Characterization of cultured insect cells selected by Bacillus thuringiensis crystal toxin.
Selection for resistance against Bacillus thuringiensis (Bt) Cry1Ac10 in the Trichoplusia ni (Hubner) 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.
Liu
Kaiyu
K
Institute of Entomology, Central China Normal University, Wuhan 430079, People's Republic of China.
Zheng
Binglian
B
Hong
Huazhu
H
Jiang
Caifu
C
Peng
Rong
R
Peng
Jianxin
J
Yu
Zehua
Z
Zheng
Jin
J
Yang
Hong
H
D000116:Acetylgalactosamine / Q000378:metabolism; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000633:toxicity*; D001427:Bacterial Toxins / Q000633:toxicity*; D002460:Cell Line / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004351:Drug Resistance / Q000187:drug effects* / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D004731:Endotoxins / Q000633:toxicity*; D006460:Hemolysin Proteins; D019476:Insect Proteins / Q000378:metabolism; D009036:Moths / Q000166:cytology*; D012641:Selection, Genetic; D014415:Tunicamycin / Q000378:metabolism
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D014415:Tunicamycin; D000116:Acetylgalactosamine