Comparison of the transcriptome of the ethanol adapted yeast and control at 10% ethanol

In this study, using DNA microarray analysis, we compared the comprehensive expression profiles of two yeast trains, i.e, the previously obtained ethanol-adapted yeast strain and the parental strain as control (FY834), under the ethanol stress condition (YPD medium contained 10% ethanol). As a result, we identified certain genes and functional categories of the genes that are possible involved in growth under the ethanol stress condition. The ethanol adapted and FY834 yeasts were cultivated in YPD medium containing 10% ethanol. For the control, FY834 strain was cultivated in YPD medium. Cells were harvested in the logarithmic growth phase and then immediately frozen in liquid nitrogen. Total RNA was extracted by the hot phenol method and purified into mRNA using an Oligo dT30 mRNA purification kit. Cy3-labelled cDNA targets were prepared from 1.5 µg of mRNA samples of yeasts grown in the ethanol stress condition. Cy5-labelled cDNA targets were prepared from 1.5 µg of mRNA samples of yeast grown in YPD. Cy3-and Cy5-labelled cDNA targets were mixed and then hybridized with probes on the DNA microarray, Yeast gene chip ver.2. (DNA Chip Research Inc.,Japan). The preparation of fluorescent-dye-labeled cDNA targets, hybridization, and washing were carried out as described in instruction manuals supplied by the manufacturer of the DNA microarray.