title: Oxygen availability strongly affects chronological lifespan and thermotolerance in batch cultures ofSaccharomyces cerevisiae.
abstract: Stationary-phase (SP) batch cultures ofSaccharomyces cerevisiae, in which growth has been arrested by carbon-source depletion, are widely applied to study chronological lifespan, quiescence and SP-associated robustness. Based on this type of experiments, typically performed under aerobic conditions, several roles of oxygen in aging have been proposed. However, SP in anaerobic yeast cultures has not been investigated in detail. Here, we use the unique capability ofS. cerevisiaeto grow in the complete absence of oxygen to directly compare SP in aerobic and anaerobic bioreactor cultures. This comparison revealed strong positive effects of oxygen availability on adenylate energy charge, longevity and thermotolerance during SP. A low thermotolerance of anaerobic batch cultures was already evident during the exponential growth phase and, in contrast to the situation in aerobic cultures, was not substantially increased during transition into SP. A combination of physiological and transcriptome analysis showed that the slow post-diauxic growth phase on ethanol, which precedes SP in aerobic, but not in anaerobic cultures, endowed cells with the time and resources needed for inducing longevity and thermotolerance. When combined with literature data on acquisition of longevity and thermotolerance in retentostat cultures, the present study indicates that the fast transition from glucose excess to SP in anaerobic cultures precludes acquisition of longevity and thermotolerance. Moreover, this study demonstrates the importance of a preceding, calorie-restricted conditioning phase in the acquisition of longevity and stress tolerance in SP yeast cultures, irrespective of oxygen availability.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands. ; Current address: Division of Systems and Synthetic Biology, Department of Biology and Biological Engineering & The Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Markus M
authors.initials: MM
authors.lastname: Bisschops
authors.affiliation: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Vos
authors.affiliation: Instituto de Ciencias de la Vid y del Vino, CSIC, Universidad de La Rioja, Gobierno de La Rioja, Logroño, Spain. ; Current address: Quercus Europe S.L., L'Hospitalet de Llobregat, Catalonia, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Martínez-Moreno
authors.affiliation: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors.forename: Pilar T
authors.initials: PT
authors.lastname: Cortés
authors.affiliation: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors.forename: Jack T
authors.initials: JT
authors.lastname: Pronk
authors.affiliation: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors.forename: Pascale
authors.initials: P
authors.lastname: Daran-Lapujade
keywords: anaerobiosis; chronological lifespan; conditioning; energetics; stationary phase; thermotolerance; transcriptional response