RESUMEN
A new coelomycete, Morinia longiappendiculata sp. nov., isolated from living stems of four plant species in central Spain, is described. The distinctive morphological characteristics of this fungus are the production of conidia with long basal and apical appendages on filiform conidiogenous cells that contrasts with the short-appendaged conidia and cylindrical conidiogenic cells of the type species, M. pestalozzioides. Comparative sequence analysis of the ITS rDNA region and fragments of the translation elongation factor 1alpha, actin and chitin synthase 1 genes and the study of the HPLC profiles of the M. longiappendiculata and M. pestalozzioides isolates supported the recognition of the new species. Comparison of the ITS rDNA sequences of the Morinia isolates with GenBank sequences indicated that the genus belongs to the Amphisphaeriaceae with the highest similarity to Bartalinia and Truncatella. Bresadola's original definition of M. pestalozzioides is updated by adding information on conidiogenesis and molecular data. A lectotype and epitype are designated for the species. A study of bioactive metabolites revealed that M. pestalozzioides cultures produced moriniafungin, a novel sordarin analog with potent antifungal activity.
Asunto(s)
Magnoliopsida/microbiología , Xylariales/clasificación , Actinas/genética , Quitina Sintasa/genética , Cromatografía Líquida de Alta Presión , ADN Espaciador Ribosómico/genética , Factores Eucarióticos de Iniciación/genética , Indenos/metabolismo , Tallos de la Planta/microbiología , Esporas Fúngicas/citología , Xylariales/química , Xylariales/citología , Xylariales/genéticaRESUMEN
Inhibition of protein synthesis is one of the validated and highly successful targets for inhibition of bacterial growth; this mechanism is a target of a large number of clinical drugs. Ribosomal protein S4, a primary protein, is a potential target for the discovery of antibacterial agents. We describe, using an antisense-sensitized rpsD Streptomyces aureus strain, the discovery and activity of lucensimycins A and B. [structure: see text].
Asunto(s)
Antibacterianos/biosíntesis , ADN sin Sentido/genética , Streptomyces/genética , Streptomyces/metabolismo , Antibacterianos/farmacología , ADN Bacteriano/genética , Diseño de Fármacos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Compuestos de Espiro/farmacologíaRESUMEN
The manipulation of growth conditions of microorganisms is a common strategy used by pharmaceutical companies to improve the quantities and spectra of secondary metabolites with potential therapeutic interest. In this work, the effects of fermentation media on secondary metabolite production from a set of Actinomycetes was statistically compared. For this purpose, we created an automated method for comparing the ability of microorganisms to produce different secondary metabolites. HPLC analyses guided the selection of those media in which a wider chemical diversity was obtained from microorganisms inoculated in a wide spectrum of production media. Fermented media yielding a better secondary metabolite profile were included in subsequent drug discovery screening.
Asunto(s)
Actinobacteria/crecimiento & desarrollo , Actinobacteria/metabolismo , Cromatografía Líquida de Alta Presión , Medios de Cultivo , Microbiología Industrial/métodos , Actinobacteria/clasificación , Clasificación , Industria Farmacéutica/métodos , FermentaciónRESUMEN
Echinocandins, the lipopeptide class of glucan synthase inhibitors, are an alternative to ergosterol-synthesis inhibitors to treat candidiasis and aspergillosis. Their oral absorption, however, is low and they can only be used parenterally. During a natural product screening program for novel types of glucan synthesis inhibitors with improved bioavailability, a fungal extract was found that inhibited the growth of both a wild-type Saccharomyces cerevisiae strain and the null mutant of the FKS1 gene (fks1::HIS). The mutant strain was more sensitive to growth inhibition, suggesting that the fungal extract could contain an inhibitor of glucan synthesis. A novel acidic steroid, named arundifungin, was purified from a fungal extract obtained from a liquid culture of Arthrinium arundinis collected in Costa Rica. Arundifungin caused the same pattern of hallmark morphological alterations in Aspergillus fumigatus hyphae as echinocandins, further supporting the idea that arundifungin belongs to a new class of glucan synthesis inhibitors. Moreover, its antifungal spectrum was comparable to those of echinocandins and papulacandins, preferentially inhibiting the growth of Candida and Aspergillus strains, with very poor activity against Cryptococcus. Arundifungin was also detected in nine other fungal isolates which were ecologically and taxonomically unrelated, as assessed by sequencing of the ITS1 region. Further, it was also found in two more Arthrinium spp from tropical and temperate regions, in five psychrotolerant conspecific isolates collected on Macquarie Island (South Pacific) and belonging to the Leotiales, and in two endophytes collected in central Spain (a sterile fungus belonging to the Leotiales and an undetermined coelomycete) (AU)
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