Doctor of Philosophy, The Ohio State University, 0, Biochemistry Program, Ohio State

Metabolomics provides a global analysis of metabolites from many biochemical pathways, giving an unbiased view of cellular activity. The metabolome is acted upon by endogenous factors such as genome-encoded enzymes and influenced by the environment, thus it is reflective of the phenotypic state (Chapter 1). Nuclear magnetic resonance (NMR) spectroscopy is a key tool for metabolomics measurements due its high reproducibility, quantitative nature, and ability to detect all abundant known and unknown metabolites in a single set of measurements. One of the major challenges in NMR-based metabolomics is accurate and efficient metabolite identification and quantification (Chapter 2). We have developed the COLMARq web server which facilitates semi-automated metabolite identification, quantification, and statistical analysis of cohorts of samples. COLMARq is the first openly accessible web server targeted toward quantitative metabolomics analysis of cohorts of 2D NMR spectra (Chapter 3). P. aeruginosa is a Gram-negative, opportunistic pathogen that exhibits resistance to many antibiotics leading to acute and chronic infections in immunocompromised individuals. P. aeruginosa readily forms biofilms in diverse environments, which are a self-produced gel-like matrix of extracellular polymeric substances encasing the cells. Biofilms are difficult to detect and eradicate, greatly contributing to the persistence of infection. Therefore, there is a critical need for new approaches to accurately identify, regulate, and prevent biofilm formation (Chapter 4). We used an untargeted 2D NMR- based metabolomics approach to identify statistically significant differences in 52 metabolites between P. aeruginosa grown in the planktonic and biofilm states. Among them, the metabolites of the cadaverine branch of the lysine degradation pathway were systematically decreased in biofilm. Exogenous supplementation of cadaverine caused significantly increased planktonic growth, decreased biofilm a (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2021, Microbiology

The corrinoid-dependent trimethylamine (TMA) methyltransferase MttB is notable for encoding the 22nd amino acid pyrrolysine, which is essential for catalyzing the demethylation of TMA. However, recent work investigating the MttB protein superfamily has shown most microbial MttB homologs lack the codon for pyrrolysine. Recently it has been shown that these non-pyrrolysine encoding MttB homologs catalyze demethylation of quaternary amines (QAs), including glycine betaine (MtgB), L¬-carnitine (MtcB), and proline betaine (MtpB). A major goal of the work presented in this dissertation has been to further characterize the diversity of the MttB superfamily, to understand functional divergence of these non-pyrrolysine MttB homologs. A notable link between gut microbial metabolism of dietary QAs and cardiovascular disease has spurred renewed interest into microbial methylamine metabolism. Specifically, dietary glycine betaine, choline, and L-carnitine are cleaved by the colonic microbiota to form TMA. Markedly, dietary L-carnitine is predominantly initially microbially reduced to γ-butyrobetaine, which is also cleaved to TMA. Formed TMA can be oxidized by a hepatic enzyme FMO3 to trimethylamine-N-oxide (TMAO), high serum levels of which correlate with atherosclerosis onset, and occurrence of major adverse cardiac events. Consequently, there is great interest in identifying ways to limit TMAO formation in vivo. One such means to do so could be to manipulate the composition of the gut microbiota via a probiotic to disfavor TMA formation from dietary QAs. However, anaerobic microbial QA metabolism is understudied – especially of γ-butyrobetaine - and that knowledge gap must be filled. Recent characterization of multiple QA-dependent MttB homologs has demonstrated a novel mechanism of microbial QA metabolism which does not generate TMA. Genomic potential for QA demethylation has been identified in multiple human gut symbionts, including Eubacterium limosum ATCC 8486, which (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2014, Microbiology

Predicting carbon flow within an organism requires a complete knowledge of the pathways that compose the organism's metabolic networks. Even in pathways that have been characterized, an incomplete knowledge of the regulation of the responsible genes and enzymes disallows prediction of carbon flow through the network. By investigating the interplay of the pathways that compose the networks, this work intends to offer insights into the strategies employed by the model organism Rhodobacter sphaeroides for metabolic regulation. Chapter 2 investigate which enzymes participate in carbon flow through the C4/C3 node of central metabolism. The growth of strains with mutations in two different malic enzyme genes were compromised in their ability to grow with some substrates that require C4 to C3 conversion (succinate and (S)-malate), but their growth was unimpaired during growth with acetate, which is assimilated via succinate and malate. A pyruvate phosphate dikinase mutant was unable to grow on acetate, suggesting that gluconeogenesis occurs exclusively from pyruvate during acetate growth. Growth results with a pyruvate carboxylase mutant indicated that pyruvate carboxylase is responsible for C3 to C4 conversion on substrates that are to be assimilated through C3 intermediates. Chapters 3 and 4 examine the role of carbon flow through intermediary pathways of short chain acyl-CoA assimilation in R. sphaeroides. R. sphaeroides employs the ethylmalonyl-CoA pathway for acetyl-CoA assimilation, which shares reactions with polyhydroxybutyrate biosynthesis, and the first committed reaction is catalyzed by crotonyl-CoA carboxylase/reductase (Ccr). Transcript levels of ccr were 30-fold higher during acetate growth than succinate growth, and ccr promoter-reporter fusions were likewise regulated. Mutating the gene that encodes PhaR, a transcriptional regulator of polyhydroxybutyrate synthesis, did not affect regulation. PccR was identified as a regulator of pccB, the gene for the Bet (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2023, Translational Plant Sciences

The composition and organization of genomes, or genome architecture, underlies the ecology and adaptability of organisms, though the fundamental evolutionary drivers of divergent genome architecture remain cryptic. Genome architecture varies across life with prokaryotes exhibiting streamlined genomes that are replete with gene clusters comprised of colocalized genes with cooperative functions. In contrast, multicellular eukaryotes trend toward larger genomes with a higher degree of dispersed gene coordination within the genome. Fungi lie along the center of this continuum, which positions the lineage as a model system for identifying the fundamental rules of life that drive divergent genome architecture. In particular, independent evolution of genomic regions apart from evolutionary pressures acting on the genome as a whole, or selfishness, is a controversial proposed driver of divergent genome architecture. Horizontal gene transfer is linked to the transmission of selfish elements and is hypothesized to increase the prevalence of clustered genome architecture by facilitating the dissemination of genomic regions with complex selectable phenotypes. The primary objective of my dissertation is to quantitatively determine the influence of selfishness in shaping divergent gene cluster architecture. In Chapter 1, I synthesize how divergent architecture evolves, the functions and human-utility of different gene clusters, and the implications and models that explain selection on gene cluster architecture. In Chapter 2, I implement a computational framework that harnesses the exponentially-expanding dataset of fungal genomes. I use this platform to standardize downstream large-scale comparative genomic analysis. In Chapter 3, I more comprehensively and accurately identify gene clusters compared to contemporary algorithms by developing an evolution-informed approach to detecting gene clusters. I implement this algorithm to identify overlooked gene clusters de novo, and char (open full item for complete abstract)

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

Leishmaniasis is a neglected protozoan disease affecting over 12 million people globally. Cutaneous leishmaniasis (CL) is the most common form, characterized by chronic skin lesions. Currently, there are no approved vaccines for human use. We have generated centrin knock out Leishmania (L.) mexicana (LmexCen-/-) mutants using CRISPR/Cas9. Centrin is a cytoskeletal protein required only for intracellular amastigote replication in Leishmania. Here, we investigated the safety, immunogenicity, and efficacy of LmexCen-/- parasites in vitro and in vivo. Our data shows that LmexCen-/- amastigotes present a growth defect, which results in significantly lower parasitic burdens and increased protective cytokine production in infected macrophages and dendritic cells, compared to LmexWT. Furthermore, LmexCen-/- parasites are safe in susceptible mouse models and efficacious against challenge with LmexWT in genetically different BALB/c and C57BL/6 mice. Vaccinated mice did not develop cutaneous lesions, displayed protective immunity, and showed significantly lower parasitic burdens compared to the controls. Overall, we demonstrate that LmexCen-/- parasites are a promising candidate vaccine against CL in pre-clinical models. Next, we explored the metabolic drivers of these vaccine-mediated immunological profiles. Metabolomics are emerging as a useful tool to uncover unknown networks that govern immune regulation and determine functional specialization. We analyzed the metabolic changes occurring after immunization with LmexCen-/- and compared them with LmexWT infection. Our results show enriched aspartate metabolism and pentose phosphate pathway (PPP) in ears immunized with LmexCen-/- parasites. These pathways are both known to promote M1 polarization in macrophages, and PPP in particular induces nitric oxide production in macrophages cultured with LmexCen-/-, suggesting a shift to a pro-inflammatory phenotype following immunization. Furthermore, immunized mice showed enriched t (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2021, Molecular Genetics

Mitochondrial Complex I (CI), also known as NADH:ubiquinone oxidoreductase is the first and largest enzyme complex of the mitochondrial electron transport chain (ETC) and entry point for electrons from NADH. The fully assembled complex has a molecular weight of ~1 MDa and is L-shaped with a membrane arm embedded in the inner mitochondrial membrane and soluble arm protruding into the mitochondrial matrix. Together, eukaryotic CI is composed of more than 40 subunits: 14 core subunits conserved from bacteria in addition to 25-35 non-core or accessory subunits, plus 9 non-protein cofactors (1 flavin mononucleotide and 8 iron-sulfur clusters). Due to the obvious complexity of the holoenzyme, the assembly process requires proteins not included in the final complex that are collectively termed assembly or biogenesis factors. Unexpectedly, defects in CI are implicated in a number of severe human disorders including Leigh syndrome, lactic acidosis and stroke-like episodes (MELAS) syndrome, and Parkinson's disease. However, the underlying genetic defects have been identified in only 60% of patients with CI deficiency, occurring in genes encoding a CI subunit or previously identified biogenesis factor. It is generally accepted that the causative mutations occurred in genes encoding novel CI biogenesis factors in the remaining 40% of patients. Chlamydomonas reinhardtii is an established model system for the study of mitochondrial respiration. In contrast to other model systems, Chlamydomonas CI mutants are still viable but have a characteristic slow growth in the dark (SID) phenotype in respiratory conditions (dark plus acetate). In Chapter 2, with the goal of identifying novel genes encoding factors controlling mitochondrial CI biogenesis, an insertional mutagenic screen was previously performed in Chlamydomonas. Of more than 54,000 insertional mutants, 22 were SID, 13 of which were also reduced for CI activity and/or assembly and termed “amc” for assembly of mitochondria (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2020, Ohio State University Nutrition

Dietary vitamin A can be obtained in two forms: provitamin A carotenoids (β-carotene, α-carotene, and β-cryptoxanthin) and preformed vitamin A, which exists as retinyl esters (RE) and retinol. β-Carotene can be enzymatically cleaved at the central 15, 15′ bond to give two molecules of retinal. In addition, this carotenoid can undergo oxidative cleavage at bonds other than the central 15, 15′ bond to yield retinoid-like compounds called β-apocarotenoids. Published evidence from our laboratory show that these cleavage products are antagonists of α, β, and γ isoforms of retinoic acid receptors. β-Apocarotenoids have been identified and quantified in fruits and vegetables such as cantaloupes, sweet potatoes, and cassavas biofortified with β-carotene. However, little is known about the intestinal absorption of β-apocarotenoids. It is well established that the liver is the major organ responsible for the uptake, storage, and mobilization of retinoids. Preformed vitamin A, consumed from the diet, is processed into REs during intestinal absorption and packaged into chylomicrons. After remodeling, chylomicron remnant REs are taken up by hepatocytes, hydrolyzed to unesterified retinol, and are either transported to peripheral tissues to meet their retinoid needs or transferred to hepatic stellate cells for re-esterification and storage. Thus, hydrolysis of REs in the liver is important for the maintenance of vitamin A homeostasis but the retinyl ester hydrolase (REH) involved in this process is yet to be established. Evidence from in vitro studies suggest that the enzyme is carboxylesterase Ces1d (ES-10) but this has not been confirmed in studies using animal models. In the first study, we examined the uptake and metabolism of β-apocarotenoids in Caco-2 human intestinal cells. Caco-2 cells were grown on six-well plastic plates until a differentiated cell monolayer was achieved. β-Apocarotenoids were prepared in Tween 40 micelles, delivered to differentiated cells in se (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2020, Molecular Medicine

In the metabolism of cancer, phosphatidylinositols (PI) sit at the apex of signaling decisions and structure. PI phospholipids like other phospholipids can be synthesized via two major pathways: the Lands' Cycle and the Kennedy Pathway. One key regulator of arachidonic acid-containing PI (AA-PI) levels in the Lands' cycle remodeling pathway is membrane bound O-acyltransferase domain containing 7 (MBOAT7). For the first time in this work, MBOAT7 and AA-PI was found to be upregulated in clear cell Renal Cell Carcinoma (ccRCC) tumors compared to the normal adjacent tissue. The reduction in AA-PI leads to a decrease in tumor growth/formation, cellular proliferation, and cell migration. We also found that the implications of MBOAT7 deficiency extend to glycolysis and the Citric Acid cycle. Previously, cancer cell signaling research has focused on the terminal step in phosphoinositide (PIP3,4,5) production, which has been the focus of an entire class of small molecule inhibitors. Phosphoinositide signaling can play a critical role in cellular functions; many of these critical to cancer metabolism. However, my work demonstrates that the initial phosphatidylinositol generation through MBOAT7 is equally important to downstream phosphoinositide and therapeutically relevant for the treatment of ccRCC with potential implications for other cancers.

Doctor of Philosophy, The Ohio State University, 1987, Graduate School

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

PhD, University of Cincinnati, 2014, Medicine: Pathobiology and Molecular Medicine

Exercise has benefits on body and fat mass, glucose metabolism, and lipid metabolism. Likewise, exercise is an effective therapy against the metabolic syndrome. Yet, the molecular pathways underlying the advantageous effects of exercise are imperfectly understood. Emerging evidence suggests that the melanocortin system and the fibroblast growth factor 21 (FGF21) signaling axis, two endocrine pathways involved in regulation of energy homeostasis, are mediators of exercise benefits.

Doctor of Philosophy (PhD), Ohio University, 2014, Molecular and Cellular Biology (Arts and Sciences)

The past decade has witnessed remarkable progress toward understanding the reprogrammed metabolism in cancer, an emerging hallmark as well as an active area of basic, translational, and clinical research. About ninety years ago, Otto Warburg pioneered quantitative investigations of cancer metabolism and discovered that cancer cells exhibit a phenotype of increased glycolysis even under aerobic conditions, known as the Warburg effect. Warburg speculated that the reason for the upregulated glycolysis was for compensating the ATP shortage due to dysfunctions of mitochondria in cancer cells. Despite subsequent progresses, the biological reasons for ATP synthesis by aerobic glycolysis in cancer cells are only partially understood. Intriguingly, intratumoral (extracellular) ATP levels are 103 to 104 times higher than those in normal tissues. We showed that although extracellular ATP is not known to cross the plasma membrane by itself, extracellular ATP in the range of the intratumoral ATP levels induced large intracellular ATP concentration increase in A549 human lung cancer cells and promoted cancer cell survival. More importantly, we reported that a nonhydrolyzable fluorescent ATP was internalized by A549 cells through macropinocytosis as visualized by fluorescence microscopy. The induced ATP increase was reduced by the macropinocytosis inhibitor EIPA but persisted even when mitochondrial oxidative phosphorylation and glycolysis were inhibited, without involving transcription or translation. The increases were also observed in several other cancer cell lines, but not in noncancerous cells. Furthermore, extracellular ATP enhanced cancer cell survival under various stress conditions and promoted drug resistance to tyrosine kinase inhibitors that compete with ATP for their anticancer action. Collectively, these results provide the first piece of evidence that extracellular ATP is internalized by cancer cells via macropinocytosis and potentially other endocytic process, whi (open full item for complete abstract)

Master of Science, Miami University, 2014, Physics

Many common causes of death, like cancer and Alzheimers, have a component involving metabolic dysfunction - thus the development of tools capable of extracting functional information is useful. NADH is a coenzyme prevalent in metabolic pathways related to mitochondrial function. Because NADH fluorescence depends on its conformational state, i.e., on its protein-bound state, it is a convenient non-invasive functional probe. Here we implement a spectral-phasor approach capable for measuring small (1 - 10 nm) shifts in NADH autofluorescence when suspensions of Saccharomyces cereviseae are perturbed using mitochondrial functional modiers (cyanide and FCCP) and metabolic substrates (glucose and ethanol). The ability of a spectral-phasor approach in detecting small changes in autofluorescence is compared to the well-known spectral decomposition technique. Additionally, we explore the use of pressure in the 100-500 atm range as a metabolic perturbant by demonstrating the ability to monitor metabolic responses in a recently-constructed, high-pressure microperfusion system.

Doctor of Philosophy, The Ohio State University, 2013, Entomology

The plant hormone ethylene regulates a variety of physiological and developmental processes important for plant survival, including fruit ripening, abscission, senescence and responses to biotic and abiotic stresses. Plants increase their ethylene production to trigger senescence, or in response to herbivore and pathogen attack. Ethylene insensitive petunias, Petunia x hybrida transformed with 35S::etr1-1, line 44568 (etr1-1) were developed to produce longer lasting flowers but the impact of herbivores, especially to western flower thrips (WFT), on these plants is unknown. The WFT is an important pest in flowering plants and vegetable crops worldwide. They cause significant damage to the foliage, flowers and fruits decreasing plant production and value. Resistant varieties, based on ethylene induction have been shown to be an alternative to manage WFT. Assays using whole petunia plants or individual flowers of wild-type Petunia x hybrida `Mitchell Diploid' (MD) and etr1-1 petunias showed that WFT infestation induced ethylene production from petunia flowers. WFT laid more eggs on etr-1 petunias flowers compared to MD petunia flowers, suggesting that etr1-1 petunia flowers are better host for thrips oviposition. Bioassays were performed using individual WFT females or larvae on leaves and corollas. Oviposition did not differ between etr1-1 and MD petunia on leaves. However, on corollas WFT showed higher oviposition and lower egg and larvae mortality on etr1-1 vs MD petunias. Thrips oviposition rate and fecundity was higher on etr1-1 petunia corollas compared to MD corollas. Life-table analysis indicated that etr1-1 petunia corollas are better for WFT performance than MD petunia corollas. In addition, etr1-1 and MD petunia corollas response to thrips attack was evaluated by measuring changes in primary (amino acids) and secondary (phenolics) metabolism between etr1-1 and MD petunia corollas. Petunia corollas increased in total non-essential amino acids after WFT at (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2009, Microbiology

Cells in all domains of life have developed complex regulatory schemes to ensure nitrogen homeostasis. The mechanisms associated with nitrogen homeostasis have been examined in a wide variety of organisms and the molecular aspects of these regulatory systems present a view of an essential global regulatory program for each organism. Recognizing that a similar complex regulatory scheme was most likely present in the Archaea, we chose to investigate the response of Haloferax volcanii to variations in the amount and the quality of its nitrogen source as a model of global regulation in the Archaea. Analysis of the recently sequenced H. volcanii genome showed that this organism encodes enzymes for the core ammonia assimilation pathways found in all organisms and several enzymes for the assimilation of nitrogen from alternative substrates. Phyletic distribution studies and phylogenetic analyses indicate that many of these alternative nitrogen assimilation pathways are absent in other Archaea and that they many have been acquired by the haloarchaea through horizontal gene transfer (HGT) from bacterial genomes. To investigate the global transcriptome response of H. volcanii to changes in nitrogen availability, a genome-wide tiled array was constructed and used to characterize the RNA populations of cells undergoing balanced growth, during growth with a poor nitrogen source and under conditions of nitrogen starvation. Changes in the RNA populations indicated that genes encoding core nitrogen assimilation pathways showed differential expression. However, the regulatory proteins common to the bacterial systems, and those described for Archaea, were absent in H. volcanii. An analysis of the RNAs identified a specific regulatory protein of the AsnC family in the negative regulation of the glnA gene and showed that the general transcription factor (GTF) genes, tbp and tfb, also exhibited differential expression. These data also uncovered the regulated expression of numerous genes (open full item for complete abstract)

MS, Kent State University, 2012, College of Arts and Sciences / School of Biomedical Sciences

Thyroid hormone plays a critical role in growth, development and energy metabolism. The identification of novel target genes of thyroid hormone would greatly inform our complete understanding of T3 physiology. I have studied two genes, SGK1 (serum and glucocorticoid inducible kinase1), and ANGPTL4 (Angiopoietin like protein-4) as the potential target genes of thyroid hormone in the liver. SGK1, a component of the PI-3 kinase pathway, is ubiquitously expressed and plays a role in numerous physiological functions. Previous studies in our lab showed T3-mediated induction of SGK1, and also a PI-3kinase dependent phosphorylation of SGK1 by T3. As T3 induces and activates SGK1, I speculated that SGK1 might be contributing to T3- mediated transcription of its target genes. Dual luciferase assays following SGK1 activity inhibition by GSK650394 and T3 treatment, showed a dose-dependent decrease in the activity of the DR4 and CPT1α promoters. Also, real time PCRs performed following SGK1 activity inhibition and T3 treatment, showed a decreased induction of endogenous T3-target genes like G6P, PEPCK, and CPT1α suggesting that SGK1 is a modulator of transcriptional activity of T3. ANGPTL4 is expressed mainly in metabolic tissues like liver and adipose tissue. ANGPTL4 inhibits LPL activity, and the role of thyroid hormone in regulation of LPL has led me to hypothesize that T3 regulates ANGPTL4. My studies showed that T3 induces ANGTPL4 mRNA and protein. I have also looked at the role of PGC1α, a transcriptional co-activator, in the T3 regulation of ANGPTL4. PGC1α overexpression not only enhanced T3 induction of ANGPTL4, but also induced ANGPTL4 expression even in the absence of T3. However, T3 did not induce PGC1α which is contrary to the observations in rat livers. LPL assays using fluorescence based substrate DGGR were performed to look for the functional significance of T3 induction of ANGPTL4. The concentrated conditioned media samples from HepG2 cells treated with vehicle/T (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2011, Chemistry

Silent information regulator 2 (Sir2) enzymes or sirtuins are a family of intracellular protein deacetylases that can catalyze the beta-nicotinamide adenine dinucleotide (beta-NAD+)-dependent deacetylation of N(epsilon)-acetyl-lysine on protein substrates. These enzymes are evolutionarily conserved among all the three kingdoms of life, with the yeast Sir2 being the founding family member. In humans, seven sirtuins, SIRT1-7, have been identified. Protein acetylation/deacetylation plays a critical role in biological processes such as metabolism, gene transcription, neurodegeneration, apoptosis, the cell-cycle, aging, cell fate, and cytoskeletal organization. The past few years have witnessed a tremendous interest in investigating the unique mechanism for the sirtuin-catalyzed deacetylation reaction. There has also been a great deal of effort invested in the employment of different strategies to identify different types of inhibitors for this enzymatic deacetylation reaction. These inhibitors hold great potential toward a fuller exploration of sirtuin biology and pharmacology as well as toward developing novel therapeutics for metabolic and age-related diseases as well as cancer. This study discovered i) two potent, cell-permeable, and proteolytically stable small molecule human sirtuin inhibitors that harbor the previously identified sirtuin inhibitory acetyl-lysine analog, thioacetyl-lysine; and ii) a novel sirtuin inhibitory warhead, L-2-amino-7-carboxamidoheptanoic acid, that may function both to elucidate the sirtuin mechanism and in the development of new sirtuin inhibition therapies.

Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, 2024, College of Arts and Sciences

Phenolic acids are microbial products of non-absorbed fibers that are fermented by bacteria using indigestible components that reach the gastrointestinal (GI) tract. It has been shown that phenolic acid compounds significantly impact the human body, particularly their microbial metabolism and their ability to influence several aspects of gut homeostasis. For this reason, more attention should be placed on investigating these metabolites. Multiple factors may influence the biosynthesis of phenolic acids, including age, medications, and several environmental factors, but the production of gut metabolites is primarily affected by diet. In this research we aim to enhance the knowledge on the synergistic relationship between gut microbes, diets, and the biosynthesis of phenolic acids. Chapter I summarizes our current understanding of phenolic acid in the GI tract, fermentative pathways, etiology, and beneficial impacts of phenolic acids. In chapter II we aim to construct an in vitro fermentation model to find efficient ways to increase the generation of phenolic acids in the gut using different combinations of probiotics, prebiotics, and other factors, including fats, sugars, and amino acids. Chapter III discusses the development and complete validation of a high-throughput, fast, and reliable liquid chromatography-mass spectrometry method to quantify phenolic acids (ferulic acid, caffeic acid, and gallic acid) in biological samples. In conclusion, there are many studies that support the benefits of prebiotics on our health, but further investigations are needed to understand the interactions between prebiotics and the gut microbiota as they alter the biosynthesis of phenolic acids, which may be vital in enhancing health benefits, including reduced levels of oxidative stress, reduction of inflammation, enhancement of gut microbiota composition, improvement of metabolic health, and contribution to the prevention of chronic diseases such as obesity, diabetes, cardiovascula (open full item for complete abstract)

Master of Science, The Ohio State University, 1969, Graduate School

Master of Science, The Ohio State University, 1969, Graduate School