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Do the worms change colors as they age?
How can scientists draw comparisons between an organism with a life span of 2
weeks vs. an organism with a life span of 70+ years? A human blood cell lives
longer than C. elegans.
How many offspring can one C. elegans produce within
their lifespan?
Once they reach maturity (and full size) can you tell how
old they are?
How long has NASA been studying C. elegans?
What is abnormal behavior for a worm?
How do worms go to the bathroom in space?
Questions & Answers
Why are scientists studying C. elegans?
C. elegans is a common, well-studied organism used in biomedical research
as a model for human development, genetics, aging, and disease. The recent award
of a Nobel Prize
in Medicine to three pioneering worm researchers has demonstrated the value
that has been placed on the worm as a great model organism by the scientific
and medical communities. 
What similarities exist between C. elegans
and humans?
Although C. elegans is a primitive, free living (non-parasitic) organism,
it shares many of the same biological characteristics found that are found in
you and I. The worm is conceived as a single cell that develops, proceeding through
morphogenesis (formation of the structure of an organism or part; differentiation
and growth of tissues and organs during development) and growth to the adult.
It has a nervous system, muscles to help it move, and a gut. It also is capable
of performing very simple behaviors. It produces sperm and eggs, and reproduces,
although normally as a hermaphrodite (one having both male and female sexual
organs). After reproduction, the worm gradually gets older, slows down and finally
dies.
How long do C. elegans live?
In the wild, a mere 2-3 weeks. However, a special type of liquid media (a nutrient
rich broth that the C. elegans lived in and used as a food source) was
used for the ICE mission, in which worms can life for 3 months.
Did you expect the C. elegans to
reproduce normally in space?
It is known that C. elegans can reproduce in space. However whether
or not they reproduce normally over generations in space is not yet fully understood
and is one of the questions that will be more clearly answered from this mission.
Who was elegans and why was a worm named
after him/her?
Actually the name Caenorhabditis elegans comes from a blend of Greek and
Latin words: Caeno, recent; rhabditis, rod; elegans, nice. C. elegans
was initially named Rhabditis elegans by French biologist Emile Maupas in 1900
and then renamed Caenorhabditis by German biologist Gunther Osche in 1952.
How did studying C. elegans advance
the US toward its' goal of sending humans to Mars?
C. elegans is an important, well-studied organism used in biomedical research
as a model for human development, genetics, aging, and disease and C. elegans
is also a particularly excellent research organism for space because the worm
is small, easy to grow and easy to keep alive, has a manageable number of genes,
and reproduces quickly so many generations can be studied over a short time.
By applying carefully what we learn about C. elegans in space, we will
better understand how biological organisms sense and respond to the spaceflight
environment over multiple generations. This is a crucial step towards establishing
a permanent manned presence at Mars, or space in general. As an example, by using
whole genome microarray analysis for ICE, all worm genes can be analyzed for
responses to the space environment. These responses may reveal new aspects that
could indicate how humans might respond in a similar environment. It is important
to recognize that follow-up studies, both on ground and space laboratories, are
necessary to confirm how humans will respond.
How many offspring can one C. elegans
produce within their lifespan?
On earth the typical brood size, of hermaphrodite C. elegans that
are on agar with bacteria (E. coli) as a food source is 200-300 eggs.
Do the worms change different colors as
they age?
The worms are mostly transparent at all stages, as they age they may become slightly
more opaque, but this is one of the advantages of the worms for research: that
investigators using a simple microscope, can view their internal organs/cells
without any sort of invasive techniques. Experiments are in planning to examine
worms on the Space Station with a video camera so that investigators on Earth
can view their development and examine them for differences between earth-grown
worms.
How can scientists draw comparisons between
an organism with a life span of 2 weeks vs. an organism with a life span of 70+
years? A human blood cell lives longer than C. elegans.
Scientists utilize a wide variety of model specimens to infer effects on humans.
Certain organisms are best suited for the study of certain systems. C. elegans
are particularly good for studying the muscular system. Some organisms are used
to do scientific tests due to their short life span. Short life span allows the
scientist to study effects over multiple generations in a relatively short timeframe.
In order to get a true sense of what is happening you need to be able to study
the effects on multiple individuals. This is typically not possible in studies
on humans in space. Lastly, since some experiments might have harmful side effects
it is useful to start by studying effects on different organisms.
C. elegans are well characterized organisms that have a lot of biological
functions that are similar to humans thus allowing the scientist to infer what
might happen to humans. It is a first step in understanding what effects space
might have on the crew. When multiple experiments conducted on different organisms
are completed a picture of what should be tested on the crew (using humans) is
developed. This strategy is used in modern science and medicine to find new cures
for different diseases/ailments that occur to humans here on earth. For example,
the treatment of diabetes was developed by conducting experiments on organisms
other than humans.
How many offspring can one C. elegans produce
within their lifespan?
Each C. elegans worm can produce approximately 300 offspring during their
life. The worms typically live 2 to 3 weeks.
Once they reach maturity (and full size) can you
tell how old they are?
Not easily, once the worms pass through all of the larval stages, the young adult
worms look similar to old adult worms. However, to assess life span, we transfer
individual worms from plate to plate so we can watch how long they live. Very
old worms look deteriorated relative to younger worms.
How long has NASA been studying C. elegans?
The first experiment utilizing C. elegans in space was conducted on STS
(Space Transportation System)-42, which launched in January 1992. The experiment
was designed to study the biological effects of exposure to cosmic rays. This
mission contributed to helping scientists understand how to protect space travelers
on long missions.
What is abnormal behavior for a worm?
Abnormal behavior in the simplest form is defined as any behavior that is different
from the worm's (C. elegans) normal behavior. Experiments that test for
change in behavior are designed in such a way that they compare the behavior
of worms in a typical environment to the behavior of the worms that are being
exposed to a different environment. Some examples of abnormal worm behavior include,
but are not limited to, movement in a figure 8, jerky (erratic) movement and
no movement. Worms normally show a sine wave movement (wavy motion). It is important
to remember that we do not know what changes in behavior the space environment
might produce. We can only compare the space worms to the worms grown on Earth.
The worms grown on Earth are called the control group. By comparing the space
worms with the worms in the control group we will determine if the worms behave
normally or abnormally in space.
How do worms go to the bathroom in space?
Like you (only much simpler!), C. elegans have a mouth where they take
in food, a pharynx that pumps the food into the intestines, a digestive system
that enables them to process the food and use the nutrients contained within
the food for energy, and an excretory system that enables them to eliminate the
waste products from their bodies. So, when C. elegans need to use the
"loo" in the space environment after they eat their food, their bodies
utilize the digestive and excretory systems used on Earth to process food and
remove energy and waste so they can continue to grow, eat and live.
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Above: Image of the worm's culture chamber. A total of four chambers
were used for the flight.
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Above: Centrifuge parts
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Above: Culture bags and Experiment Containers
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NASA Official: BJ Navarro Curator:
NASA Ames Life Sciences Outreach
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