GM Controversy Ethics Gene flow Resistance Harm to other
organisms Allergens???
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Overview Introduction: GM foods, allergies, controversy Paper 1
Paper 2 Paper 3 Paper 4 Current regulations Conclusions
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Paper 1: Identification of a Brazil-nut allergen in transgenic
soybeans New England Journal of Medicine 1996
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Purpose: To assess ability of proteins from 1)soybeans (Glycine
max) 2)transgenic soybeans 3)Brazil nuts (Bertholletia excelsa)
4)purified 2S albumin to bind to IgE serum
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Methods: Radio allergosorbent test (RAST) 4 serums Sodium
dodecyl sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) 9
serums Skin Prick Tests
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RAST basics
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Results: RAST More inhibition of IgE binding = more allergic.
Triangles= WT Squares= GM soybean Circles= Brazil nut
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Results: SDS-PAGE IgE binding Total Proteins IgE binding
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Results: Skin-Prick Test
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Main Points: GM soybean protein successfully competed with
Brazil nut protein. IgE from 8/9 allergic to Brazil nut bound to
introduced 2S albumin in GM soybeans.
Slide 20
Overview Introduction: GM foods, allergies, controversy Paper 1
Paper 2 Paper 3 Paper 4 Current regulations Conclusions
Slide 21
Paper 2 Lack of detectable allergenicity of transgenic maize
and soya samples Journal of Allergy and Clinical Immunology
2005
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Purpose: Monitor 5 GM products whose transgenes came from
sources with no allergenic history
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Methods: Food Survey Previous exposure? Skin Prick Tests 27
kids with food allergies 50 patients with asthma rhinitis
SDS-PAGE
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Flour products tested
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Food survey results
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Western Blot
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Testing Lab Supply SDS PAGE Western Blot
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SDS PAGE Western Blot
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Skin prick and IgE results
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Main Point: No detectable difference in IgE reactivity between
wild type and GM soybeans or corn.
Slide 31
Overview Introduction: GM foods, allergies, controversy Paper 1
Paper 2 Paper 3 Paper 4 Current regulations Conclusions
Slide 32
Paper 3 A comparative study of the allergenic potency of
wild-type and glyphosate- tolerant gene-modified soybean cultivars
Acta pathologica, microbiologica et immunologica Scandinavica
2003
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Purpose: To compare allergenicity of 8 wild type and 10 GM
soybeans varieties (all for CP4 EPSPS)
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Methods: RAST (serum from 10 patients) SDS-PAGE Histamine
Release test Skin prick tests
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RAST results More inhibition of labeled IgE binding = more
original serum bound first.
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RAST results Concentration of extract needed for 50% inhibition
of IgE binding (variety #12)
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Histamine Release results Notice lack of any major differences
no where to point an arrow! Skin Prick Test Histamine Release
(0=negative, 6=lots)
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Histamine Release for patient I Pretty similar!
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Main Points: Difference between patients response, but no
statistical difference between WT and TG soybeans. Addition of CP4
EPSPS gene higher allergenicity
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Overview Introduction: GM foods, allergies, controversy Paper 1
Paper 2 Paper 3 Paper 4 Current regulations Conclusions
Slide 41
Paper 4 Genetic modification removes an immunodominant allergen
from soybean Plant Physiology 2003
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Purpose: To silence the Gly m Bd 30K (P34) gene
transgenically
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P34 A major soybean allergen More than 65% of soy-sensitive
patients react only to the P34 protein Less than 1% of total
protein Pigs, calves and salmon also allergic
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Methods: Created a P34 silencing vector (plasmid pKS73) Grew
these into homozyous strains Used SDS-PAGE for presence of P34
protein
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Results
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Soybean Protein Map
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Protein Analysis Wild typeP34 Silenced Missing P34 proteins and
intermediates
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Main Points: TG and WT were indistinguishable in size, shape,
protein and oil content P34 gene silencing was successful
Slide 49
Overview Introduction: GM foods, allergies, controversy Paper 1
Paper 2 Paper 3 Paper 4 Current regulations Conclusions
Slide 50
Whos in charge? Coordinated Framework for the Regulation of
Biotechnology - 1986 3 regulatory bodies of genetically modified
foods: (Animal and Plant Health Inspection Service)
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Considerations: Effect on environment (animals, insects)
Transferable to wild type Digestive stability Toxicity
Weediness
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FDA Food additives Manufacturers responsible for checking
Voluntary consultation process - but all on U.S. market have
undergone
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Conclusions Allergens can be added Mostly, there is no
difference Can also remove allergens Continue studies Continue
monitoring
Slide 54
Additional Works Consulted USDA Website. Biotechnology FAQs.
Accessed 11/21/2009.
http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?contentidonly=true&navi
d=AGRICULTURE&contentid=BiotechnologyFAQs.xml
http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?contentidonly=true&navi
d=AGRICULTURE&contentid=BiotechnologyFAQs.xml Singer, S.,
Raven, D., Johnson G., Losos, J. 2005. Biology 7 th Edition. McGraw
Hill. New York, NY.