Master of Science (MS), Wright State University, 2007, Biochemistry and Molecular Biology

The ability to detect chemical and biological agents is arguably one of the highest priority technical challenges today. The capability to obtain specific information at and near single-molecule resolution is the ultimate goal in chemical and biological agent detection. Metallic nanostructures, nanoshells and nanorods in particular, are attractive substrates because of their plasmonic properties. Combining the specificity of biomolecular recognition with these nanostructures might lead to increased sensitivity and selectivity. Localization of biological recognition motifs to the surface of these nanostructures could provide a mechanism for highly specific and directed energy transfer when bound to its target. This study utilizes nanoshells functionalized with antibodies specific for Escherichia coli, and investigates at both the microscopic and macroscopic scales the ability of these biofunctionalized nanoshells to bind and destroy their target micro-organism when excited using 808 nm near infrared laser radiation. Extension of the technique to Bacillus subtilis spores as well as bacteriophage specific to Escherichia coli are also explored. The bacteriophage is a viral surrogate, and provides a means to explore proof of principle of the interactions between nanoshells and viruses. It is demonstrated that appropriately biofunctionalized nanoshells recognize and bind to their target species, and that the nanoshell successfully couples the energy transfer from an IR laser to the target species. A ratio of nanoshells to Escherichia coli of ~104 for a 50% bacterial cell survival rate is determined, and a possible mechanism for this is discussed. Finally, this ratio is found to decrease by 4-5 orders of magnitude for the case of two Escherichia coli bacteriophage considered, and the significance of this is described.

Committee: Madhavi Kadakia (Advisor) Subjects: Biology, Molecular

Bachelor of Science, Wittenberg University, 2022, Biochemistry/Molecular Biology

Antibiotic resistance in bacteria is becoming a significant concern, originating from the increased amount of antibiotics prescribed by doctors and patients failing to complete their course of treatment. Resistant bacteria are quickly adapting to new forms of antibiotics and are becoming more deadly. Based on the Centers for Disease Control and Prevention's 2019 estimate, in the United States approximately 2.8 million antibiotic resistant infections occur each year and about 90,000 deaths can be attributed to bacterial infections1. Therefore, it is essential that high school and undergraduate students interested in going into the medical field are introduced to the idea of antibiotic resistance. Several different methods of growing resistance to kanamycin and ampicillin in E. coli were created and tested to provide a laboratory experience to students at an introductory chemistry level. Multiple procedures were created using either solid or liquid medium, however, the most practical and successful procedure involved growing resistance in liquid medium in a single flask, which was left to grow over the course of a week. Additionally, the ability for already resistant strains to lose their inherent resistance was also tested through continually propagating cultures in liquid medium without antibiotic. It was found that, through this method, kanamycin resistance in E. coli could be lost in about three weeks or less.

Committee: Daniel Marous (Advisor); Michelle McWhorter (Committee Member); Margaret Goodman (Committee Member) Subjects: Biochemistry; Biology; Cellular Biology; Microbiology; Molecular Biology

Bachelor of Arts, Wittenberg University, 2022, Chemistry

According to the CDC, in the United States, about 3 million antibiotic resistant infections occur each year with 35,000 deaths from bacterial infections. The large quantity of antibiotics that are prescribed to patients increases the ability of bacteria to develop this resistance, especially when patients do not complete their full course of medication. With the development of bacterial resistance becoming a global phenomenon, it is crucial that the public become more educated on this issue. Toward this end, a method has been developed that demonstrates the growth of antibiotic resistance and could be incorporated into a high school or undergraduate laboratory curriculum. This lab experience would be ideal for students who are considering a medical or scientific research career, allowing them to witness resistance firsthand. It would also serve to educate other individuals, making them aware of the general issues associated with bacterial resistance. Over the course of a week, resistance is gradually evolved in E. coli. The students would then determine the minimum inhibitory concentration of the resistant strain and compare their value to the wildtype level.

Committee: Daniel Marous (Advisor); Justin Houseknecht (Committee Member); Matthew Collier (Committee Member) Subjects: Biochemistry; Biology; Cellular Biology; Microbiology; Molecular Biology

Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Environmental justice issues are understood to exist and persist throughout the country and across the world; environmental hazards frequently impact poor and minority populations disproportionately more than non-Hispanic Whites (herein referred to as White) and upper income communities. With much of the world urbanizing, increasing numbers of people interact with urban streams. Throughout these interactions, urban streams can impact the health and well-being of surrounding communities. This study addresses a gap in the literature by assessing the quality of natural resources by race and class, where past studies have examined access to green space, activity of anglers, and drinking water quality. The following study contributes to this body of work by investigating if recreational water quality of urban streams, as measured by E. coli levels, is correlated to the composition of surrounding communities. Existing data from local and federal agencies that collect water quality data, as well as data from the U.S. Census Bureau, is utilized to determine if those neighborhoods that have proportionately larger minority and low-income populations are associated with lower overall water quality for four cities. Mixed effect multilevel linear regression models suggest that those who rent are most potentially exposed, with an average increase of 0.00655 MPN/100mL / CFU/100mL in average log transformed E. coli for every one percent increase in renters in the combined city models and an average increase of 0.00855 MPN/100mL in average log transformed E. coli for every one percent increase in renters in Austin in models run by city. Occupied housing is also shown to be significant, with an average increase of 0.02300 MPN/100mL / CFU/100mL in average log transformed E. coli for every one percent increase in occupied housing in combined city models. Asian populations showed a negative relationship with E. coli in Austin in by city models, where there is an average decrease of 0.03 (open full item for complete abstract)

Committee: Kerry Ard (Advisor); Rachel Gabor (Committee Member); Mazeika Sullivan (Committee Member) Subjects: Environmental Justice

Master of Science, The Ohio State University, 2016, Comparative and Veterinary Medicine

It has been hypothesized that the use of veterinary antimicrobials in livestock populations may lead to an increase in bacterial resistance to these antimicrobials among both animals and humans. Additionally, the transfer of resistance genes among bacterial pathogens may result in increased risk of food-borne disease resulting from pathogens with reduced susceptibility to the antimicrobials commonly used to treat them. Our objective is to measure changes in antimicrobial susceptibility of fecal Escherichia coli between 2001 and 2011 on 16 Ohio dairy farms. We assessed the reduced susceptibility proportions (RSP) of the 17 select antimicrobials, excluding apramycin, included in the National Antimicrobial Resistance Monitoring System surveillance program. We also examined the difference in the reduced susceptibility index (RSI) for these 16 herds. Over a 2 year period (2001-2002) 9,253 fecal samples were collected via rectal palpation from cows on 42 Ohio dairy farms. In 2011 we returned to 16 of these same 42 herds and collected a composite sample of 400 fecal samples (25 samples from each of the 16 herds) using the same methods of collection as in the previous study period. Results of the RSP data shows an increase in resistance to 4 antimicrobials (Ampicillin, Cephalothin, Chloramphenicol and Sulfamethoxazole) and no significant change in resistance to the remaining 12 antimicrobials included in our study.

Committee: Thomas Wittum Dr. (Advisor); Andrew Niehaus Dr. (Committee Member); Gustavo Schuenemann Dr. (Committee Member) Subjects: Comparative; Epidemiology; Health Sciences; Veterinary Services

Master of Science, The Ohio State University, 2015, Food, Agricultural and Biological Engineering

Adding an electric field to the whole shell egg and its extracted components can cause several effects on the overall processing of an egg. This study shows that frequency can significantly influence the conductivity of individual egg components such as the yolk, thin and thick albumen with medium range frequencies having the most effect. 1000Hz, 10000Hz, 100000Hz were found to yield the greatest conductivity for the liquid egg components; yolk, thin albumen, and thick albumen respectively. These same frequencies were found to significantly (p < 0.05) be more conductive than any other frequency with the respective egg component except yolk where there was no significant difference between the 1000Hz, 10000Hz, and 100000Hz. Though no increased heating rate was observed in the experiments with a whole shell egg, individual components are rather conductive and susceptible to ohmic heating. Also, it was observed that a whole shell egg, in an electric field, will yield non-thermal effects of lethality against internally inoculated microorganisms. Adding a moderate electric field (MEF) of 15.7 V/cm to eggs being heated in a water bath can on average, decrease the recovered microorganism population by 0.94 log CFU/g when plated on the selective media Sorbitol Macconkey Agar (SMAC) as compared to results from conventional heating alone. These results suggest that a water bath or ozone and water bath pasteurization technique could be improved upon using MEF, by reducing time and energy required to safely process a whole shell egg yielding a better quality product at lower cost.

Committee: Sudhir Sastry (Advisor); Ahmed Yousef (Committee Member) Subjects: Agricultural Engineering; Food Science

Master of Science in Engineering, University of Akron, 2009, Chemical Engineering

Microbial biofilm formation on surfaces leads to significant losses in terms of energy,equipment damage, product contamination, medical infections, etc. and also raises serious environmental concerns. To prevent formation of biofilms, a detailed investigation into the initial stage of bacterial attachment was conducted using three types of bacterial species; Pseudomonas aeruginosa PAO1, Escherichia coli and Pseudomonas putida. Several approaches were evaluated and finally a reproducible procedure was adopted to study initial bacterial attachment. The procedure primarily involved monitoring and counting the number of attached cells on the glass walls of the flow chambers, through which a bacterial suspension was circulated and, subsequently, saline was passed for washing to remove loosely attached cells. Preliminary investigations in terms of fluid flow behaviors, consistency check, and the effect of various factors including the attachment locations within the chamber, on the attachment results were conducted prior to employing the flow chamber systems to study the initial bacterial attachment. Using the flow chambers systems, the effects of chamber wall shear, medium pH, chamber, and two potential antifoulants, Zosteric acid and Rhamnolipids, on attachments were examined. The three bacterial species used showed similar behavior (peaking at different shear stress values) in response to varying shear conditions in their environment. The antifouling properties of zosteric acid were not convincing enough, however promising results were seen while studying rhamnolipids in the case of all three bacterial strains. The effect of other factors like pH, presence of zosteric acid impurities, surface conditioning were also explored. These conditions however proved to have no effect on the initial bacterial attachment but provided useful information for future studies.

Committee: Bi-min Zhang Newby PhD (Advisor) Subjects: Chemical Engineering; Environmental Science

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, University of Akron, 2024, Integrated Bioscience

The scientific reciprocity of environmental geomicrobiology and biotechnology harnessing microbially induced carbonate precipitation (MICP) is epitomized by cave speleothem research; delineating environmental conditions uncovers factors that inform the development of industrial bacteriogenic mineralization processes, with greater control over the end products. Reconciling bacterial metabolism and CaCO3 precipitation has the potential to recontextualize geological precipitation events as microbial byproducts, warranting interdisciplinary investigation. In Wind Cave, South Dakota, I identified a complex weave of speleoclimatic, geochemical, and microbiological dynamics that controls the materialization and polymorphism of CaCO3 secondary deposits known as frostwork. Microclimatic monitoring and analysis suggested an evaporative environment, modelled from detailed temperature, humidity and airflow data. Airflow measurements support a causal link between cave wind directionality and the occurrence of frostwork. Sequential deposition of carbonate phases characterizes bulk frostwork formations according to shifting Mg2+/Ca2+ ratios over the speleothem lifetime, yielding multiaggregate formations consisting of calcite, aragonite, hydromagnesite, dolomite, opal, and smectite. Thin sections showed diagenetic fabrics indicative of oscillating supersaturation conditions in response to surface seasonal climatic changes. Scanning electron microscopy (SEM) analyses identified frostwork's aragonite crystal topography as a microecological niche supporting filamentous Actinomyces bacteria, leaving room for a microbial component to Wind Cave frostwork development. To begin to monitor the impact of factors controlling crystal growth in vitro I developed two parallel techniques for measuring bacteriogenic carbonate precipitation in Escherichia coli cultures, using i) image analysis for agar media, and ii) inductively coupled plasma–optical emission spectroscopy (ICP-OES) ion quantifica (open full item for complete abstract)

Committee: Hazel Barton (Advisor); John Senko (Committee Member); Andreas Pflitsch (Committee Member); Bogdan Onac (Committee Member); Brian Bagatto (Committee Member) Subjects: Biology; Geobiology; Microbiology; Mineralogy

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1966, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1968, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2024, Animal Sciences

Extraintestinal pathogenic Escherichia coli (ExPEC) presents a substantial public health threat due to its ability to cause severe infections such as urinary tract infections, bloodstream infections, and meningitis. Recent evidence suggests that birds, particularly poultry, may serve as reservoirs for ExPEC strains pathogenic to humans. Avian pathogenic E. coli (APEC), the avian counterpart of ExPEC, causes multisystemic infections known as colibacillosis, resulting in high morbidity, mortality, and economic losses in poultry production. Current APEC control methods, relying on antibiotics and vaccines, face challenges due to rising multidrug resistance and vaccine failures against heterologous serotypes, highlighting the need for novel alternatives. In this study, we synthesized derivatives of a previously characterized piperazine-based quorum sensing inhibitor (QSI), QSI-5, through structural modifications preserving the piperazine core. This resulted in six derivatives, which were screened against APEC O78 using the autoinducer-2 indicator bacteria Vibrio harveyi BB170 to evaluate their efficacy in quorum sensing (QS) inhibition. Two derivatives such as 1-(naphthalen-2-ylmethyl)-4-(3-phenylpropyl)piperazine (OA4-108) and 1-((5-chlorobenzo[b]thiophen-3-yl)methyl)-4-(3-phenylpropyl)piperazine (OA4-109) exhibited enhanced activity at a 50 µM concentration, showing 100% inhibition in the screening assay. These two analogues also inhibited the bacterial motility and biofilm formation and displayed minimal to no toxicity on chicken and sheep red blood cells, chicken and human macrophage cells (HD-11, THP-1), and human intestinal epithelial cells (Caco-2). Additionally, they reduced the survival of APEC O78 in HD-11 and THP-1 cells. In vivo analysis using the wax moth model demonstrated the non-toxicity of these molecules, along with improved larval survival rates and reduced APEC load. Furthermore, OA4-108 and OA4-109 also showed quorum-sensing inhibition in multiple u (open full item for complete abstract)

Committee: Gireesh Rajashekara (Advisor); Timothy J Johnson (Committee Member); James R Fuchs (Committee Member) Subjects: Animal Sciences

PhD, University of Cincinnati, 2023, Medicine: Molecular Genetics, Biochemistry, & Microbiology

Shiga toxin-producing Escherichia coli O157:H7 is a food borne pathogen responsible for bloody diarrhea, and potentially life-threatening hemolytic uremic syndrome. The study of O157:H7 has been ongoing since the first recorded outbreak in 1982. These studies have been limited by the lack of an adequate model system. Recent developments in stem cell technology have allowed for production of intestinal stem cell models that mimic the small intestine. Human intestinal organoids (HIOs), and enteroids (HIEs) have shown value for studying O157:H7 by studies in our lab. This work focuses on utilizing HIE monolayers (HIEMs), reverse polarity HIEs (RPHIEs), and HIOs to study O157:H7. It highlights the advantages of each potential model, addresses their disadvantages, and identifies methods to use these models for addressing key scientific gaps in O157:H7 literature. HIEMs have been used previously to study many enteric pathogens, including O157:H7. However, unlike previous HIEM studies, saline was added to the apical surface, while maintaining culture media in the basolateral well. The monolayers continued to grow and differentiate with apical saline. Apical infection with O157:H7 or commensal E. coli resulted in robust bacterial growth from 105 to over 108 over 24 hours. Despite this robust bacterial growth, commensal E. coli neither adhered to the cells nor damaged the epithelial barrier over 30 hours. However, O157:H7 was almost fully adhered (90%) by 18 h with epithelial damage observed by 30 hours. O157:H7 contains the locus of enterocyte effacement (LEE) pathogenicity island responsible for attachment and damage to the intestinal epithelium. Previous studies report the ability of nutrients such as biotin, D-serine, and L-fucose to downregulate LEE gene expression. O157:H7 treated with biotin or L-fucose, but not D-serine displayed both decreased attachment and reduced epithelial damage over 36 hours. While advantageous HIEMs have their limitations, we worke (open full item for complete abstract)

Committee: Alison Weiss Ph.D. (Committee Chair); David Askew Ph.D. (Committee Member); Katherine Vest Ph.D. (Committee Member); William Miller Ph.D. (Committee Member); David Haslam M.D. (Committee Member) Subjects: Microbiology

Doctor of Philosophy, The Ohio State University, 2023, Comparative Biomedical Sciences

Urinary tract infections (UTIs), including cystitis and pyelonephritis, are one of the most common infections across species. Approximately 80% of these infections are caused by uropathogenic Escherichia coli (UPEC). The host's innate immune response is paramount in the defense against UPEC and is initiated by urinary tract epithelial cells with subsequent recruitment of leukocytes. Despite a robust immune response, UPEC can persist in the urinary tract, can cause recurrent infections, and can be resistant to antibiotic therapy. There is a growing and imminent risk for antibiotic resistant UTIs, thus necessitating investigations into alternative therapeutic options. One possibility is utilizing mechanisms to enhance existing host innate immune defenses; however, our understanding of innate immunity against UPEC, especially in the kidney, is limited. In this work, we aimed to characterize the host immune response to UPEC in cell culture and in various important mouse models of UTI to identify potential targets for augmenting host defense against UPEC. The first portion of this thesis investigates the in vitro pathogenesis of UPEC in one of the host's most important UTI renal defenders, the kidney collecting duct intercalated cell. Previous work from our lab and others have shown that intercalated cells are required for protection against UPEC due to direct binding to these cells, their role in immune cell recruitment, and secretion of bactericidal antimicrobial peptides. We found that upon UPEC infection, intercalated cells activate multiple innate immune pathways including those associated with pattern recognition receptor (PRR) signaling. We identified that nucleotide oligomerization domain (NOD) 2 and Toll-like receptor (TLR) 4 are two intercalated cell PRRs that, upon initial activation, can protect against subsequent UPEC infection. Additionally, NOD2 activation induces upregulation of multiple innate immune pathway genes along with genes associated with vari (open full item for complete abstract)

Committee: John David Spencer (Advisor); Kara Corps (Committee Member); Rachel Cianciolo (Committee Member); Brian Becknell (Committee Member); Sheryl Justice (Advisor) Subjects: Biology; Immunology; Microbiology; Molecular Biology; Pathology

Doctor of Philosophy, The Ohio State University, 2022, Microbiology

The cell envelope of Gram-negative bacteria is a complex structure which can be broken down into several components. Two bilayers, an inner and outer membrane, surround an aqueous periplasmic compartment. Within this compartment is contained the peptidoglycan layer, which is essential for maintaining cell structure and protecting against osmotic stresses. The inner membrane contains two leaflets composed of phospholipids and demarcates the cytoplasm. Conversely, the outer membrane is asymmetrical in nature, containing one inner leaflet of phospholipids and an outer leaflet of glycolipids termed lipopolysaccharide (LPS). LPS is an essential component of many Gram-negative cell envelopes, and its tight packing at the cell surface prevents the entry of small, nonpolar molecules into the periplasm. It is this impermeability that is responsible for the increased resistance of Gram-negative organisms to some antibiotic regimens. The biogenesis of LPS occurs at the inner membrane, after which LPS is transported to the cell surface via the lipopolysaccharide transport (Lpt) machinery. Seven essential proteins, LptA-G, work to extract LPS from the inner membrane, transport it across a periplasmic bridge, and selectively insert it into the outer leaflet of the outer membrane. The engine of this system is the LptB2FGC ATP-binding cassette (ABC) transporter, which harnesses cytoplasmic ATP to pump LPS to the outer membrane. Like other ABC transporters, LptB2FGC contains two cytoplasmic nucleotide binding domains (LptB2) and two transmembrane domains (LptF and LptG). LptB2 are responsible for binding and hydrolyzing ATP, and the resulting conformational changes are physically transmitted to LptF and LptG in a process called coupling. Numerous cytoplasmic extensions of LptF and LptG interact with each individual LptB monomer to allow for coupling, including the eponymous coupling helices and cytoplasmic loops. Intriguingly, the architecture of the LptB2FGC transporter deviates (open full item for complete abstract)

Committee: Natividad Ruiz (Advisor); Irina Artsimovitch (Committee Member); Jane Jackman (Committee Member); Ross Dalbey (Committee Member) Subjects: Biology; Medicine; Microbiology; Molecular Biology