Abstract: The proteomic difference between the resistant BTI-Tn-5B1-4 selected by Bt Cry1Ac and the susceptible cell from the same cell clone was compared using dielectrophoresis (2-DE) and peptide mass fingerprint technology. 707±25 dots (n=3) were detected on the resistant cell's proteomic 2-DE map, and 637±19 （n=3）on the susceptible cell's proteomic 2-DE map with Melanie Viewer Ⅱ software. More than ten unmatched dots with good repetition and high resolution have been detected. One differential dot with good repetition on the susceptible cell's 2-DE map was measured using the peptide mass fingerprint technology and searched in the SWISS-PROT database, and the results showed that the protein was homologous with the periplasmic protein .

Key words: BTI-Tn-5B1-4 cell, Cry1Ac, resistance, dielectrophoresis, peptide mass fingerprint