martes, febrero 21, 2006

Ecología burocrática

Approving Genetically Modified Crops: A Bureaucratic Ecology

Prof. Joe Cummins, February 16, 2006

In the United States approval of genetically modified (GM) crops involves interaction of several bureaucratic domains. These include primarily the USDA Animal and Plant Health Inspection Service (APHIS) and the Food and Drug Administration (FDA), while the Environmental Protection Agency (EPA) has a limited role in reviewing plant incorporated protection against pests. There seems to be rigid bureaucratic niches that are guarded by bureaucrats who seem willing to sacrifice the public and the environment to maintain the hegemony of their niche. The bureaucratic environment seems to consist of weasel holes leading to burrows or lairs providing protection from discomfort resulting from the ire of multinational corporations. An example of what I am trying to describer is the approval of lysine enhanced maize and the response to public comments , a part of the approval process.

Maize is a major food and feed crop worldwide. However, existing commercial maize lines are not a complete food or feed because they are deficient in the essential amino acid, lysine. For many years efforts have been made using traditional breeding to produce lysine enriched lines and advanced opaque lines have fulfilled that need. However, the Monsanto corporation developed a maize line using genetic engineering to introduce a bacterial gene into the maize that lead to enhanced lysine production in the GM maize. Maize was modified with a bacterial gene to enhance lysine production, that construct included a promoter from maize, an intron from rice, a chloroplast targeting sequence from maize and a transcription terminator from maize. The original genetic construction included adjoining lox recombination signals surrounding a CaMV promoter driving a paromomycin antibiotic resistance selection marker , a bleomycin antibiotic resistance marker along with a transcription termination signal from Agrobacterium. An ampicillin antibiotic resistance marker was present on the plasmid containing the integration cassette but that gene was not added to the maize chromoeomes. The original maize line included a gene for Cre recombinase which could be triggered to cut the integration cassette at the lox signal genes removing the antibiotic resistance amerkers from the maize. The cre recominase gene was removed from the final commercial maize line using crossing and selection (1,2).

FDA-APHIS approved the lysine enhanced maize for production as animal feed and that approval was rapidly followed by FDA approval of the maize for human consumption. Aphis undertook an environmental assessment which led to a finding of no significant impact but limited the review to the issue of the GM maize becoming a plant pest. FDA concluded their consultation for approval of high lysine maize allowing use of the crop for consumption in food and feed(4) APHIS undertook public consultation but limited the discussion to the issue of whether or not GM high lysine maize could be considered a plant pest. APHIS defines Pest: ³Any form of plant or animal life, or any pathogenic agent, injurious or potentially injurious to plants or plant products. Other injurious pests are those capable of causing damage to the agriculture, forestry, and natural resources of a country whether or not the pest is already established in the country².

Replying to comments APHIS declares ³The commenter suggests that APHIS has not adequately evaluated all possible unintended effects of integration or expression of the transgene. He further cites a specific example of an unintended effect due to posttranslational modification of the protein in the host organisms as compared to the native state that affected the allergenicity of the protein.² Strangely, APHIS seems to consider that allergenicity does not deem a plant to be a pest even though it is certainly an injurious trait and should have been considered. The FDA consultation (2) considered allergenicity but failed to deal with the case in which a bean gene specifying an enzyme was transferred to pea leading to the production of a modified enzyme that was immunologically active producing a strong inflammatory response in mammals fed the modified peas (6). Both APHIS (1) and FDA (2) considered allergenicity and both noted that the transgenic protein was immunologically active but neither agency took time to look for inflammatory responses or other immunotoxic effects which can be toxic to fatal in mammals. Certainly, crops that are fatal to mammals shouldbe considered pests, or one might think so.

APHIS further comments ³A similar point was made by another commenter regarding potential of Ogenome-wide¹ damage due to the use of Ocre¹ recombinase in the development of this variety. APHIS disagrees with these suggestions. Differences detected in such genome-wide analyses are only relevant to APHIS¹ assessment if they result in measurable phenotypic changes that affect plant pest risk. APHIS is satisfied that the phenotypic data submitted by the applicant is sufficient to determine that LY038 in no more likely to be a plant pest risk than the non-modified recipient organism.² Strangely, APHIS really made no effort to scrutinize phenotypic data which would result from chromosome instability. Normally, it would be common sense to examine the chromosomes of recombinant organisms and that would be easier than looking for phenotypic changes resulting from chromosomal instability.

In conclusion, APHIS preferred to ignore observation from public consultation that certainly fit their own definition of the term ³plant pest². Along with that both APHIS and FDA allowed submission of chicken feeding studies of the GM high lysine maize that showed the maize did not kill the birds outright and immediately but there was no necropsy data provided in the data set used to review the GM maize. The tissues and organs of the animals should have been examined by qualified veterinary pathologists.Both USDA/APHIS and FDA should have reviewed feeding studies with at least one mammal along with the chickens. Certainly, the data from which the GM maize was approved are not sufficient to insure that the GM maize is not a ³plant pest² according to the APHIS definition. Neither .the USDA/APHIS review nor the FDA review seem to be realistic appraisals of the human and environmental impacts of the modified maize and both dealt with immunological and genetic impacts in a cavalier manner. It would be better to have a single agency oversee the approval of GM crops and to have an adjudication of such approvals by an independent body.

Reference

1.Luca, D. Petition for determination of non regulated status for lysine maize LY038 2004 http://www.aphis.usda.gov/brs/not_reg.html
2. FDA CFSAN/Office of Food Additive Safety Biotechnology Consultation Note to the File BNF No. 000087 2005
http://www.cfsan.fda.gov/~rdb/bnfm087.html

3.USDA/AP{HIS Environment Assessment and Finding of No Significant Impact Petition for determination of non regulated status for lysine maize LY038 2005 http://www.aphis.usda.gov/brs/not_reg.html
4. FDA CFSAN/Office of Food Additive Safety Biotechnology Consultation Agency Response Letter BNF No. 000087 2005
http://www.cfsan.fda.gov/~rdb/bnfl087.html

5. APHIS Definitions 2006
http://www.aphis.usda.gov/ppq/pim/exports/glossary_definition.html#16
6. Prescott VE, Campbell PM, Moore A, Mattes J, Rothenberg ME, Foster PS, Higgins TJ and Hogan SP. Transgenic expression of bean alpha-amylase inhibitor in peas results in altered structure and immunogenicity. J
Agric Food Chem. 2005 Nov 16;53(23):9023-30

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