Microbiology Commons^™

Investigating The Dna-Binding Role Of Tbp1 In Toxoplasma Gondii: Expression And Characterization Of A Recombinant Protein, Madison T. Jeckell

Honors Theses and Capstones

Toxoplasma gondii is an obligate intracellular parasite with a complex life cycle and an unusual transcriptional machinery compared to other eukaryotes. Unlike most organisms, Toxoplasma lacks multiple well-conserved promoter motifs and has multiple TATA-binding proteins (TBPs), including TBP1, whose function in DNA binding and transcription regulation is poorly understood. This study aimed to generate and express a recombinant TBP1 protein from Toxoplasma to enable future DNA-binding assays and motif identification. Using RT-PCR, the TgTBP1 gene was amplified and cloned into a pGEX vector to produce a GST-tagged protein. The recombinant plasmid was transformed into E. coli BL21 cells, and protein …

Investigation Of Multiple Factors Influencing The Vector-Borne Transmission Of Salmonella Typhimurium Via Blattella Germanica, Landen Sean Van Hulzen

Dissertations and Theses

The German cockroach (Blattella germanica) is a common urban pest that lives ubiquitously in human structures around the world. German cockroaches are a severe public health threat as they are known carriers and vectors of human pathogens including Salmonella enterica, Escherichia coli, Shigella spp, and more. German cockroach infestations have been associated with Salmonellosis outbreaks. While mechanical transmission by the German cockroach vector is well known, new research suggests that more nuanced biological transmission has a role in maintaining and transmitting Salmonella enterica serovar Typhimurium (S. Typhimurium). Despite this recent finding, many biological variables influencing vector-borne transmission of S. Typhimurium …

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 …

Role Of Coronavirus Envelope Protein On Infectivity, Garrett E. Zaagman

Dissertations

Coronaviruses infect a wide range of hosts and have caused recent human pandemics. While much has been learned, gaps remain in understanding viral assembly and egress, particularly the role of the envelope (E) protein in specific infectivity. To study this, recombinant MHV viruses were created with E gene deletions and HiBiT-tagged spike (S) proteins to monitor virion release. In mouse cells, MHV∆E S-HiBiT secreted less spike and fewer infectious particles, indicating reduced specific infectivity. Comparisons between human HeLa-CEACAM and mouse DBT cells showed species-specific support for virus production. TMED10, a host membrane protein, was tested as a potential E-interacting partner …

Exploring The Role Of Host Immune Responses And Bacterial Sensory Pathways In The Development Of Treponema Denticola-Mediated Periodontal Disease, Annie N. Hinson

Theses and Dissertations

Periodontitis is a chronic inflammatory disease driven by dysbiotic microbial communities and maladaptive host responses. Treponema denticola, a spirochete pathobiont, is strongly associated with disease severity. However, the molecular mechanisms underlying its interaction with host tissues and regulation of virulence remain incompletely understood. This work examines both the epithelial immune responses and bacterial transduction systems that shape T. denticola pathogenesis. Transcriptomic analysis of gingival keratinocytes revealed IL-36γ as the most highly induced cytokine following infection with T. denticola. Functional studies demonstrated that IL-36γ induction occurs in a dose- and time-dependent manner through TLR2/6 signaling, requiring the NF-κB, PI3K/Akt, and …

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 …

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 …

Molecular Mechanisms Of Kynurenine-Mediated Lifespan Regulation In Yeast, Ryan E. Counterman Jobb

Theses and Dissertations

The kynurenine pathway is a highly conserved pathway that acts as the primary pathway for tryptophan catabolism and has been found to be involved in lifespan regulation across many diverse organisms. Caloric restriction (CR) is the only known dietary intervention to date that both increases the mean lifespan and the health span of multiple organisms, although the molecular mechanisms of these effects are not fully understood. There are known and sometimes contradictory relationships between the kynurenine pathway activity and the life- extending effect of CR but the crosstalk between the two is not well characterized. Understanding these relationships could lead …

Practical Experimental Microbiology: Laboratory Manual, Rivka Levron

Open Touro Created

2025

Microbiology, especially the laboratory component, is a highly practical and useful course for students pursuing many career options. While a number of excellent microbiology laboratory manuals are available, many are more suitable for a full-year course in microbiology or for more advanced studies.

Microbiology Experimental Laboratory Manual is comprehensive in teaching students basic microbiological techniques, i.e., how to grow and stain bacteria, how to identify bacteria and fungi, and means of identifying different species of bacteria microscopically. Further experiments enable students to identify the most effective soap/detergent from those readily available; to discover which spices have the most anti-bacterial …

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 …

The Role Of Horizontal Gene Transfer In Antibiotic Resistance Amidst Prevalent Community And Healthcare-Associated Mrsa Rates, Gabrielle Nascimento

Honors College Theses

In recent decades, cases of community-acquired MRSA (CA-MRSA) and healthcare-associated MRSA (HA-MRSA) have been on the rise. The ability of antibiotic resistance to transfer between microorganisms greatly expands its threat to the effective treatment and containment of bacterial infections. The mecA gene is found on a mobile cassette within the Staphylococcal cell and encodes for PBP2a, an alternate version of penicillin-binding protein (PBP) with less binding affinity for β-lactam antibiotics, increasing resistance to the effects of antibiotics. The goal of this research is to investigate the horizontal transfer of the mecA gene between various Staphylococcus species as well as to …

Analysis Of The Microbiome Of Amblyomma Americanum In The Statesboro Region, Ella Zierdt, Lorenza Beati, Mary Humphrey, Saviour Dralabu

Honors College Theses

The lone star tick, Amblyomma americanum, is the most common tick in Georgia. It is mainly known as an Ehrlichia spp. vector, but its microbiome can be diverse, depending on geography, developmental stage, and season. Little is known about bacterial diversity in ticks from the southeastern U.S. A Nanopore MinION sequencer was used for a preliminary analysis of the bacterial microbiome in A. americanum from the Statesboro region. DNA was extracted from 39 nymphs, 35 males, and 39 females. DNA samples were pooled by month of collection and life stage/sex, amplified with barcoded 16SrDNA primers, and sequenced. Approx. 77% …

Interactions Between Lipopolysaccharide And Capsule Retention In Klebsiella Pneumoniae And The Resultant Effects On Macrophages, Juliane Leigh Nguy

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is the third most common cause of nosocomial infections in the United States. The capsular polysaccharides (CPS) are virulence factors allowing K. pneumoniae to evade host immune systems. The current model of capsule structure indicates that CPS fibrils interact with the external O-antigen of lipopolysaccharide molecules to enhance retention to the bacterial outer membrane. These interactions may influence pathogenicity in clinically relevant strains. This study characterized alterations to LPS and CPS structure, the impact of these changes on capsule retention, membrane permeability, biofilm formation, and macrophage interactions. LPS and CPS were quantified and visualized in four strains of …

A Novel Silver-Ruthenium-Based Antimicrobial Kills Gram-Negative Bacteria Through Oxidative Stress-Induced Macromolecular Damage, Patrick O. Tawiah

Theses and Dissertations

The rise in drug-resistant bacteria, together with the decline in antibiotic development, requires new strategies for infectious disease control. Gram-negative pathogens are particularly challenging to combat due to their outer membrane. This study highlights the effectiveness of the silver-containing antimicrobial AGXX® against the Gram-negative bacterium Escherichia coli. AGXX® is a promising silver coating that presumably kills bacteria through the generation of reactive oxygen species (ROS). However, neither AGXX®’s mode of action is fully understood, nor have its effects on Gram-negative bacteria or bacterial response and defense mechanisms towards AGXX® been studied in detail. Here, I report that the bactericidal …

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 …

Reversible Degradation Of Peptidoglycan By Lytic Transglycosylases, Aaron Devereaux

Theses and Dissertations (Comprehensive)

Antimicrobial resistance continues to be a burden on the global healthcare system with an estimated cost of billions of dollars and millions of deaths each year. Recently, there has been little to no development on new antibiotics to treat bacterial infection, and any that are developed become resisted to within a few years. Both Gram-positive and Gram-negative bacteria contain a mesh-like layer called peptidoglycan (PG) that surrounds their cells providing strength, cell shape, and protection from their environments. This layer is a polymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) connected via a b-1,4-glycosidic bond, with each strand being cross-linked …

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 …

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 …