METABOLIC PRODUCTS OF MICROORGANISMS .263. NIKKOMYCINS SZ, SX, SOZ AND SOX, NEW INTERMEDIATES ASSOCIATED TO THE NIKKOMYCIN BIOSYNTHESIS OF STREPTOMYCES-TENDAE

New intermediates associated with nikkomycin biosynthesis, called nikkomycins S(z), S(x), So(z) and So(x), were isolated and characterized from the culture broth of Streptomyces tendae Tu 901/S 2566. They are analogues to octosyl acids, shunt metabolites of polyoxin biosynthesis. The decreasing amounts of nikkomycins S(z) and S(x), produced in the culture medium, shows a significant correlation to the increasing amounts of the biologically active nikkomycins Z and X, dependent on the increasing concentration of iron.