Antibiotic Produced by Fusarium equiseti NRRL 5537

Abstract

Fusarium equiseti NRRL 5537 grown on an autoclaved white corn grit medium for 3 to 4 weeks at room temperature produced a substance in excess of 5 g/kg of substrate that inhibited some gram-positive bacteria including mycobacteria. Most Bacillus subtilis, Mycobacterium phlei , and Staphylococcus aureus strains were inhibited when 1 μg of the antibiotic per ml was incorporated into the culture medium. Except for Neisseria perflava , gram-negative bacteria, yeasts, and molds were not inhibited by 128 μg/ml. The antibiotic was recovered as a white powder, had a melting point of 65 to 66 C, and had an intraperitoneal mean lethal dose in white mice of 63 mg/kg of body weight. In thin-layer chromatographic analysis the compound appeared as a single spot in two different solvent systems. Mass spectrometry determined that the molecular weight of the antibiotic was 373 with a molecular formula of C 22 H 31 NO 4 . Chemical microanalysis was in accord with the formula.

Comparison of the chemistry and diversity of endophytes isolated from wild-harvested and greenhouse-cultivated yerba mansa (Anemopsis californica)

“…Compound 1 inhibited growth of S. aureus (IC 50 of 50 µg/mL), but complete growth inhibition was not achieved against this organism (MIC > 50 µg/mL, the highest concentration tested). The activity of equisetin ( 4 ) agreed with literature (MIC of 1 µg/mL against S. aureus and inactive against P. aeruginosa ) (Burmeister et al, 1974; Hellwig et al, 2002). 5'-epiequisetin ( 5 ) has not been previously evaluated for antimicrobial effects, and it demonstrated an MIC of 1 µg/mL against S. aureus.…”

Hymenosetin, a 3-decalinoyltetramic acid antibiotic from cultures of the ash dieback pathogen, Hymenoscyphus pseudoalbidus

“…Examples are equisetin (a well-known "mycotoxin" from Fusarium equiseti; Burmeister et al, 1974), phomasetin (from Fusarium heterosporum and a Phoma sp. ; Singh et al, 1998), altersetin (from endophytic Alternaria spp.…”

Control of the Stereochemical Course of [4+2] Cycloaddition during trans‐Decalin Formation by Fsa2‐Family Enzymes

“…Decalin‐containing pyrrolidin‐2‐ones, represented by equisetin ( 1 ), constitute a bioactive scaffold produced by filamentous fungi that is biosynthesized by polyketide (PKS)/nonribosomal peptide synthetase (NRPS) hybrid enzymes . A linear polyene intermediate, which is formed by the action of a highly reducing, iterative type I PKS module in collaboration with a trans‐acting enoyl reductase (trans‐ER), serves as a substrate for intramolecular [4+2] cycloaddition catalyzed by Fsa2 and its homologues.…”