Digital Commons Network^™

Developing Regulated Crispr Systems To Control Bacterial Microbiomes, Gregory M. Pellegrino

Electronic Thesis and Dissertation Repository

Changes to the human microbiome’s composition and metabolome are associated with numerous diseases and alterations to xenobiotic metabolism. As such, targeting the human microbiome is an increasingly popular option for therapeutic interventions. However, traditional therapies that target the microbiome such as antibiotics lack specificity, which can affect the beneficial species of the microbiome and cause adverse health outcomes such as the rise of antimicrobial-resistant bacteria. Therefore, the research and development of specific, targeted antimicrobial therapies is crucial to effectively treating microbiome dysbioses.
CRISPR and CRISPRi provide easily modifiable, RNA-guided mechanisms mediated by the Cas9 or dCas9 enzymes to induce sequence-specific …

Effect Of Plant Genotype On Plant-Microbe Interactions And Multi-Generation Ecosystem Selection Of Microbial Communities Associated With Plant Biomass In Arabidopsis Thaliana, Nachiket Shankar

Graduate Doctoral Dissertations

The microbiome's role in shaping host phenotypes is a critical area of investigation, with implications for ecology, evolution, and host health. Dynamic plant-microbe interactions are influenced by factors like soil type, environment, and genotype. Understanding their impact on microbial communities is key for tailored plant benefits. An artificial ecosystem selection experiment was done for eight generations with Arabidopsis thaliana Ler and Cvi. This revealed distinct microbial communities shaped by genotypes and biomass treatments. Initially, environment dominated, but over time, genotype and biomass gained influence, explaining ~40% of the variation. Moreover, genotype-specific rhizobacterial associations were observed, enhancing understanding of community dynamics …

Investigating Soil Microbiome Changes During Panax Quinquefolius Cultivation In New Gardens, Pok Man Paul Wan

Electronic Thesis and Dissertation Repository

Ginseng (Panax quinquefolius) is susceptible to ginseng replant disease (GRD), resulting in root rot and decreased yield when ginseng is grown in soils previously used for ginseng crops. Although fungal and oomycete pathogens are implicated, GRD is a complex disease and the changes in the soil when initially cultivating ginseng that lead to GRD remain unclear. This thesis reported changes in the soil microbiome from three new gardens in Norfolk County, Ontario over three years starting from seeding with ginseng. Over this period of cultivation, metabarcoding of the V4 region of the 16S ribosomal RNA gene clearly showed …

Evaluating The Role Of The Bovine Vaginal Microbiome In Neonatal And Maternal Health Outcomes, Riley D. Messman

Theses and Dissertations

The dam vaginal microbiota is the first major microbial inoculating community within the neonate. The composition of the dam vaginal microbiota has implications in calf commensal microbiota development. Alterations of the dam microbial community prior to parturition could alter inoculating communities and immune responses in both the dam and calf. Thus, authors aimed to elucidate the microbial community composition of the bovine dam vaginal and calf nasal microbiota post-partum after utilizing betadine lavages (BL). The dam vaginal and calf nasal microbial communities and immune responses were evaluated at 0-, 15-, 30- and 60-day post-partum. Microbiota composition of the dam haircoat, …

Consumption Of A Western Diet Enhanced Colitis-Associated Colorectal Cancer And Dysbiosis Of The Fecal Microbiome In Mice Notwithstanding Dietary Intervention Or Fecal Microbiome Transfer, Daphne Michelle Rodriguez Jimenez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In a rodent model of inflammation-associated colorectal cancer, consumption of a Western-style diet increases gut inflammation and enhances risk of developing colon tumors. The goal of this dissertation was to understand the contribution of bacteria within the large intestine on colon inflammation and colon tumorigenesis. Two pre-clinical animal studies were performed using two different intervention strategies to shift the microbiome, and potentially gut inflammation and tumor development: 1) an experiment using dietary supplementation with black raspberries, a functional food enriched in bioactive anthocyanins with purported antiinflammatory activity, and 2) an experiment using fecal microbiota transfer from mice fed a healthy …

Functionalizing Conjugative Systems To Deliver Crispr Nucleases For Targeted Bacterial Killing, Thomas A. Hamilton

Electronic Thesis and Dissertation Repository

The interactions between humans and microbes are intimately important to human health, with both commensal and pathogenic bacteria affecting homeostasis and disease. Increasing concern over antibiotic resistance in bacterial pathogens represents a significant threat to human health, and use of traditional antibiotics to treat infections can be detrimental to commensal bacteria as well as pathogens, demonstrating a need for more specific antibacterial reagents. RNA-guided CRISPR nucleases, which can target and cleave genomes of interest, are a potential tool for specific bacterial targeting. A key limitation to the use of CRISPR antimicrobials is effective and robust delivery to the target bacteria. …

Characterization Of Antimicrobial Properties Of Excrement And Functional Microbiome Of Black Vultures (Coragyps Atratus), Bridgette Gray

Theses

Black vultures, Coragyps atratus, are obligate scavenging birds that consume and dispose of decaying carcasses and carrion. They fulfill a key ecological niche in the environments in which they live. It has been observed that these vultures sometimes excrete bodily waste onto their legs. This adaptive behavior could help aid them in controlling bacteria and other microbes they encounter while stepping into a carcass to eat. This study directly examined the antimicrobial properties of the excrement of black vultures across various bacterial species utilizing a zone of inhibition test and a nematode species utilizing a survival assay. The black vulture …

​ Soilborne Pathogens Of Strawberry In The Central Coast Region Of California: ​ Survey And Cover Cropping With Wheat For Management Of Macrophomina Phaseolina, Mary Steele

Master's Theses

Surveys of the four major soilborne pathogens of strawberry (Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae) to determine their relative prevalence were conducted in Watsonville-Salinas, CA in 2021 and in Santa Maria, CA in 2022. All four major pathogens were detected at relatively similar prevalence in Watsonville-Salinas, between 22% and 31% of sampled fields. In Santa Maria, M. phaseolina was far more prevalent at 52% of sampled fields, the other three falling between 14% and 17%. Additionally replicated greenhouse and field trials were conducted to evaluate the effects of wheat as …

The Effects Of Aloe Vera On The Human Gut Microbiome, Samantha Leon

Honors Theses

The human gut microbiome is a diverse community of bacteria influenced by multiple factors including host age, geographical location, and diet. This study observed the effects of aloe vera juice on the human gut microbiome. Fecal samples were taken every two weeks over a period of one year; the subject consumed aloe vera juice in alternating cycles of consumption “on” and abstaining “off” with each cycle lasting for eight weeks. The bacterial community in each sample was characterized using 16S rRNA gene sequencing. Sequences were identified and their relative abundances were used to look for patterns distinguishing “on” and “off” …

Impact Of Daily Sweet Potato Ingestion On Alterations To The Gut Microbiome, Cholesterol, And Exercise Performance, Johneric William Smith

Theses and Dissertations

The importance of the gut microbiome is being explored in relation to multiple facets of health and performance. The purpose of this study was to explore the impact of frequent sweet potato ingestion on alterations of the gut microbiome which might in turn alter cholesterol levels and exercise performance. Thirteen recreationally trained males had fecal and blood samples collected and exercised to fatigue with and without exogenous carbohydrate ingestion prior to and following 42 days of daily sweet potato ingestion. Bacterial communities were extracted from fecal samples and bacterial DNA were sequence. Blood samples were analyzed for total cholesterol, low-density …

Comparative Analysis Of Rhizosphere And Endosphere Microbiome Of Different Blueberry Species (Vaccinium Sp.), Niladri Bhowmik

Master's Theses

Blueberries are an important agricultural commodity in all over the United States. Due to its health benefits, there is a huge demand globally, thus expanding the industry. Breeding programs are essential to maintain such industries. Challenges that play a role in contemporary breeding programs are various biotic and abiotic stress factors. Studies have shown that microorganisms are recruited by plants to alleviate them during stressful conditions. Though blueberries have been cultivated for about 100 years, how the microbiome has been affected due to this is poorly understood. We hypothesized that interspecific crosses and artificial selection have significantly changed the microbiome …

Ecology, Evolution, And Gene Transfer Between Diatoms And Bacteria, Cory B. Gargas

Graduate Theses and Dissertations

Although photosynthetic macro-eukaryotes (i.e., plants) make up the majority of organic biomass on earth, bacteria are the second largest taxonomic group, by biomass. Bacteria are ubiquitous in our environment, living on, and within, man-made surfaces, natural environments, and eukaryotes themselves. The relationship between bacteria and eukaryotes has existed from the very beginning of eukaryotic life in the form of bacterial endosymbioses that resulted in mitochondria and plastids. Other eukaryote–bacteria relationships have evolved since then, ranging from the beneficial (e.g., mutualistic) to harmful (e.g., parasitic or pathogenic). Understanding these eukaryote–bacteria relationships is key to understanding both the evolution of important ecosystem …

Determining The Effects Of Maternal Adiposity On Preterm Neonatal Microbiome And Short Chain Fatty Acid Profiles, Dalton James, William A. Clark Phd, Kristy L. Thomas

Undergraduate Honors Theses

The gut microbiota and its metabolites have vast impacts on the human digestive system, immune system, and health outcomes. Short chain volatile fatty acids (SCVFAs) present in feces can be representative of the interactions of the microbiota present in the gut. Low microbiota diversity in the human gut is highly associated with obesity and adverse health outcomes. Furthermore, the maternal microbiome has a direct impact on neonatal microbiota through various pathways such as environment, skin flora, breast milk composition, and vaginal secretions. This study is aimed to further understand the associations between various factors (maternal adiposity, gestational time, length of …

Unraveling Plant-Microbe-Microbe Interactions: Host And Microbial Colonization Determinants Across Experimental Scales, Bridget O'Banion

Doctoral Dissertations

Plant microbiomes are assembled and modified through a complex milieu of biotic and abiotic factors. Despite dynamic and fluctuating contributing variables, specific host and microbial mechanisms are likely important mediators of interactions. We combine information from large-scale datasets across diverse plant hosts with experimental genetic manipulation assays in model Arabidopsis seedlings to converge on a conserved role for metabolite production and transport in mediating host-microbe interactions. Applying a diverse set of analytical tools to microbial communities at various complexity levels will advance our knowledge of the scalability of observed phenotypes and, ultimately, help to decipher the mechanisms dictating plant–microbe interactions …

Bifidobacterial Metabolism Of Fucosylated Human Milk Oligosaccharides Influences Structure And Function Of The Infant Gut Microbiome, Liv R. Dedon

Doctoral Dissertations

Human milk contains human milk oligosaccharides (HMOs) that are indigestible and pass intact through the infant gastrointestinal tract where they are available for microbial metabolism. HMOs incorporate the same monosaccharide building blocks but vary structurally in primary sequence of monomeric components. Primary sequences are further diversified by degree of polymerization, branching, and secondary modifications such as fucosylation. Fucosylated HMOs (fHMOs) are highly abundant and can account for over 30% of total HMOs. Infant-colonizing Bifidobacterium longum subsp. infantis (B. infantis) possesses a specialized gene cluster conveying the ability to metabolize fHMOs. This study presents an in-depth analysis of B. …

Small Molecule Compounds, Active Ingredients Of Tcm, As Novel Therapeutics For Eosinophilic Esophagitis, Anish Maskey

NYMC Student Theses and Dissertations

Eosinophilic Esophagitis (EoE), a chronic inflammatory condition of the esophagus, characterized by esophageal dysfunction and eosinophilic inflammation. Current treatments for EoE include dietary elimination and swallowed steroids. Recently, Dupixent was approved for the treatment of EoE, but it has side effects such as eye inflammation and eczema. Traditional Chinese Medicine (TCM) practice has been used to improve GI symptoms in EoE patients. Two key active ingredients of a TCM formula, 7,4’-Dihydroxyflavone (DHF) and Berberine (BBR), have shown remarkable results in treating EoE.

To understand the role of two active ingredients in EoE, different experimental models were used. First, a computational …

Diet And Salivary Microbiome On Cardiovascular Risk And Glycemic Control In Participants With And Without Type 1 Diabetes: The Cacti Study, Tiantian Pang

USF Tampa Graduate Theses and Dissertations

Introduction: The prevalence of type 1 diabetes mellitus (T1DM) has been increasing drastically in the United States. People with T1DM are at a higher risk of developing diabetes-related complications, including cardiovascular disease (CVD). Diet is one of the most modifiable factors and healthy eating could reduce CVD risk among individuals with T1DM. The current 2015-2020 Dietary Guidelines for Americans focus on overall healthy eating patterns rather than individual foods and nutrients. A healthy dietary pattern or high-quality diet can be measured by diet quality indexes, and generally contains minimal ultra-processed foods (UPF). Although substantial evidence has linked poor diet quality …

Investigating The Potential Role Of Termites As Pathogen Vectors In The Decline Of Ironwood Trees (Casuarina Equisetifolia) In Guam, Garima Setia

LSU Master's Theses

Termites have been found associated with the decline of Casuarina equisetifolia (ironwood), an important agro-forestry species in Guam. While the ironwood tree decline (IWTD) was first reported in 2002, its association with termites as well as with bacteria Ralstonia solanacearum and Klebsiella species (K. oxytoca and K. variicola) was determined in 2010 and 2012 respectively. In 2019, the termite species attacking the ironwood trees were identified as Nasutitermes takasagoensis, Coptotermes gestroi, and Microcerotermes crassus. However, the role of termites in IWTD is not known. Since termites are repositories of bacteria and consume wood, termite foragers might …

Effects Of Traumatic Brain Injury On The Intestinal Tract And Gut Microbiome, Anthony Desana

Theses and Dissertations--Physiology

Traumatic brain injury (TBI) initiates not only complex neurovascular and glial changes within the brain but also pathophysiological responses that extend beyond the central nervous system. The peripheral response to TBI has become an intensive area of research, as these systemic perturbations can induce dysfunction in multiple organ systems. As there are no approved therapeutics for TBI, it is imperative that we investigate the peripheral response to TBI to identify targets for future intervention. Of particular interest is the gastrointestinal (GI) system. Even in the absence of polytrauma, brain-injured individuals are at increased risk of suffering from GI-related morbidity and …

Cutaneous Microbiome Of Red Fox (Vulpes Vulpes) Infected With Sarcoptic Mange (Sarcoptes Scabiei), Jacqueline C. Robidoux

Honors Theses and Capstones

Sarcoptic mange is a parasitic skin disease that affects countless mammals worldwide, including red foxes (Vulpes vulpes). The symptoms, such as hair loss, crusting, and the number of mites, vary between individual foxes. Sarcoptic mange damages the skin barrier, which in turn disrupts the biodiversity of bacteria in the microbiome. It is unknown what the biodiversity of bacteria is at each stage of the disease. This experiment will compare the microbiomes of different samples with and without mange; in hopes to reveal a connection between the different severities of sarcoptic mange and the biodiversity of bacteria and fungi …

Host-Microbe Interactions In Non-Native Estuarine Anemones: Biogeography And Temperature, Parker K. Lund

Cal Poly Humboldt theses and projects

Non-native species are increasing in prevalence around the world, resulting in negative economic and ecological impacts. However, the broad distributions of non-native species also offer a system for investigating the response of host-associated microbial communities to environmental factors across a range of ecological scales. At the broadest scale, I investigated the geography of microbial communities in the non-native estuarine anemone Diadumene lineata on the west coast of the United States of America. Across latitudes, microbial community composition was very similar and displayed a high percentage of Klebsiella spp. at all sites. However, the communities in California tended to exhibit higher …

Characterization Of Fiber Intake, The Gut-Brain-Axis, And Glycemic Control In Nh Bhutanese Refugees, Brandy Moser

Master's Theses and Capstones

The gut microbiome has a significant influence on chronic diseases, potentially through mediating inflammation and the gut-brain axis, yet underlying pathways remain unclear. Microbiomes are highly variable and can be influenced by a variety of lifestyle and environmental factors, like diet and medication use. The study of both the composition and function of the gut microbiome is warranted, yet many gaps remain particularly in our knowledge about the gut microbiome function in the context of chronic diseases. Refugee groups in the US, such as the Bhutanese refugee population in New Hampshire, are at higher risk for chronic diseases but underrepresented …

An Analysis On How Housing Status Influences The Gut-Brain-Axis For Populations In And Around The Skid Row Area Of Los Angeles, California, Mauricio Guzman

Pitzer Senior Theses

Over recent years, the “microbiota-gut-brain axis” (MGBA) has garnered significant attention in the scientific community. Specifically, perturbations of the MGBA via stress and dietary intake have been linked to a wide-range of diseases including gastrointestinal diseases, metabolic diseases, mood disorders, and cognitive diseases. However, most studies have been solely conducted on mice models and have yet to consider the more complex, intricate systems that impact the human body. In addition, researchers have yet to consider the populations who may be most susceptible to chronic stress and negative dietary outcomes. Drawing from the fields of medical sociology, non-invasive human biology, and …