FIG 3 .

E. coli biofilm bacteria add a palmitate chain to their lipid A. (A) Proposed structures corresponding to major peaks detected by MALDI-TOF mass spectrometry, according to previously reported structures of Gram-negative bacterial lipid A. (B to F) MALDI-TOF analysis of lipid A extracted from E. coli K-12 BW25113 bacteria. The E. coli K-12 BW25113 bacteria were 24-h planktonic bacteria (B), 96-h BW25113 biofilm bacteria (C), 96-h BW25113 ΔpagP biofilm bacteria (D), 96-h BW25113 ΔpagP mutant biofilm bacteria complemented with plasmid pPagP (E), and 96-h BW25113 ΔpagP mutant planktonic bacteria complemented with plasmid pPagP (F).