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Journal of Bacteriology, January 1999, p. 396-400, Vol. 181, No. 2
Department of Molecular Cell Biology,
Received 27 July 1998/Accepted 4 November 1998
Trehalose and glycogen accumulate in Saccharomyces
cerevisiae when growth conditions deteriorate. It has been
suggested that aside from functioning as storage factors and stress
protectants, these carbohydrates may be required for cell cycle
progression at low growth rates under carbon limitation. By using a
mutant unable to synthesize trehalose and glycogen, we have
investigated this requirement of trehalose and glycogen under
carbon-limited conditions in continuous cultures. Trehalose and
glycogen levels increased with decreasing growth rates in the wild-type
strain, whereas no trehalose or glycogen was detected in the mutant.
However, the mutant was still able to grow and divide at low growth
rates with doubling times similar to those for the wild-type strain, indicating that trehalose and glycogen are not essential for cell cycle
progression. Nevertheless, upon a slight increase of extracellular carbohydrates, the wild-type strain degraded its reserve carbohydrates and was able to enter a cell division cycle faster than the mutant. In
addition, wild-type cells survived much longer than the mutant cells
when extracellular carbon was exhausted. Thus, trehalose and glycogen
have a dual role under these conditions, serving as storage factors
during carbon starvation and providing quickly a higher carbon and ATP
flux when conditions improve. Interestingly, the CO2
production rate and hence the ATP flux were higher in the mutant than
in the wild-type strain at low growth rates. The possibility that the
mutant strain requires this steady higher glycolytic flux at low growth
rates for passage through Start is discussed.
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Function of Trehalose and Glycogen in Cell Cycle
Progression and Cell Viability in Saccharomyces
cerevisiae

*
Corresponding author. Mailing address: Department of
Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH
Utrecht, The Netherlands. Phone: 31 30 2533189. Fax: 31 30 2513655. E-mail: J.Boonstra{at}bio.uu.nl.
Present address: Department of Molecular Biology, University of
Geneva, CH-1211 Geneva, Switzerland.
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