Microgravity perturbs the physiology and behaviour of microorganisms and mammalian cells, which results in specific responses that can lead to new insights.These new findings can help further research on Earth.Hitching the future ride on space shuttle (2017-2018), the samples will be grown on the International Space Station as part of the Network biology of stress responses and cell flocculation of Saccharomyces cerevisiae in microgravity conditions investigation.
The Space Biology Group (ETH Zürich) began to develop bioreactor for yeast cultivation in space in 1991. The first generation of space bioreactor, fitting in a Type II/E container (Biorack), was flown on STS-65 in 1994 and on STS-76 in 1996 (Walther et al., 1994). In this experiment the growth of the cells (S.cerevisiae) under microgravity was investigated. The research on yeast continued on. The next step was to study the stress response in S.cerevisiae under gravitational changes (YSTRES/SACESTRE). The experiment flew on STS-107. The experiment was totally lost in the tragic accident of Columbia. SACESTRE and YING-C (Belgium team) are now parts of the current YEAST BIOREACTOR proposal.
To be able to compare results from different samples over time, it is substantial to achieve growing conditions that are highly reproducible, stable and defined over prolonged time, for this a bioreactor for continuous cultivation is needed. The third objective of this proposal is to develop such an instrument fitting into the incubator (SSBRP) as example. Microsensors will be used to measure the biological parameters and a small pump will provide the fresh medium at a fixed flow rate. The size and the geometry will be adapted to the containers (for instance CCU size), and automation of the sampling should be achieved to reduce the hand-on manipulation. Bioreactors will allow conceiving new experiments with cells that have experienced microgravity for several generations and to better use the mission time at disposition. It will be then possible to perform an experiment after different time period in microgravity, allowing in this way to compare cells' reactions.
This research project is situated at the cutting edge of multidisciplinary research in yeast biology and cellular microgravity research. The systems biology approach for microgravity research, using various complementing omics technologies and network-biology modelling, will provide new, important insights into the effect of microgravity on cellular physiology.