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Fact sheet number: FS-2003-03-119-MSFC
Release date:

Group Activation Packs (GAP) Yeast Experiment

Experiment Name: Group Activation Packs (GAP) Yeast Experiment

Mission: Experiment to International Space Station on Russian Progress Flight 13P; experiment conducted during Expedition 8

Experiment Location: Destiny Laboratory Module

Principal Investigators: Timothy G. Hammond, M.B., B.S., Tulane University Medical Center, New Orleans

NASA Research Partnership Center Director: Dr. Louis Stodieck, BioServe Space Technologies, University of Colorado, Boulder

NASA Research Partnership Market Manager: Brian Mitchell, NASA Marshall Space Flight Center, and Huntsville, Ala.


The objective of NASA's biotechnology cell science research aboard the International Space Station is to provide a controlled environment for the cultivation of cells into healthy, three-dimensional tissues that retain the form and function of natural, living tissue.

As normal human cells grow and replicate, they form complex "colonies" of fibers, proteins and other structures that make up living tissue. Studying this mechanism outside the human body is difficult, however, because cells do not easily associate to form these cellular colonies outside living organisms.

Most cultivated cells form flat, thin specimens that offer only limited insight into the way cells work together. Scientists were excited, therefore, to discover that cells grown in microgravity -- the low-gravity environment inside spacecraft orbiting the Earth -- much more closely resemble those found in human bodies.

The genes of every living organism determine the organism's physical traits and how each cell operates. For example, kidney cells receive instructions from genes that tell the cells how to form and how to operate together to remove wastes from the body. Scientists want to understand how the cells receive instructions from genes and express specific genetic traits - gene expression patterns.

Understanding gene expression patterns and how they are altered when cells are grown in the low-gravity, or microgravity inside the Space Station, will help scientists learn how cells respond to gravity. This information could be used eventually to improve the method for culturing cells here on Earth. Improved cell culturing techniques could help scientists improve pharmaceutical testing and drug development processes, produce new biological products, and potentially produce tissues that can be implanted inside humans to replace diseased tissues or organs.

The challenge in studying human cells or cells from other mammals is that the genome - the entire group of genes that make up each living creature and determine its traits - is large and complex. This makes it difficult to study how gravity or microgravity affects individual genes that control specific cells.

For this experiment, scientists will study yeast cells, which are eukaryotic cells - cells that contain a distinct nucleus bound by a cell membrane. Mammalian cells have a similar eukaryotic structure. However, yeast cells are far simpler and have a well-characterized, much smaller genome. This will make it easier for scientists to study how microgravity is altering the cells' makeup and potential their function.

This experiment will study how individual genes respond to microgravity conditions. The results could help scientists understand how mammalian cells will respond when they are grown in microgravity as well as improve culturing techniques of mammalian cells on Earth.

Experiment Operations

The yeast cells will be cultured inside Group Activation Packs - a cell growth and storage system developed by BioServe Space Technologies located at the University of Colorado in Boulder.

BioServe is one of 15 NASA Research Partnership Centers managed by NASA's Space Product Development Program at NASA's Marshall Space Flight Center in Huntsville, Ala. BioServe has developed numerous facilities designed to conduct biotechnology experiments in space and has flown research on more than 23 missions including three missions aboard the International Space Station.

Two Group Activation Packs will be flown. Each contains eight Fluid Processing Apparatuses that hold the yeast cultures, growth medium and fixative, a chemical used to preserve the cells for post-flight examination.

To activate the experiment, the Space Station crew will insert a crank into the top of the GAP. This causes the yeast cells to mix with the liquid growth medium. The cells will grow in the cultures for three days. Then the crank will be turned again, releasing the fixative.

The preserved cells will be placed in a special stowage container. They will be returned to Earth where scientists will compare them to similar yeast cells grown inside a ground control unit. By comparing the genes of the Earth-produced cells with the cells grown in space, scientists can determine how microgravity altered the genetic makeup of the cells.


This experiment is one of a series of investigations that is being flown as part of NASA's cellular biotechnology research program conducted by NASA researchers in academia, government and industry. The potential benefits and applications include:

Increased understanding of basic cell biology, as well as the effects of gravity on terrestrial cell biology;

Potential production of living, functional replacement tissue for research and medical applications;

Identification of new technologies that will advance science on Earth; and

Potentially impact the determination of health remedies and countermeasures for future long-term space flight.

More Information

More information on this experiment and other Space Station experiments is available at:

Steve Roy
Public Affairs Office
(256) 544-0034

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