Strain specific protein identifications in ECM biofilm sample. All indicates no strain specific peptides were observed where the peptide sequence is present in homologous proteins of each of the four strains used for Mascot and Sequest searches. Strain key: 1: Rd aka KW20; 2: R2846; 3: R2866; 4: 86-028NP. U indicates one protein, a thioredoxin, with a peptide not found in any of the four strains searched. See reference 13 for strain information.