Structural elucidation of aculeximycin. IV. Absolute structure of aculeximycin, belonging to a new class of macrolide antibiotics.

Aculeximycin (1) produced by Streptosporangium albidum possesses a 30-membered polyhydroxy macrocyclic lactone and five sugars including aculexitriose. We have described the determination of the planar structure of N-diacetylated aculeximycin (2) using degradation products, which were obtained by DBU-methanol treatment, ozonolysis and periodative oxidation. In order to determine the relative and absolute configurations of aculeximycin, first, the relative and absolute configurations of the degradation products 10, 11, 12 and 13 were determined.

Microbial conversion of milbemycins: oxidation of milbemycin A4 and related compounds at the C-25 ethyl group by Circinella umbellata and Absidia cylindrospora.

Microbial oxidation of milbemycin A4 at the C-25 ethyl group was performed. Milbemycin A4 was converted to 31- and 32-hydroxy derivatives by Circinella umbellata SANK 44272 along with 24- and 30-hydroxy derivatives. Related compounds, 5-ketomilbemycin A4 5-oxime and 13 beta-fluoromilbemycin A4 were similarly converted to the hydroxylated compounds by this microorganism.

Novel microbial metabolites of the phoslactomycins family induce production of colony-stimulating factors by bone marrow stromal cells. I. Taxonomy, fermentation and biological properties.

Three metabolites were isolated from the culture broth of an actinomycete strain identified as Streptomyces platensis SANK 60191, that induce the production of colony-stimulating factors (CSFs) by stromal cell line KM-102 at ED50 concentrations from 40 to 200 ng/ml. The compounds induced quantities of granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF) comparable to those induced by interleukin-1, a strong CSF inducer. These metabolites were called leustroducsins (A, B and C) and were later found to be structurally related to phoslactomycins.