Gene expression of E. coli MG1655 at attachment, colony formation and maturation during biofilm formation

Gene expression changes during biofilm formation processes were investigated. The gene expression was compared at attachment, colony formation and maturation during biofilm formation. At the same time, the gene expressions were also compared with exponential phase and stationary phase in planktonic cells. The gene expression pattern at attachment and colony formation processes showed similar pattern with those in planktonic exponential phase, and the gene expression pattern at maturation process showed similar pattern with those in planktonic stationary phase. During the maturation process, metabolic activities of the cells in the biofilms decreased, and the genes involved in the anaerobic respiration and efflux pumps were induced. The analysis revealed that gene expression pattern was changed and the physiological states were changed dramatically during maturation process in the biofilms. Keywords: time course Affymetrix E. coli antisense genome array was used to compare the gene expression among biofilm formation processes (attachment, colony formation and maturation) 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 2 h, 24 h and 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 5 different samples.