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26-04-2003, 12:30 PM
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Yet another toxin to be put into GM food without proper testing of its safety
http://www.epa.gov/fedrgstr/EPA-PEST...y-07/p5620.htm [Federal Register: March 7, 2003 (Volume 68, Number 45)] .. ENVIRONMENTAL PROTECTION AGENCY [OPP-2002-0350; FRL-7285-8] Notice of Filing a Pesticide Petition to Establish a Tolerance for a Certain Pesticide Chemical in or on Food snip for brevity Mycogen/Dow AgroSciences PP 0G6112 This notice of filing summarizes information submitted and cited by Mycogen/Dow AgroSciences in support of a request for a temporary exemption from tolerance residues of the plant-incorporated protectant Bacillus thuringiensis (B.t. Cry34/35Ab1 Insecticidal Crystal Protein (ICP), and the genetic material necessary for its production in corn (formerly known as Bacillus thuringiensis (B.t.)) 149B1 protein and the genetic material necessary for its production in corn). The Mycogen/Dow AgroSciences and Pioneer Hi-Bred experimental use permits associated with the petition are 68467-EUP-3, 68467-EUP-5, 68467-EUP-T, 68467-EUP- I, 29964-EUP-1, 29964-EUP-3, 29964-EUP-U, and 29964-EUP-L. A. Petition Summary for B.t. Cry34/35Ab1 ICP Uses B.t. Cry34/35Ab1 ICP is expressed in corn plants to provide protection from key coleopteran insect pests such as the western corn rootworm. B.t. Cry34/35Ab1 transgenic plants are derived from transformation events that contain the insecticidal genes via a plasmid insert. The B.t. Cry34/35Ab1 ICP poses no foreseeable risks to non- target organisms including mammals, birds, fish, beneficial insects, and earthworms. B.t. Cry34/35Ab1-protected field corn provides growers with a highly efficacious tool for controlling important insect pests in corn in a manner that is fully compatible with integrated pest management practices. B. Product Identity and Chemistry The Cry34Ab1 and Cry35Ab1 genes were isolated from Bacillus thuringiensis strain PS149B1 and modified before insertion into corn plants. The Cry34/35Ab1 ICP has been adequately characterized. Several safety studies were conducted using microbially produced test substances that contained 54% of the Cry34Ab1 (14 kDa) protein and 37% of the Cry35Ab1 (44 kDa) protein. Studies conducted to establish the equivalence of the Cry34/35Ab1 ICP obtained from corn or from a microbial source demonstrate that the materials are similar with respect to molecular weight, immunoreactivity, lack of post- translational modification (glycosylation) N-terminal amino acid sequence, and spectrum of bioactivity. A qualitative analytical method (lateral flow immunoassay) for the detection of the Cry34Ab1 (14 kDa) protein has been submitted (MRID #45383401). C. Mammalian Toxicity Profile Cry proteins have been deployed as safe and effective pest control agents in microbial Bacillus thuringiensis formulations for almost 40 years. There are currently 180 registered microbial Bacillus thuringiensis products in the United States for use in agriculture, forestry, and vector control. The numerous toxicology studies conducted with these microbial products show no significant adverse effects, and demonstrate that the products are practically non-toxic to mammals. An exemption from the requirement of a tolerance has been in place for these products since at least 1971 (40 CFR 180.1011). Toxicology studies conducted to determine the toxicity of Cry34/ 35Ab1 ICP demonstrated that the proteins have very low toxicity. The acute oral LDSUB50/SUB of Cry34Ab1 (14 kDa) is greater than 5,000 milligrams/kilogram (mg/kg), and at 54% purity, the acute LDSUB50/SUB for pure protein is greater than 2,700 mg/kg. The acute oral LDSUB50/SUB of Cry35Ab1 (44 kDa) is greater than 5,000 mg/kg, and at 37% purity, the acute LDSUB50/SUB for pure protein is greater than 1,850 mg/kg in male mice when the proteins were tested individually. When tested as a mixture (1:3 molar ratio of Cry34Ab1:Cry35Ab1 proteins), the acute oral LDSUB50/SUB of PS149B1 Cry34/35Ab1 proteins in male and female mice is greater than 5,000 mg/ kg, and greater than 2,000 mg/kg of an equimolar (1:3) mixture of pure proteins. In in vitro studies, Cry34/35Ab1 ICP exhibited a high rate of digestibility under simulated gastric conditions (referred to as SGF) in the presence of pepsin. The Cry34Ab1(14 kDa protein) was greater than 90% digested in SGF 6.2 minutes. The Cry35Ab1 (44 kDa protein) was greater than 97% digested in less than 5 minutes. Also, thermolability testing results showed that the ICP was deactivated following exposure to 60 °C, 75 °C, and 90 °C for 30 minutes. A search of relevant data bases indicated that the amino acid sequences of the Cry34/35Ab1 ICP exhibit no significant homology to the sequences of known protein allergens. Thus, Cry34/35Ab1 ICP is highly unlikely to exhibit an allergic response. The genetic material necessary for the production of the Cry34/ 35Ab1 ICP is nucleic acid (DNA) which is common to all forms of plant and animal life. There are no known instances where nucleic acids have caused toxic effects as a result of dietary exposure. Collectively, the available data on Cry34/35Ab1 ICP along with the safe use history of microbial Bacillus thuringiensis products establishes the safety of the plant-incorporated protectant B.t. Cry34/35Ab1 ICP and the genetic material necessary for its production in all raw agricultural commodities. snip |
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