Selection for resistance against Bacillus thuringiensis (Bt) Cry1Ac10 in the Trichoplusia ni (Hübner) cell line BTI-TN-5B1-4 (TnH5) was tested, and the development of resistance in the selected cells was like a S-form curve. Monitoring at the Cry1Ac10 50th challenge, the resistance ratio was 1, 294-fold as many as that of initial cells. But the resistance to Cry1Ac10 declined gradually when the selection was relaxed. The resistance declined rapidly at the low level of resistance and slowly at the high level of resistance. This resistant cell had high resistance to all the tested solubilized trypsin–treated mixture of crystal multitoxins of B. thuringiensis subsp. aizawai GC-91, an engineering bacterium of Bt, B. thuringiensis subsp. aizawai HD-133 and B. thuringiensis subsp. kurstaki HD-1, and low cross-resistance (19.7-fold) to activated Cry1C. Both N-acetyl-d-galactosamine (GalNAc) and tunicamycin did not inhibit the toxicity of Cry1Ac10 to the susceptible TnH5 cells. Comparison of the total proteins of the selected resistant cells with that of the nonselected susceptible cells by two-dimensional electrophoresis analysis showed that were obvious differences among the 11 protein expressions. These results strongly suggest that there exists an unknown mechanism of resistance in the cell line that was different from the reported mechanisms in insects.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 40 • No. 10