Safety Evaluation of Stacked Genetically Modified Corn Event (MON89034 ×MON88017) Using Zebrafish as an Animal Model

This study assessed the effect of feeding stacked genetically modified (GM) corn event (MON89034 × MON88017) on embryonic development, adult tissue histology and assessed the possibility of transgenic DNA transfer, using zebrafish as an animal model. Adult zebrafish were separated into male and female groups. After 3 weeks of feeding with experimental diets, males and females were paired once a week and fertilized embryos were collected, then the male and female fish were re-turned to their sex-specific groups. This fertilization and embryo collection process were repeated 3 times. Embryonic morphological measurements were obtained on developing embryos up to 96 hours after fertilization, and then the embryos were fixed in 4% phosphate-buffered paraformal-dehyde for morphologic assessment. At the end of the feeding study, various adult zebrafish tissues were histologically examined for abnormalities. Both zebrafish tissues and embryos were analyzed for presence of plant specific genes and transgenic sequences. No changes or abnormalities were observed in embryonic morphology nor in any of the tissues examined histologically. In addition, no plant DNA reference genes or transgenic DNA were found in any of the analyzed samples. These results demonstrate that the safety and nutrition of MON89034 × MON88017 corn are similar to non-GM corn.

Decreased bioavailability of aminomethylphosphonic acid(AMPA)in genetically modified corn with activated carbon or calcium montmorillonite clay inclusion in soil

The widespread use of pesticides has resulted in detectable residues throughout the environment,sometimes at concentrations well above regulatory limits.Therefore,the development of safe,effective,field-practical,and economically feasible strategies to mitigate the effects of pesticides is warranted.Glyphosate is an organophosphorus herbicide that is degraded to aminomethylphosphonic acid(AMPA),a toxic and persistent metabolite that can accumulate in soil and sediment and translocate to plants.In this study,we investigated the binding efficacy of activated carbon(AC)and calcium montmorillonite(CM)clay to decrease AMPA bioavailability from soil and AMPA translocation to plants.Adsorption isotherms and thermodynamic studies on AC and CM were conducted and showed tight binding(enthalpy values>-20 k J/mol)for AMPA with high capacities(0.25 mol/kg and 0.38 mol/kg,respectively),based on derivations from the Langmuir model.A hydra assay was utilized to indicate toxicity of AMPA and the inclusion of 1%AC and CM both resulted in 90%protection of the hydra(**p≤0.01).Further studies in glyphosate-contaminated soil showed that AC and CM significantly reduced AMPA bioavailability by 53%and 44%,respectively.Results in genetically modified(GM)corn showed a conversion of glyphosate to AMPA in roots and sprouts over a 10-day exposure duration.Inclusion of AC and CM reduced AMPA residues in roots and sprouts by 47%-61%.These studies collectively indicate that AC and CM are effective sorbents for AMPA and could be used to reduce AMPA bioavailability from soil and AMPA residues in GM corn plants.