Metabolic products of microorganisms 167. Cyclopaldic acid from Aspergillus duricaulis. 1. Production, isolation and bioloical properties.

In the course of a screening for new metabolites from fungi we isolated a substance with antimicrobial activity from cultures of Aspergillus duricaulis (CBS 481.65) (Tü 679). It was antagonized by putrescine, spermidine, spermine, arginine, citrulline, lysine, ornithine, in higher concentration by aspraagine and glutamine too. The effect of ethylenediaminetetraacetate on the susceptibility of Streptomyces viridochromogenes (Tü 57) and Bacillus subtilis ATCC 6051 to this antibiotic has been studied. The substance was characterized and identified as cyclopaldic acid.