The clue to the body's biological clock?
By COLLEEN CREAMER
for The City Paper
If you’ve ever wondered why your body doesn’t take lack of sleep lying down, professors at Vanderbilt University’s Biological Sciences Department may be close to finding the clue in pond scum.
A research team headed by biologist Carl Johnson has discovered the structure of the day/night rhythms of algae, the simplest organism recently found to have an internal clock. When fully unlocked, the mystery of the algae’s timing could have implications for jet lag, Seasonal Affective Disorder and insomnia. The human biological clock controls a number of functions, one of which is the wake-sleep cycle.
“We are trying to figure out what the cogs and gears of this clock are,” said Johnson. “And when you talk about cogs and gears, they are going to be proteins.” The applied aspects, said Johnson, will come from understanding how the mechanism works so researchers can find ways to manipulate it and use the information to create drug and other therapies.
The therapies could allow people to effectively fly from one time zone to another or work odd shifts, live in climates with little sun or just sleep better.
“It’s not just a matter of discomfort. It’s also a matter of performance and alertness, and that’s important in cases of airline pilots,” said Johnson. “It’s important in the case of industrial accidents as in a Nissan plant, but it’s also important in places like Three Mile Island and Chernobyl, both [accidents] of which happened at a time when they could have been related to a lack of alertness.”
Johnson said his team studied a species of blue/green algae whose genetics could be manipulated to speed up and slow down in order to isolate a protein, the beginning of unraveling how the clock works in the body.
“What all this means is that bacteria, fruit flies and plants and humans have internal clocks, and proteins are mediating it, and it tends to run a little fast or a little slow,” Johnson said. “That is our own internal frequency.” People have a clock, said Johnson, that is somewhere around 24 hours and will synchronize to a schedule. But, he added, biological clocks were not developed for fast time changes, the reason humans suffer jet lag when they travel or change work shifts.
“The clock in us doesn’t shift immediately,” Johnson said. “It was never designed to do that, because during evolution we were never subjected to rapid time changes. This gets back to the cellular nature of the clock because there is good evidence now that virtually the trillions of cells in our bodies have their own little clocks.”
Johnson said that for many years it was thought that very simple organisms, of which bacteria are an example, did not have day/night rhythms until biologists in Asia made a discovery using simple methods.
“There was this group in Taiwan that didn’t know enough not to do the experiment,” Johnson said. “They isolated blue/green algae in rice paddies, and they observed things that kind of looked like rhythms.” Johnson said the Taiwanese team put the algae into constant light and discovered that the algae would “photosynthesize” for 12 hours and then shut off and begin the cycle again somewhat like sleeping and waking states.
Johnson said understanding our internal clocks could reveal the underpinnings of Seasonal Affective Disorder, a form of winter depression linked to short days.
“We are thought to have evolved in Africa, and there is a lot of light down there. And we may have adapted to that even though we spread all over the world,” said Johnson.
