Microscopic pacemakers--also known as circadian clocks--are found in everything from pond scum to human beings and appear to help organize a dizzying array of biochemical processes. Despite the important role that they play, scientists are just beginning to understand the benefits that these internal pacemakers provide when they work and the problems they cause when they malfunction.
A study performed by researchers at Vanderbilt University and published in the Aug. 24 issue of the journal Current Biology sheds new light on this issue. Using blue-green algae--the simplest organism known to possess these mechanisms--the researchers report that the benefits of biological clocks are directly linked to environments with regular day/night cycle and totally disappear in conditions of constant illumination.
"Circadian clocks are so widespread that we think they must enhance the fitness of organisms by improving their ability to adapt to environmental influences, specifically daily changes in light, temperature and humidity," says Carl H. Johnson, professor of biological sciences and Kennedy Center investigator who directed the study. "Some people have even suggested that, once invented, these clocks are such a powerful organizational tool that their benefits go beyond responding to external cycles. However, there have been practically no rigorous tests of either proposition."
To test these ideas directly, Johnson's research team used genetic engineering techniques to completely disrupt the biological clocks in one group of algae and to damp the frequency of the clocks in a seco
Contact: David F. Salisbury