Association with pathogenic bacteria affects life‐history traits and population growth inCaenorhabditis elegans

Abstract

Determining the relationship between individual life-history traits and population dynamics is an essential step to understand and predict natural selection. Model organisms that can be conveniently studied experimentally at both levels are invaluable to test the rich body of theoretical literature in this area. The nematode Caenorhabditis elegans, despite being a well-established workhorse in genetics, has only recently received attention from ecologists and evolutionary biologists, especially with respect to its association with pathogenic bacteria. In order to start filling the gap between the two areas, we conducted a series of experiments aiming at measuring life-history traits as well as population growth of C. elegans in response to three different bacterial strains: Escherichia coli OP50, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa PAO1. Whereas previous studies had established that the latter two reduced the survival of nematodes feeding on them compared to E. coli OP50, we report for the first time an enhancement in reproductive success and population growth for worms feeding on S. enterica Typhimurium. Furthermore, we used an age-specific population dynamic model, parameterized using individual life-history assays, to successfully predict the growth of populations over three generations. This study paves the way for more detailed and quantitative experimental investigation of the ecology and evolution of C. elegans and the bacteria it interacts with, which could improve our understanding of the fate of opportunistic pathogens in the environment.

The role of commensal microbes in the lifespan of Drosophila melanogaster

“…In particular, many studies have been initiated since the development and wide application of metagenomic sequencing analysis. In recent years, studies on the treatment and prevention of diseases through the production of changes in the host’s intestinal environment have been carried out, and many research teams have suggested that the intestinal microbiota can affect the host’s metabolic diseases [1], immune diseases [2], development [3, 4], reproduction [5], biorhythms [6], and even behavior and mood [7].…”

Sex matters: effects of sex and mating in the presence and absence of a protective microbe

“…We used an obligate outcrossing worm population (line EEVD00 from Henrique Teotonio (Theologidis et al, 2014)) where worms carry the fog-2(q71) mutation, preventing hermaphrodites from producing sperm (Theologidis et al, 2014). Worms were kept on Nematode Growth Medium (NGM) (Brenner, 1974), and fed non-pathogenic Salmonella , hereafter referred to as food (Desai et al, 2019; Diaz et al, 2015; Kloock et al, 2020). For pathogenic infection, the Gram positive Staphylococcus aureus strain MSSA476 (Holden et al, 2004) was used.…”

Sex Matters: Effects of Sex and Mating in the Presence and Absence of a Protective Microbe

“…We used an obligate outcrossing worm population [line EEVD00 from Henrique Teotonio (Theologidis et al, 2014)] where worms carry the fog-2(q71) mutation, preventing hermaphrodites from producing sperm (Theologidis et al, 2014). Worms were kept on Nematode Growth Medium (NGM) (Brenner, 1974), and fed with nonpathogenic Salmonella enterica, hereafter referred to as food (Diaz et al, 2015;Desai et al, 2019;Kloock et al, 2020). For pathogenic infection, the Gram-positive Staphylococcus aureus strain MSSA476 (Holden et al, 2004) was used.…”