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The afsA gene of Streptomyces griseus has been postulated to encode a key enzyme for A-factor biosynthesis from primary metabolites commonlypresent in Streptomyces strains. Escherichia coli cells harboring afsA under the control of the T7 promoter specified distinct A-factor activity in the culture broth, as determined by induction of streptomycin production and aerial mycelium and spore formation in an A-factor-deficient S. griseus mutant strain. Production of the substance(s) having A-factor activity was inhibited by cerulenin, an inhibitor of fatty acid biosynthesis. These observations suggest that afsA encodes a key enzyme in the A-factor biosynthetic pathway in which a /?-keto acid derived from fatty acid biosynthesis and a glycerol derivative serve as precursors.

Bioactive Fluorinated Derivative of Amphotericin B. -The synthesis of the first stable, fluorinated derivative of amphotericin B (I) is described. Compound (I) shows hemolytic, K + permeable, and antifungal activities similar to those of amphotericin B. -(MATSUMORI, N.; UMEGAWA, Y.; OISHI, T.; MURATA*, M.; Bioorg. Med. Chem. Lett. 15 (2005) 15, 3565-3567; Dep. Chem., Grad. Sch. Sci.

The structure of threo-SSMs 5 and 6 in Figure 1 was mistakenly drawn for the configuration of a 2-NH group, where a C-N bound should have been drawn with a bold line as shown below. FIGURE 1 Chemical structures of sphingomyelin (D-erythro-SSM, SSM), SSM enantiomer (L-erythro-SSM, ent-SSM), SSM diastereomer (L-threo-SSM, threo-SSM), and their deuterated analogs. (Corrected)