Life Sciences Commons^™

The Genomic Dynamics Of Fermented Food Microbes, Katherine Chacón-Vargas

Doctoral Dissertations

Along with the agriculture and domestication revolution, humans have utilized bacteria, yeasts, and molds for millennia in the production of traditionally fermented foods and beverages. Fermentation is a very ancient practice of high relevance nowadays since it contributes with a great variety of foods worldwide. Microbial fermentation allows metabolic transformation of the raw food materials leading to biochemical changes that played a key role in food preservation, health benefits, nutrition, flavors, and texture, among others. Food fermentation practices could diverge from traditional artisanal spontaneous fermentation to industrialize methods with specialized microbial starters and although fermented environments tend to be very …

What I Talk About When I Talk About Integration Of Single-Cell Data, Yang Xu

Doctoral Dissertations

Over the past decade, single-cell technologies evolved from profiling hundreds of cells to millions of cells, and emerged from a single modality of data to cover multiple views at single-cell resolution, including genome, epigenome, transcriptome, and so on. With advance of these single-cell technologies, the booming of multimodal single-cell data creates a valuable resource for us to understand cellular heterogeneity and molecular mechanism at a comprehensive level. However, the large-scale multimodal single-cell data also presents a huge computational challenge for insightful integrative analysis. Here, I will lay out problems in data integration that single-cell research community is interested in and …

Genome Evolution In The Salicaceae: Genetic Novelty, Horizontal Gene Transfer, And Comparative Genomics, Timothy Yates

Doctoral Dissertations

Genome evolution is a powerful force which shapes genomes over time through processes like mutation, horizontal transfer, and sexual reproduction. Although questions which aim to explore genome evolution are broad, they are all understood through the discovery and comparison of genetic variation. For example, genetic diversity may explain differences in phenotypes, etiology of disease, and is essential for phylogenomic analysis. Recently, the democratization of next generation and third generation DNA sequencing technologies have allowed for genomics to produce large amounts of sequence data. This has facilitated the capture of genetic variation at species and population scales.

Populus and Salix are …

Mechanisms By Which Xenorhabdus Nematophila Interacts With Hosts Using Integrated -Omics Approaches, Nicholas C. Mucci

Doctoral Dissertations

Nearly all organisms exist in proximity to microbes. These microbes perform most of the essential metabolic processes necessary for homeostasis, forming the nearly hidden support system of Earth. Microbial symbiosis, which is defined as the long-term physical association between host and microbes, relies on communication between the microbial community and their host organism. These interactions among higher order organisms (such as animals, plants, and fungi) and their bacteria links metabolic processes between interkingdom consortia. Many questions on microbial behavior within a host remain poorly understood, such as the colonization efficiency among different microbial species, or how environmental context changes their …

Multi-Omic Systems Biological Analysis Of Host-Microbe Interactions, Piet Jones

Doctoral Dissertations

Systems biology offers the opportunity to understand the complex mechanisms of various biological phenomena. The wealth of data that is produced, at an increasing rate, provides the potential to meet this opportunity. Here we take an applied approach to integrate multiple omic level data sources in order to generate biologically relevant hypotheses. We apply a novel analysis pipeline to model both, in concert, the microbial and transcriptomic signature from COVID-19 positive patients. We show patients may suffer from an increased microbial burden, with an increased pathogen potential. Gene expression evidence further shows patients may exhibit a compromised barrier immunity, owing …

Genomic Organization And Expression Of The Wc1 Hybrid Coreceptor And Pattern Recognition Receptor On Porcine Gamma Delta T Cells, Lauren Le Page

Doctoral Dissertations

gd T cells are a crucial component of the immune response to a number of increasingly relevant and largely zoonotic pathogens to which efficacious vaccination is lacking. In ruminants and swine, gd T cells represent a major population of peripheral blood and epithelial tissue-resident lymphocytes. gdT cells respond to both protein and non-protein antigens independently of MHC presentation and possess immunological memory. Upon activation, gamma delta T cells illicit a variety of effector functions and play an indispensable role of orchestrating the downstream immune response. These characteristics make gamma delta T cells a promising candidate for recruitment by vaccination, however, …

Genetic And Environmental Regulation Of Plant Growth, Kirk J-M Mackinnon

Doctoral Dissertations

Field grown crops are continually exposed to a variety of external stimuli that influence plant responses. Light, temperature, and water availability interact to affect many economically important traits including growth rate, size, and lifespan. My research is focused on the intersection of genetic and environmental factors influencing plant growth. Specifically, I am interested in elucidating the regulation of rhythmic genes in response to photo- and thermocycles and identifying novel candidate genes associated with growth and drought traits. Understanding the gene regulatory networks that mediate time-of-day signaling is vital to identifying candidate genes across the pan-genome associated with traits of interest.

Mapping Selected Polyphenols Metabolism By Gut Bacteria And Their Genes, Ermin Zhao

Doctoral Dissertations

The human gut microbiome is a huge enzyme repository for dietary polyphenols metabolism, especially considering most of the polyphenols cannot be digested in the host and their biological functions are limited. Poor bioaccessibility based on traditional pharmaceutical ADME (absorption, distribution, metabolism, and excretion) assessment is the main problem facing the widely medical application of most polyphenols. Gut bacteria have the potential to mediate a wide range of biotransformation reactions of polyphenols, which leads to the production of many bioactive metabolites. In the past decades, mounting evidence in traditional ADME study have demonstrated gut bacteria play an irreplaceable role in dietary …

Discovering Mechanisms Driving Adaptive Evolution In The Cross-Kingdom Fungal Pathogen Fusarium Oxysporum, Dilay Hazal Ayhan

Doctoral Dissertations

Fusarium oxysporum is a cross-kingdom pathogenic fungus that can cause vascular wilt disease in many economically important plants and local or disseminated infections in humans. Although it lacks a sexual stage in its life cycle, F. oxysporum can adapt to a wide range of hosts because of accessory chromosomes (ACs) which are enriched in host-specific genes and repeat content. This dissertation investigates the mechanisms that drive the adaptive evolution in the cross-kingdom pathogen F. oxysporum using comparative genomics and an experimental evolution approach. The first chapter compares phenotypes and genomes of a plant pathogenic isolate F. oxysporum f. sp. lycopersici …

Applications Of Comparative Genomics And Data Science To Agricultural And Clinical Research, Katrina A. Schlum

Doctoral Dissertations

The advent of inexpensive, high-throughput whole genome sequencing (WGS) technologies has led to the generation of thousands of related genomes, even from a single study. Large-scale genome analysis has resulted in hypothesis-generating approaches in the fields of clinical, human and agriculture genomics. Additionally, population-level genomic sampling has resulted in a decrease in false positives in genotype-phenotype associations and an increase in understanding of the basis of disease, antibiotic and pesticide resistance. Deeper understanding of migration, genetic divergence and evolution has also been made possible due to WGS. This research applies comparative genomics, population genomics and data science approaches to whole …

Using Multi-Omics Approaches To Study Flowering Time And Fruit Development In Perennial Fruit Species, Jiali Yu

Doctoral Dissertations

Perennial fruiting plants coordinate their reproductive activities with seasonal changes in the temperate climates, with a pattern of bud set, dormancy establishment, fulfillment of chilling, flowering, fruit set, and fruit ripening. These processes have been optimized for the production of orchard plants that reliably produce quality fruit for human consumption. The understanding of molecular controls of dormancy in fruit trees has grown rapidly in the past decade, however, the complex mechanisms remain largely unknown. This dissertation presents my findings on genetic and epigenetic changes in Prunus species from dormancy to flowering using transcriptomics and epigenomics approaches. First, I compared the …

Effects Of Tempeh Fermentation On Soy Free And Bound Phenolics: Release, Transformation, And Stimulated Production, Amadeus Driando Ahnan

Doctoral Dissertations

The fermentation of tempeh, a traditional source of protein originated in Indonesia, has been reported to enhance the health-promoting potentials of various grains, legumes, and beans. Tempeh fermentation on soybeans can modulate the bioavailability of phenolic compounds, particularly isoflavones, bioactive compounds that have been found to be protective against lung, prostrate, and colon cancers. However, the mechanism of the protective benefits was unknown. Using whole-food and in vitro models, this study addressed this research gap by investigating the effects of tempeh fermentation using various cultures on the compositions of soy free, bound, and minor phenolics, as well as their antioxidative, …

The Effect Of Nuclear Perturbations On The 3d Organization Of The Genome, Rosela Golloshi

Doctoral Dissertations

Cells in our body experience constant mechanical forces that influence biological functions such as growth and development. The nucleus has been implicated as a key mechanosensor and can directly influence chromatin organization and epigenetic alterations leading to gene expression changes. However, the mechanism by which such mechanical forces lead to genomic alterations and expression of mechanosensitive genes is not fully understood. The work presented in this dissertation investigates the effect of mechanical and epigenetic perturbations on the 3D genome organization. To investigate this 3D genome folding, we use Chromosome Conformation Capture followed by high throughput sequencing (Hi-C) (Chapter-1) which identifies …

3d Genome Architecture Under Stress: A Survey Of Ionizing Radiation, Progeria, And Osmotic Stress, Jacob Tyler Sanders

Doctoral Dissertations

The human nucleus contains 2 meters of DNA which is intricately folded into a three-dimensional (3D) structure. It has become increasingly clear that this 3D structure plays an important role in the expression of genes. Proper gene expression is necessary for cellular homeostasis, cell state, and response to environmental/physical perturbations. Faithful repair of damage DNA damage is necessary to prevent genomic aberrations, such as translocations, which may lead to misregulation of gene expression. Hi-C, a sequencing technique that labels proximal chromatin interactions, provides a clearer picture of how the genome is spatially organized within the nucleus. Here, we discuss the …

Accessory Genes Contribute To Rewiring The Transcriptional Network In Fusarium Oxysporum, He Yang

Doctoral Dissertations

The presence of accessory chromosomes is one of the most fascinating features in the genomes of Fusarium oxysporum (Fo) species complex that includes both plant and animal pathogens. In plant-pathogenic Fo strains, these accessory chromosomes govern host-specific pathogenicity through unique sets of virulence factors, including secreted effectors and plant cell wall degrading enzymes, while the identity of such factors are largely unknown in human infecting strains. This dissertation is composed of three projects that focused on studying the gene composition and transcriptional regulation of human-pathogenic Fo strains. The first project deciphered the genome of the clinical Fo strain, …

Characterizing Adaptive Non-Coding Changes In The Regulation Of Human Gene Expression, Jason Pizzollo

Doctoral Dissertations

Differential patterns of gene expression contribute to phenotypic differences between species. Understanding evolutionary changes in gene regulatory elements can help explain traits that separate humans from closely related species. Here, in two separate studies, we investigate gene expression and gene regulatory differences between humans our closest living evolutionary relatives, chimpanzees, in the context of uniquely human traits: increased susceptibility to epithelial cancers and neural developmental and functional processes that underlie our increased cognitive capacity. Using genomic methods to study gene expression and open chromatin, we compare human and chimpanzee responses to a serum challenge, an assay that that mimics patterns …

De-Coding The Impact Of Evolved Changes In Gene Expression And Cellular Phenotype On Primate Evolution, Trisha Zintel

Doctoral Dissertations

The goal of the dissertation work outlined here was to investigate the influence of proximal processes contributing to evolutionary differences in phenotypes among primate species. There are numerous previous comparative analyses of gene expression between primate brain regions. However, primate brain tissue samples are relatively rare, and my results have contributed to the pre-existing data on more well-studied primates (i.e. humans, chimpanzees, macaques, marmosets) as well as produced information on more rarely-studied primates (i.e. patas monkey, siamang, spider monkey). Additionally, the primary visual cortex has not previously been as extensively studied at the level of gene expression as other brain …

Drivers And Consequences Of Carbon Use Efficiency - And Its Measurement In Soil, Grace Pold

Doctoral Dissertations

Soils serve as massive carbon sinks, but their ability to continue this ecological service is contingent on how the resident soil microbial community will respond to the ongoing climate crisis. One key dimension of the microbial response to warming is its carbon use efficiency (CUE), or the fraction of carbon taken up by an organism which is allocated to growth rather than respiration. However, the scientific community is still in the early stages of understanding the drivers, consequences - and even accurate measurements of - CUE. In this dissertation, I first quantified the variability of CUE and its responsiveness to …

A Plant Pathology View Of Signaling: A Computational Study Of Fusarium Oxysporum Kinomes And Downy Mildew Resistance In Sweet Basil, Gregory Deiulio

Doctoral Dissertations

This dissertation is composed of two projects that focus on pathogen and plant signaling within the framework of plant pathology. The first project targets protein kinases within the species complex Fusarium oxysporum based on genomic information and tracks their presence/absence and copy number variation across evolutionary time. We have predicted the kinomes of 19 Ascomycete fungi using the kinase annotating software Kinannote. Among Fusaria, kinases related to the perception of the environment, such as Histidine kinases, are proliferated. Similarly, I observed the expansion of Target of Rapamycin (TOR) kinase that regulates cell growth and development in responding to environmental cues. …

Impacts Of Genome And Nuclear Architecture On Molecular Evolution In Eukaryotes, Xyrus Maurer-Alcalá

Doctoral Dissertations

The traditional view of genomes suggests that they are static entities changing slowly in sequence and structure through time (e.g. evolving over geological time-scales). This outdated view has been challenged as our understanding of the dynamic nature of genomes has increased. Changes in DNA content (i.e. polyploidy) are common to specific life-cycle stages in a variety of eukaryotes, as are changes in genome content itself. These dramatic genomic changes include chromosomal deletions (i.e. paternal chromosome deletion in insects; Goday and Esteban 2001; Ross, et al. 2010), developmentally regulated genome rearrangements (e.g. the V(D)J system in adaptive immunity in mammals; Schatz …

Bioinformatic And Experimental Approaches For Deeper Metaproteomic Characterization Of Complex Environmental Samples, Ramsunder Mahadevan Iyer

Doctoral Dissertations

The coupling of high performance multi-dimensional liquid chromatography and tandem mass spectrometry for characterization of microbial proteins from complex environmental samples has paved the way for a new era in scientific discovery. The field of metaproteomics, which is the study of protein suite of all the organisms in a biological system, has taken a tremendous leap with the introduction of high-throughput proteomics. However, with corresponding increase in sample complexity, novel challenges have been raised with respect to efficient peptide separation via chromatography and bioinformatic analysis of the resulting high throughput data. In this dissertation, various aspects of metaproteomic characterization, including …

All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang

Doctoral Dissertations

Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O.sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Using population genetics analyses of South Asian and US weedy rice, my research reveals multiple independent evolution events giving rise to weed groups in the two geographic areas. Weeds in South Asia have highly heterogenous genetic backgrounds, with contributions from both cultivated varieties (aus and indica) …

Assessment Of Genetic And Education Recovery Plan Objectives For The Bog Turtle (Glyptemys Muhlenbergii), Cassie Marie Dresser

Doctoral Dissertations

Unprecedented declines in biodiversity are threatening the natural world as we know it. Without human intervention, two thousand species listed under the US Endangered Species Act are likely to disappear. Fortunately, these species receive federal protection and increased research effort is needed to create and satisfy the objectives outlined in the mandated Species Recovery Plan. In this dissertation, I address three conservation objectives outlined in the Recovery Plan for North America’s smallest and rarest turtle, the Bog Turtle (Glyptemys muhlenbergii): (1) investigate the potential genetic differentiation in southern portions of the species’ range, (2) investigate the genetic impacts …

Detection, Diversity, And Evolution Of Fungal Nitric Oxide Reductases (P450nor), Steven Adam Higgins

Doctoral Dissertations

Nitrous oxide (N₂O) is a gas responsible for significant ozone layer depletion and contributes to greenhouse effects in Earth’s atmosphere. N₂O is primarily generated by denitrification, whereby nitrate (NO_3-) or nitrite (NO_2-) is converted to gaseous N₂O or N2. Teragram quantities of N₂O are emitted annually from agricultural soils treated with nitrogenous fertilizers due to the activity of soil microbiota. Although bacteria and fungi harbor genes permitting denitrification, fungi lack NosZ, an enzyme responsible for reducing N₂O into inert N2 gas. Historically, scientists have linked fungi …

Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney

Doctoral Dissertations

The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF …

Role Of Hormonal And Developmental Signaling In Plant-Cyst Nematode Interaction, Sarbottam Piya

Doctoral Dissertations

Plant-parasitic cyst nematodes are one of the most destructive root parasites that cause severe yield losses in many crop plants. These obligate parasites induce a specialized multi-nucleate feeding site called syncytium. This study was conducted to explore the roles of phytohormones particularly auxin and ethylene, and miRNA-mediated crosstalk between development and defense responses in establishing the compatible interaction between Arabidopsis and Heterodera schachtii. Using yeast two-hybrid assay, a complete protein-protein interaction map between Auxin/indole-3-acetic acid (Aux/IAA) proteins and auxin response factors (ARFs) was generated. In addition, gene co-expression profiles of ARFs and Aux/IAAs were incorporated with protein-protein interaction data. …

Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li

Doctoral Dissertations

Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this tetrameric …

Expansion Of And Reclassification Within The Family Lachnospiraceae, Kelly N. Haas

Doctoral Dissertations

Many of the taxa in the family Lachnospiraceae are currently misclassified as Clostridium spp. Here attempt to rectify many of these issues, beginning with an in-depth genomic and physiologic analysis of Clostridium methoxybenzovorans, culminating in the assertion that is a heterotype of Clostridium indolis, followed by reclassification of the broader group in which this organism resides. We propose two novel genera, Lacriformis and Enterocloster, to reclassify this clade, this includes reclassification of Clostridium sphenoides, Clostridium indolis, Clostridium saccharolyticum, Clostridium celerecrescens, Clostridium xylanolyticum, Clostridium algidixylanolyticum, Clostridium aerotolerans, Clostridium amygdalinum, and …

Uncovering The Genetic Basis For Biofuel-Related Traits In Brachypodium Distachyon, Scott J. Lee

Doctoral Dissertations

Biofuels derived from plant biomass present a promising avenue to address the negative aspects of fossil-fuel dependence. The sustainability of biofuel production relies in part on the efficient degradation of lignocellulosic feedstocks. In order to capitalize on the potential of lignocellulosic biofuels, the genes underlying natural genetic variation for conversion efficiency must be determined. We have developed a robust and high-throughput assay to measure feedstock quality using the anaerobic bacterium Clostridium phytofermentans. We have measured biomass accumulation phenotypes and utilized this assay to perform quantitative trait locus (QTL) mapping and a genome-wide association study (GWAS) in the model grass species …

Novel Advancements For Improving Sprout Safety, Kyle S. Landry

Doctoral Dissertations

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the …