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AND FRUIT FLIES AID NEW RESEARCH ADVANCES IN THE BODY'S 24-HOUR CLOCK
have always measured their existence by outward signs of the passage of
time, day and night or sunrise and sunset. Commonly referred to as a 24-hour
clock or circadian rhythm in humans, a
cluster of cells in the brain regulates our metabolism, digestion and
the sleep-wake cycle.
Gaining control of this clock, researchers claim, could produce many benefits,
including lowering blood pressure, improving drug metabolism, overcoming
jet lag and helping shift workers function more effectively.
But, as often happens in science, key tools that are now making it possible
to understand the clock's mechanism came from an unexpected direction.
begun in the early 1950s led to identifying the compound luciferase as
the enzyme responsible for the bioluminescent "fire" of fireflies.
Decades later, researchers at the University of California-San Diego isolated
and cloned the luciferase gene and subsequently developed a new molecular
probe by attaching the luciferase gene to other genes in plants and animals.
This technology allowed scientists to measure activities of specific genes
of interest under natural conditions and opened up a whole new way to
study how genes regulate life processes.
"Biological clock" genes
More recently, researchers at the NSF Science and Technology Center at
the University of Virginia and other locations were able to use the luciferase
technology to show periodic cycling as a luminescent glowing when "biological
clock" genes turned on and off in living plants and animals. These
plants and animals, with well-studied genes, include a mustard plant (Arabidopsis
thaliana) and a fruit fly species (Drosophila melanogaster).
This research has allowed new ways to precisely monitor clock gene activity
and has increased our understanding of the importance of human beings'
internal 24-hour clock and its role in everyone's daily life.
Plant genes and clocks
This kind of modification of plants has generated high interest in the
agricultural, energy and environmental communities. Further,
it is expected that scientists may soon be able to increase certain plants'
value as crops or as renewable resources if they can modify those crops'
growing seasons or metabolic cycles to suit seasonal conditions of specific
Other research is trying to control the way humans' 24-hour clock synchronizes
with other internal clocks (such as women's reproductive cycles) or external
clocks (such as the sun) that are on different schedules. This control
could be useful for people with sleep disorders or shift workers who need
to stay alert while they work through the night.