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Know When To Fold 'Em, Know When To Grow 'Em
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The experiment, flown in a Wisconsin Center for Space Automation and
Robotics'
(WCSAR) ASTROCULTURE(TM) locker, was designed to test if
microgravity would aid the genetic transfer process. Instead of older
methods -- such as cross pollination and grafting -- that can take years to
produce results, researchers now use bacteria to transfer the gene carrying
the desired trait to seedlings. These seedlings will, in turn, pass the
trait along to future generations of the plant. In Earth-based
laboratories, however, the expected success rate for this process is at
best 1 plant in 1,000, or 0.1 percent. To obtain data on the effects of
microgravity on this process, industry partners Rapigen, LLC, The Indiana
Crop Improvement Association, Inc., Christophersen & Associates, Inc., and
the University of Toledo worked through the WCSAR Commercial Space Center
to fly the experiment.
In the experiment, approximately 1,000 soybean seedlings had their growing
point (meristem) region damaged just before launch, and were wrapped in
water-soaked paper rolls that were then placed in a modified
ASTROCULTURE(TM) locker. Damaging the growing point provided a point of
entry for bacteria containing the gene to be transferred, in this case a
marker gene that is fluorescent and easily tracked. The bacteria was mixed
into growth media and transferee into the containers with the paper rolls
once on orbit.
"The level of genetic transfer was way beyond our expectations," says Ray
Bula, a Principal with Rapigen LLC and a retired director of WCSAR. "We
thought that if we could double the rate of transfer seen on Earth, it
would have been promising."
Instead of simply doubling, according to Bula, there was more than a
ten-fold increase in genetic transfer compared with the ground-based
control experiment. While this was extremely successful, an unanticipated
result was a high rate of infection. For a number of reasons, the growth
of bacteria is much more difficult to control in microgravity than it is on
Earth. As a result, the high rate of infection blocked the vascular system
of the plants. Bula states that this problem can be corrected, in part, by
reducing the amount of bacteria since less is needed to do the job in
microgravity.
"WCSAR is excited about the outcome of the gene transfer experiment
conducted during the STS-95 mission," states Dr. Weijia Zhou, Director of
WCSAR. "This is an another illustration of the successful collaboration
between WCSAR and its industrial partners. Thanks to NASA, WCSAR and its
industrial partners were able to perform this novel experiment in the
microgravity environment. These results are the first steps leading to
genetic engineered commercial products that will contribute to the economic
competitiveness of U.S. industry."
While cautioning that further experimentation is needed to verify the
results and refine the methodology, Bula is excited by the results. And
for good reason: genetically engineered varieties will make up more than
70 percent of the soybeans planted nationally this year, and improved gene
transfer opens the door to a host of other exciting possibilities including
plants that are insect resistant -- reducing the need for chemical
insecticides -- and plants that incorporate medical vaccines.
Work is already underway on a second gene transfer experiment. This
experiment will include refinements from the data gathered on STS-95, and
instead of a marker gene will transfer a gene to the soybeans that has a
medical application.
Commercial experimentation, such as the successful experiments in
ASTROCULTURE(TM), are made possible through NASA's Space Product
Development Program, a partnership between NASA, academia, and U.S.
Industry. Working through Commercial Space Centers that are funded by both
NASA and Industry, companies can do research designed to produce the
products and technologies of tomorrow. The research effort belongs to the
industries involved, who are responsible for designing, funding, and
analyzing the research. NASA, as its part of the partnership, provides
access to microgravity for selected research.
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