On antibiotics from gliding bacteria, part 94.: Cyrmenins, new β-methoxyacrylate inhibitors of the electron transport -: Production, isolation, physico-chemical and biological properties

New antibiotic compounds, named cyrmenins, were isolated from the culture broth of strains of the myxobacteria Cystobacter armeniaca and Archangium gephyra. The compounds belong to the group of beta-methoxyacrylate (MOA) inhibitors and are the first naturally occuring nitrogen-linked MOAs. The cyrmenins show nearly the. same antifungal activity as strobilurin A, but are less toxic in a growth inhibition assay with L929 mouse cells. Cyrmenins inhibit NADH oxidation by submitochondrial particles from beef heart. Investigations by difference spectroscopy showed that cyrmenin B-1 blocks the electron transport within the cytochrome bc(1)-segment (complex III) of the respiratory chain.