Saccharomyces cerevisiae sorted and untreated

Gene expression of a vital, stained and sorted subpopulation of Saccharomyces cerevisiae with high affinity to glucose, harvested at a dilution rate of D=0.160 h-1, and of cells from the whole population without further treatment grown at the same dilution rate were analysed. The isolation of RNA was accomplished by using lyticase to lyse the cells and the Qiagen RNeasy Mini Kit with some modifications within the manufacturers´ protocol. 6 µg of the total RNA per sample was used for each microarray experiments. The indirect labelling by the tyramide-signal-amplification method (MicromaxTM TSATM labelling and detection Kit from Perkin Elmer life sciences) was used to increase the Cy3 and Cy5 signals of microarray detection. Each cDNA containing Biotin- and Fluorescein-nucleotides respectively was purified with a QIAquick PCR purification kit and suspended in 11 µl of the formamide containing hybridization buffer. The slides were hybridized at 42°C over night under a cover slip. The microarrays were scanned by the Axon 4000B scanner; image intensity data were extracted and analysed with GenePix® Pro 6.0 software. Data from different scans of Dye-swap experiment were extracted by GenePix Pro 6.0 software, normalized and united. An outliertest has been applied in order to find outliers amongst the gene replicats. Subsequently, a t-test (1% and 5% probability of error) has been used in order to find regulated genes. Keywords: sorted yeast cells Microarray experiments were realised with dye swap and cDNA labelling was proceeded in loop design.