&lt;em&gt;C. elegans&lt;/em&gt; Chemotaxis Assay

Margie, Olivia; Palmer, Christopher; Chin-Sang, Ian D.

doi:10.3791/50069

Cited by 116 publications

(106 citation statements)

References 13 publications

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“…The plates were incubated at 23°C in darkness for one hour. IJs were counted in the positive (host side) and negative (blank side) zones and then scored using a chemotaxis index [26]. The assay format was adapted from Grewal et al [1994] [27].…”

Section: Methodsmentioning

confidence: 99%

A neuropeptide modulates sensory perception in the entomopathogenic nematode Steinernema carpocapsae

et al. 2017

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Entomopathogenic nematodes (EPNs) employ a sophisticated chemosensory apparatus to detect potential hosts. Understanding the molecular basis of relevant host-finding behaviours could facilitate improved EPN biocontrol approaches, and could lend insight to similar behaviours in economically important mammalian parasites. FMRFamide-like peptides are enriched and conserved across the Phylum Nematoda, and have been linked with motor and sensory function, including dispersal and aggregating behaviours in the free living nematode Caenorhabditis elegans. The RNA interference (RNAi) pathway of Steinernema carpocapsae was characterised in silico, and employed to knockdown the expression of the FMRFamide-like peptide 21 (GLGPRPLRFamide) gene (flp-21) in S. carpocapsae infective juveniles; a first instance of RNAi in this genus, and a first in an infective juvenile of any EPN species. Our data show that 5 mg/ml dsRNA and 50 mM serotonin triggers statistically significant flp-21 knockdown (-84%***) over a 48 h timecourse, which inhibits host-finding (chemosensory), dispersal, hyperactive nictation and jumping behaviours. However, whilst 1 mg/ml dsRNA and 50 mM serotonin also triggers statistically significant flp-21 knockdown (-51%**) over a 48 h timecourse, it does not trigger the null sensory phenotypes; statistically significant target knockdown can still lead to false negative results, necessitating appropriate experimental design. SPME GC-MS volatile profiles of two EPN hosts, Galleria mellonella and Tenebrio molitor reveal an array of shared and unique compounds; these differences had no impact on null flp-21 RNAi phenotypes for the behaviours assayed. Localisation of flp-21 / FLP-21 to paired anterior neurons by whole mount in situ hybridisation and immunocytochemistry corroborates the RNAi data, further suggesting a role in sensory modulation. These data can underpin efforts to study these behaviours in other economically important parasites, and could facilitate molecular approaches to EPN strain improvement for biocontrol.

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Section: Methodsmentioning

confidence: 99%

A neuropeptide modulates sensory perception in the entomopathogenic nematode Steinernema carpocapsae

et al. 2017

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“…A schematic of the four quadrants assay adapted from Margie et al (2013). For head avoidance assay, plates were divided into quadrants two test (A and D) and two controls (B and C).…”

Section: Figurementioning

confidence: 99%

Capsaicin and its analogues impede nocifensive response ofCaenorhabditis elegansto noxious heat

Nkambeu

Salem

Beaudry

2020

Preprint

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Capsaicin is the most abundant pungent molecule identified in red chili peppers, and it is widely used for food flavoring, in pepper spray for self-defense devices and recently in ointments for the relief of neuropathic pain. Capsaicin and several other related vanilloid compounds are secondary plant metabolites. Capsaicin is a selective agonist of the transient receptor potential channel, vanilloid subfamily member 1 (TRPV1). After exposition to vanilloid solution, C. elegans wild type (N2) and mutants were placed on petri dishes divided in quadrants for heat stimulation. Thermal avoidance index was used to phenotype each tested C. elegans experimental groups. The data revealed for the first-time that capsaicin can impede nocifensive response of C. elegans to noxious heat (32°C -35°C) following a sustained exposition. The effect was reversed 6h post capsaicin exposition.Additionally, we identified the capsaicin target, the C. elegans transient receptor potential channel OCR-2. Further experiments also undoubtedly revealed anti-nociceptive effect for capsaicin analogues, including ginger (Zingiber officinale) and turmeric (Curcuma longa) secondary metabolites.

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“…For this reason, we treated male and female isopods separately. In order to test whether secretions act as a chemoattractant for C. elegans, adult male and female isopods were washed, and the wash solution was used to test chemoattraction in standard assays (Bargmann et al, 1993;Margie et al, 2013). Post-hoc Tukey's Honest Significant Difference (HSD) tests showed that neither N2 nor PB306 had a statistically significant attractive or repulsive behavior towards any isopod wash (Figure 1, Supplemental Table 1, Supplemental Table 2).…”

Section: Elegans Adults Are Not Attracted To Compounds From the Tementioning

confidence: 99%

Caenorhabditis elegansnematodes are not attracted to the terrestrial isopodPorcellio scaber

Archer¹,

Deiparine²,

Andersen

2020

Preprint

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Phoresy is a behavior in which an organism, the phoront, travels from one location to another by 'hitching a ride' on the body of a host as it disperses. Some phoronts are generalists, taking advantage of any available host. Others are specialists and travel only when specific hosts are located using chemical cues to identify and move (chemotax) toward the preferred host. Free-living nematodes, like Caenorhabditis elegans, are often found in natural environments that contain terrestrial isopods and other invertebrates. Additionally, the C. elegans wild strain PB306 was isolated associated with the isopod Porcellio scaber. However, it is currently unclear if C. elegans is a phoront of terrestrial isopods, and if so, whether it is a specialist, generalist, or developmental stage-specific combination of both strategies. Because the relevant chemical stimuli might be secreted compounds or volatile odorants, we used different types of chemotaxis assays across diverse extractions of compounds or odorants to test whether C. elegans is attracted to P. scaber. We show that two different strains -the wild isolate PB306 and the laboratory-adapted strain N2 -are not attracted to P. scaber during either the dauer or adult life stages. Our results indicate that C. elegans was not attracted to chemical compounds or volatile odorants from P. scaber, providing valuable empirical evidence to suggest that any associations between these two species are likely opportunistic rather than specific phoresy.

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<em>C. elegans</em> Chemotaxis Assay

Cited by 116 publications

References 13 publications

A neuropeptide modulates sensory perception in the entomopathogenic nematode Steinernema carpocapsae

A neuropeptide modulates sensory perception in the entomopathogenic nematode Steinernema carpocapsae

Capsaicin and its analogues impede nocifensive response ofCaenorhabditis elegansto noxious heat

Caenorhabditis elegansnematodes are not attracted to the terrestrial isopodPorcellio scaber

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