Interrelationships in trace-element metabolism in metal toxicities in a cobalt-resistant strain of Neurospora crassa

Abstract

A strain of Neurospora crassa was isolated by training the mould to grow on media containing high concentrations of Co2+. This strain, the CoR strain, exhibited approximately tenfold the resistance of the parent strain to Co2+ and Ni2+ but not to Zn2+ or Cu2+. Co2+ toxicity in the CoR strain was reversed by Mg2+ but not by Fe3+. Also, Co2+ did not affect iron metabolism in this strain. It is suggested that the mechanism of resistance in the CoR strain involves an alteration in the pattern of iron metabolism such that the latter is no longer adversely affected by toxic concentrations of Co2+. The CoR strain is genetically stable and is most probably a result of a resistance mutation in N. crassa induced by Co2+.