RT-PCR analysis of cfaE transcription in H10407 and derivative strains. Amplification of cDNA products was performed with primer pairs CFAE1 and CFAE2 (A), or CFAE1 and Kan-rev (B). Lanes are as follows: 1, Fermentas 1 kb Generuler marker; 2, control lacking reverse transcriptase enzyme; 3, control lacking RNA; 4, H10407; 5, H10407P; 6, H10407Kan; 7, KB101; 8, H10407Kan(pcfaEgent) and 9, KB101(pcfaE).