Science in Society Archive

GM food safe?

Recent incidents and scientific findings cast grave doubts over the safety of GM food and feed. We shall be circulating a selection of the following reports.

  1. Cows Ate GM Maize & Died
  2. Transgenic DNA and Bt Toxin Survive Digestion
  3. Bt Toxin Binds to Mouse Intestine
  4. Syngenta’s Spanish GM Trojan Horse
  5. Liver of Mice Fed GM Soya Works Overtime
  6. Animals Avoid GM, for Good Reasons

Liver of Mice Fed GM Soya Works Overtime

The liver cells of mice fed GM soya are more active in gene expression. Dr. Mae-Wan Ho reports on further evidence that GM feed affects the physiology of animals for reasons yet unknown.

Liver is a primary site for transforming the products of digestion, and is strategically located between the digestive tract and the general circulation. It degrades and detoxifies toxic compounds from the gut and general circulation, and excretes them into the bile. It synthesizes many protein components of blood plasma and exercises an important degree of control over the general metabolism.

Researchers in Italy, from the University of Urbino and University of Perugia, have investigated the effect of GM soya incorporated into the feed on the liver of newborn mice. Pregnant Swiss mice were fed on a standard lab chow containing wheat, barley, maize, alfafa, skimmed milk, minerals and 14% GM soybean engineered for tolerance to Roundup (glyphosate) herbicide. Control mice were fed on the same lab chow plus wild soybean. The litters obtained were analysed 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.

The liver cells from control mice examined at 1, 2, 5 and 8 months of age generally showed nuclei that were round, containing clumps of condensed (inactive) chromatin (complex of protein and DNA that make up chromosomes) distributed both at the nuclear periphery and in the middle of the nucleus. The rest of the nucleus similarly looked well organised, as typical of a liver working normally. The nucleoli inside the nucleus were also round. The nucleoli (singular: nucleolus) are the sites of gene transcription. A roundish shape again indicates a low level of activity.

The nuclei of liver cells from 1 month-old mice fed on GM soya showed roundish shapes similar to controls. But those from 2, 5 and 8 month-old mice frequently showed an irregular wavy shape, with many pores between the nucleus and the cytoplasm, and a tendency to be less organised inside the nucleus. The nucleoli were irregularly shaped with numerous centres containing small fibrils that are indicative of gene transcription activity.

Antibody labelling revealed a stronger labelling 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.

An irregularly shaped nucleus generally represents a high rate of gene expression activity that’s needed to support an increase in metabolic activity. An increase in the nucleus-cytoplasmic interface provided by the wavy shape of the nucleus in the GM-fed mice may improve molecular traffic between two cellular compartments. This is also consistent with increased nuclear pore frequency in the cells from GM-fed mice and the increased activity of the nucleoli.

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 mechanisms responsible for such alterations remain unknown.”

Article first published 2004


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