RESUMO
'Streptomyces tsukubaensis' was the first tacrolimus producer strain identified. Although it has been included in the Streptomyces genus, its taxonomic position has not been rigorously determined. By using a polyphasic approach, we have established that the tacrolimus producer strain 'S. tsukubaensis' NRRL 18488 represents a unique species in the Streptomyces genus, which is phylogenetically distant from other subsequently described producers. This fact means a horizontal transference of the tacrolimus-producing gene cluster. Physiology, nutrient requirement, and molecular genetics analyses of tacrolimus biosynthesis in 'S. tsukubaensis' necessitate chemically defined or semi-defined media, which work as a jigsaw puzzle and allow for pieces (nutrients) exchange. To date, studies related to 'S. tsukubaensis' have been mainly focused in the improvement of tacrolimus production using complex industrial fermentation media, which difficulty allows testing of tacrolimus overproduction enhancers or inhibitors because of the presence of non-defined substances. In the present work, two semi-defined media were developed in order to study the main factors involved in tacrolimus production in 'S. tsukubaensis'.
Assuntos
Meios de Cultura/química , Streptomyces/classificação , Streptomyces/metabolismo , Tacrolimo/metabolismo , Técnicas de Tipagem Bacteriana , Composição de Bases , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomyces/crescimento & desenvolvimentoRESUMO
The number of tacrolimus (FK506)-producing isolates has increased remarkably because of the clinical importance of tacrolimus as an immunosuppressant. However, the taxonomy of several of these isolates has not been studied. The taxonomic status of strain ATCC 55098(T), a tacrolimus-producing strain, was determined in this study. The genotypic, phenotypic and chemotaxonomic properties were consistent with the inclusion of strain ATCC 55098(T) in the genus Streptomyces. The 16S rRNA gene sequence of strain ATCC 55098(T) was determined and used to generate phylogenetic trees with corresponding sequences of the most closely related type strains (≥ 98â% 16S rRNA gene sequence similarity) of species of the genus Streptomyces. Strain ATCC 55098(T) formed a distinct phylogenetic branch adjacent to a cluster comprising Streptomyces fulvissimus NBRC 13482(T) and Streptomyces flavofungini NBRC 13371(T). However, morphological and physiological tests and DNA-DNA relatedness distinguished strain ATCC 55098(T) from its closest phylogenetic neighbours. On the basis of these results, strain ATCC 55098(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces tacrolimicus sp. nov. is proposed. The type strain is ATCC 55098(T) (â=âCECT 7664(T)).
Assuntos
Imunossupressores/metabolismo , Streptomyces/classificação , Streptomyces/isolamento & purificação , Tacrolimo/metabolismo , DNA Bacteriano/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Streptomyces/genética , Streptomyces/metabolismoRESUMO
Carotenoids are important pigments produced by plants and many microorganisms, including fungi, microalgae, cyanobacteria, and bacteria. Marine actinomycetes are a group of bacteria that produce a variety of metabolites with economic potential. Here, we describe a general method of selecting marine actinomycetes as carotenoids' producers. The screening is carried out at two levels: the first one involves a quick selection of strains by visual color inspection, and the second consists in the analysis of the extracts by HPLC. The taxonomic analysis of the producing strains gives us an overview of the groups of actinomycetes in which carotenoids can be found.