tailieunhanh - Báo cáo khoa học: Training of yeast cell dynamics

In both industrial fermenters and in their natural habitats, microorganisms often experience an inhomogeneous and fluctuating environment. In this paper we mimicked one aspect of this nonideal behaviour by imposing a low and oscillating extracellular glucose concentration on nonoscillating suspensions of yeast cells. The extracellular dynamics changed the intracel-lular dynamics – which was monitored through NADH fluorescence – from steady to equally dynamic; the latter followed the extracellular dynamics at the frequency of glucose pulsing | iFEBS Journal Training of yeast cell dynamics Karin A. Reijenga1 Barbara M. Bakker1 Coen C. van der Weijden1 and Hans V. Westerhoff1 2 3 1 Department of Molecular CellPhysiology CRbCS BioCentrum Amsterdam Faculty of Earth and Life Sciences Vrije Universiteit Amsterdam the Netherlands 2 Department of MathematicalBiochemistry BioCentrum Amsterdam Swammerdam Institute for Life Sciences the Netherlands 3 Stellenbosch Institute for Advanced Study University of Stellenbosch South Africa Keywords dynamics glycolysis oscillations training yeast Correspondence H. V. Westerhoff Department of Molecular CellPhysiology CRbCS BioCentrum Amsterdam Faculty of Earth and Life Sciences Vrije Universiteit Amsterdam the Netherlands Fax 31 20 444 7229 Tel 31 20 444 7230 E-mail Present address DSM Anti-Infectives PO 425 NL-2600 MA Delft the Netherlands Received 28 September 2004 revised 18 January 2005 accepted 24 January 2005 doi In both industrial fermenters and in their natural habitats microorganisms often experience an inhomogeneous and fluctuating environment. In this paper we mimicked one aspect of this nonideal behaviour by imposing a low and oscillating extracellular glucose concentration on nonoscillating suspensions of yeast cells. The extracellular dynamics changed the intracellular dynamics - which was monitored through NADH fluorescence - from steady to equally dynamic the latter followed the extracellular dynamics at the frequency of glucose pulsing. Interestingly the amplitude of the oscillation of the NADH fluorescence increased with time. This increase in amplitude was sensitive to inhibition of protein synthesis and was due to a change in the cells rather than in the medium the cell population was trained to respond to the extracellular dynamics. To examine the mechanism behind this training we subjected the cells to a low and constant extracellular glucose concentration. Seventy-five minutes of adaptation to