Impact of a Complex Food Microbiota on Energy Metabolism in the Model OrganismCaenorhabditis elegans

Abstract

The nematode Caenorhabditis elegans is widely used as a model system for research on aging, development, and host-pathogen interactions. Little is currently known about the mechanisms underlying the effects exerted by foodborne microbes. We took advantage of C. elegans to evaluate the impact of foodborne microbiota on well characterized physiological features of the worms. Foodborne lactic acid bacteria (LAB) consortium was used to feed nematodes and its composition was evaluated by 16S rDNA analysis and strain typing before and after colonization of the nematode gut. Lactobacillus delbrueckii, L. fermentum, and Leuconostoc lactis were identified as the main species and shown to display different worm gut colonization capacities. LAB supplementation appeared to decrease nematode lifespan compared to the animals fed with the conventional Escherichia coli nutrient source or a probiotic bacterial strain. Reduced brood size was also observed in microbiota-fed nematodes. Moreover, massive accumulation of lipid droplets was revealed by BODIPY staining. Altered expression of nhr-49, pept-1, and tub-1 genes, associated with obesity phenotypes, was demonstrated by RT-qPCR. Since several pathways are evolutionarily conserved in C. elegans, our results highlight the nematode as a valuable model system to investigate the effects of a complex microbial consortium on host energy metabolism.

Virulence behavior of uropathogenic Escherichia coli strains in the host model Caenorhabditis elegans

“…The numbers of live E. coli bacteria in the worm intestine were determined after 48 hr of infection, as described (Zanni et al, ). Briefly, for each sample, 10 infected worms were washed three times with 500 μl of M9 buffer to remove bacteria on nematode surface.…”

“…The numbers of live E. coli bacteria in the worm intestine were determined after 48 hr of infection, as described (Zanni et al, 2015).…”

A Combined Proteomics, Metabolomics and In Vivo Analysis Approach for the Characterization of Probiotics in Large-Scale Production

“…Worms were fed with US-7 or IT-3 sample. Each product, suspended in sterile H2Odd, corresponding to 10 mg of bacterial cells in 25 µL, was spread on 3.5 cm diameter NGM plates, as described in [9].…”

“…Proteomics platforms may hence represent a precious tool in high-throughput profiling of probiotic formulations. Proteomic analyses has been successfully applied for the identification of proteins involved in probiotic interaction with the environment, including behavior in food matrix and ability to survive in the host intestine, as well as in detecting protein modifications that affect probiotic efficacy [8,9]. Furthermore, when comparing multiple strain formulations, the species-specificity of protein sequences allows us to assign the differential proteins to individual strains.…”

Modeling Host-Microbiome Interactions in Caenorhabditis elegans

“…A consortium of Lactobacillus delbrueckii, Lactobacillus fermentum, and Leuconostoc lactis affect energy metabolism in C. elegans. The lactic acid bacteria (LAB) microbial consortia decrease worm lifespan when compared with animals fed with conventional E. coli, cause accumulation of lipid droplets, and alter expression of obesity phenotype genes, nhr-49, pept-1, and tub-1 (Zanni et al, 2015).…”