Regulation of Distinct Attractive and Aversive Mechanisms Mediating Benzaldehyde Chemotaxis in Caenorhabditis elegans
Abstract
Olfactory-mediated chemotaxis in nematodes provides a relatively simple system to study biological mechanisms of information processing. Analysis of the kinetics of chemotaxis in response to 100% benzaldehyde revealed an initial attractive response that is followed by a strong aversion to the odorant. We show that this behavior is mediated by two genetically separable attraction- and aversion-mediating response pathways. The attraction initially dominates behavior but with prolonged exposure habituation leads to a behavioral change, such that the odorant becomes repulsive. This olfactory habituation is susceptible to dishabituation, thereby re-establishing the attractive response to the odorant. Re-examination of the putative olfactory adaptation mutant adp-1(ky20)revealed that the phenotype observed in this line is due to a supersensitivity to a dishabituating stimulus, rather than a defect in the adaptation to odorants per se. A modified benzaldehyde chemotaxis assay was developed and used for the isolation of a mutant with a specific defect in habituation kinetics, expressed as a persistence of the attractive response.
Footnotes
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↵1 Corresponding author.
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E-MAIL bill.nuttley{at}utoronto.ca; FAX (416) 978-3844.
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Article and publication are at www.learnmem.org/cgi/doi/10.1101/lm.36501.
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- Received August 31, 2000.
- Accepted March 13, 2001.
- Cold Spring Harbor Laboratory Press