Host Microbiome Interactions Impacting Pathogen And Mutualist Colonization Within Defensive Symbioses

Download or read book Host-microbiome Interactions Impacting Pathogen and Mutualist Colonization Within Defensive Symbioses written by Jennifer Bratburd and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial interactions shape the world around us. One major determinant of the effect a microbe will have on its environment is the microbe's ability to colonize. For pathogens, colonization directly impacts the host's health and many hosts have mechanisms to limit or otherwise control microbial colonization. These limitations may also prove challenging for commensal or mutualistic microbes, which themselves may be critical many aspects of host health, including defending the host against pathogens. In this dissertation, I explore a spectrum of host-microbiome interactions, ranging from an individual mutualistic bacterial strains of the fungus-growing ant system to whole human gut microbial communities using several approaches to better understand defensive mutualisms. In Chapter 1, I discuss how understanding defensive symbiosis of social animal models, in particular insect systems, may help in understanding with human problems with controlling pathogens in large social populations. In Chapter 2, I present experimental colonization data and comparative genomics that suggests the lack of specificity from the symbiont in the fungus-growing ant and Pseudonocardia mutualism. To explore pathogen interactions with a more complex microbial community, in Chapter 3, I investigate how human gut microbial community responds to infection of the host in a gnotobiotic mouse model with metagenomics and metabolomics approaches. I contrast host without microbiota and hosts with microbiota but no infection to find that infection greatly perturbs the communities and I find particular metabolites in abundance on in the presence of both microbial community and pathogen. Expanding on human gut microbiome and germ-free mouse model approach, in Chapter 4, I use human stool samples as donors to inoculate germ-free in order to identify variability in the microbiome resistance to infection and apply metagenomic techniques to examine commonalities of resistant microbiomes. I find limited evidence of shared taxonomic groups in resistant microbes, but some indication of shared functional genes in the metagenomes associated with pathogen resistance. Together, these approaches provide insight into the complexity of host interplay with defensive microbes.