Dietary manipulation of intestinal microbes prolongs survival in a mouse model of Hirschsprung disease.

Unlabelled: Enterocolitis is a common and potentially deadly manifestation of Hirschsprung disease (HSCR) but disease mechanisms remain poorly defined. Unexpectedly, we discovered that diet can dramatically affect the lifespan of a HSCR mouse model ( , ) where affected animals die from HAEC complications. In the model, diet alters gut microbes and metabolites, leading to changes in colon epithelial gene expression and epithelial oxygen levels known to influence colitis severity.

Salmonella re-engineers the intestinal environment to break colonization resistance in the presence of a compositionally intact microbiota.

The gut microbiota prevents harmful microbes from entering the body, a function known as colonization resistance. The enteric pathogen Salmonella enterica serovar (S.) Typhimurium uses its virulence factors to break colonization resistance through unknown mechanisms.

Serotonin reduction in post-acute sequelae of viral infection.

Post-acute sequelae of COVID-19 (PASC, "Long COVID") pose a significant global health challenge. The pathophysiology is unknown, and no effective treatments have been found to date. Several hypotheses have been formulated to explain the etiology of PASC, including viral persistence, chronic inflammation, hypercoagulability, and autonomic dysfunction.

Host cells subdivide nutrient niches into discrete biogeographical microhabitats for gut microbes.

Changes in the microbiota composition are associated with many human diseases, but factors that govern strain abundance remain poorly defined. We show that a commensal Escherichia coli strain and a pathogenic Salmonella enterica serovar Typhimurium isolate both utilize nitrate for intestinal growth, but each accesses this resource in a distinct biogeographical niche. Commensal E.

The longitudinal and cross-sectional heterogeneity of the intestinal microbiota.

A central goal of microbiome research is to understand the factors that balance gut-associated microbial communities, thereby creating longitudinal and cross-sectional heterogeneity in their composition and density. Whereas the diet dictates taxa dominance, microbial communities are linked intimately to host physiology through digestive and absorptive functions that generate longitudinal heterogeneity in nutrient availability. Additionally, the host differentially controls the access to electron acceptors along the longitudinal axis of the intestine to drive the development of microbial communities that are dominated by facultatively anaerobic bacteria in the small intestine or obligately anaerobic bacteria in the large intestine.

Anaerobic Respiration of NOX1-Derived Hydrogen Peroxide Licenses Bacterial Growth at the Colonic Surface.

The colonic microbiota exhibits cross-sectional heterogeneity, but the mechanisms that govern its spatial organization remain incompletely understood. Here we used Citrobacter rodentium, a pathogen that colonizes the colonic surface, to identify microbial traits that license growth and survival in this spatial niche. Previous work showed that during colonic crypt hyperplasia, type III secretion system (T3SS)-mediated intimate epithelial attachment provides C.

Commensal Enterobacteriaceae Protect against Salmonella Colonization through Oxygen Competition.

Neonates are highly susceptible to infection with enteric pathogens, but the underlying mechanisms are not resolved. We show that neonatal chick colonization with Salmonella enterica serovar Enteritidis requires a virulence-factor-dependent increase in epithelial oxygenation, which drives pathogen expansion by aerobic respiration. Co-infection experiments with an Escherichia coli strain carrying an oxygen-sensitive reporter suggest that S.

Proteomic Profiling of During Host Infection Using Bio-Orthogonal Noncanonical Amino Acid Tagging (BONCAT).

and are the causative agents of melioidosis and glanders, respectively, and are often fatal to humans and animals. Owing to the high fatality rate, potential for spread by aerosolization, and the lack of efficacious therapeutics, and are considered biothreat agents of concern. In this study, we investigate the proteome of , a closely related surrogate for the two more virulent species, during infection of host cells, and compare to that of in culture.

Identification of a U/Zn/Cu responsive global regulatory two-component system in Caulobacter crescentus.

Despite the well-known toxicity of uranium (U) to bacteria, little is known about how cells sense and respond to U. The recent finding of a U-specific stress response in Caulobacter crescentus has provided a foundation for studying the mechanisms of U- perception in bacteria. To gain insight into this process, we used a forward genetic screen to identify the regulatory components governing expression of the urcA promoter (P ) that is strongly induced by U.