Response to high hydrostatic pressure

S. cerevisiae Y440 Mat a leu2 was grown in YEPD at 28 degrees C with aeration to exponential growth phase and was subjected to a hydrostatic pressure of 50 and 200 MPa for 30 minutes at room temperature. Total RNA was extracted using phenol/chloroform and further precipitated with 3 M sodium acetate / absolute ethanol. Extracted RNA samples were treated for 10 min with 0.5 U of RNAse-free DNAse I / ]g RNA at 37 oC to remove any residual genomic DNA. RNA pellets were washed in 70 % ethanol and resuspended in DEPC treated water. Purified mRNA from pressurized and unpressurized cells was reversed-transcribed, labeled with fluorescent-tagged nucleotides, and hybridized against a common refernce pool of mRNA for 18 h at 65 0C on cDNA microarray. After several washes, arrays were scanned using a commercially available scanning laser microscope (GenePix 4000) from Axon Instruments (Foster City, CA), the data obtained was normalized (mean value) applying a linear regression method. An all pairs experiment design type is where all labeled extracts are compared to every other labeled extract Keywords: Computed all_pairs