RESUMEN
The endophytic Streptomyces coelicolor strain AZRA 37 was isolated from the surface sterilized root of Azadirachta indica A. Juss., commonly known as neem plant in India. Since only a few reports are available regarding epigenetic modulations of microbial entities, S. coelicolor was treated with different concentrations of 5-azacytidine for this purpose and evaluated for its antibacterial potential against five human pathogenic bacteria (Aeromonas hydrophila IMS/GN11, Enterococcus faecalis IMS/GN7, Salmonella typhi MTCC 3216, Shigella flexneri ATCC 12022 and Staphylococcus aureus ATCC 25923). The crude extract obtained from cultures treated with 25 µM concentration of 5-azacytidine, was found effective against all five pathogenic bacteria tested while the untreated control was only active against 3 pathogenic bacteria. HPLC analysis of crude compounds from treated cultures showed a greater number of compounds than that of the control. Extraction of whole cell protein and its SDS PAGE analysis showed an additional major protein band in 25 µM 5-azacytidine treated culture and MALDI TOF MS/MS analysis revealed that this protein belongs to the porin family.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/farmacología , Epigénesis Genética , Regulación Bacteriana de la Expresión Génica , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Antibacterianos/biosíntesis , Antibacterianos/química , Azacitidina/farmacología , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/química , Cromatografía Líquida de Alta Presión , Humanos , Pruebas de Sensibilidad Microbiana , Filogenia , ARN Ribosómico 16S/genética , Metabolismo Secundario , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Streptomyces coelicolor/clasificación , Streptomyces coelicolor/efectos de los fármacos , Streptomyces coelicolor/aislamiento & purificaciónRESUMEN
UNLABELLED: Soils host diverse microbial communities that include filamentous actinobacteria (actinomycetes). These bacteria have been a rich source of useful metabolites, including antimicrobials, antifungals, anticancer agents, siderophores, and immunosuppressants. While humans have long exploited these compounds for therapeutic purposes, the role these natural products may play in mediating interactions between actinomycetes has been difficult to ascertain. As an initial step toward understanding these chemical interactions at a systems level, we employed the emerging techniques of nanospray desorption electrospray ionization (NanoDESI) and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry to gain a global chemical view of the model bacterium Streptomyces coelicolor interacting with five other actinomycetes. In each interaction, the majority of secreted compounds associated with S. coelicolor colonies were unique, suggesting an idiosyncratic response from S. coelicolor. Spectral networking revealed a family of unknown compounds produced by S. coelicolor during several interactions. These compounds constitute an extended suite of at least 12 different desferrioxamines with acyl side chains of various lengths; their production was triggered by siderophores made by neighboring strains. Taken together, these results illustrate that chemical interactions between actinomycete bacteria exhibit high complexity and specificity and can drive differential secondary metabolite production. IMPORTANCE: Actinomycetes, filamentous actinobacteria from the soil, are the deepest natural source of useful medicinal compounds, including antibiotics, antifungals, and anticancer agents. There is great interest in developing new strategies that increase the diversity of metabolites secreted by actinomycetes in the laboratory. Here we used several metabolomic approaches to examine the chemicals made by these bacteria when grown in pairwise coculture. We found that these interspecies interactions stimulated production of numerous chemical compounds that were not made when they grew alone. Among these compounds were at least 12 different versions of a molecule called desferrioxamine, a siderophore used by the bacteria to gather iron. Many other compounds of unknown identity were also observed, and the pattern of compound production varied greatly among the interaction sets. These findings suggest that chemical interactions between actinomycetes are surprisingly complex and that coculture may be a promising strategy for finding new molecules from actinomycetes.
Asunto(s)
Metaboloma , Interacciones Microbianas , Streptomyces coelicolor/química , Streptomyces coelicolor/metabolismo , Actinobacteria , Bacterias , Microbiología del Suelo , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Streptomyces coelicolor/aislamiento & purificaciónRESUMEN
Large numbers of filamentous actinomycetes which formed distinctive red coloured colonies were isolated from three out of four composite soil samples using a medium designed to be selective for members of the Streptomyces violaceoruber clade, a taxon which includes the model organisms "Streptomyces coelicolor" A3(2) and "Streptomyces lividans" 66. The isolation medium, dextran-histidine-sodium chloride-mineral salts agar supplemented with antibacterial and antifungal antibiotics, also supported the growth of representatives of the S. violaceoruber clade. One hundred and ninety one representatives of the isolates that produced red colour colonies on the isolation medium were distributed into four colour groups based on their ability to form distinctive pigments and morphological properties typical of members of the S. violaceoruber clade, an assignment that was confirmed by corresponding 16S rRNA gene sequencing studies. The selective isolation and characterisation procedures used in the present investigation provide a practical means of determining the taxonomic diversity, geographical distribution and roles of representatives of the S. violaceoruber clade in natural habitats.