Metabolic cross-feeding in imbalanced diets allows gut microbes to improve reproduction and alter host behaviour

Abstract

The impact of commensal bacteria on the host arises from complex microbial-diet-host interactions. Mapping metabolic interactions in gut microbial communities is therefore key to understand how the microbiome influences the host. Here we use an interdisciplinary approach including isotope-resolved metabolomics to show that in Drosophila melanogaster, Acetobacter pomorum (Ap) and Lactobacillus plantarum (Lp) a syntrophic relationship is established to overcome detrimental host diets and identify Ap as the bacterium altering the host's feeding decisions. Specifically, we show that Ap uses the lactate produced by Lp to supply amino acids that are essential to Lp, allowing it to grow in imbalanced diets. Lactate is also necessary and sufficient for Ap to alter the fly's protein appetite. Our data show that gut bacterial communities use metabolic interactions to become resilient to detrimental host diets. These interactions also ensure the constant flow of metabolites used by the microbiome to alter reproduction and host behaviour.

Gut microbiome modulates Drosophila aggression through octopamine signaling

“…Treatment with heat-killed bacteria. Treatment with heat-killed bacteria was performed with modification as previously described 61,62 . Briefly, the bacterial load (CFUs) in vials was assessed following bacterial inoculation in three independent experiments.…”

Probiotics Improve Eating Disorders in Mandarin Fish (Siniperca chuatsi) Induced by a Pellet Feed Diet via Stimulating Immunity and Regulating Gut Microbiota

“…L. plantarum is a rod-shaped, gram-positive, non-spore-forming facultative anaerobic bacteria that belong to the Lactobacillaceae family. It has been reported to reduce the adhesion and growth of harmful bacteria via producing antimicrobial compounds [41][42][43], improve the growth and feed efficiency of carp (Catla catla) [44,45], grouper (Epinephelus coioides) [46], tilapia (Oreochromis niloticus) [47], shrimp (Penaeus indicus) [48] and pacific white shrimp (Litopenaeus vannamei) [49] and enhance the immunity and survival rate of pacific white shrimp (Litopenaeus vannamei) [50,51] and tilapia [52]. Previous studies have shown that L. rhamnose can affect the appetite and energy metabolism of the host by regulating the expression of γ-aminobutyric acid and its receptors in the central nervous system [53][54][55][56][57].…”

Visualization of endogenous gut bacteria in Drosophila melanogaster using fluorescence in situ hybridization

“…This has multiple advantages such as the analysis of a potential preference of the one or the other bacterial species for a certain gut compartment or a co-occurrence of certain bacteria in the form of consortia. As an exchange of metabolites between gut microbiome members of Drosophila was demonstrated [ 28 , 29 ] such a co-occurrence seems likely. When, where and how the bacteria interact or whether the metabolites instead are exchanged via a long distance, however, is not yet fully understood.…”