Modulation of sensory perception by hydrogen peroxide enables Caenorhabditis elegans to find a niche that provides both food and protection from hydrogen peroxide
Fig 7
C. elegans assess faithfully the threat of hydrogen peroxide via sensory perception.
H2O2 and bacteria trigger opposite locomotory behaviors through their action on the nematode’s sensory neurons. H2O2 and bacteria attenuate each other’s effects: H2O2 prevents or weakens sensory perception of bacteria and some bacteria express enzymes that degrade H2O2. The relative strength of this cross-inhibition leads to the differential sensory neuronal perception of H2O2 and bacteria, enabling the nematode to faithfully respond to the lethal threat of H2O2 by switching between locomotory behaviors that promote attraction or avoidance. H2O2 excites the ASJ sensory neurons that promote H2O2 avoidance. Bacteria excite, in a H2O2-sensitive manner, the ASEL, ADF, AWA, and BAG sensory neurons that promote attraction and inhibit the ASH and ASK neurons that promote aversion. The diminished sensory perception of bacteria unable to degrade H2O2 in the environment represents a general mechanism enabling nematodes to leave food patches that do not express sufficient levels of H2O2-degrading enzymes.
