Streptomyces bullii sp. nov., isolated from a hyper-arid Atacama Desert soil

A Streptomyces strain isolated from a hyper-arid Atacama Desert soil was characterised using a polyphasic taxonomic approach. The strain, designated C2^T, had chemical and morphological properties typical of the genus Streptomyces. The isolate formed a branch in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces chromofuscus and was also loosely related to Streptomyces fragilis NRRL 2424^T. DNA:DNA relatedness values between the isolate and its two phylogenetic neighbours showed that it formed a distinct genomic species. The strain was readily distinguished from these organisms using a combination of morphological and phenotypic data. Based on the genotypic and phenotypic results, isolate C2^T represents a novel species in the genus Streptomyces, for which the name Streptomyces bullii sp. nov. is proposed. The type strain is C2^T (=CGMCC 4.7019^T = KACC 15426^T).     

Streptomyces leeuwenhoekii sp. nov., the producer of chaxalactins and chaxamycins,forms a distinct branch in Streptomyces gene trees

A polyphasic study was carried out to establish the taxonomic status of an Atacama Desert isolate, Streptomyces strain C34^T, which synthesises novel antibiotics, the chaxalactins and chaxamycins. The organism was shown to have chemotaxonomic, cultural and morphological properties consistent with its classification in the genus Streptomyces. Analysis of 16S rRNA gene sequences showed that strain C34^T formed a distinct phyletic line in the Streptomyces gene tree that was very loosely associated with the type strains of several Streptomyces species. Multilocus sequence analysis based on five house-keeping gene alleles underpinned the separation of strain C34^T from all of its nearest phylogenetic neighbours, apart from Streptomyces chiangmaiensis TA-1^T and Streptomyces hyderabadensis OU-40^T which are not currently in the MLSA database. Strain C34^T was distinguished readily from the S. chiangmaiensis and S. hyderabadensis strains by using a combination of cultural and phenotypic data. Consequently, strain C34^T is considered to represent a new species of the genus Streptomyces for which the name Streptomyces leeuwenhoekii sp. nov. is proposed. The type strain is C34^T (= DSM 42122^T = NRRL B-24963^T). Analysis of the whole-genome sequence of S. leeuwenhoekii, with 6,780 predicted open reading frames and a total genome size of around 7.86 Mb, revealed a high potential for natural product biosynthesis.     

Streptomyces polyrhachii sp. nov., a novel actinomycete isolated from an edible Chinese black ant (Polyrhachis vicina Roger)

A novel actinomycete, designated strain NEAU-ycm1^T, was isolated from an edible Chinese black ant (Polyrhachis vicina Roger) and characterized with a polyphasic approach. The organism was found to have morphological and chemotaxonomic characteristics typical of streptomycetes. Phylogenetic analysis based on the almost complete 16S rRNA gene sequence show that the novel isolate belongs to the genus Streptomyces and forms a separate subclade. The closest phylogenetic relatives were identified as the type strains of Streptomyces intermedius NBRC 13049^T (97.74 %), Streptomyces aureoverticillatus NRRL B-3326^T (97.69 %), Streptomyces rutgersensis NBRC 12819^T (97.68 %), Streptomyces gougerotii NBRC 3198^T (97.68 %) and Streptomyces diastaticus subsp. diastaticus NBRC 3714^T (97.68 %). Similarities to other type strains of the genus Streptomyces were lower than 97.55 %. A comparison between strain NEAU-ycm1^T and the closest related Streptomyces type strains revealed that it is different from them in morphological, physiological and biochemical characteristics. Therefore, it is proposed that NEAU-ycm1^T (=CGMCC 4.7094^T = DSM 42102^T) represents a novel species of the genus of Streptomyces, for which the name Streptomyces polyrhachii sp. nov. is proposed.     

Streptomyces deserti sp. nov., isolated from hyper-arid Atacama Desert soil

The taxonomic position of a Streptomyces strain isolated from a hyper-arid desert soil was established using a polyphasic approach. The organism had chemical and morphological properties typical of the genus Streptomyces and formed a phyletic line at the periphery of the Streptomyces coeruleorubidus subcluster in the 16S rRNA gene tree. DNA:DNA relatedness values between the isolate and its nearest phylogenetic neighbours, Streptomyces lomondensis NRRL 3252^T and Streptomyces lusitanus NRRL B-12501^T were 42.5 (±0.48)% and 25.0 (±1.78)%, respectively. The isolate was readily distinguished from these organisms using a combination of morphological and phenotypic properties. On the basis of these results, it is proposed that isolate C63^T (CGMCC 4.6997^T, = KACC 15425^T) be classified as the type strain of Streptomyces deserti sp. nov.     

Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov., isolated from a hay meadow soil

Two filamentous actinomycetes isolated from a hay meadow soil were provisionally assigned to the genus Streptomyces based on morphological features. The isolates were found to have chemical and morphological properties typical of the genus Streptomyces and formed distinct phyletic lines in the 16S rRNA gene tree. Isolate I36^T was most closely related to Streptomyces glauciniger NBRC 100913^T and isolate I37^T to Streptomyces mirabilis NBRC 13450^T. Low DNA:DNA relatedness values were recorded between each of the isolates and their closest phylogenetic neighbour. The isolates were also distinguished from their nearest phylogenetic neighbour, and from one another, using a combination of phenotypic properties. These data indicate that the isolates should be recognised as new species in the genus Streptomyces. The names proposed for these new taxa are Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov. with isolate I36^T (=CGMCC 4.7016^T = KACC 15424^T) and isolate I37^T (=CGMCC 4.7020^T = KACC 15428^T) as the respective type strains.     

The <Emphasis Type="Italic">Streptomyces violaceusniger</Emphasis> clade: a home for streptomycetes with rugose ornamented spores

The taxonomic status of 16 strains received as Streptomyces hygroscopicus, Streptomyces melanosporofaciens, Streptomyces sparsogenes, Streptomyces sporoclivatus and Streptomyces violaceusniger was evaluated in a polyphasic study. Eleven of the organisms formed a distinct clade in the Streptomyces 16S rRNA gene tree with the type strains of Streptomyces asiaticus, Streptomyces cangkringensis, Streptomyces indonesiensis, Streptomyces javensis, Streptomyces malaysiensis, Streptomyces rhizosphaericus, Streptomyces yatensis and Streptomyces yogyakartensis, the members of this group produced rugose ornamented spores in spiral spore chains. The eleven strains were assigned to three established and four novel species, namely Streptomyces albiflaviniger sp. nov., Streptomyces demainii sp. nov., Streptomyces geldanamycininus sp. nov., Streptomyces griseiniger sp. nov., and Streptomyces hygroscopicus, Streptomyces melanosporofaciens and Streptomyces violaceusniger. It is also proposed that S. sporoclivatus becomes a subjective synonym of S. melanosporofaciens. S. sparsogenes NRRL 2940^T, which produced ridged ornamented spores in spiral spore chains, formed a distinct phyletic line in the Streptomyces 16S rRNA gene tree and was readily distinguished from the other strains using a range of phenotypic properties. S. violaceusniger strains NRRL 8097, NRRL B-5799, NRRL 2834 and ISP 5182 fell outside the S. violaceusniger 16S rRNA gene clade and formed either smooth or ridged ornamented spores in either flexuous or spiral spore chains. These organisms were distinguished from one another and from their closest phylogenetic neighbors and were considered to merit species status as Streptomyces auratus sp. nov., Streptomyces phaeoluteichromatogenes sp. nov., Streptomyces phaeogriseichromatogenes sp. nov., and Streptomyces phaeoluteigriseus sp. nov., respectively. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of the tested strains are S. albiflaviniger NRRL B-1356^T (AJ391812), S. auratus NRRL 8097^T (AJ391816), S. geldanamycininus NRRL 3602^T (DQ334781), S. griseiniger NRRL B-1865^T (AJ391818), S. hygroscopicus NRRL 2387^T (AJ391820), NRRL 2339 (AJ391821) and NRRL B-1477 (AJ391819), S. demainii NRRL B-1478^T (DQ334782), S. melanosporofaciens NRRL B-12234^T (AJ391837), S. phaeogriseichromatogenes NRRL 2834^T (AJ391813), S. phaeoluteichromatogenes NRRL B-5799^T (AJ391814), S. phaeoluteigriseus ISP 5182^T (AJ391815), S. sparsogenes NRRL 2940^T (AJ391817), S. sporoclivatus NRRL B-24330^T (AJ 781369), S. violaceusniger ISP 5563^T (AJ 391823) and NRRL B-1476^T (AJ 391822).     

Streptomyces jiujiangensis sp. nov., isolated from soil in South China

An actinomycete capable of lysing cyanobacteria, strain JXJ 0074^T, was isolated from a soil sample collected from Jiangxi province, south China, and characterized by using polyphasic taxonomy. The new isolate showed morphological and chemotaxonomic properties typical of members of the genus Streptomyces. Phylogenetic analysis of the near-complete 16S rRNA gene sequence indicated that strain JXJ 0074^T should be affiliated to the genus Streptomyces and exhibited highest similarities to Streptomyces shenzhenensis DSM 42034^T (98.99 %) and Streptomyces lucensis NBRC 13056^T (98.60 %), while the similarities to other members of the genus are lower than 98.22 % similarity. However, the DNA–DNA hybridization values between strain JXJ 0074^T and S. shenzhenensis DSM 42034^T or S. lucensis NBRC 13056^T were 46.2 ± 2.6 and 32.6 ± 3.1 %, respectively. Thus, on the basis of the polyphasic data, strain JXJ 0074^T represents a novel species of the genus Streptomyces, for which the name Streptomyces jiujiangensis sp. nov. is proposed. The type strain is JXJ 0074^T (= BCRC 16953^T = KCTC 29262^T).     

<Emphasis Type="Italic">Streptomyces caldifontis</Emphasis> sp. nov., isolated from a hot water spring of Tatta Pani,Kotli, Pakistan

A Gram-staining positive, non-motile, rod-shaped, catalase positive and oxidase negative bacterium, designated NCCP-1331^T, was isolated from a hot water spring soil collected from Tatta Pani, Kotli, Azad Jammu and Kashmir, Pakistan. The isolate grew at a temperature range of 18-40 °C (optimum 30 °C), pH 6.0–9.0 (optimum 7.0) and with 0–6 % NaCl (optimum 2 % NaCl (w/v)). The phylogenetic analysis based on 16S rRNA gene sequence revealed that strain NCCP-1331^T belonged to the genus Streptomyces and is closely related to Streptomyces brevispora BK160^T with 97.9 % nucleotide similarity, followed by Streptomyces drosdowiczii NRRL B-24297^T with 97.8 % nucleotide similarity. The DNA–DNA relatedness values of strain NCCP-1331^T with S. brevispora KACC 21093^T and S. drosdowiczii CBMAI 0498^T were 42.7 and 34.7 %, respectively. LL-DAP was detected as diagnostic amino acid along with alanine, glycine, leucine and glutamic acid. The isolate contained MK-9(H₈) as the predominant menaquinone. Major polar lipids detected in NCCP-1331^T were phosphatidylethanolamine, phosphatidylinositol and unidentified phospholipids. Major fatty acids were iso-C_{16: 0}, summed feature 8 (18:1 ω7c/18:1 ω6c), anteiso-C_15:0 and C_16:0. The genomic DNA G + C content was 69.8 mol %. On the basis of phylogenetic, phenotypic and chemotaxonomic analysis, it is concluded that strain NCCP-1331^T represents a novel species of the genus Streptomyces, for which the name Streptomyces caldifontis sp. nov. is proposed. The type strain is NCCP-1331^T (=KCTC 39537^T = CPCC 204147^T).     

Streptomyces amritsarensis sp. nov., exhibiting broad-spectrum antimicrobial activity

A new actinobacterium strain, designated 2A^T, was isolated from a soil sample collected from Guru Nanak Dev University, Punjab (India) and characterized using a polyphasic taxonomic approach. It showed antimicrobial activity against various Gram-positive and Gram-negative bacteria including drug resistant bacteria and fungi. The strain had chemotaxononomic and morphological properties typical of the genus Streptomyces. The 16S rRNA gene sequence of the strain showed 99.9, 99.5 and 99.5 % similarity with Streptomyces flavotricini DSM 40152^T, Streptomyces toxytricini DSM 40178^T and Streptomyces globosus DSM 40815^T, respectively. This strain formed a coherent cluster with them and shared DNA–DNA homology of 37.6 ± 0.6, 34.4 ± 0.5 and 33.1 ± 0.4 % with type strains, S. flavotricini DSM 40152^T, S. globosus DSM 40815^T and S. toxytricini DSM 40178^T, respectively. Further, the strain was readily distinguished from the phylogenetic close relatives in a variety of morphological, physiological and biochemical properties. Based on the genotypic and phenotypic characteristics, it is proposed that strain 2A^T represents a novel species in the genus Streptomyces, for which the name Streptomyces amritsarensis sp. nov. is proposed, with the type strain 2A^T (=MTCC 11845^T=JCM 19660^T).     

<Emphasis Type="Italic">Streptomyces tunisialbus</Emphasis> sp. nov., a novel <Emphasis Type="Italic">Streptomyces</Emphasis> species with antimicrobial activity

A novel actinomycete strain designated S2^T was isolated from Tunisian rhizosphere soil of Lavandula officinalis. This isolate exhibited broad spectrum antibacterial activity against several Gram-positive and Gram-negative bacteria and also antifungal activity against yeast and filamentous fungi. The isolate S2^T presents morphological and chemotaxonomic characteristics typical of the members of the genus Streptomyces. Whole cell hydrolysates of S2^T were found to contain LL-diaminopimelic acid. The major fatty acids were identified as C16:0, anteiso-C15:0 and iso-C16:0 whereas the predominant menaquinones were found to be MK-9(H6) and MK-9(H8). The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and three unidentified compounds. The G+C content of the genomic DNA was determined to be 71.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S2^T belongs to the genus Streptomyces and is closely related to Streptomyces netropsis DSM 40259^T with 99.86% sequence similarity. Multi-locus sequence analysis (MLSA) based on four house-keeping gene alleles (gyrB, recA, trpB, rpoB) showed that isolate S2^T is closely related to S. netropsis, with an MLSA distance greater than 0.007. The DNA–DNA relatedness between strain S2^T and its near phylogenetic neighbour was 63.6 ± 2.3%, which is lower than the 70% threshold value for delineation of genomic prokaryotic species. This isolate was also distinguished from the type strain S. netropsis DSM 40259^T, using a combination of morphological and physiological features. Based on its phenotypic and molecular properties, strain S2^T is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces tunisialbus sp. nov. is proposed. The type strain is S2^T (= JCM 32165^T = DSM 105760^T).     

Streptomyces fukangensis sp. nov., a novel alkaliphilic actinomycete isolated from a saline-alkaline soil

An alkaliphilic actinobacterium, designated EGI 80050^T, was isolated from a desert soil sample of Xinjiang, north-west China, and characterized by a polyphasic approach. The isolate was observed to produce purple orange-yellow aerial mycelium and dark orange-yellow substrate mycelium on yeast extract-malt extract agar medium. Whole-cell hydrolysates of strain EGI 80050^T were found to contain ll-diaminopimelic acid as the diagnostic diamino acid, and galactose, glucose, rhamnose and mannose as the main sugars. The major fatty acids identified were C_16:0-iso (36.8 %), C_15:0-anteiso (17.3 %), 15:0-iso (13.2 %) and 14:0-iso (10.5 %). The predominant menaquinones detected were MK-9(H₆) and MK-9(H₈), while the characteristic polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, phosphatidylmethylethanolamine and three unknown phospholipids. The G+C content of the genomic DNA was determined to be 67.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences affiliated the strain EGI 80050^T to the genus Streptomyces. Levels of 16 rRNA gene sequence similarities between strain EGI 80050^T and Streptomyces candidus NRRL ISP-5141^T, Streptomyces cremeus NBRC 12760^T, Streptomyces spiroverticillatus NBRC 12821^T, Streptomyces violaceorectus NBRC 13102^T, Streptomyces cinereoruber subsp. cinereoruber NBRC 12756^T were 96.7, 96.6, 96.6, 96.6 and 96.6 %, respectively. Based on the phenotypic, chemotaxonomic and phylogenetic data, strain EGI 80050^T is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces fukangensis sp. nov. (type strain EGI 80050^T = BCRC 16945^T = JCM 19127^T) is proposed.     

Two novel species Enterococcus lemanii sp. nov. and Enterococcus eurekensis sp. nov., isolated from a swine-manure storage pit

A polyphasic taxonomic study using morphological, biochemical, chemotaxonomic and molecular genetic methods was performed on six strains of unknown Gram-positive, nonspore-forming, facultative anaerobic coccus-shaped bacteria isolated from a swine-manure storage pit. On the basis of the 16S rRNA, RNA polymerase α-subunit (rpoA) and 60 kDa chaperonin (cpn60) gene sequence analyses, it was shown that all the isolates were enterococci but formed two separate lines of descent. Pairwise 16S rRNA gene sequence comparisons demonstrated that the two novel organisms were most closely related to each other (97.9 %) and to Enterococcus aquimarinus (97.8 %). Both organisms contained major amounts of C_16:0, C_16:1 ω7c, C_16:1 ω7c, and C_18:1 ω7c/12t/9t as the major cellular fatty acids. Based on biochemical, chemotaxonomic and phylogenetic evidence, the names Enterococcus lemanii sp. nov. (type strain PC32^T = CCUG 61260^T = NRRL B-59661^T) and Enterococcus eurekensis sp. nov. (type strain PC4B^T = CCUG 61259^T = NRRL B-59662^T) are proposed for these hitherto undescribed species.     

Erratum to: Two novel species Enterococcus lemanii sp. nov. and Enterococcus eurekensis sp. nov., isolated from a swine-manure storage pit

A polyphasic taxonomic study using morphological, biochemical, chemotaxonomic and molecular genetic methods was performed on six strains of an unknown Gram-positive, nonspore-forming, facultative anaerobic coccus-shaped bacterium isolated from a swine-manure storage pit. On the basis of 16S rRNA, RNA polymerase-subunit (rpoA), and the 60-kilodalton chaperonin (cpn60) gene sequence analyses, it was shown that all the isolates were enterococci but formed two separate lines of descent. Pairwise 16S rRNA sequence comparisons demonstrated that the two novel organisms were most closely related to each other (97.9 %) and to Enterococcus aquimarinus (97.8 %). Both organisms contained major amounts of C_16:0, C_16:1 ω7c, and C_18:1 ω7c/12t/9t as the major cellular fatty acids. Based on biochemical, chemotaxonomic, and phylogenetic evidence, the names Enterococcus lemanii sp. nov. (type strain PC32^T = CCUG 61260^T = NRRL B-59661^T) and Enterococcus eurekensis sp. nov. (type strain PC4B^T = CCUG 61259^T = NRRL B-59662^T) are proposed for the hitherto undescribed species.     

Streptomyces poriferorum sp. nov., a novel marine sponge-derived Actinobacteria species expressing anti-MRSA activity

Marine sponges represent a rich source of uncharacterized microbial diversity, and many are host to microorganisms that produce biologically active specialized metabolites. Here, a polyphasic approach was used to characterize two Actinobacteria strains, P01-B04^T and P01-F02, that were isolated from the marine sponges Geodia barretti (Bowerbank, 1858) and Antho dichotoma (Esper, 1794), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains P01-B04^T and P01-F02 are closely related to Streptomyces beijiangensis DSM 41794^T, Streptomyces laculatispora NRRL B-24909^T, and Streptomyces brevispora NRRL B-24910^T. The two strains showed nearly identical 16S rRNA gene sequences (99.93%), and the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values were 99.96% and 99.6%, respectively, suggesting that these strains are affiliated with the same species. Chemotaxonomic and culture characteristics of both strains were also consistent with the genus Streptomyces, while phenotypic properties, genome-based comparisons, and phylogenomic analyses distinguished strains P01-B04^T and P01-F02 from their closest phylogenetic relatives. In silico analysis predicted that the 8.9 Mb genome of P01-B04^T contains at least 41 biosynthetic gene clusters (BGCs) encoding secondary metabolites, indicating that this strain could express diverse bioactive metabolites; in support of this prediction, this strain expressed antibacterial activity against Gram-positive bacteria including a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) EAMC30. Based on these results, the marine sponge-associated isolates represent a novel species of the genus Streptomyces, for which the name Streptomyces poriferorum sp. nov. is proposed, with P01-B04^T (=DSM 111306^T = CCM 9048^T) as the type strain.     

<Emphasis Type="Italic">Streptomyces sudanensis</Emphasis> sp. nov., a new pathogen isolated from patients with actinomycetoma

Nine strains isolated from mycetoma patients and received as Streptomyces somaliensis were the subject of a polyphasic taxonomic study. The organisms shared chemical markers consistent with their classification in the genus Streptomyces and formed two distinct monophyletic subclades in the Streptomyces 16S rRNA gene tree. The first subclade contained four organisms, including the type strain of S. somaliensis, and the second clade the remaining five strains which had almost identical 16S rRNA sequences. Members of the two subclades were sharply separated using DNA:DNA relatedness and phenotypic data which also showed that the subclade 1 strains formed an heterogeneous group. In contrast, the subclade 2 strains were assigned to a single genomic species and had identical phenotypic profiles. It is evident from these data that the subclade 2 strains should be recognised as a new species of Streptomyces. The name proposed for this new species is Streptomyces sudanensis sp. nov. The type strain is SD 504^T (DSM = 41923^T = NRRL B-24575^T). Erika T. Quintana and Katarzyna Wierzbicka contributed equally to this work. The GenBank accession numbers for the 16S rRNA gene sequences of Streptomyces somaliensis DSM 40738^T and Streptomyces sudanensis DSM 41607, DSM 41608, DSM 41609, SD 504^T and SD 509 are EF540897, EF540898, EF540999, EF515876 and EF540900.     

<Emphasis Type="Italic">Streptomyces gamaensis</Emphasis> sp. nov., a novel actinomycete with antifungal activity isolated from soil in Gama,Chad

During an investigation exploring potential sources of novel species and natural products, a novel actinomycete with antifungal activity, designated strain NEAU-Gz11^T, was isolated from a soil sample, which was collected from Gama, Chad. The isolate was found to have morphological and chemotaxonomic characteristics typical of members of the genus Streptomyces. 16S rRNA gene sequence similarity studies showed that strain NEAU-Gz11^T belongs to the genus Streptomyces with high sequence similarity to Streptomyces hiroshimensis JCM 4098^T (98.0 %). Similarities to other type strains of the genus Streptomyces were lower than 98.0 %. However, the physiological and biochemical characteristics and low levels of DNA–DNA relatedness could differentiate the isolate genotypically and phenotypically from S. hiroshimensis JCM 4098^T. Therefore, the strain is concluded to represent a novel species of the genus Streptomyces, for which the name Streptomyces gamaensis sp. nov. is proposed. The type strain is NEAU-Gz11^T (=CGMCC 4.7304^T=DSM 101531^T).     

Classification of Streptomyces phylogroup pratensis (Doroghazi and Buckley, 2010) based on genetic and phenotypic evidence,and proposal of Streptomyces pratensis sp. nov.

The Streptomyces phylogroup pratensis (Doroghazi and Buckley, 2010) contains isolates obtained from grassy fields, as well as Streptomyces flavogriseus ATCC 33331 and strain CGMCC 4.1868. This latter strain was received as Streptomyces griseoplanus but was subsequently found to be mislabeled, and S. flavogriseus ATCC 33331 (=IAF-45-CD) was shown to be clearly distinct from the type strain S. flavogriseus ATCC 25452^T (=CGMCC 4.1884^T). In order to evaluate the taxonomic position of phylogroup pratensis further, sequences of the 16S rRNA gene and five protein-coding housekeeping genes (atpD, gyrB, recA, rpoB and trpB) were determined for six strains of the phylogroup and type strains of 19 related species, which were selected by a BLAST search based on the sequences of the phylogroup. The 16S rRNA gene sequences for the phylogroup were identical to those of eight species belonging to cluster I of the S. griseus clade. However, in all the individual protein-coding gene and MLSA phylogenies, the phylogroup strains without exception formed an obviously distinct cluster that could be equated with a new species status. The phylogenetic evidence for the new species assignment was also supported by corresponding DNA–DNA hybridization values and by phenotypic characteristics. It is therefore proposed that the phylogroup should be classified as Streptomyces pratensis sp. nov., and the type strain is ch24^T (=CGMCC 4.6829^T = NRRL B-24916^T).     

Streptomyces calidiresistens sp. nov., isolated from a hot spring sediment

A Streptomyces-like actinomycete strain, designated as YIM 78087^T, was isolated from a sediment sample collected from Hehua hot spring in Tengchong, Yunnan province, south-west China. The taxonomic position of strain YIM 78087^T was investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain YIM 78087^T belongs to the genus Streptomyces and is closely related to Streptomyces fimbriatus DSM 40942^T, Streptomyces marinus DSM 41968^T and Streptomyces qinglanensis DSM 42035^T (97.18, 97.05 and 97.1 % similarity, respectively). Combined with the low values of DNA–DNA hybridization between strain YIM 78087^T and its closest neighbours, these analyses indicated that this new isolate represents a different genomic species in the genus Streptomyces. The predominant menaquinones of strain YIM 78087^T were identified as MK-9 (H₄) and MK-9 (H₆). The major fatty acids were identified as anteiso-C_15:0 (28.4 %), anteiso-C_17:0 (23.0 %) and iso-C_16:0 (15.1 %). The whole-cell hydrolysates found to contain glucose, mannose and ribose. The DNA G+C content was determined to be 73.0 mol%. Based on the comparative analysis of phenotypic and genotypic characteristics, it is proposed that strain YIM 78087^T represents a novel species of the genus Streptomyces, for which the name Streptomyces calidiresistens sp. nov., is proposed. The type strain is YIM 78087^T (=BCRC 16955^T=DSM 42108^T=JCM 19629^T).     

<Emphasis Type="Italic">Saccharothrix ghardaiensis</Emphasis> sp. nov., an actinobacterium isolated from Saharan soil

The taxonomic position of a new Saccharothrix strain, designated MB46^T, isolated from a Saharan soil sample collected in Mzab region (Ghardaïa province, South Algeria) was established following a polyphasic approach. The novel microorganism has morphological and chemical characteristics typical of the members of the genus Saccharothrix and formed a phyletic line at the periphery of the Saccharothrix espanaensis subcluster in the 16S rRNA gene dendrograms. Results of the 16S rRNA gene sequence comparisons revealed that strain MB46^T shares high degrees of similarity with S. espanaensis DSM 44229^T (99.2%), Saccharothrix variisporea DSM 43911^T (98.7%) and Saccharothrix texasensis NRRL B-16134^T (98.6%). However, the new strain exhibited only 12.5–17.5% DNA relatedness to the neighbouring Saccharothrix spp. On the basis of phenotypic characteristics, 16S rRNA gene sequence comparisons and DNA-DNA hybridizations, strain MB46^T is concluded to represent a novel species of the genus Saccharothrix, for which the name Saccharothrix ghardaiensis sp. nov. (type strain MB46^T = DSM 46886^T = CECT 9046^T) is proposed.