The study investigated the effect of different carbon sources on E. coli global gene expression. We grew MG1655 cells aerobically in MOPS minimal medium with either glucose, glycerol, succinate, L-alanine, acetate, or L-proline as the carbon supply. Samples were taken from each culture at mid log phase and were RNA-stabilized using Qiagen RNAProtect Bacterial Reagent (Qiagen). Total RNA was then isolated using MasterPure kits (Epicentre Technologies). Purified RNA was reverse-transcribed to cDNA, labeled and hybridized to Affymetrix GeneChipĂ’ E. coli Antisense Genome Arrays as recommended in the technical manual (www.affymetrix.com). This sample is from glycerol-grown cells.