Exploring Effects of C. elegans Protective Natural Microbiota on Host Physiology

Abstract

The Caenorhabditis elegans natural microbiota was described only recently. Thus, our understanding of its effects on nematode physiology is still in its infancy. We previously showed that the C. elegans natural microbiota isolates Pseudomonas lurida MYb11 and P. fluorescens MYb115 protect the worm against pathogens such as Bacillus thuringiensis (Bt). However, the overall effects of the protective microbiota on worm physiology are incompletely understood. Here, we investigated how MYb11 and MYb115 affect C. elegans lifespan, fertility, and intestinal colonization. We further studied the capacity of MYb11 and MYb115 to protect the worm against purified Bt toxins. We show that while MYb115 and MYb11 affect reproductive timing and increase early reproduction only MYb11 reduces worm lifespan. Moreover, MYb11 aggravates killing upon toxin exposure. We conclude that MYb11 has a pathogenic potential in some contexts. This work thus highlights that certain C. elegans microbiota members can be beneficial and costly to the host in a context-dependent manner, blurring the line between good and bad.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

“…To determine bacterial growth in mono- and co-culture either in the presence or absence of supplementation, similarly to the computational section, the two naturally associated Caenorhabditis elegans microbiota isolates Pseudomonas lurida MYb11 and Ochrobactrum vermis MYb71 were used. Fluorescently labeled MYb11::dTomato 21 and MYb71::GFP were used to distinguish the two bacterial species in a mixed community. For comparison, reverse labels were also tested, using MYb71::dTomato and MYb11::sfGFP, to ensure no impact of the fluorescent label (Supplementary Figure S2).…”

“…Fluorescent colonies of MYb71 were verified by PCR and sequencing using 2 pairs of MYb71-specific primers to the glmS gene region: (i) oDB097 (5’-CGCTCTGATCGATGAGACC-3’) and oDB098 (5’-TTGCGCGGCTGRTCGAC-3’), and (ii) oDB097 and a transposon WP11 primer (5’-CACGCCCCTCTTTAATACGA-3’) 49 . MYb11::sfGFP was similarly confirmed by PCR and sequencing, following our previous protocol 21 .…”

“…Hence, to overcome these limitations in current microbiome manipulation approaches, we need to focus on prebiotics with well-controlled modes of action (e.g., microbial pathways of prebiotics degradation) that preferentially modulate the abundance of resident microbial species. Since mechanisms of pathogenicity are often complex and context specific 21 , it is preferred if these species are native to the microbiome of the host, as unwanted side-effects due to the introduction of foreign bacterial species might be avoided. Within this work, we will refer to prebiotics that specifically modulate the abundance of selected bacterial strains within the microbiome of a specific host as “precision prebiotics”.…”

Microbiome Signature of Endophytes in Wheat Seed Response to Wheat Dwarf Bunt Caused by Tilletia controversa Kühn

“…significantly inhibited the germination rate of T. controversa and was previously reported to inhibit the growth of phytopathogenic fungi, such as A. flavus and F. verticillioides ( 57 ). P. lurida can protect Caenorhabditis elegans against pathogens such as Bacillus thuringiensis ( 58 ). C. flaccumfaciens has been reported against Erwinia amylovora ( 59 ).…”

Methods to extract and study the biological effects of murine gut microbiota using Caenorhabditis elegans as a screening host

“…In recent years, Caenorhabditis elegans has emerged as a powerful tool to understand the complexity of microbiota-host interactions [10][11][12][13]. C. elegans is a transparent nematode worm used as a model organism to study all aspects of animal development, metabolism, behavior, and lifespan due to functional and genetic similarities with more complex organisms, including mammals [14].…”