Gene expression of E. coli MG1655 pOX38Km at the outside and inside of biofilms

Gene expression changes between outside and inside of biofilms were investigated. The gene expression was compared between the outside and inside of the biofilms. At the same time, the gene expressions were also compared with exponential phase and stationary phase in planktonic cells. The gene expression analysis showed that the physiological activities were higher at the outside of the biofilms than those at the inside of the biofilms. The genes induced at the ouside of the biofilms included genes involved in the stress responses and adhesions. Keywords: different growth phase Affymetrix GeneChip E. coli Genome 2.0 Array was used to compare the gene expression among biofilms (outside and inside) and planktonic cells (exponential phase and stationary phase). All samples were grown in MOPS minimal media with 0.2% glucose at 37ºC. Biofilms were grown on glass surface in flow cells (1 x 4 x 40 mm), and samples were taken at 72 h. Planktonic cell were grown for 6 h (exponential phase) and 24 h (stationary phase). Experiments were repeated 3 times, which resulted in 3 replicates of 4 different samples.