Scientists propose better profiling for GM crops
profiles for the coming generation of genetically modified
organisms (GMOs), Spanish scientists have reported.
The invention, published in the American Chemical Society's journal Analytical Chemistry, analyses the potential changes in the composition of amino acids (the building blocks of proteins) in transgenic crops. The new technique should be welcomed by both industry and consumers alike, particularly in the GM-sceptic European Union, since it has the potential to improve the nutritional and safety profiling of the crops and show how transgenic organisms may match or differ from their conventional counterparts Focusing on the chemical structure of the amino acids, lead author Miguel Herrero and co-workers from Spain's Institute of Industrial Fermentations (CSIC) in Madrid used the technique to measure the presence of "L" or "D" forms of the amino acid, which may affect nutritional quality and digestibility. The L/D system is a way of explaining the spatial configuration of amino acids. The compounds are non-superimposable mirror images of each other; in the same way as one's left hand is the same but opposite of one's right hand. Each form has different properties, with D-amino acids, for example, appeared to be involved with ageing and disease in humans. "The analysis of chiral amino acids in transgenic foods demonstrated for the first time in the present work, apart from having interesting nutritional and safety implications, can be used as an additional indicator for assessing the existence (or not) of unexpected modifications in other metabolic pathways linked to the amino acids profile within a GMO," wrote the researchers. The researchers combined micellar electrokinetic chromatography (MEKC) with a chiral selector and laser-induced fluorescence (LIF) to investigate the prevalence of L- and D-amino acids in conventional and transgenic (Bt) maize varieties. Herrero and co-workers report that the technique was able to separate the amino acids in less than 25 min, and found that the conventional maize varieties showed different profiles for the L- and D-amino acids, said to reflect the variability expected from nature. Comparison with the corresponding transgenic varieties and found no significant difference in the amino-acid profiles. "This result seems to indicate that, in these maize samples, the new inserted Cry1Ab transgene has not modified any metabolic pathway linked to the detected amino acids, which seems to add a further proof about the safety equivalence of these samples," said the researchers. "From our results, it can be concluded that the use of enantioselective procedures can open new perspectives in the study of the chemical composition, unexpected modifications, or both of GMOs," they concluded. Source: Analytical Chemistry Published on-line ahead of print, ASAP Article 10.1021/ac070454f S0003-2700(07)00454-4 "Analysis of Chiral Amino Acids in Conventional and Transgenic Maize" Authors: M. Herrero, E. Ibanez, P.J. Martin-lvarez, and A. Cifuentes
