SDS-PAGE gel showing in vitro digestion of Cry1Ac protoxin by diluted T. ni larval midgut fluid from the susceptible and GLEN-Cry1Ac-BCS strains. Lanes: 1 and 2, 10% larval gut fluid from susceptible and GLEN-Cry1Ac-BCS strains, respectively; 3 to 7, Cry1Ac protoxin incubated with 10%, 1%, 0.1%, 0.01%, and 0.001% gut fluid, respectively, from susceptible larvae; 8 to 12, Cry1Ac protoxin incubated with 10%, 1%, 0.1%, 0.01%, and 0.001% gut fluid, respectively, from GLEN-Cry1Ac-BCS larvae; 13, Cry1Ac protoxin control.