YEAST IN NO GRAVITY - THE INFLUENCE OF MICROGRAVITY ON CELLULAR ADHESIONS, BIOFILM
FORMATION AND IN INVASIVE GROWTH IN THE MODEL EUKARYOTE SACCHAROMYCES CEREVISIAE
(YING-A: PART 1)
Research Area: Microbiology
Expedition(s): 14
Principal Investigator(s): ● Ronnie Willaert, PhD, Vrije Universiteit Brussel,
Brussels, Belgium
● Freddy Delvaux, PhD, Katholieke Universiteit,
Heverlee, Belgium
● Jens Nielsen, PhD, Technical University of Denmark,
Kongens Lyngby, Denmark
● Lode Wyns PhD, Free University, Brussels, Belgium
RESEARCH OBJECTIVES
Yeast In No Gravity - The Influence of Microgravity on Cellular Adhesions, Biofilm Formation
and In Invasive Growth in the Model Eukaryote Saccharomyces cerevisiae (YING-A: Part 1)
studies the influence of microgravity on Flo proteins of the yeast Saccharomyces cerevisiae,
which are involved in cell surface interactions on solid substrate and cell-cell interactions in
liquid media. The final goal is to obtain information on the importance of microgravity on the
formation of organized cell structures (flocculation, biofilm, invasion) and the entire “Flo
processes” itself.
RESULTS
Yeast cells were grown on Yeast extract Peptone Dextrose (YPD) agar plates during 300 hour at
an average temperature of 19.28°C. Colony morphology was assessed by photographing the
plates at 2 time points in orbit, after 97.5rh and 216.3hr. For the ground reference experiments,
photographs were taken every day. Both the CMBSESA1 and Σ1278b yeast colonies covered a
larger surface on 0.8% agar than on 2% agar throughout the experiment, which is in accordance
with previous studies. Two-dimensional spreading of the yeast colonies grown on semi-solid
agar medium was reduced under microgravity in the Σ1278b laboratory strain but not in the
CMBSESA1 industrial strain. This was supported by the Σ1278b proteome map under
microgravity conditions, which revealed up-regulation of proteins linked to anaerobic
conditions. The Σ1278b strain showed a reduced invasive growth in the center of the yeast
colony. Bud scar distribution was slightly affected with a switch toward more random budding.
Together, microgravity conditions disturb spatially programmed budding patterns and generate
strain-dependent growth differences in yeast colonies on semi-solid medium. Proteomics
analysis showed that the Σ1278b WT showed a more anaerobic fermentative growth in
microgravity compared to the ground samples, since many enzymes involved in the Krebs cycle
were less abundant in microgravity, which indicates a higher request for energy in microgravity.