Comparison of reaction of Streptomyces strain to cadmium and copper ions

Comparative tests on the sensitivity of actinomycetes to cadmium and copper ions were carried out on 19 wild strains of the genus Streptomyces. The strains were tested by placing solutions of cadmium chloride on filter paper disks in quantities of 20 and 40 μg Cd2+, and also 20, 40 and 80 μg Cu2+ converted to metal. Both conidial and vegetative forms of actinomycetes were used as inoculum. Differentiation was found in the reactions of the actinomycetes on the tested metals depending on the nutrient used, especially on nitrogen sources. Copper ions have a greater effect on the vegetative forms of these organisms than cadmium ions, while cadmium ions exert an inhibiting effect on the process of conidia germination.