AGRO 48 |
| Since the debut of genetically enhanced crops in the field in the mid-1990s, their potential risk to ecosystems has been of concern to some government agencies and others. Risk assessment of Bt proteins in soil has been hindered by lack of efficient quantitative detection methods due to the low extractability of Bt proteins from soil. Recently, we adopted a novel approach using a synthetic invertebrate gut fluid as an extraction buffer, which can effectively extract Bt proteins from soil. Coupled with an immunoassay, this system provides a powerful tool to quantitatively assess the Bt protein in soil. We validated the Cry1F and Cry1Ac quantitative ELISA methods using synthetic gut fluid as an extraction system for soil over the range of 18 to 180 ng/g dry weight. Both assays demonstrated good accuracy and precision with a detection limit of 4.5 ng/g. These methods were then applied to determine Cry1F and Cry1Ac levels in soil samples collected from fields where transgenic Herculex I corn and WideStrike cotton had been grown for 3 consecutive years. Confirmatory bioassays were also conducted. The negligible levels of Bt protein in soil after cultivation of Bt crops will be discussed. |
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New Developments and Issues in Agrochemical Sciences
8:00 AM-11:00 AM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster
Sci-Mix
Division of Agrochemicals |