biosensors are ultimately concerned with converting a physicochemical stimulus into a detectable signal. Among the many existing variants, whole-cell biosensors (WCBs) stand out due to their versatility and engineering potential. WCBs are a type of biosensor in which a physiologically active cell sustains an array of biomolecular elements - receptors, transporters, regulators, etc. - capable of …

Full Issue, Catalina Cuellar-Gempeler

Humboldt Journal of Microbiology

No abstract provided.

Antimicrobial-Resistant Enterococcus In Urban Communities: Insights Into Human Infection Risks, Sumit Kumar Paudel

Wayne State University Dissertations

The complexity of community risk factors and transmission routes has been a major challenge to the containment of community-acquired antibiotic resistance. Possible factors range from environmental contamination, antibiotic misuse, and human exposure via animals, food, the environment, and human-to-human transmission. What has been missing from previous research is the integration of findings in animal and environmental sectors with bacteria implicated in community infections. To gain a better understanding of antibiotic resistance acquired in the community, a one health approach is clearly needed. Specifically, we aim to investigate the prevalence of antibiotic-resistant Enterococcus in wildlife, their gene profiles in comparison with …

Microbial And Plant Biodiversity In Appalachian Agroecosystems And Their Implications For Soil Health, Kinsey Reed Close

Graduate Theses, Dissertations, and Problem Reports (ETD)

The sustainability of agricultural landscapes depends on understanding the complex interactions between plants, soil, and microbes. In Appalachia, a region shaped by complex terrain and long histories of human and ecological interaction, small family farms produce hay, livestock, and row crops. These agroecosystems, though often treated as “artificial” by many ecologists, have the potential to support both food production and biodiversity conservation if managed with an understanding of ecological complexity. This dissertation examines how plant and microbial diversity interact with soil and management to influence nutrient cycling, soil health, and long-term resilience in Appalachian agricultural systems. A literature review revealed …

René Dubos: An Annotated Bibliography, Carol L. Moberg

René Dubos: An Annotated Bibliography

René Dubos (1901–1982), a prominent 20th century scientist, humanist, and philosopher, was a prolific author. Affiliated for more than 50 years with The Rockefeller Institute for Medical Research/The Rockefeller University, his studies ranged from antibiotics and the role of bacteria in human diseases to formulating broad ecological and environmental questions affecting human health and disease. His seminal writings explore a lifelong belief that a living organism—whether microbe, human being, society, or the Earth itself—could be understood only through its relationships with everything else.

This comprehensive bibliography of more than a thousand works by René Dubos includes brief annotations for each …

Impact Of Glufosinate On Soil Microbial Community Dynamics, Sarobi Das

Biology Dissertations - Archive

The increasing global regulations of glyphosate due to its possible carcinogenicity and environmental hazards have necessitated the search for alternative herbicides. Glufosinate-ammonium offers a sustainable attribute due to its low toxicity and limited reported herbicide resistance cases. Despite its increasing agricultural importance, very limited studies are done on its environmental impact, especially on the soil systems. This thesis examines the ecological behavior of glufosinate in soil, precisely focusing on its effect on the dynamics of soil microbiome and the potential use of Bradyrhizobium japonicum USDA110 for bioremediation by reversing the effect of microbial dysbiosis. A series of 30-day mesocosm studies …

Novel Infection By Mucor Hiemalis Kills Caenorhabditis Hosts Through Intestinal Perforation, Jay Ni

West Chester University Graduate Theses, Dissertations, and Final Projects

The nematode Caenorhabditis elegans has emerged as a popular model system to investigate cell biology and host-pathogen interactions. Presently, C. elegans is studied as a natural host of intracellular pathogens such as microsporidia and Orsay virus along with extracellular bacterial and fungal pathogens. The use of C. elegans as a model in host-pathogen research is limited by the number of naturally occurring pathogens to the organism. Through a sampling project to identify new pathogens of C. elegans, we identified the fungus Mucor hiemalis as a pathogen of Caenorhabditis species. We observed the fungus in the intestinal lumen of wild-caught …

Clonal Variation In Effector Gene Expression As A Mechanism For Pathogenic Adaptation In Magnaporthe Oryzae, Rebekah J. Ellsworth

Theses and Dissertations--Plant Pathology

Magnaporthe oryzae is a filamentous fungal pathogen that causes destructive diseases in cereals, including rice blast, wheat blast, and gray leaf spot. It is responsible for 10–30% annual yield losses in rice (Nalley et al., 2016) and up to 100% loss in wheat under favorable conditions (Kohli et al., 2011). Disease management typically relies on the use of resistant cultivars, but M. oryzae rapidly overcomes host resistance by mutating or deleting avirulence (AVR) genes recognized by host immune receptors. This rapid adaptation, often occurring within one to two growing seasons, presents a major challenge to breeding for durable resistance.

The …

Genetic Analysis Of Methionine Restriction-Associated Mitochondrial Unfolded Protein Response Signaling., Josh D. Dodge

Biology Dissertations - Archive

The lifespan of an organism is dictated by various genetic and environmental factors. One such determinant is the health of mitochondria which are organelles that mediate various critical cell functions including a significant role in generating the vast supply of cellular energy. Indeed, the gradual decline of mitochondrial function is believed to be a hallmark and possible cause of aging. Paradoxically, mild mitochondrial dysfunction early in life extends lifespan in various model organisms. Cells use diverse approaches to promote mitochondrial homeostasis, including the transcriptional reprogramming of cells by mitochondrial unfolded protein response (UPRmt) to mitigate mitochondrial stress. Consistently, UPRmt activation …

For Dust Thou Art, And Unto Dust Shalt Thou Return — Testing Soil-Derived Plant-Beneficial Bacteria For Potential As Biofertilizers, Johnathon Brim, Blake Oler, Jacob Hardy, Joseph Richardson, Ryan Bjazevich, Kate Whalen, Emmelia Wevers, Foxx Naylor, Ethan Shreeve, Alex Cherry, Ethan Cherry, Tanner Gunnell, Jayden Longhurst, Andrew Burrows, Mailon Odell, Jacob Sy, Jeffrey Schacterle

Library/Life Sciences Undergraduate Poster Competition 2025

• The results of plant testing have shown that bacteria treated seeds outperform the control seeds on a consistent basis
• We will continue to receive more data from out own experiments as well as crowdsourcing methods.
• Our next step is to begin comparing results of our soil/seed treatment against commercially available fertilizers that use beneficial bacteria.

Unveiling The Bacterial Communities Of Aphaenogaster: Taxonomic Composition, Developmental And Species Influences, And The Impact Of Climate Change, Lily Kelleher

West Chester University Master’s Theses

Ants are vital keystone species in many ecosystems because they provide ecosystem services such as: seed dispersal, soil bioturbation, and pest control. However, ant bacterial symbioses remain largely unstudied, but these interactions are crucial because microbes play a vital role in the ants’ overall health. Today, global climate change is impacting our biodiversity, and we can use information about how changing temperatures impact the symbiotic bacterial communities associated with ants to predict future impact. Aphaenogaster rudis and A. fulva remain understudied in terms of their bacterial community and are important North American species. For this study, ants from several colonies …

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 …

Spermidine And Polyamine Blockade As Key Mediators Of Intestinal Epithelial Cell Functions, Madison Lynn Flory

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Frequently, alterations in the composition of the gut microbiota and its metabolites are linked with intestinal diseases, including inflammatory bowel disease and colorectal cancer. However, the direct connections between alterations in the microbiome and disease states often remain elusive. Prior research has identified increases in both polyamines, which are a class of microbial metabolite, and in the abundance of bacteria that can produce polyamines, in a murine colorectal cancer model. Understanding the significance of the interaction between these microbial metabolites and intestinal epithelial cells (IECs) will provide new and expanded evidence of the importance of the gut microbiome in colorectal …

Characterization Of A Highly Arsenic-Resistant Microbe, Eleanor E. Windholz

Honors Theses

Heavy metal pollution in our terrestrial and aquatic ecosystems is a major global concern, as chronic exposure to heavy metals such as arsenic and chromium has dire effects on mammalian health. In these polluted, arsenic-rich environments, microorganisms resistant to heavy metals have been isolated. The microbe isolated in this paper was resistant to As(V) up to 1100 mM, which is significantly higher than most published strains, and resistant to Cr(VI) at concentrations up to 5 mM. The microbe was tentatively identified as Micrococcus luteus, but its high arsenic resistance suggests it may be a novel strain. The ability of the …

Investigation Of Hydrogen Gas Production And Motility In Δselab And Δfdhf Mutants Of Clostridioides Difficile, Ria D. Gupta

Honors Undergraduate Theses

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium and the leading cause of antibiotic-associated diarrhea worldwide. During infection, antibiotic-induced disruption of the gut microbiota allows C. difficile to colonize and proliferate. Motility, enabled by flagella, is an important factor in colonization and may be influenced by metabolic activity. Recent experiments have observed gas production during C. difficile motility assays, but the biochemical basis of this phenomenon remains unknown. Because gas formation in other bacteria such as E. coli involves the formate hydrogenlyase complex and the enzyme formate dehydrogenase (FDH), we hypothesize that C. difficile gas production under motility conditions is …

Assessing The Role Of Daily Thermal Fluctuations In The Performance Of Mitochondrial Energy Transduction Of The Centrarchid, Lepomis Cyanellus, Grayson Hofmann

Masters Theses

Freshwater systems are affected by current climate extremes, forcing species found in these systems to withstand drastic changes in temperature. Temperature changes affect these organisms by altering their metabolic rate and energy balance. Increases in temperature can lead to an increase in oxygen consumption, which ultimately increases the need for more energy production. Mitochondrial energy transduction of green sunfish (Lepomis cyanellus) and many other fish species after a thermal insult, has hardly been explored. This study complements the limited research available on mitochondrial function in similar species, as they ignore the possibility of consecutive thermal events, which are …

Functional Characterization Of The Hdt5 Gene In Aspergillus Flavus Morphogenesis, Mycotoxin Production, And Fungal Phytopathogenicity, Brenda Omburo

Graduate Research Theses & Dissertations

The present study aimed at elucidating the role of hdt5 in fungal morphology, mycotoxin production and in plant virulence in Aspergillus flavus. Currently, methodologies to prevent the negative impact of A. flavus are insufficient. It is known that expression of the hdt5 gene is dependent on hbx1, a master regulatory gene that affects expression of hundreds of genes in the A. flavus genome, controlling both development and secondary metabolism. However, while the aflatoxin gene cluster has been elucidated, the genetic regulatory mechanisms controlled by hdt5 are not fully understood. For this study, therefore, a complete strain set composed of a …

An Exploration Of Social Isolation’S Effects On The Gastrointestinal And Metabolic Health Of A Social Mammal, Daniel Adam Nuccio

Graduate Research Theses & Dissertations

Human health can be impacted considerably by subjective feelings of loneliness, resulting in mental illness and the dysregulation of normal cardiovascular, immune and endocrine functioning. This occurs because social isolation serves as a form of chronic stress for social mammals, spurring physiological responses akin to those associated with more standard forms of stress. On account of their highly social nature, prairie voles (Microtus ochrogaster) subsequently have become one of the model organisms of choice for investigating the effects of social isolation on the development of disease in social mammals.

This dissertation seeks to expand the scientific community’s understanding of the …

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 …