[Gradient extraction of ammonium specific ionophore antibiotics from mycelium]

Streptomyces brunneofungs 118 and S.griseolus 224 were isolated from natural objects and shown to synthesize ammonium specific products belonging to macrotetrolide compounds. Gradient extraction was applied to the mycelium and it was demonstrated that the compounds were rather labile both in the native cells and on synthetic carriers and could be hydrolyzed by aqueous solutions of acetone and ethanol to various linear oligomers of narctinic acids. Acetone mainly stabilized the monomer and dimer fragments whereas in the ethanol extracts a complete set of the oligomers (from the monomer to the tetramer) was detectable. Graident extract of suspension of the microbial intact cells is useful in the study of some properties and the primary identification of biologically active hydrophobic products even at the early stages of their isolation.