Response of Saccharomyces cerevisiae to stress-free acidification.
Genome-wide transcriptional analysis of a Saccharomyces cerevisiae batch culture revealed that more than 829 genes were regulated in response to an environmental shift from pH 6 to pH 3 by added sulfuric acid. This shift in pH was not detrimental to the rate of growth compared to a control culture that was maintained at pH 6 and the transcriptional changes most strikingly implicated not up- but down-regulation of stress responses. In addition, the transcriptional changes upon acid addition indicated remodeling of the cell wall and central carbon metabolism. The overall trend of changes was similar for the pH-shift experiment and the pH 6 control. However, the changes in the pH 6 control were much weaker and occurred 2.5 h later than in the pH-shift experiment. Thus, the reaction to the steep pH decrease was an immediate response within the normal repertoire of adaptation shown in later stages of fermentation at pH 6. Artificially preventing the yeast from acidifying the medium may be considered physiologically stressful under the tested conditions.
Chen
Allen Kuan-Liang
AK
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
Gelling
Cristy
C
Rogers
Peter L
PL
Dawes
Ian W
IW
Rosche
Bettina
B
D000220:Adaptation, Biological / Q000235:genetics*; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D002952:Citric Acid Cycle / Q000235:genetics; D015536:Down-Regulation; D045222:Electron Transport Chain Complex Proteins / Q000096:biosynthesis / Q000235:genetics; D005285:Fermentation / Q000235:genetics; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D024101:Mitochondrial Proteins / Q000096:biosynthesis / Q000235:genetics; D011767:Pyruvate Decarboxylase / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*
D045222:Electron Transport Chain Complex Proteins; D024101:Mitochondrial Proteins; D011767:Pyruvate Decarboxylase; D005947:Glucose