Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria

Abstract

Caenorhabditis elegans is one of the major model systems in biology based on advantageous properties such as short life span, transparency, genetic tractability and ease of culture using an Escherichia coli diet. In its natural habitat, compost and rotting plant material, this nematode lives on bacteria. However, C. elegans is a predator of bacteria, but can also be infected by nematopathogenic coryneform bacteria such Microbacterium and Leucobacter species, which display intriguing and diverse modes of pathogenicity. Depending on the nematode pathogen, aggregates of worms, termed worm-stars, can be formed, or severe rectal swelling, so-called Dar formation, can be induced. Using the human and animal pathogens Corynebacterium diphtheriae and Corynebacterium ulcerans as well as the non-pathogenic species Corynebacterium glutamicum, we show that these coryneform bacteria can also induce star formation slowly in worms, as well as a severe tail-swelling phenotype. While C. glutamicum had a significant, but minor influence on survival of C. elegans, nematodes were killed after infection with C. diphtheriae and C. ulcerans. The two pathogenic species were avoided by the nematodes and induced aversive learning in C. elegans.

Insight of Genus Corynebacterium: Ascertaining the Role of Pathogenic and Non-pathogenic Species

“…In addition, they observed that both non-toxigenic and toxigenic strain of C. diphtheriae (lack pili) aggravated the death of the nematode comparing with the control NCTC13129, toxigenic and piliated strain (Broadway et al, 2013 ). Recently, a work using the same model, investigated other characteristics related with the pathogenicity of C. diphtheriae, C.ulcerans, and C. glutamicum , in addition of pili and nematode killing analysis (Antunes et al, 2017 ).…”

First report of Meloidogyne naasi parasitizing turfgrass in Portugal

“…In Caenorhabditis elegans (Maupas, 1900) Dougherty, 1955, this aggregation may be caused by a Leucobacter pathogen, that causes adhesion at the tail spikes within minutes of exposure, followed by bacterial proliferation in the host and death of all trapped nematodes in 24 to 28 hr (Hodgkin et al, 2013). Artificial exposure of C. elegans to other coryneform bacteria of the genus Corynebacterium has resulted in a similar aggregation, leading to nematode lysis and death after 2 to 4 days incubation (Antunes et al, 2016). Although we cannot deny or confirm the cause since it was not an objective of this investigation, we cannot exclude the action of a similar organism.…”

Corynebacterium diphtheriae Virulence Analyses Using a Caenorhabditis elegans Model

“…For example, C. diphtheriae NCTC13129 was found to localize to the pharynx and hindgut of C. elegans N2. C. diphtheriae ISS3319 and C. diphtheriae DSM 43988 both colonize in the midgut, but not in the hindgut, of the nematode (Ott et al, 2012), whereas C. diphtheriae CDC-E8392 colonizes in the midgut and hindgut of the nematode in 48 hr, but only in the midgut of C. elegans N2 after chase with E. coli OP50 (Antunes et al, 2016). Thus, it is important to include some controls, such as C. diphtheriae NCTC13129, when setting up new experiments.…”