|Goodman, Cynthia - Cindy|
Submitted to: Congress on In Vitro Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/9/2003
Publication Date: 5/19/2003
Citation: GOODMAN, C.L., NABLI, H., BAUM, J., MALVAR, T., ISAAC, B., MCINTOSH, A.H., LEE, Y., PHIPPS, S.M. Effect of Bt Proteins on the Viability of Selected Insect Cell Lines. CONGRESS ON IN VITRO BIOLOGY. 2003. v. 39. p. 34A. Interpretive Summary:
Technical Abstract: Bt proteins (Cry proteins) are anti-insect proteins that are generated by the bacterium Bacillus thuringiensis. These proteins are commonly used as a means to control pest insects (either by direct application or by insertion of their genes into plant genomes). Although many studies have been undertaken to determine their mechanism(s) of action and their species specificities, much variation exists between proteins. Therefore, in vitro studies were undertaken to aid in the evaluation of these biocontrol agents. The responses to selected Bt proteins of cell lines from the corn earworm/cotton bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), a major pest of corn and cotton, were determined using a viability assay. Additionally, the degree to which the proteins bound to the cells was evaluated by Western blot. The cell lines tested included those from the following tissues: larval midgut (BCIRL-HzMG8, RP-HzGUT-AW), larval fat body (BCIRL-HzFB33), and pupal ovaries (BCIRL-HzAM1). The Cry proteins used in our studies included the lepidopteran-specific protein Cry1Ac and the coleopteran-specific protein Cry3Bb. For each protein, no differences were seen in the degree to which they bound to each lepidopteran cell line (e.g., Cry1Ac bound similarly to each cell line). However, binding differences were noted between proteins (i.e., Cry1Ac bound to a greater degree than Cry3Bb). In the viability studies, none of the lepidopteran cell lines exhibited changes in viability when exposed to Cry3Bb, whereas many of these lines exhibited dose-dependent reductions in viability when exposed to Cry1Ac. Effects of pH on cell viability and cell-protein interactions were noted as well, with the latter being minimally affected by changes in pH.