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March 11, 2002
Caenorhabditis elegans — C. elegans for short
— is a tiny worm, slightly smaller than an eyelash.
It normally lives in compost heaps, but, in the last 30 years, it
has moved into the research laboratory where it has become a valuable
animal model for exploring the basic processes involved in the development
and behavior of multi-cellular organisms, including humans. The
tiny worm is made up of less than 1,000 cells, yet it possesses
a nervous system, digestive tract, musculature and reproductive
system. Scientists have completely mapped its genome and the stages
in its development. By introducing mutations in the worm's genome
and then observing the consequences, researchers are beginning to
learn the basic links between gene expression and an organism's
behavior.
Not
only is the worm extremely simple, it is also transparent. All its
internal organs are clearly visible. This allows researchers to
use genetic engineering to insert DNA sequences that produce green,
blue and red fluorescent proteins. These fluorescent labels become
clearly visible when living worms are viewed under different colored
lights. By inserting label sequences in different genes, the researchers
can identify the specific cells where the gene is expressed by the
bright, fluorescent glow.
Research
involving C. elegans has already made some major contributions
to understanding human biology. The genes that regulate a critical
process called programmed cell death in both worms and humans were
first found in C. elegans. Similarly, the genes that control
the growth of axons - the thin wire-like extensions that neurons
produce to make connections with other neurons - were discovered
initially in the worm and then later in humans.
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Exploring
the Miller Worm Farm
The sign on the laboratory door reads "Miller Worm Farm."
David Miller's laboratory is at the center of a growing number
of laboratories on the Vanderbilt campus where C. elegans
are studied. The worm, as it is fondly known, shares many
fundamental cellular processes with human beings. By studying
a simpler "model" organism like the worm, he and his colleagues
are learning more about the processes at work in more complex
organisms, including humans.
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Parkinson’s,
drug abuse connection
Could a lowly worm offer new insights to a disease as complex
as Parkinson's? Randy Blakely and his colleagues at Vanderbilt's
Center for Molecular Neuroscience believe so. They have turned
to C. elegans to study the death of dopamine neurons
- the same type of nerve cells that die in humans suffering
from Parkinson's disease.
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Identification
of worm sex signals reveal proteins can lead dual lives
David Greenstein and Michael Miller didn't set out to discover
a new birth control method for microscopic worms. But, in
identifying the biological signal that sperm use to "talk"
to eggs in C. elegans they may have done just that.
Their discovery that a well-known protein unexpectedly plays
such a totally new role is forcing biologists to ask themselves
if other well known proteins may be leading dual lives.
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Studies
ranging from special pores in cell membranes to the effects
of drugs on nerve cells
A number of other scientists at Vanderbilt have begun using
C. elegans in their research. Several are using the
worm to study different aspects of the molecular structure,
function and regulation of special pores in the cell membrane
called ion channels. Another is investigating the way that
drugs of abuse,interfere with the normal function of the neurotransmitter
dopamine.
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Students
feed the worms and learn about research
Two undergraduate students, Kim Dalton and Carolyn Maune,
have worked in the Worm Farm for three years. They have been
responsible for feeding the worms and keeping them healthy.
In addition, they are conducting an experiment that may help
shed new light on the function of one of the worm's genes.
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Worm
facts
Learn more about the elegant worm, including its size,
color, habitat, food, life cycle, genome, development, structure,
nervous system and movement.
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Making
worms that glow in the dark
It all began with a fluorescent jellyfish found in the
Pacific Northwest. A group of scientists identified the fluorescent
protein that it uses, cloned the gene that produces it. When
they inserted this gene into other organisms, researchers
found that it continued to function, creating fluorescent
protein in the living bodies of plants and animals. This has
become a powerful tool for cell biologists.
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The C.
elegans world wide
web server is communications hub of the C. elegans research
community. In addition to technical information, it includes background
information on the animal for non-scientists and written material
from Sydney Brenner explaining his reasons for advocating the use
of the nematode as an animal model.
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