Yeast Rising to the Space Station

Chefs across the globe may not know it yet, but their baker's yeast just left the kitchen and blasted off into low Earth orbit. Hitching a ride on the space shuttle Atlantis on July 8, 2011, the samples will be grown on the International Space Station as part of the Genotypic and Phenotypic Changes in Yeast Related to Selective Growth Pressures Unique to Microgravity or Micro-4 investigation. Capable of raising more than just breads, this useful organism will help researchers better understand the impact of the space environment on live cells in humans.

This yeast S.cerevisiae has been of use since the ancient Egyptians first figured out how to harness it for wine and bread making. In modern times it is still used for baking and was the first organism to have its genome fully sequenced. Scientists hope that by studying the changes of yeast in microgravity, they will better understand the changes human cells may experience during long-duration spaceflight.

Gaining better knowledge of genetic alterations by studying yeast growth during this microgravity research may also help in understanding how these changes could manifest in human disease here on Earth.

This investigation is a collaboration with BioServe Space Technologies, Durham Veterans Affairs Medical Center, and the University of Toronto. According to Michael Costanzo, Ph.D. and one of the co-investigators for Micro-4 at the University of Toronto, the similarities between human cells and the yeast's genetic makeup makes it ideal for study in space. "We are examining which genes are important for cell growth and survival in a zero gravity environment.

The results of our 'yeastnaut' experiments may provide insight into which set of human genes are important and how these genes work together to help organisms/humans deal with extreme environments associated with space travel such as zero-gravity and elevated radiation."

Two different sets of experiments will take place as part this study. The first will grow yeast cells in petri dishes using temperature-controlled chambers. On July 12, scientists on the ground remotely changed the temperature from 4° C to 30° C the optimal temperature for yeast cell growth to activate the on orbit samples. The cells continue to grow for 48 hours before the temperature is cooled again and the samples are stowed for return to Earth for analysis.

The second experiment includes the use of a liquid media to grow the yeast. During the mission, astronauts will transfer the samples to fresh liquid media twice before stowing them, as well.