Streptomyces durmitorensis sp. nov., a producer of an FK506-like immunosuppressant.

Screening of soil samples from the Durmitor National Park, Serbia and Montenegro, for strains producing immunosuppressants with a similar mechanism of action to FK506 resulted in the isolation of the actinomycete strain MS405(T). Isolate MS405(T) was found to have morphological and phenotypic properties that were consistent with its classification as a Streptomyces strain. The DNA G+C content of strain MS405(T) was 72 mol%. 16S rRNA gene sequence data confirmed the taxonomic position of the strain, following the generation of phylogenetic trees by using various treeing algorithms. On the basis of 16S rRNA gene sequence similarity, strain MS405(T) was shown to belong to the Streptomyces albidoflavus 'supercluster', being related to Streptomyces aureus DSM 41785(T) (99.59 % similarity) and Streptomyces kanamyceticus DSM 40500(T) (99.32 %). The 16S-23S rRNA internally transcribed spacer (ITS) region exhibited variations in length and sequence composition, showing limited usefulness in phylogenetic analyses. However, DNA relatedness values support the classification of this isolate within a novel species. A number of physiological and biochemical tests distinguished strain MS405(T) from its closest phylogenetic neighbours. Therefore, strain MS405(T) represents a novel species, for which the name Streptomyces durmitorensis sp. nov. is proposed, with the type strain MS405(T) (=DSM 41863(T) =CIP 108995(T)).