EN
During the early epoch of biological evolution, aluminium was not available for the primitive organisms because of the low solubility of aluminium compounds. This can explain why aluminium is toxic for the present-day living organisms. We studied the toxic effect of aluminium by feeding Drosophila melanogaster adults for 24 hrs. with a 1% sugar solution containing different concentrations of aluminium sulphate. The effect of magnesium chloride was also tested in combination with aluminium. After 24 hrs. we calculated the survival rate, and solubilised the flies in concentrated nitric acid in a microwave oven. The Al, Na, Mg and Zn content of the solubilised flies was measured with the ICP-AES method. We found no change in the Zn content while the Al and Mg content changed according to the treatment, and the Na content decreased significantly (20-30%) in all the cases. We suppose that the flies were mainly killed by the elevated sodium efflux resulting in a decreased intracellular pH. The cause of the elevated Na efflux could be the increased rigidity of the cell membrane caused by the aluminium. We discuss the experimental results and the supposable mechanism of toxicity.