Biology subjects

Aumiller, K.

Publications and source records attributed to Aumiller, K..

3 recordsLinked to original sources

bioRxiv2024

A conserved genetic basis for commensal-host specificity through live imaging of colonization dynamics

Animals throughout the metazoa selectively acquire specific symbiotic gut bacteria from their environment that aid host fitness. Current models of colonization suggest these bacteria use weakly specific receptors to stick to host tissues and that colonization results when they stick in a region of the host gut that overlaps with their nutritional niche. An alternative model is that unique receptor-ligand binding interactions provide specificity for target niches. Here we use live imaging of individual symbiotic bacterial cells colonizing the gut of living Drosophila melanogaster to show that Lactiplantibacillus plantarum specifically recognizes a distinct physical niche in the host gut. We find that recognition is controlled by a colonization island that is widely conserved in commensals and pathogens from the Lactobacillales to the Clostridia. Our findings indicate a genetic mechanism of host specificity that is broadly conserved. One-Sentence SummaryHost-symbiont specificity is encoded by a conserved colonization island that provides molecular precision to host niche access.

microbiology↗

bioRxiv2021

A gut commensal niche regulates stable association of a multispecies microbiota

The intestines of animals are typically colonized by a complex, relatively stable microbiota that influences health and fitness, but the underlying mechanisms of colonization remain poorly understood. As a typical animal, the fruit fly, Drosophila melanogaster, is associated with a consistent set of commensal bacterial species, yet the reason for this consistency is unknown. Here, we use gnotobiotic flies, microscopy, and microbial pulse-chase protocols to show that a commensal niche exists within the proventriculus region of the Drosophila foregut that selectively binds bacteria with exquisite strain-level specificity. Primary colonizers saturate the niche and exclude secondary colonizers of the same strain, but initial colonization by Lactobacillus physically remodels the niche to favor secondary colonization by Acetobacter. Our results provide a mechanistic framework for understanding the establishment and stability of an intestinal microbiome. One-Sentence SummaryA strain-specific set of bacteria inhabits a defined spatial region of the Drosophila gut that forms a commensal niche.

microbiology↗

bioRxiv2021

A chemically-defined growth medium to support Lactobacillus-Acetobacter community analysis

Lactobacilli and acetobacters are commercially important bacteria that often form communities in natural fermentations, including food preparations, spoilage, and in the digestive tract of Drosophila melanogaster fruit flies. Communities of these bacteria are widespread and prolific, despite numerous strain-specific auxotrophies, suggesting they have evolved nutrient interdependencies that regulate their growths. The use of a chemically-defined medium (CDM) supporting the growth of both groups of bacteria would greatly facilitate identification of the precise metabolic interactions between these two groups of bacteria. While numerous such media have been developed that support specific strains of lactobacilli and acetobacters, there has not been a medium formulated to support both genera. We developed such a medium, based on a previous Lactobacillus CDM, by modifying the nutrient abundances to improve growth of both groups of bacteria. We further simplified the medium by substituting casamino acids for individual amino acids and the standard Wolfes vitamins and mineral stocks for individual vitamins and minerals, resulting in a reduction from 40 to 8 stock solutions. The new CDM and variations of it support robust growth of lactobacilli and acetobacters. We provide the composition and an example of its use to measure nutritional interactions.

microbiology↗