Purdue University 's Richard Vierling is preparing to have his successful soybean DNA transplant experiments recreated on board a NASA space shuttle scheduled for launch April 13. Vierling's first microgravity experiments were conducted in late 1998 by the oldest man to ever fly in space, former astronaut and U.S. Senator John Glenn.
Those experiments, which tested whether DNA transfer could be conducted in microgravity, proved not only that it could be done, but also that it was more successful and efficient than DNA transfers in a control group here on earth.
Of the soybean seedlings from the first space experiment, 9 percent exhibited the trait introduced. On earth, less than 1 percent of the control group showed the trait. "The rate of transient expression in a space environment was more than tenfold over the success rate of a comparable terrestrial experiment," Vierling says.
Those experiments seem to indicate that space may be a better environment for conducting gene transfers. "Genes were transferred more efficiently to targeted cells in space than on earth. The results were so significant, we're going to improve our experiments and try them again," he says.
Vierling, an adjunct associate professor of agronomy, is also director of the Indiana Crop Improvement genetics program. He is working on this project in conjunction with Stephen Goldman, a professor of biology at the University of Toledo. Their initial success was reported in the January 2000 edition of the journal Chemical Innovation produced by the American Chemical Society.
Vierling says despite modern advances in biotechnology, genetic engineering is still a very inexact science. "Some plant species are easier to work with than others," he says. "Soybeans in particular are very inefficient to work with, and we're hoping to learn through these experiments ways that we can improve our odds of success even here on earth."
The first space mission involved about 1,000 soybeans in what Vierling describes as "a crude experiment." "We didn't even know if you could do gene transfer in space," he says. "Some people had told us that it wouldn't be possible."
He says some of the initial misgivings centered around the fact that the bacteria used to transfer the DNA must be mobile. "They have to 'swim' in a solution, and liquids are hard to control in zero gravity. You must keep the liquid in contact with the cells to be successful," Vierling says.
However, the "floating" effect of space may be a benefit in this case, a hypothesis they hope to explore in this next round of experiments. Vierling already has applied for a patent based on the initial experiment results.
Vierling says commercial genetic transformation and regeneration of whole plants now is limited by the the low success rates. "We hope to learn what makes space a more efficient environment for these experiments and then design equipment for use on earth to increase our efficiencies here," he says.
The Purdue soybeans will have another Purdue Boilermaker connection while on board the space shuttle Atlantis this spring. Payload specialist Mary Ellen Webber, a Purdue chemical engineering graduate, will be among the crew at liftoff scheduled for 8:41 p.m. April 13.
Purdue researcher Rick Vierling inspects soybean seedlings grown in the lab. Germinated soybean seeds will fly on board a space shuttle later this spring, to further test genetic engineering in microgravity. When the seedlings return from space, they should look much like those pictured here. (Purdue Agricultural Communications Photo by Tom Campbell)
Marshall Space Flight Center
March 8, 2000
After a year's analysis of data collected during the STS-95 flight, scientists reported the mission's microgravity experiments are contributing information to such diverse fields as medicine, agriculture and manufacturing. The investigations were managed by NASA's Lead Center for Microgravity Research -- the Marshall Space Flight Center in Huntsville, Ala.
During the mission, Glenn -- the subject of various life science experiments on the aging process -- worked as a payload specialist, or scientist in orbit. In microgravity -- the near-weightlessness of space -- he and other crew members activated and monitored experiments aimed at improving life on Earth.
Glenn worked with several experiments that may help improve treatments for life-threatening diseases. One result: treating solid tumors may become more effective using drugs enclosed in liquid-filled microcapsules that can be injected into arteries leading directly to the tumor. A new microencapsulation electrostatic processing system using microballoons was tested in space, and results are being used to refine the manufacturing process on Earth.
STS-95 results from another commercial experiment are being evaluated by a biopharmaceutical company that is testing advanced cell separation technologies. These technologies could be used to produce hemoglobin products to replace whole human blood in transfusions.
High-quality protein crystals were produced during the closely watched flight, and scientists obtained the best data ever collected on human recombinant insulin crystals. Using the crystal data, scientists can model the structure of this type of insulin more accurately, and pharmaceutical companies may be able to use the structural data to improve insulin treatments used to control diabetes. Other protein crystals grown during the mission could help pharmaceutical companies learn more about how to treat AIDS and Chagas' disease -- a deadly parasitic disease that primarily attacks cardiac muscle.
A portion of the microgravity experiments flown on STS-95 were funded and developed by commercial companies under NASA's Space Product Development Program, which encourages industry to investigate the commercial potential of space. Several research efforts involved independent, commercial firms. A number of other experiments were developed and flown through NASA's Commercial Space Centers -- located in regions across the United States. These centers partner with companies to develop products using insight gained from space research.
Investigators reported results from both life and microgravity experiments Jan. 27-28 at the Symposium on the STS-95 Research Results, sponsored by NASA Headquarters' Office of Life and Microgravity Sciences and Applications and the National Institute on Aging.
More detailed descriptions of the results presented on microgravity experiments.