Ambruticin represents a new class of antibiotics isolated from a strain of Polyangium cellulosum var. firlvum, a bacterium belonging to the class Myxobacteriales.This antibiotic is a cyclopropyl-polyene-pyran acid and is active in vitro against fungi.Myxobacteria are ubiquitous microorganisms found in soil, on the bark of trees , and on animal dung. These organisms are not detected by the routine methods used in culturing bacteria and fungi but require special techniques for their isolation1). In the course of our program to screen the Myxobacteriales as a source of biologically active compounds, an isolate of Polyangium cellulosum var. firlvum was found to have interesting antifungal properties. The present communication deals with the production and recovery of the antibiotic substances as well as the isolation and characterization of one of the antibiotics from this organism. Fourteen-liter capacity stir vessels (NBS FS-314) containing 10 liters fermentation medium were inoculated with seed culture (5-10 % v/v) and incubated at 32°C with 300 rpm agitation and sterile air supplied at 2 liters/minute through a single sparge hole. Peak titers occurred in -96 hours and harvested broths were pooled and stored at 4°C.Fermentation samples were monitored by a microbiological disc or cylinder-plate assay procedure using SABOURAUD dextrose agar and Microsporum fulvutn or Penicillium sp. (WLRI 0135) as the assay organism.* Proposed USAN

In the course of our work in chromone chemistry1 the hydrolysis of chromone-3-carboxylic esters la and lb was studied. It was found that acid condition gave the expected chromone-3-carboxylic acids 5a and 5b in good yields'. Basic condition, however, resulted in facile rearrangement in high yields to the known 3-acyl-4-hydroxycoumar-ins2•3 3a and 3b.

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