One study shows that the liver cells of mice fed GM soya are more active in gene expression exhibiting further evidence that GM feed effects the physiology of animals for reasons yet unknown. Another study results in Bt toxin binding to mouse intestine. Years after Bt corn have been commercially planted on millions of hectares worldwide, a Bt toxin is found to be highly immunogenic. A third study reveals transgenic deoxyribonucleic acid (DNA) and Bt toxin survive digestion. Which means that neither DNA nor toxin protein breaks down completely in the gut.
In the first study, researchers in Italy from the University of Urbino and University of Perugia have investigated the effect of GM soya mixed into the feed on the liver of newborn mice. Pregnant Swiss mice were fed on a standard lab chow containing wheat, barley, miaze, lafa, skimmed milk minerals and 14 percent of GM soybean engineered for tolerance to roundup (glyphosate) herbicide. Control mice were fed on the same lab chow plus wild soybean. The two sets of litters were analyzed at different times after birth.
No significant differences in body weight or liver weight were found. But when the livers of the mice were examined on electron microscopy, significant differences became apparent. Antibody labeling revealed a stronger labeling in GM-fed mice compared to controls for all gene-splicing factors, indicating a high level of gene expression. But there were no differences in enzyme activities in the rest of the cell, indicating that metabolic activity has not increased. The results suggest that GM-fed mice liver modify their metabolic activity, especially in transcriptional activities without increasing major proteins or changing the cytoplasm. But "the mechanism responsible for such alternation remain unknown."
In the second study researchers from the Center for Genetic Engineering and Biotechnology, Havana, Cuba, reported in 1999 that Cry 1 Ac is a powerful immunogen and when fed to mice, induced antibody responses similar to those obtained with the cholera toxin. In 2000, Cuban researchers teamed up with scientist from the Autonomous University of Mexico in Cuautitla, Mexico and showed that Cry 1 Ac actively binds to the inner and surface of the mouse small intestines, especially to the "brush order" and membranes on the side of the cells that line the small intestines.
(Antonio M. Claparols is president of the Ecological Society of the Philippines and IUCN regional councilor)