[Effect of calcium ions on the differentiation of actinomycetes]

The influence of Ca2+ on the formation of the aerial mycelium in 23 actinomycete strains was studied. It was shown that in concentrations up to 5 mM exogenous Ca2+ induced the formation of the aerial mycelium in 11 out of the 23 actinomycete strains tested. The Ca2+ channel blockers (verapamil and nifedipine), calmodulin inhibitor (chlorpromazine) and Ca2+ chelator (EGTA) inhibited the aerial mycelium formation in 3 streptomycete strains out of the 23 actinomycetes. Chlorpromazine and nifedipine proved to be the most active inhibitors when used in concentrations of 0.2 to 2.5 mumol/disk. The Ca2+ concentrations of 5 mM were found to stimulate the formation of the submerged spores in S. hygroscopicus 155. The activity of ATP synthase was stimulated in the aerial and submerged spores after the Ca2+ uptake.