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Experiment/Payload OverviewYeast-GAP studies the effects of genetic changes of yeast cells exposed to the space environment. The results will help scientists to understand how cells respond to radiation and microgravity, will impact the determination of health remedies and will increase the basic understanding of cell biology.
Principal Investigator
Information Pending
Payload Developer
University of Colorado at Boulder, BioServe Space Technologies, Boulder, CO, United States
National Aeronautics and Space Administration (NASA)
Sponsoring Organization:Exploration Systems Mission Directorate (ESMD)
ISS Expedition Duration:October 2003 - September 2006
8, 13
Previous ISS MissionsExperiments focusing on how microorganisms react to microgravity began with NASA's Biosatellite program in the 1960s and have continued to play an integral part in NASA's research program.
This experiment was designed to study how individual genes respond to microgravity conditions. To achieve this, scientists studied yeast cells, eukaryotic cells, or cells that contain a distinct nucleus bound by a cell membrane. Mammalian cells have a similar eukaryotic structure, and the results of this experiment could aid in understanding more complex mammalian cell response to microgravity. Yeast cells are far simpler than mammalian cells because they have a well-characterized, much smaller genome. This makes it easier for scientists to study how microgravity alters the makeup of the cells and their potential function.
Yeast is an ideal candidate for such a study because it is hardy enough to resist the rigors of flight, requires no refrigeration, and poses little risk to ISS crewmembers. The experiment used genetically engineered cells of brewer's yeast (Saccharomyces cerevisiae) and a special cell growth chamber called a group activation pack (GAP) developed by BioServe Space Technologies. The goal is to identify the precise genes of yeast that are affected by growth in microgravity to understand differences in the growth of yeast cells in space and on Earth.
Due to upmass limitations following the Columbia accident in 2003, Yeast-GAP was separated into two phases. Two GAPs were flown to ISS on 13 Progress and operated during ISS Expedition 8. The remaining two GAPs, Yeast-GAP-2, are identical to the first Yeast-GAP investigation were flown as a Sortie investigation on STS-115/12A during ISS Expedition 13.
Understanding how microbes reproduce and mutate in space may lead to the development of additional countermeasures to protect crewmembers on future long duration missions.
Earth ApplicationsAny insight into the genetic controls of a single-celled organism like yeast or certain bacteria can yield tremendous benefits on Earth, including increased antibiotic production as well as further insight into general cell biology. Research, such as Yeast-GAP, can lead to further developments in cancer research.
Crewmembers activated the yeast samples by inserting a crank into the GAP and turning the handle then deactivating after 30 minutes. There were a total of thirty-two FPAs contained with in four GAPs. The yeast samples were returned to scientists on Earth for detailed analysis.
Operational ProtocolsCrewmembers activated Yeast-GAP by inserting a crank into each of the GAPs. Once the crank was turned, this allowed the nutritious medium to be introduced to the dominant yeast. Once activated the yeast was allowed to reproduce for 30 minutes or 5 generations. After the 30 minutes, the experiment was deactivated by crewmembers using the crank. Once the handle of cranked, a fixative solution was introduced to the yeast and they were held in stasis for the return to Earth.
Samples were returned on space shuttle flight STS-114/LF1 in August 2005. Samples also flew as a sortie mission on STS-115 and returned in September 2006. Further analysis is ongoing. (Evans et al. 2009)
NASA Image: ISS008E14397 - ISS Science Office, Mike Foale is holding the GAP for the Yeast-GAP experiment during Increment 8.
Scanning electrograph image of Saccharomyces cerevisiae cells grown on Earth.
Scanning electrograph image of Saccharomyces cerevisiae cells grown on the International Space Station.