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Sea slugs have a sleep cycle, too

Union Leader Correspondent

November 22. 2012 8:27PM

HENNIKER - What do the lion-hooded nudibranch and an average human being have in common? Well, just like the nudibranch, a fancy name for a sea slug, human beings wake up and go to sleep based on internal clocks.

Researchers at New England College are trying to find out how those clocks work.

Circadian rhythm, the daily cycle of waking and sleeping that humans and animals follow, has been studied for years, said Dr. Jim Newcomb, associate professor of biology at New England College.

Though scientists know that humans have an internal clock that, using the light as a cue, sets and resets itself to control things like falling asleep, the raising and lowering of our body temperatures from day to night, and the slowing of our heartbeats, they don't quite know how that internal clock works on a cellular level.

To try to figure that out, Newcomb has begun researching the lion-hooded nudibranch, a sea slug found in the kelp beds and eel grass that grows in the water along the Pacific coast. Though it may seem odd to study a slug to try to figure out how something in a human being works,

Newcomb said the nudibranch has a brain that's wired kind of like ours, only much, much simpler. Think of it as the difference between a Chevy built in 2012 and a 1957 Chevy. Both of them are propelled by motors, but the newer car, like the human brain, has a whole lot more going on. By studying the sea slug - the 57 Chevy in this analogy - Newcomb can isolate the clock and all its specific components in a way he couldn't with a human brain.

"Once we find out where the clock is, we can find out how that clock is telling that circuit in the slug that it's now time to swim," said Newcomb. "We can then take that simple system and extrapolate it to see how it works in humans."

Knowing how circadian rhythm works is important because the body's internal clock impacts everything from productivity at work to disease and disorders. Whether people follow their natural rhythms can impact their health, said Newcomb, but scientists don't yet know why folks who work the third shift are more likely to have heart attacks, or why flying to New Zealand causes the physical and mental symptoms of jet lag to set in. Sea slugs may just help solve that mystery.

Working beside Newcomb in the lab is Lauren Kirouac, who graduated with a degree in health science from New England College and is hanging around with Newcomb and the slugs until she begins school to become a physician's assistant in January.

Kirouac said working with the slugs has been fascinating, especially discovering that they have their own unique perfume that's not at all unpleasant to be around.

"They're like jelly that smells cool," she said. "They're very easy to work with."

Newcomb's research with the slugs is a partnership with Dr. Win Watson of the University of New Hampshire and is funded through the New Hampshire Network of Biomedical Research Excellence grant which brings small teaching colleges together with larger research institutions to give students at the smaller schools more experience in the lab.

"The students at New England College really get a chance to experience what happens at one of the big research institutions without having to give up the benefits of being at a small school," said Newcomb.

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Nancy Bean Foster may be reached at


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