title: Serotonin-dependent kinetics of feeding bursts underlie a graded response to food availability in C. elegans.
abstract: Animals integrate physiological and environmental signals to modulate their food uptake. The nematode C. elegans, whose food uptake consists of pumping bacteria from the environment into the gut, provides excellent opportunities for discovering principles of conserved regulatory mechanisms. Here we show that worms implement a graded feeding response to the concentration of environmental bacteria by modulating a commitment to bursts of fast pumping. Using long-term, high-resolution, longitudinal recordings of feeding dynamics under defined conditions, we find that the frequency and duration of pumping bursts increase and the duration of long pauses diminishes in environments richer in bacteria. The bioamine serotonin is required for food-dependent induction of bursts as well as for maintaining their high rate of pumping through two distinct mechanisms. We identify the differential roles of distinct families of serotonin receptors in this process and propose that regulation of bursts is a conserved mechanism of behaviour and motor control.
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.|FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Kyung Suk
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Shachar
authors.initials: S
authors.lastname: Iwanir
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Ronen B
authors.initials: RB
authors.lastname: Kopito
authors.affiliation: Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Scholz
authors.affiliation: FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Calarco
authors.affiliation: Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.|The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: David
authors.initials: D
authors.lastname: Biron
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.|FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Erel
authors.initials: E
authors.lastname: Levine
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001419:Bacteria / Q000254:growth & development*; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D004783:Environmental Microbiology; D005247:Feeding Behavior / Q000502:physiology*; D007700:Kinetics; D009154:Mutation; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D011985:Receptors, Serotonin; D012701:Serotonin