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The 16S rRNA gene sequence of ‘Streptomyces hyalinum’ NBRC 13850T shows 99.7 % similarity to that of Embleya scabrispora DSM 41855T; however, it shows Streptomyces spp. Phylogenetic analysis based on 16S rRNA gene sequences clearly suggests that ‘S. hyalinum’ belongs to the genus Embleya rather than to Streptomyces . The strain possesses ll-diaminopimelic acid in the cell wall. The major menaquinone observed is MK-9(H6), and MK-9(H4) and MK-9(H8) are minor components. The major polar lipids are diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. In this study, the whole genome of strain NBRC 13850T was sequenced, and digital DNA–DNA hybridisation between ‘S. hyalinum’ NBRC 13850T and E. scabrispora DSM 41855T demonstrated 31.2 % of relatedness value between the two genomes. Morphological, chemotaxonomic, biochemical and physiological data also revealed that ‘S. hyalinum’ can be easily differentiated from E. scabrispora (the only the valid species of the genus Embleya ) and that it merits separate species status. This phenotypic and genetic evidence reveals that ‘S. hyalinum’ represents a novel species of the genus Embleya ; the name Embleya hyalina sp. nov. is proposed for this species. The type strain is NBRC 13850T (=ATCC 29817T=MB 891-A1T). We also emended the description of the genus Embleya considering the feature of E. hyalina.

Two new furanone-containing polyketides, linfuranones B and C, were isolated from a plant-associated actinomycete of the genus Sphaerimonospora. Their structures were determined by NMR and MS spectroscopic analyses, and the absolute configurations were established by anisotropic methods and chemical degradation approaches. In silico analysis of biosynthetic genes suggested that linfuranone B is generated from linfuranone C by oxidative cleavage of the polyketide chain. Linfuranones B and C induced preadipocyte differentiation into matured adipocytes at 20-40 μM without showing cytotoxicity.

To identify the species of butyrolactol-producing Streptomyces strain TP-A0882, whole genome-sequencing of three type strains in a close taxonomic relationship was performed. In silico DNA-DNA hybridization using the genome sequences suggested that Streptomyces sp. TP-A0882 is classified as Streptomyces diastaticus subsp. ardesiacus. Strain TP-A0882, S. diastaticus subsp. ardesiacus NBRC 15402T, Streptomyces coelicoflavus NBRC 15399T, and Streptomyces rubrogriseus NBRC 15455T harbor at least 14, 14, 10, and 12 biosynthetic gene clusters (BGCs), respectively, coding for nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). All 14 gene clusters were shared by S. diastaticus subsp. ardesiacus strains TP-A0882 and NBRC 15402T, while only four gene clusters were shared by the three distinct species. Although BGCs for bacteriocin, ectoine, indole, melanine, siderophores such as deferrioxamine, terpenes such as albaflavenone, hopene, carotenoid and geosmin are shared by the three species, many BGCs for secondary metabolites such as butyrolactone, lantipeptides, oligosaccharide, some terpenes are species-specific. These results indicate the possibility that strains belonging to the same species possess the same set of secondary metabolite-biosynthetic pathways, whereas strains belonging to distinct species have species-specific pathways, in addition to some common pathways, even if the strains are taxonomically close.

Streptomyces hyaluromycini MB-PO13T (=NBRC 110483T = DSM 100105T) is type strain of the species, which produces a hyaluronidase inhibitor, hyaluromycin. Here, we report the draft genome sequence of this strain together with features of the organism and generation, annotation and analysis of the genome sequence. The 11.5 Mb genome of Streptomyces hyaluromycini MB-PO13T encoded 10,098 putative ORFs, of which 5317 were assigned with COG categories. The genome harbored at least six type I PKS clusters, three type II PKS gene clusters, two type III PKS gene clusters, six NRPS gene clusters, and one hybrid PKS/NRPS gene cluster. The type II PKS gene cluster including 2-amino-3-hydroxycyclopent-2-enone synthetic genes was identified to be responsible for hyaluromycin synthesis. We propose the biosynthetic pathway based on bioinformatic analysis.

Iron and heme play very important roles in various metabolic functions in bacteria, and their intracellular homeostasis is maintained because high concentrations of free forms of these molecules greatly facilitate the Fenton reaction-mediated production of large amounts of reactive oxygen species that severely damage various biomolecules. The ferric uptake regulator (Fur) from Burkholderia multivorans ATCC 17616 is an iron-responsive global transcriptional regulator, and its fur deletant exhibits pleiotropic phenotypes. In this study, we found that the phenotypes of the fur deletant were suppressed by an additional mutation in hemP . The transcription of hemP was negatively regulated by Fur under iron-replete conditions and was constitutive in the fur deletant. Growth of a hemP deletant was severely impaired in a medium containing hemin as the sole iron source, demonstrating the important role of HemP in hemin utilization. HemP was required as a transcriptional activator that specifically binds the promoter-containing region upstream of a Fur-repressive hmuRSTUV operon, which encodes the proteins for hemin uptake. A hmuR deletant was still able to grow using hemin as the sole iron source, albeit at a rate clearly lower than that of the wild-type strain. These results strongly suggested (i) the involvement of HmuR in hemin uptake and (ii) the presence in ATCC 17616 of at least part of other unknown hemin uptake systems whose expression depends on the HemP function. Our in vitro analysis also indicated high-affinity binding of HemP to hemin, and such a property might modulate transcriptional activation of the hmu operon. IMPORTANCE Although the hmuRSTUV genes for the utilization of hemin as a sole iron source have been identified in a few Burkholderia strains, the regulatory expression of these genes has remained unknown. Our analysis in this study using B. multivorans ATCC 17616 showed that its HemP protein is required for expression of the hmuRSTUV operon, and the role of HemP in betaproteobacterial species was elucidated for the first time, to our knowledge, in this study. The HemP protein was also found to have two additional properties that have not been reported for functional homologues in other species; one is that HemP is able to bind to the promoter-containing region of the hmu operon to directly activate its transcription, and the other is that HemP is also required for the expression of an unknown hemin uptake system.

Fur (ferric uptake regulator) is an iron-responsive transcriptional regulator in many bacterial species, and the fur mutant of Burkholderia multivorans ATCC 17616 exhibits pleiotropic phenotypes, such as an inability to efficiently use several carbon sources, as well as high sensitivity to hydrogen peroxide (H(2)O(2)), paraquat (a superoxide-producing compound) and nitric oxide (NO). To gain more insight into the pleiotropic role of the Fur protein of ATCC 17616, spontaneous suppressor mutants of the ATCC 17616 fur mutant that restored tolerance to NO were isolated and characterized in this study. The microarray-based comparative genomic analysis and subsequent sequencing analysis indicated that such suppressor mutants had a 2 bp deletion in the oxyR gene, whose orthologues encode H(2)O(2)-responsive transcriptional regulators in other bacterial species. The suppressor mutants and the reconstructed fur-oxyR double-deletion mutant showed indistinguishable phenotypes in that they were all (i) more resistant than the fur mutant to H(2)O(2), superoxide, NO and streptonigrin (an iron-activated antibiotic) and (ii) able to use carbon sources that cannot efficiently support the growth of the fur mutant. These results clearly indicate that the oxyR mutation suppressed the pleiotropic effect of the B. multivorans fur mutant. The fur-oxyR double mutants were found to overexpress the KatG (catalase/peroxidase) and AhpC1 and AhpD (alkyl hydroperoxide reductase subunits C and D) proteins, and their enzymic activities to remove reactive oxygen and nitrogen species were suggested to be responsible for the suppression of phenotypes caused by the fur mutation.