Validation of down-regulated genes by qRT-PCR. The down-regulated genes identified in microarray (open bars) and qRT-PCR (grey bars) analyses. The characterized genes incubated with A549 cells for different time periods (0.5 h or 1 h) are marked on the x-axis. For consistency, each gene is indicated by the TIGR4 genome accession number (SP), not the gene name. The fold changes (mean) from all the repeated assays with standard deviations are marked on the y-axis. Scales on the y-axis (0~-5, -5~-80) are not continuous due to large changes for some genes.