The protein produced by Bt crops is generally called a Bt protoxin which can be represented by a pen without a cap. So once the pest consumes a part of a Bt plant, the Bt protoxin (pen) meets with a receptor inside the insect's gut which is represented by the cap of the pen. When the protoxin (pen) and the receptor (cap) bind together in alkaline gut condition, they become an activated toxin, ready to poison the gut of the pest such as cotton bollworm, the eggplant fruit and shoot borer, and the Asian and European corn borers.
When non-target organisms (like humans and animals) ingest a part of a Bt plant, the toxin will not be activated because the receptor (cap) is only present in the gut of target organisms. Thus, the Bt protoxin will not take its action and become a toxin. Bt plants therefore are as safe as its conventional counterparts for food and feed. It has been proven safe by international food safety agencies since Bt corn were introduced in 1996.
For more information about Bt technology, read ISAAA Pocket K No. 6 at http://isaaa.org/resources/publications/pocketk/6/default.asp.
|Artwork by Rene Aranda, Philippine Star.|
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