Streptomyces asenjonii sp. nov., isolated from hyper-arid Atacama Desert soils and emended description of Streptomyces viridosporus Pridham et al. 1958.

A polyphasic study was undertaken to establish the taxonomic status of Streptomyces strains isolated from hyper-arid Atacama Desert soils. Analysis of the 16S rRNA gene sequences of the isolates showed that they formed a well-defined lineage that was loosely associated with the type strains of several Streptomyces species. Multi-locus sequence analysis based on five housekeeping gene alleles showed that the strains form a homogeneous taxon that is closely related to the type strains of Streptomyces ghanaensis and Streptomyces viridosporus. Representative isolates were shown to have chemotaxonomic and morphological properties consistent with their classification in the genus Streptomyces. The isolates have many phenotypic features in common, some of which distinguish them from S. ghanaensis NRRL B-12104T, their near phylogenetic neighbour. On the basis of these genotypic and phenotypic data it is proposed that the isolates be recognised as a new species within the genus Streptomyces, named Streptomyces asenjonii sp. nov. The type strain of the species is KNN35.1bT (NCIMB 15082T = NRRL B-65050T). Some of the isolates, including the type strain, showed antibacterial activity in standard plug assays. In addition, MLSA, average nucleotide identity and phenotypic data show that the type strains of S. ghanaensis and S. viridosporus belong to the same species. Consequently, it is proposed that the former be recognised as a heterotypic synonym of the latter and an emended description is given for S. viridosporus.

Rhodococcus jostii: a home for Rhodococcus strain RHA1.

The taxonomic position of Rhodococcus strain RHA1, an effective degrader of polychlorinated biphenyls with a large linear chromosome, was established using a polyphasic approach. The morphological and chemotaxonomic properties of the strain were typical of members of the genus Rhodococcus. The strain shared a high level of 16S rRNA sequence similarity (99.9 %) with the type strain of Rhodococcus jostii, a member of the Rhodococcus erythropolis subclade. The two strains shared a DNA:DNA relatedness value well above the cut-off point recommended for the circumscription of genomic species and had a broad range of phenotypic properties in common. The combination of genomic and phenotypic data show strain RHA1 to be a bona fide member of the species Rhodococcus jostii.

Verrucosispora fiedleri sp. nov., an actinomycete isolated from a fjord sediment which synthesizes proximicins.

A novel filamentous actinobacterial organism, designated strain MG-37(T), was isolated from a Norwegian fjord sediment and examined using a polyphasic taxonomic approach. The organism was determined to have chemotaxonomic and morphological properties consistent with its classification in the genus Verrucosispora and formed a distinct phyletic line in the Verrucosispora 16S rRNA gene tree. It was most closely related to Verrucosispora maris DSM 45365(T) (99.5 % 16S rRNA gene similarity) and Verrucosispora gifhornensis DSM 44337(T) (99.4 % 16S rRNA gene similarity) but was distinguished from these strains based on low levels of DNA:DNA relatedness (~56 and ~50 %, respectively). It was readily delineated from all of the type strains of Verrucosispora species based on a combination of phenotypic properties. Isolate MG-37(T) (=NCIMB 14794(T) = NRRL-B-24892(T)) should therefore be classified as the type strain of a novel species of Verrucosispora for which the name Verrucosispora fiedleri is proposed.

Verrucosispora wenchangensis sp. nov., isolated from mangrove soil.

An actinomycete strain 234402(T) was isolated from a mangrove soil sample collected in Wenchang, China. Phylogenetic analysis of the 16S rRNA gene sequence of strain 234402(T) indicated that the highest similarity was to Verrucosispora sediminis MS426(T) (99.25%). The cell wall contained meso-diaminopimelic acid. The major menaquinones were MK-9(H(4)) and MK-9(H(6)), with MK-9(H(8)) as minor components. The characteristic whole-cell sugars were xylose, mannose and glucose. The phospholipid profile was found to comprise phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside and an unknown phospholipid. The DNA G+C content was 69.2 mol%. The results of physiological and biochemical tests and low DNA-DNA relatedness demonstrated strain 234402(T) could be readily distinguished from the closely related Verrucosispora species. On the basis of these phenotypic and genotypic data, strain 234402(T) represents a novel species of the genus Verrucosispora, for which the name Verrucosispora wenchangensis sp. nov. is proposed. The type strain is 234402(T) (=CCTCC AA 2011018(T)=DSM 45674(T)).

Verrucosispora maris sp. nov., a novel deep-sea actinomycete isolated from a marine sediment which produces abyssomicins.

Verrucosispora isolate AB-18-032(T), the abyssomicin- and proximicin-producing actinomycete, has chemotaxonomic and morphological properties consistent with its classification in the genus Verrucosispora. The organism formed a distinct phyletic line in the Verrucosispora 16S rRNA gene tree sharing similarities of 99.7%, 98.7% and 98.9% with Verrucosispora gifhornensis DSM 44337(T), Verrucosispora lutea YIM 013(T) and Verrucosispora sediminis MS 426(T), respectively. It was readily distinguished from the two latter species using a range of phenotypic features and from V. gifhornensis DSM 44337(T), its nearest phylogenetic neighbor, by a DNA G+C content of 65.5 mol% obtained by thermal denaturation and fluorometry and DNA:DNA relatedness values of 64.0% and 65.0% using renaturation and fluorometric methods, respectively. It is apparent from the combined genotypic and phenotypic data that strain AB-18-032(T) should be classified in the genus Verrucosispora as a new species. The name Verrucosispora maris sp. nov. is proposed for this taxon with isolate AB-18-032(T) (= DSM 45365(T) = NRRL B-24793(T)) as the type strain.

Reclassification of 'Dactylosporangium variesporum' as Saccharothrix variisporea corrig. (ex Tomita et al. 1977) sp. nov., nom. rev.

In the course of a polyphasic study it was observed that 'Dactylosporangium variesporum' NRRL B-16296 is misclassified in the genus Dactylosporangium as it exhibits properties consistent with its assignment to the genus Saccharothrix. Phylogenetic analyses based on 16S rRNA gene sequences show that the strain falls within the evolutionary radiation of the genus Saccharothrix, a result which is supported by corresponding chemotaxonomic and morphological markers. The strain is phylogenetically most closely, albeit loosely, related to Saccharothrix espanaensis, but can be readily distinguished from this and other species of the genus Saccharothrix with validly described names by using a range of phenotypic properties. The combined genotypic and phenotypic data demonstrate conclusively that this strain should be classified as a new species in the genus Saccharothrix for which the name Saccharothrix variisporea sp. nov. is proposed. The type strain is NRRL B-16296(T) (=ATCC 31203(T) =DSM 43911(T) =JCM 3273(T) =NBRC 14104(T)).

Diversity of culturable actinomycetes in hyper-arid soils of the Atacama Desert, Chile.

The Atacama Desert presents one of the most extreme environments on Earth and we report here the first extensive isolations of actinomycetes from soils at various locations within the Desert. The use of selective isolation procedures enabled actinomycetes to be recovered from arid, hyper-arid and even extreme hyper-arid environments in significant numbers and diversity. In some cases actinomycetes were the only culturable bacteria to be isolated under the conditions of this study. Phylogenetic analysis and some phenotypic characterisation revealed that the majority of isolates belonged to members of the genera Amycolatopsis, Lechevalieria and Streptomyces, a high proportion of which represent novel centres of taxonomic variation. The results of this study support the view that arid desert soils constitute a largely unexplored repository of novel bacteria, while the high incidence of non-ribosomal peptide synthase genes in our isolates recommend them as promising material in screening for new bioactive natural products.

Albidopyrone, a new alpha-pyrone-containing metabolite from marine-derived Streptomyces sp. NTK 227.

Albidopyrone, a new alpha-pyrone-containing secondary metabolite, was produced by Streptomyces sp. NTK 227, a strain isolated from Atlantic Ocean sediment and found to be a member of the Streptomyces albidoflavus 16S rRNA gene clade. The structure of the compound was determined by MS and NMR spectroscopy, and found to have a moderate inhibitory activity against protein-tyrosin phosphatase B.

Caboxamycin, a new antibiotic of the benzoxazole family produced by the deep-sea strain Streptomyces sp. NTK 937.

Caboxamycin, a new benzoxazole antibiotic, was detected by HPLC-diode array screening in extracts of the marine strain Streptomyces sp. NTK 937, which was isolated from deep-sea sediment collected in the Canary Basin. The structure of caboxamycin was determined by mass spectrometry, NMR experiments and X-ray analysis. It showed inhibitory activity against Gram-positive bacteria, selected human tumor cell lines and the enzyme phosphodiesterase.

Amycolatopsis regifaucium sp. nov., a novel actinomycete that produces kigamicins.

The taxonomic position of seven soil actinomycetes provisionally assigned to the genus Amycolatopsis was established in a polyphasic study. The isolates, which had identical 16S rRNA gene sequences, had closest similarity to the type strain of Amycolatopsis orientalis. A representative isolate, strain GY080T, had chemotaxonomic properties that were typical of the genus Amycolatopsis and could be distinguished from the type strain of A. orientalis using DNA-DNA relatedness data. All of the isolates shared a phenotypic profile that distinguished them from representatives of phylogenetically closely related species. Amplified rDNA restriction analysis showed that the isolates formed a homogeneous group that was distinctly separate from single-membered groups consisting of representative Amycolatopsis type strains, including that of A. orientalis. Based on the combined genotypic and phenotypic evidence, it is proposed that the seven isolates be classified as representatives of a novel species for which the name Amycolatopsis regifaucium sp. nov. is proposed. The type strain is GY080T (=DSM 45072T=NCIMB 14277T).