Isolation and Some Characteristics of Haemin Dependent Mutants of Bacillus subtilis

SUMMARY: Haemin dependent mutants were isolated from Bacillus subtilis after (a) ultraviolet irradiation and selection by streptomycin, (b) exposure of the organisms to copper ions and (c) treatment with N-methyl-N'-nitro-N-nitro-soguanidine. The isolates were grown in a synthetic medium containing hae-min when substances able to neutralize inhibitory factors and to stabilize the medium were included. Two of the mutants were capable of growth in media supplemented only with δ-aminolaevulinic acid, the first intermediate of porphyrin synthesis. Transformation of the mutants to haemin independence was accomplished using deoxyribonucleic acid.