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Full-Text Articles in Life Sciences

Identification Of The Type Eleven Secretion System (T11ss) And Characterization Of T11ss-Dependent Effector Proteins, Alex S. Grossman Dec 2022

Identification Of The Type Eleven Secretion System (T11ss) And Characterization Of T11ss-Dependent Effector Proteins, Alex S. Grossman

Doctoral Dissertations

Host-associated microbes live in dangerous environments as a result of host immune killing, nutrient provisioning, and physiological conditions. Bacteria have evolved a host of surface and secreted proteins to help interact with this host environment and overcome nutrient limitation. The studies included within this dissertation describe the identification of a novel bacterial secretion system which has evolved to transport these symbiosis mediating proteins. This system, termed the type eleven secretion system (T11SS), is present throughout the Gram negative phylum Proteobacteria, including many human pathogens such as Neisseria meningitidis, Acinetobacter baumanii, Haemophilus haemolyticus, and Proteus vulgaris. Furthermore, …


An Investigation Of Intrinsic And Extrinsic Factors That Influence Soil Microbial Succession During Human Decomposition, Allison R. Mason Aug 2022

An Investigation Of Intrinsic And Extrinsic Factors That Influence Soil Microbial Succession During Human Decomposition, Allison R. Mason

Doctoral Dissertations

Decomposer organisms play a vital role in terrestrial nutrient cycling, breaking down complex organic compounds and providing nutrients for primary producers. Microbial communities and other decomposers associated with a vertebrate carcass, or the “necrobiome”, are critical for degradation and recycling of soft tissues following vertebrate mortality. The impact of microbial decomposers in vertebrate decomposition has been shown with regard to soil microbial communities, where the presence of soil microbes impact decomposition rate and undergo succession. However, current assessments of microbial ecology within decomposition-impacted soils have primarily focused on one aspect of microbial succession: succession of bacterial taxa for forensic applications. …


Enterobactin-Based Immune Interventions Against Gram-Negative Bacterial Infections, Huiwen Wang Aug 2022

Enterobactin-Based Immune Interventions Against Gram-Negative Bacterial Infections, Huiwen Wang

Doctoral Dissertations

Enterobactin (Ent)-mediated iron acquisition is critical for many Gram-negative bacteria to survive in the host. Given the bacteriostatic effect of lipocalin-2 resulting from its potent Ent-binding ability, immune interventions directly targeting Ent is a promising antimicrobial strategy against Gram-negative bacterial infections. Moreover, hyperimmune egg yolk antibody is an emerging passive immune agent for the control of bacterial infections. Oral administration of anti-Ent egg yolk antibody may confer passive immune protection against Ent-dependent enteric pathogens. In this dissertation study, multidisciplinary approaches in conjunction with different model systems (in vitro, in vivo, and ex vivo) were used to …


Metabolism In The Colonocyte: Where Bacteria And Diet Meet, Bohye Park May 2022

Metabolism In The Colonocyte: Where Bacteria And Diet Meet, Bohye Park

Doctoral Dissertations

The host-microbiome interaction and the functions of microbial-derived metabolites, including butyrate, are important in colon health. Butyrate is the preferred energy source in colonocytes and has multiple physiological functions in the colon. A metabolic shift in colonocytes toward increased glucose utilization from butyrate oxidation is followed by several critical genetic modifications in cancerous colonocytes. Moreover, it has been suggested that the gut-microbiota composition is influenced by environmental factors, such as diets and the host's physiological status. Therefore, an understanding of the role of colonocyte metabolism toward impacting the host-microbiota commensal relationship would be an important step in understanding the functional …


Cat Covid, Cmv And Chemokines, Oh My!, Trevor Hancock May 2022

Cat Covid, Cmv And Chemokines, Oh My!, Trevor Hancock

Doctoral Dissertations

Cytomegalovirus (CMV) is an important pathogen infecting most humans worldwide. CMV infection within immunocompromised individuals can cause severe morbidity and potential mortality. Disease during CMV infection is due to virus dissemination and subsequent inflammation. Host immune cells lie at the intersection potentially mediating both. The CMV-encoded viral chemokine vCXCL-1 is a proposed virulence factor in mouse models increasing immune cell recruitment and disease. However, the primary immune cell mediator is undetermined. To identify targets, Chapter 2 examines CXCR2 expression (receptor for vCXCL-1) among various mouse tissues and human peripheral blood under steady-state conditions. In vitro, isoforms of HCMV’s vCXCL-1 …


Mechanisms By Which Xenorhabdus Nematophila Interacts With Hosts Using Integrated -Omics Approaches, Nicholas C. Mucci May 2022

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 …


The Spatial, Temporal, And Ecological Constraints Of Plant-Host Associated Microbial Communities, Jonathan Dickey May 2022

The Spatial, Temporal, And Ecological Constraints Of Plant-Host Associated Microbial Communities, Jonathan Dickey

Doctoral Dissertations

With the development of next generation sequencing technology, ecologists have recently been able to describe microbial communities across a wide array of niches at an accelerated pace. De-novo-based patterns in richness and relative abundance have been described for bacterial and fungal communities in terrestrial, aquatic, and host-associated microhabitats. A recent synthesis has shown that these communities exhibit similar geographical patterns that have been traditionally described for plant and animals. Yet, there is a lack of hypothesis-based research for host-associated microbial communities. Throughout this dissertation, I will address how spatial scale, sequencing resolution, and manipulative rainfall exclusion govern host-associated microbial communities …


Making Sense Of Soil Microbiome Complexity For Plant And Ecosystem Function In A Changing World, Kendall K. Beals May 2022

Making Sense Of Soil Microbiome Complexity For Plant And Ecosystem Function In A Changing World, Kendall K. Beals

Doctoral Dissertations

Soils contain the highest biodiversity on Earth. While the importance of the soil microbiome for larger-scale ecological phenomena such as nutrient and carbon cycling, plant growth and plant community dynamics is well-established, the fundamental question of the ecological and evolutionary function of this immense belowground microbial diversity for plant and ecosystem function still remains a great challenge in microbial ecology research. The objective of this dissertation is to understand how the importance of soil microbial community composition for plant and ecosystem function and how changes to soil microbial community composition from climate change-induced disturbance events, specifically fire, influence plant and …


Multi-Omic Systems Biological Analysis Of Host-Microbe Interactions, Piet Jones May 2022

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 …