Investigation of differential expression: Differentiating cells vs Salmonella infected cells (t3)

Dictyostelium discoideum is a professional phagocyte and it uses phagocytosis as a way to get food. However, there are a number of bacteria that subvert this professional phagocyte. In this study we investigated whether Salmonella typhimurium is also pathogenic for D. discoideum. AX2 cells were grown in a 1000-fold excess of E.Coli B/r in Soerensen phosphate buffer under shaking. Cells were washed and resuspended at a concentration of 2 x 10^6 per ml with a 1000-fold excess of S. typhimurium or in phosphate buffer. After 0, 3, 6, 9 and 12 hours, cells were washed free of bacteria and total RNA was extracted. RNA from the 3 and 6 hour time points was used for DNA microarray analysis.