Microbiology Commons^™

Investigating The Development Of Alcohol Tolerance In The Eskape Pathogens, Hannah Durkee

West Chester University Master’s Theses

Antiseptics and disinfectants are used globally to kill or inhibit the growth of bacteria to prevent infection. Considering the well-documented development of antibiotic resistance, the potential for evolved tolerance to alcohol-based antimicrobial agents raises concern. The ESKAPE bacterial pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are a major cause of healthcare-associated mortality and present a threat to public health due to the progression of multi-drug resistance. We conducted an experiment to determine if the ESKAPE pathogens develop an increased tolerance to ethanol upon repeated exposure by selecting for survivors after a …

Fungal Activity In Fusarium Keratoplasticum Isolates With And Without Endohyphal Bacteria On Various Carbon Sources, Maya Brown

Honors College Theses

In recent years, the fungus Fusarium keratoplastic has been associated with failed sea turtle eggs. One fungal isolate collected from a failed egg collected on Wassaw Island, GA in 2020 contained endohyphal bacteria, bacteria living within the hyphae of the fungus. The type of endohyphal bacteria (EHB), as well as the relationship between the bacteria and fungal hosts, are currently unknown. Previous research on the same fungus and EHB, specifically Chitinophaga sp., discovered that EHB influenced the ability of the fungus to utilize carbon sources. Our research goal was to examine the metabolic relationship of Fusarium isolated from failed sea …

Characterization Of Serx: A Putative Periplasmic Binding Protein In A Selenate Respiring Bacteria, Henry Jacques, Susan E. Childers

Honors Theses

A selenate respiring bacterium, Dechloromonas sp. A34, was isolated from a seleniferous mining site in southeastern Idaho. A34 was of interest due to its ability to respire up to 20 mM selenate, the highest concentration tested. The strain has been proposed to represent a new species of bacteria within the Dechloromonas genera, with the prospective name Dechloromonas selenatirespirans (manuscript in preparation). Our research presents characterization of a putative periplasmic binding protein found within an operon that contains genes encoding a putative selenate reductase. The gene, named serX (selenate reductase gene X), is 855 base pairs and encodes a putative …

A Comparison Of Adenosine Triphosphate With Other Metrics Of Microbial Biomass In A Gradient From The North Atlantic To The Chesapeake Bay, Alexander B. Bochdansky, Amber A. Beecher, Joshua R. Calderon, Alison N. Stouffer, Nyjaee N. Washington

OES Faculty Publications

A new, simplified protocol for determining particulate adenosine triphosphate (ATP) levels allows for the assessment of microbial biomass distribution in aquatic systems at a high temporal and spatial resolution. A comparison of ATP data with related variables, such as particulate carbon, nitrogen, chlorophyll, and turbidity in pelagic samples, yielded significant and strong correlations in a gradient from the tributaries of the Chesapeake Bay (sigma-t = 8) to the open North Atlantic (sigma-t = 29). Correlations varied between ATP and biomass depending on the microscopic method employed. Despite the much greater effort involved, biomass determined by microscopy correlated poorly with other …

Reiq-Mediated Alarmone Signalling Regulates Growth, Stress-Induced Biofilm Formation And Spore Accumulation In Clostridioides Difficile, Areej Malik, Adenrele Oludiran, Asia Poudel, Orlando Berumen Alvarez, Charles Woodward, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The bacterial stringent response (SR) is a conserved transcriptional reprogramming pathway mediated by the nucleotide signalling alarmones, (pp)pGpp. The SR has been implicated in antibiotic survival in Clostridioides difficile, a biofilm- and spore-forming pathogen that causes resilient, highly recurrent C. difficile infections. The role of the SR in other processes and the effectors by which it regulates C. difficile physiology are unknown. C. difficile RelQ is a clostridial alarmone synthetase. Deletion of relQ dysregulates C. difficile growth in unstressed conditions, affects susceptibility to antibiotic and oxidative stressors and drastically reduces biofilm formation. While wild-type C. difficile displays increased biofilm …

Multiple Variables Influence The Finely Calibrated Antioxidant Defenses Of Clostridioides Difficile, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The obligate anaerobe Clostridioides difficile encodes multiple reductases to detoxify molecular oxygen and reactive oxygen species. Caulat and colleagues have characterized the activity and regulation of four such reductases (L. C. Caulat, A. Lotoux, M. C. Martins, N. Kint, et al., mBio 15:e01591-24, 2024, https://doi.org/10.1128/mbio.01591-24). Each proved critical for clostridial survival in a different range of oxygen concentrations; together, they ameliorate a broad range of oxidative stress levels. Moreover, two previously uncharacterized regulators were found to control reductase gene expression in response to oxidative stress. The genetic repressor Rex and the reductase FdpF are both sensitive to the NAP …

Competition Between Bradyrhizobium Strains For Soybean Nodulation, Lilia Ernestina Montanez Hernandez

Electronic Theses and Dissertations

Biological Nitrogen Fixation (BNF) has surged as a natural strategy to provide available nitrogen to crops by taking advantage of diazotrophs, microorganisms that can reduce atmospheric nitrogen to ammonia. Soybean, a major crop, greatly benefits from BNF by forming endosymbiotic relationships with rhizobacteria from the genus Bradyrhizobium, which culminates in the formation of specialized organs called nodules, where nitrogen fixation occurs. This is known as Symbiotic Nitrogen Fixation (SNF). Inoculation of soybean fields with high nitrogen fixing Bradyrhizobium strains to stimulate SNF is being used as a strategy to increase crop productivity and nitrogen content. However, in North America, SNF …

Genetic Engineering Of Escherichia Coli For The Production Of Riboflavin, Adeyemi Adesanwo

Graduate Research Theses & Dissertations

Riboflavin, a water-soluble vitamin B2, is essential for the growth and reproduction of living organisms. However, humans and animals lack a riboflavin synthesis pathway and must rely on diets derived from plants and microbes for this essential vitamin. To meet our needs for vitamin B2, industrial riboflavin production is currently being pursued using strains of Bacillus subtilis. The fermentation process is successful, but improvements are needed for better substrate-to-product conversion yield. To this end, it is imperative to develop alternative microbial strains for cost-effective riboflavin production.

Due to its simple growth requirement, well-understood genetic background, and widely available genetic tools, …

Iron–Sulfur Cluster Assembly Scaffold Protein Iscu Is Required For Activation Of Ferric Uptake Regulator (Fur) In Escherichia Coli, Huangen Ding

Faculty Publications

No abstract provided.

Advancing Biological Applications Through Microfluidic-Based Tool Development, K.M. Taufiqur Rahman

Electronic Theses and Dissertations

This research undertook an interdisciplinary approach, integrating bioengineering, microbiology, molecular biology, and systems biology to investigate bacterial dynamics behavior. Specifically, it delved into the development of microfluidic devices for biological applications such as bacterial cell counts, real-time observation of plant roots (here, specialized lectin-coated microbeads are used that mimic root characteristics), and soil microbe interactions. Furthermore, Next-Generation Sequencing and systems biology methodologies were employed to explore the intricate, multifaceted survival mechanisms of Escherichia coli persister population. Studying and quantifying persisters or testing for the existence of VBNC (viable but nonculturable) is challenging. These experiments require precise counts. It has been …

Complete Genome Sequence Of Microbacterium Foliorum Phage Curie, A Podovirus Isolated From Soil In Spokane, Washington, Emma N. Horton, Kathryn T. Cook, Kyra G. Cronin, Avery T. Haag, Sierra M. Salter, Nicole A. Stojanovic, Zoe E. Fry, Brian M. Connolly, Rebekah F. Hare, Ann-Scott H. Ettinger, Marianne K. Poxleitner, Kirk Anders

Biology Faculty Scholarship

Bacteriophage Curie is a podovirus that infects Microbacterium foliorum. The Curie genome spans 16,810 bp, has 90 bp terminal inverted repeats, and includes 23 protein-coding genes. Its genome architecture resembles phage PineapplePizza and other phi29-like phages. Together, Curie and PineapplePizza form a new actinobacteriophage Cluster GI.

Persistence Of Wastewater-Associated Antibiotic Resistant Bacteria In River Microcosms, Aoife P. Mahaney

Theses and Dissertations

The spread of antibiotic-resistant bacteria (ARB) associated with wastewater is a significant environmental concern, but little is known about the persistence and proliferation of these organisms in receiving water bodies after discharge. To address this knowledge gap, we performed a series of microcosm experiments in which river water was amended with either untreated or treated wastewater, and the abundance of viable ciprofloxacin-, Bactrim-, and erythromycin-resistant bacteria was monitored for 72 hours.

Both types of wastewater amendments increased the initial abundance of ARB compared to microcosms containing only river water. The increase was greatest with untreated wastewater, but that effect decreased …

Developing Methods For Analysis Of Chiral Small Molecules And D-Amino Acid Containing Peptides, Joshua I. Putman

Chemistry & Biochemistry Dissertations - Archive

This dissertation covers the development of methods to analyze chiral small molecules and d-amino acid containing peptides. The first section covers the development of liquid chromatographic chiral screening approaches for newly synthesized chiral molecules. The next part of the dissertation covers methodologies for the analysis of d-amino acid containing peptides. Lastly the bacterial degradation of three commonly used pesticides by bacteria harvested from Colorado potato beetles (Leptinotarsa decemliniata) is presented.

Twelve new azole compounds and eleven racemic ethanolamine derivatives were synthesized. These twenty-three compounds were evaluated using eight chiral columns, four macrocylic glycopeptides, a cyclodextrin derivative …

Harnessing Antagonistic Pleiotropy: Tolc-Dependent Coliphages Can Drive Reduced Antibiotic Resistance In E. Coli, Cooper Mckenna

CMC Senior Theses

The rise of multidrug-resistant (MDR) bacterial pathogens has been a growing concern in healthcare around the world, and bacteriophage (phage) therapy is a promising method to combat MDR infections. One defense mechanism of E. coli against antibiotics is the TolC-AcrAB efflux pump. At the same time, some phages use TolC as a surface receptor to infect the cell. This puts TolC at a crossroads in which it is beneficial to the bacteria to protect against antibiotics but harmful by allowing phage infection, creating the potential for evolutionary trade-offs. Previous research has identified only three TolC-dependent phages and shown phage-resistant E. …

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 …

Host-Defense Piscidin Peptides As Antibiotic Adjuvants Against Clostridioides Difficile, Adenrele Oludiran, Areej Malik, Andriana C. Zourou, Yonghan Wu, Steven P. Gross, Albert Siryapon, Asia Poudel, Kwincy Alleyne, Savion Adams, David S. Courson, Myriam L. Cotten, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The spore-forming intestinal pathogen Clostridioides difficile causes multidrug resistant infection with a high rate of recurrence after treatment. Piscidins 1 (p1) and 3 (p3), cationic host defense peptides with micromolar cytotoxicity against C. difficile, sensitize C. difficile to clinically relevant antibiotics tested at sublethal concentrations. Both peptides bind to Cu²⁺ using an amino terminal copper and nickel binding motif. Here, we investigate the two peptides in the apo and holo states as antibiotic adjuvants against an epidemic strain of C. difficile. We find that the presence of the peptides leads to lower doses of …

Parametric Study Of The Effect Of Increased Magnetic Field Exposure On Microalgae Chlorella Vulgaris Growth And Bioactive Compound Production, Sharanabasaweshwara Asundi, Sanurag Rout, Simone Stephen, Sanghamitra Khandual, Sandipan Dutta, Sandeep Kumar

Mechanical & Aerospace Engineering Faculty Publications

This parametric study aimed to analyze the effects of increased magnetic field exposure (MFE) on the growth and production of the bioactive compounds of Chlorella (C.) vulgaris. With the intent of studying the effect of an increased MFE, the magnetic field typically experienced by life on Earth was amplified by an order of magnitude. In the increased-MFE environment, six treatments of C. vulgaris with two repetitions for each treatment were exposed to a magnetic field of 5 Gauss (500 µT) about each axis, which was generated in a state-of-the-art Helmholtz cage. The treatments and the control were characterized by the …

Sun Damages And Preventative Measures For Keratinocyte Carcinomas, Alex Kandolin

Biology and Microbiology Graduate Students Plan B Research Projects

UV rays from the sun cause damage to our genomic DNA and in turn have the ability to cause cancer. Protection methods such as sunscreen have been used for many years, however, the introduction of polyphenols and topical creams have brought new hope to skin protection. Polyphenols are a new method using an internal approach that directly targets the damaged DNA using different mechanisms through food. When used in addition to sunscreen, the chances of skin cancer are greatly reduced. Additionally, but using topical cream such as 5-fluorouracil can be an approach to already existing lesions caused from UV radiation. …

Regulation Of Inflammatory Signaling By The Gut Microbiome, Caden Johnson

Biology and Microbiology Graduate Students Plan B Research Projects

The human gut contains trillions of bacteria that play a key role in gastric homeostasis. Commensal bacteria play a critical role in the formation of the gastrointestinal barrier that prevents invasion of other pathogenic bacteria and also serves as a secondary metabolism system that aids in the synthesis of dietary fibers into many essential nutrients such as vitamins, sugars, and especially short chain fatty acids (SCFAs) in the anaerobic conditions in the large intestine. These SCFAs assist in regulating immune tolerance to commensal bacteria of the gut and promote an anti-inflammatory state important to lowering the incidence of inflammatory disorders …

Treatment-Related Adverse Effects In African Cancer Patients: A Systematic Review, Gabriel T. Fagbenro

Biology and Microbiology Graduate Students Plan B Research Projects

Treatment associated with cancer comes with serious adverse effects which affect patients’ physiological functioning, worsen financial toxicity, reduce quality of life, and increased risk of treatment discontinuation. There is dearth of evidence on prevalence and pattern of side effects among African patients receiving cancer-directed therapies. Primary research studies reporting side effects of non-surgical interventions among patients in African countries were selected for review. The most prevalent side effects included nausea, vomiting, and loss of appetite (chemotherapy); radiation dermatitis and mucositis (radiation therapy); anaemia, neutropenia/febrile neutropenia, and thrombocytopenia (chemoradiation), and cardiotoxicity (immunotherapy). Oncologists need to pre-empt and provide necessary prophylactic and …