Biology subjects

Gervais, H.

Publications and source records attributed to Gervais, H..

4 recordsLinked to original sources

bioRxiv2020

Metabolic cooperation among commensal bacteria supports Drosophila juvenile growth under nutritional stress

The gut microbiota shapes animal growth trajectory in stressful nutritional environments, but the molecular mechanisms behind such physiological benefits remain poorly understood. The gut microbiota is mostly composed of bacteria, which construct metabolic networks among themselves and with the host. Until now, how the metabolic activities of the microbiota contribute to host juvenile growth remains unknown. Here, using Drosophila as a host model, we report that two of its major bacterial partners, Lactobacillus plantarum and Acetobacter pomorum engage in a beneficial metabolic dialogue that boosts host juvenile growth despite nutritional stress. We pinpoint that lactate, produced by L. plantarum, is utilized by A. pomorum as an additional carbon source, and A. pomorum provides essential amino-acids and vitamins to L. plantarum. Such bacterial cross-feeding provisions a set of anabolic metabolites to the host, which may foster host systemic growth despite poor nutrition. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=165 SRC="FIGDIR/small/119370v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1923739org.highwire.dtl.DTLVardef@679795org.highwire.dtl.DTLVardef@110cbecorg.highwire.dtl.DTLVardef@1bc0804_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIL. plantarum feeds lactate to A. pomorum C_LIO_LIA. pomorum supplies essential amino acids and vitamins to L. plantarum C_LIO_LIMicrobiota metabolic dialogue boosts Drosophilas larval growth C_LIO_LILactate utilization by Acetobacter releases anabolic metabolites to larvae C_LI

microbiology↗

bioRxiv2019

Commensal bacteria differentially shape the nutritional requirements of Drosophila during juvenile growth

The interplay between nutrition and the microbial communities colonizing the gastro-intestinal tract (i.e. gut microbiota) determines juvenile growth trajectory. Nutritional deficiencies trigger developmental delays, and an immature gut microbiota is a hallmark of pathologies related to childhood undernutrition. However, how commensal bacteria modulate the impact of nutrition on juvenile growth remains elusive. Here, using gnotobiotic Drosophila melanogaster larvae independently associated with two model commensal bacterial strains, Acetobacter pomorumWJL (ApWJL) and Lactobacillus plantarumNC8 (LpNC8), we performed a large-scale, systematic nutritional screen based on larval growth in 40 different and precisely controlled nutritional environments. We combined these results with genome-based metabolic network reconstruction to define the biosynthetic capacities of Drosophila germ-free (GF) larvae and its two commensal bacteria. We first established that ApWJL and LpNC8 differentially fulfills the nutritional requirements of the ex-GF larvae and parsed such difference down to individual amino acids, vitamins, other micronutrients and trace metals. We found that Drosophila commensal bacteria not only fortify the hosts diet with essential nutrients but, in specific instances, functionally compensate for host auxotrophies, by either providing a metabolic intermediate or nutrient derivative to the host or by uptaking, concentrating and sparing contaminant traces of micronutrients. Our systematic work reveals that, beyond the molecular dialogue engaged between the host and its commensal partners, Drosophila and its facultative bacterial partners establish an integrated nutritional network relying on nutrients sparing and utilization.

physiology↗

bioRxiv2017

Bacterial adaptation to host diet is a key evolutionary force shaping host-microbe symbiosis

Life on Earth was dominated by bacteria for billions of years1. About 600 million years ago, animal life emerged and micro-organisms played a crucial role in shaping animal development, physiology and evolution2-4. The two partners committed to a symbiotic relationship that persists in nearly all animals today. Such beneficial interactions are pervasive throughout nature and have been extensively characterized5,6. However, the ecological and evolutionary forces that drive the emergence and evolution of the symbiont benefits to their animal hosts remain largely elusive. Here we show that the host nutritional environment, instead of the host, is a predominant driving force in this evolutionary process and we identify a mechanism resulting from the bacterial adaptation to the diet, which confers improved functional benefit to the host. By applying experimental evolution to a model of host-bacteria beneficial symbiosis: Drosophila melanogaster associated with Lactobacillus plantarum, one of its growth promoting symbiotic bacteria7,8, we found that the de novo mutations in the same acetate kinase (ackA) locus invariably emerge first, rapidly become fixed, and such evolution occurs with or without the host. Furthermore, we demonstrate that ackA mutations trigger the increased production of N-acetyl-glutamine, which is sufficient to confer improved host growth capabilities to the evolved bacterial strains. Our study therefore identifies a specific mechanism by which a symbiotic bacterium increases its benefit to its animal host and reveals that adaptation to the host diet is a foremost step in the determination of the evolutionary course of symbiosis between an animal and its gut microbes.

evolutionary biology↗

bioRxiv2017

D-Alanine esterification of teichoic acids contributes to Lactobacillus plantarum mediated intestinal peptidase expression and Drosophila growth promotion upon chronic undernutrition

The microbial environment influence animal physiology. However, the underlying molecular mechanisms of such functional interactions are largely undefined. Previously, we showed that upon chronic undernutrition, strains of Lactobacillus plantarum, a dominant commensal partner of Drosophila, promote host juvenile growth and maturation partly via enhanced expression of intestinal peptidases. By screening a transposon insertion library of Lactobacillus plantarum in gnotobiotic Drosophila larvae, we identify a bacterial cell wall modifying machinery encoded by the pbpX2-dltXABCD operon that is critical to enhance host digestive capabilities and promote growth and maturation. Deletion of this operon leads to bacterial cell wall alteration with a complete loss of teichoic acids D-alanylation. We thus conclude that teichoic acids modifications participate in commensal-host interactions and specifically, D-alanine esterification of teichoic acids contributes to optimal L. plantarum mediated intestinal peptidase expression and Drosophila juvenile growth upon chronic undernutrition.\n\nHighlights- LpNC8 mutant library screening identifies genes affecting Drosophila growth promotion.\n- pbpX2-dlt operon is required for D-alanylation of teichoic acids and Drosophila growth.\n- Deleting the pbpX2-dlt operon alters host intestinal peptidase expression.\n- Peptidoglycan and pbpX2-dlt dependent signals are required for LpNC8 mediated growth promotion.\n\n\neTOC blurbAnimals establish interactions with their microbial communities that shape many aspects of their physiology including juvenile growth. However, the underlying molecular mechanisms are largely undefined. Matos et al. reveal that bacterial teichoic acids modifications contribute to host juvenile growth promotion.

microbiology↗