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Light-sensitive neurons and channels mediate phototaxis in C. elegans
Alex Ward1, Jie Liu, Zhaoyang Feng
1Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, USA.
Nature Neuroscience
|July 8, 2008
Summary
The nematode worm C. elegans exhibits negative phototaxis, a light avoidance behavior crucial for survival. This light sensitivity is mediated by ciliary sensory neurons and cyclic nucleotide-gated channels, similar to vertebrates.
Area of Science:
- Neuroscience
- Sensory Biology
- Genetics
Background:
- Phototaxis, or light-guided movement, is common in animals with eyes.
- C. elegans, a soil-dwelling nematode, was thought to lack phototaxis due to its dark habitat and absence of eyes.
Purpose of the Study:
- To investigate the presence and mechanism of phototaxis in C. elegans.
- To identify the sensory neurons and molecular components involved in light detection.
Main Methods:
- Behavioral assays to observe C. elegans response to light stimuli.
- Genetic analysis to identify key genes and neurons.
- Electrophysiological recordings to study cellular responses to light.
Main Results:
- C. elegans exhibits negative phototaxis, moving away from light, which enhances survival.
- Ciliary sensory neurons were identified as photoreceptor cells.
- Light activates these neurons via cyclic guanosine monophosphate (cGMP)-sensitive cyclic nucleotide-gated (CNG) channels.
Conclusions:
- C. elegans possesses a previously unrecognized light sensory system.
- The phototransduction pathway involving cGMP and CNG channels is conserved between C. elegans and vertebrates.
- This suggests ancient origins of visual systems in bilaterian ancestors.
