ION ANTAGONISMS IN MICROORGANISMS: INTERFERENCE OF NORMAL MAGNESIUM METABOLISM BY NICKEL, COBALT, CADMIUM, ZINC, AND MANGANESE

Abstract
The influence of Mg on toxicity of Ni, Co, Cd, Zn, and Mn has been demonstrated in Escherichia coli. The toxicity of these cations is markedly lowered in the presence of 200 ppm. Mg while toxicity is increased if only small amts. of Mg are present. The toxicity of Ni and Co can be similarly diminished by Mg in the case of the 3 other organisms tested: Aerobacter aerogenes, Torulopsis utilis, and Aspergillus niger. Tracer extps. with Ni57 and Co56 showed that the higher levels of Mg diminish the amts. of Ni and Co bound by the cells. The results are discussed in terms of competition for enzyme sites.