RESUMO
New antibiotic compounds, melithiazols, were isolated from the culture broth of strains of the myxobacteria Melittangium lichenicola, Archangium gephyra, and Myxococcus stipitatus. The compounds belong to the group of beta-methoxyacrylate (MOA) inhibitors and are related to the myxothiazols. The melithiazols show high antifungal activity, but are less toxic than myxothiazol A and its methyl ester in a growth inhibition assay with mouse cell cultures. The melithiazols inhibit NADH oxidation by submitochondrial particles from beef heart. Melithiazol A blocks the electron transport within the bc1-segment (complex III) and causes a red shift in the reduced spectrum of cytochrome b.
Assuntos
Acrilatos/isolamento & purificação , Acrilatos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Respiração Celular/efeitos dos fármacos , Myxococcales/metabolismo , Tiazóis/isolamento & purificação , Tiazóis/farmacologia , Acrilatos/química , Acrilatos/metabolismo , Animais , Antifúngicos/química , Antifúngicos/metabolismo , Grupo dos Citocromos b/efeitos dos fármacos , Grupo dos Citocromos b/metabolismo , Avaliação Pré-Clínica de Medicamentos , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/farmacologia , Fermentação , Humanos , Lactente , Concentração Inibidora 50 , Metacrilatos , Camundongos , Testes de Sensibilidade Microbiana , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Myxococcales/química , NAD/metabolismo , Estrobilurinas , Relação Estrutura-Atividade , Tiazóis/química , Tiazóis/metabolismoRESUMO
Using haploid and diploid Datura innoxia Mill, callus cultures and cell suspensions it was shown that meristematic material usually attains the lowest possible C-value of a given ploidy level. Parenchyma material of callus cultures, however, indicates a broad scattering of C-values up to 16 C, which is paralleled by C-value distribution of the free cell fraction in actively dividing cell suspensions. In these suspensions, cell division activity seems to be restricted to small meristem-like clusters.