title: Experience-dependent modulation of C. elegans behavior by ambient oxygen.
abstract: BACKGROUND
  Ambient oxygen (O2) influences the behavior of organisms from bacteria to man. In C. elegans, an atypical O2 binding soluble guanylate cyclase (sGC), GCY-35, regulates O2 responses. However, how acute and chronic changes in O2 modify behavior is poorly understood.
  
  
  RESULTS
  Aggregating C. elegans strains can respond to a reduction in ambient O2 by a rapid, reversible, and graded inhibition of roaming behavior. This aerokinetic response is mediated by GCY-35 and GCY-36 sGCs, which appear to become activated as O2 levels drop and to depolarize the AQR, PQR, and URX neurons. Coexpression of GCY-35 and GCY-36 is sufficient to transform olfactory neurons into O2 sensors. Natural variation at the npr-1 neuropeptide receptor alters both food-sensing and O2-sensing circuits to reconfigure the salient features of the C. elegans environment. When cultivated in 1% O2 for a few hours, C. elegans reset their preferred ambient O2, seeking instead of avoiding 0%-5% O2. This plasticity involves reprogramming the AQR, PQR, and URX neurons.
  
  
  CONCLUSIONS
  To navigate O2 gradients, C. elegans can modulate turning rates and speed of movement. Aerotaxis can be reprogrammed by experience or engineered artificially. We propose a model in which prolonged activation of the AQR, PQR, and URX neurons by low O2 switches on previously inactive O2 sensors. This enables aerotaxis to low O2 environments and may encode a "memory" of previous cultivation in low O2.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.
authors.forename: Benny H H
authors.initials: BH
authors.lastname: Cheung
authors.forename: Merav
authors.initials: M
authors.lastname: Cohen
authors.forename: Candida
authors.initials: C
authors.lastname: Rogers
authors.forename: Onder
authors.initials: O
authors.lastname: Albayram
authors.forename: Mario
authors.initials: M
authors.lastname: de Bono
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002633:Chemotaxis / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology; D006162:Guanylate Cyclase / Q000378:metabolism*; D008124:Locomotion / Q000502:physiology; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D018034:Olfactory Receptor Neurons / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D017476:Receptors, Neuropeptide Y / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C468272:NPR-1 protein, C elegans; D017476:Receptors, Neuropeptide Y; C488166:GCY-35 protein, C elegans; D006162:Guanylate Cyclase; D010100:Oxygen