title: Effect of simultaneous presentation of multiple attractants on chemotactic response of the nematode Caenorhabditis elegans.
abstract: Chemotactic behaviors of the nematode, Caenorhabditis elegans in response to chemical attractants, such as water-soluble sodium acetate and an odorant diacetyl, which were sensed by different sensory neurons, were investigated using various concentrations of these chemical attractants. In the presence of only sodium acetate attractant, the fraction of animals that were roaming around the outside of the attractant and original locations correlated negatively with the chemotaxis index for sodium acetate (P < 0.01). In contrast, the fraction of animals that remained in the original location correlated negatively with the chemotaxis index in the presence of only diacetyl attractant (P < 0.05). These results indicate that the manner of chemotaxis responses differs between sodium acetate and diacetyl. In order to investigate the effect of multiple attractants on chemotactic behaviors, the chemotactic responses to simultaneous presentation of sodium acetate and diacetyl were examined. The fraction of animals that gathered at the 0.7 M sodium acetate location was greater than that at the 0.1% diacetyl location in the presence of both attractants (P < 0.05), although the chemotaxis indexes for 0.7 M sodium acetate and 0.1% diacetyl were similar in the presence of a single attractant. On the other hand, the fraction of animals that gathered at the 0.02% diacetyl location was greater than that at the 0.1M sodium acetate location in the presence of both attractants (P < 0.05), although the chemotaxis indexes for 0.02% diacetyl and 0.1M sodium acetate were similar in the presence of a single attractant. These results suggest the existence of excitatory and/or inhibitory connections in the neuronal circuit for attractant selection, and that the efficacy of these connections may change according to the concentrations of both attractants.
authors.affiliation: Laboratory of Bioscience, Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsuura
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Oikawa
authors.forename: Tokumitsu
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Shingai
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D002630:Chemotactic Factors; D002633:Chemotaxis / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D009475:Neurons, Afferent / Q000502:physiology*
chemical_list: D002630:Chemotactic Factors