Plasticity of pheromone-mediated avoidance behavior in C. elegans

Abstract

Caenorhabditis elegans secretes a complex cocktail of small chemicals collectively called ascaroside pheromones which serves as a chemical language for intra-species communication. Subsets of ascarosides have been shown to mediate a broad spectrum of C. elegans behavior and development, such as gender-specific attraction, repulsion, aggregation, olfactory plasticity, and dauer formation. Recent studies show that specific components of ascarosides elicit a rapid avoidance response that allows animals to avoid predators and escape from unfavorable conditions. Moreover, this avoidance behavior is modulated by external conditions, internal states, and previous experience, indicating that pheromone avoidance behavior is highly plastic. In this review, we describe molecular and circuit mechanisms underlying plasticity in pheromone avoidance behavior which pave a way to better understanding circuit mechanisms underlying behavioral plasticity in higher animals, including humans.

Social and sexual behaviors in C. elegans: the first fifty years

“…Ascarosides can have multiple behavioral effects on worms, inducing aggregation, attraction/retention, aversion, and promotion of foraging, depending on their chemical structures, concentrations, and interactions; moreover, the response of the receiver depends on its sex, stage, previous experience, genetic background, and other factors (Aprison and Ruvinsky, 2019;Borne et al, 2017;Dong et al, 2016;Fagan et al, 2018;Greene et al, 2016;Hong et al, 2017;Izrayelit et al, 2012;Jang et al, 2012;Lee et al, 2019;Macosko et al, 2009;Pungaliya et al, 2009;Ryu et al, 2018;Scott et al, 2017;Sims et al, 2016;Srinivasan et al, 2008;Srinivasan et al, 2012;von Reuss et al, 2012;. (Plasticity in the aversive responses to ascarosides is the subject of another review in this issue (Cheon et al, 2020).) Furthermore, exposure to ascarosides modulates other worm sensory behaviors (Wu et al, 2019;Yamada et al, 2010;Yoshimizu et al, 2018) and can also cause physiological changes, including altered germline proliferation and germ cell function, increased stress resistance and lifespan, and changes in lipid metabolism Ruvinsky, 2015, 2016;Hussey et al, 2017;McKnight et al, 2014).…”

Neuromodulators: an essential part of survival

“…The profound influence of neuromodulators on behavior, metabolism, and overall physiology is a common thread throughout this issue (Cheon, Hwang, & Kim, 2020;Honer et al, 2020;Kim & Flavell, 2020;Kim, Lee, Kim, & Lee, 2020;Liang, McKinnon, & Rankin, 2020;Liu & Zhang, 2020;Muirhead & Srinivasan, 2020;Prahlad, 2020;Srinivasan, 2020;Takeishi, Takagaki, & Kuhara, 2020;Yang, Lee, Yim, & Lee, 2020). In this perspective, we will focus on the roles of monoamines and neuropeptides in C. elegans survival.…”

“…In this issue, Kim and Flavell (2020) highlight the recent findings from the Sengupta lab (O'Donnell, Fox, Chao, Schroeder, & Sengupta, 2020) on how OA produced by commensal bacteria alters C. elegans behavior and internal state. Cheon et al (2020; this issue) and Muirhead and Srinivasan (2020; this issue) also review how starved larvae produce the OA-like small molecule osas#9, an ascaroside component of the worm-secreted pheromone blend, which is then sensed by nociceptive ASH neurons in adults to initiate their avoidance behavior (Chute et al, 2019).…”

“…For example, there are ILPs that sometimes behave like the DAF-2 receptor in one context and opposite from DAF-2 in another context (Fernandes de Abreu et al, 2014). The articles in this collection discuss the roles of ILPs in temperature-sensing (see Takeishi, Takagaki, & Kuhara, 2020), in context-dependent avoidance behaviors (see Cheon, Hwang, & Kim, 2020;Kim & Flavell, 2020), in neuroprotection (see Liang, McKinnon, & Rankin, 2020), the dauer program (see Yang et al, 2020), and longevity (see .…”

Small flexible automated system for monitoring Caenorhabditis elegans lifespan based on active vision and image processing techniques

“…It should be pointed out that worm behaviour might be modified due to isolation in a small space 14 , and this set up does not allow long-trajectory analysis. By contrast, in our system, worms are inspected in standard Petri plates measuring 55 mm in diameter, holding 10-15 individuals and thus permitting more complex social behaviour 15 , 16 .…”