Using an unusual model organism for the field, C. elegans, scientists could make great strides investigating depression, schizophrenia, and insomnia in humans, according to an article released on August 4, 2008 in the open access journal PLoS Biology.

Caenorhabditis elegans is a microscopic worm often used in developmental biology research. They have no eyes, but respond to certain kinds of light by moving away. Led by Kenneth Miller, Ph.D. of the Oklahoma Medical Research Foundation, a team of researchers used C. elegans to examine the family of proteins associated with light recognition in animals.

They began working with worms paralyzed by a specific gene mutation. This mutation was shown previously by this team to disrupt a network of pathways that controls communications between neurons through their synapses. These, in fact, are very similar to the neuronal system in humans. Notably, they showed that exposing paralyzed worms to ultraviolet light caused the worms to return to normal levels of movement.

Miller describes this situation: “Without signals from this network, neurons cannot talk to each other or to muscle cells to produce movement, so the mutants just lie paralyzed on the culture plate even if you poke and prod them.” However, when short wavelength ultraviolet light was exposed to the worms, signal was renewed, which allowed the animals to move again. This was hypothesized to be an adaptation to prevent the worms from dying when exposed to this light. Miller explains why this is vital: “When you are only a few cells thick, getting a sunburn is fatal.”

This behavior has been linked to a sensory molecule encoded for by the gene LITE-1. According to Miller, this is a novel development: “This sensor doesn’t resemble any other light sensors previously discovered.” Humans do not have this ultraviolet light sensor, but this discovery gives scientists a new potential tool for understanding how our nerve cells communicate to produce perceptions, behaviors, and memories. Additionally, it could help us learn about disorders.

The implications on neuroscience and psychology are potentially enormous. “That doesn’t mean shining an ultraviolet light on people in wheelchairs will suddenly allow them to walk,” Miller said. “But it does give us a tool that we can use to solve the mysteries of nerve cell communication and could ultimately help us understand the biology of everything from sleep and memory to depression.”

He finally points out that this research is still in its infancy, but he has much optimism for this direction of research. “We’re a long way from any treatments based on this research, but I think
we’ve opened up a door that we didn’t know was there before… There’s a lot of work left to be done, but I’m excited to see where this discovery leads us.”

About PLoS Biology

PLoS Biology is an open-access, peer-reviewed general biology journal published by the Public Library of Science (PLoS), a nonprofit organization of scientists and physicians committed to making the world’s scientific and medical literature a public resource. New articles are published online weekly; issues are published monthly. For more information, visit http://www.plosbiology.org

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world’s scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org

A novel molecular solution for ultraviolet light detection in Caenorhabditis elegans.
Edwards SL, Charlie NK, Milfort MC, Brown BS, Gravlin CN, et al.
PLoS Biol 6(8): e198.
doi:10.1371/journal.pbio.0060198
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Written by Anna Sophia McKenney