Search

Two new tetramic acid derivatives, traminines A (1) and B (2), were isolated from a culture broth of Fusarium concentricum FKI-7550 by bioassay-guided fractionation using multidrug-sensitive Saccharomyces cerevisiae 12geneΔ0HSR-iERG6. The chemical structures of 1 and 2 were elucidated by NMR studies. Compounds 1 and 2 inhibited the growth of the multidrug-sensitive yeast strain on nonfermentable medium containing glycerol, but not on fermentable medium containing glucose. These results strongly suggest that they target mitochondrial machineries presiding over ATP production via oxidative phosphorylation. Throughout the assay monitoring overall ADP-uptake/ATP-release in yeast mitochondria, 1 and 2 were shown to inhibit one or more enzymes involving oxidative phosphorylation. Based on biochemical characterization, we found that the interference with oxidative phosphorylation by 1 is attributable to the dual inhibition of complex III and FoF1-ATPase, whereas that by 2 is solely due to the inhibition of complex III., (© The Author(s) 2021. Published by Oxford University Press on behalf of Society of Industrial Microbiology and Biotechnology.)

A new compound, fusaramin (1), along with three known compounds, sambutoxin (2), N-demethylsambutoxin (3) and (-)-6-deoxyoxysporidinone (4), was isolated from a culture broth of Fusarium sp. FKI-7550 by bioassay-guided fractionation using multidrug-sensitive Saccharomyces cerevisiae 12geneΔ0HSR-iERG6. The chemical structure of 1 was elucidated by NMR studies and electronic circular dichroism spectrum. Compound 1 showed antibacterial activity against some Gram-positive and Gram-negative bacteria and inhibited the growth of S. cerevisiae 12geneΔ0HSR-iERG6 grown on glycerol-containing medium. The MICs of 1 against wild-type and multidrug-sensitive yeasts grown on glycerol-containing medium were >128 μg ml -1 and 0.64 μg ml -1 , respectively. However, MICs of 1 against both yeast strains grown on glucose-containing medium were >128 μg ml -1 . All compounds showed inhibition of ATP synthesis via oxidative phosphorylation using isolated S. cerevisiae mitochondria.

An acinar morphogenesis inhibitor named fusarisetin A (1) that possesses both an unprecedented carbon skeleton and a new pentacyclic ring system has been identified from an in-house fractionated fungal library using a three-dimensional matrigel-induced acinar morphogenesis assay system. The structure of 1 was determined in detail by NMR and circular dichroism spectroscopy, X-ray analysis, and chemical reaction experiments., (© 2011 American Chemical Society)