We determined the complete genome sequence of Streptomyces griseus IFO 13350, a soil bacterium producing an antituberculosis agent, streptomycin, which is the first aminoglycoside antibiotic, discovered more than 60 years ago. The linear chromosome consists of 8,545,929 base pairs (bp), with an average G؉C content of 72.2%, predicting 7,138 open reading frames, six rRNA operons (16S-23S-5S), and 66 tRNA genes. It contains extremely long terminal inverted repeats (TIRs) of 132,910 bp each. The telomere's nucleotide sequence and secondary structure, consisting of several palindromes with a loop sequence of 5-GGA-3, are different from those of typical telomeres conserved among other Streptomyces species. In accordance with the difference, the chromosome has pseudogenes for a conserved terminal protein (Tpg) and a telomere-associated protein (Tap), and a novel pair of Tpg and Tap proteins is instead encoded by the TIRs. Comparisons with the genomes of two related species, Streptomyces coelicolor A3(2) and Streptomyces avermitilis, clarified not only the characteristics of the S. griseus genome but also the existence of 24 Streptomyces-specific proteins. The S. griseus genome contains 34 gene clusters or genes for the biosynthesis of known or unknown secondary metabolites. Transcriptome analysis using a DNA microarray showed that at least four of these clusters, in addition to the streptomycin biosynthesis gene cluster, were activated directly or indirectly by AdpA, which is a central transcriptional activator for secondary metabolism and morphogenesis in the A-factor (a ␥-butyrolactone signaling molecule) regulatory cascade in S. griseus.The gram-positive, soil-inhabiting, filamentous bacterial genus Streptomyces is characterized by its ability to produce a wide variety of secondary metabolites, such as antibiotics, parasiticides, herbicides, and pharmacologically active substances, including antitumor agents and immunosuppressants. Another characteristic feature of the genus is its complex multicellular development. Spores germinate to form a branched, multinucleoid substrate mycelium, which then produces an aerial mycelium. After septa have been formed at regular intervals along the aerial hyphae, long chains of uninucleoid spores are formed. Because of its complex morphogenesis and industrial and medical importance, Streptomyces has become a model prokaryote for the study of multicellular differentiation and secondary metabolism. The complete genomic sequences of two Streptomyces species, a model strain, Streptomyces coelicolor A3(2) (3), and an industrial strain, Streptomyces avermitilis (20, 36), have been published.Unlike most other eubacterial chromosomes, the chromosome of Streptomyces is linear and contains a centrally located origin of replication (oriC) and unique terminal inverted repeats (TIRs) with terminal proteins (Tpgs) covalently bound to the 5Ј ends. Replication proceeds bidirectionally from oriC, and a terminal single-stranded gap on the discontinuous lagging strand is filled in by DNA synthesis ...

We have positively identified oxygen species on Pt(111) single-crystal and polycrystalline Pt electrodes in N2-purged 0.1 M HF solution by X-ray photoelectron spectroscopy combined with an electrochemical cell. Four oxygen species (Oad, OHad, and two types of water molecules) were distinguished. The binding energies of each species were nearly constant over the whole potential region and independent of the single- or polycrystalline electrodes. The coverages, however, varied considerably and were dependent on the electrode potential. We have for the first time demonstrated clear differences in the surface oxidation processes for Pt(111) and polycrystalline Pt electrodes.

Direct observation of adsorbed species relating to the oxygen reduction reaction (ORR) on cathode catalyst surfaces is very important for an elucidation of the ORR and finding a clue of higher-performance catalysts for polymer electrolyte fuel cells. We first identified quantitatively oxygen-containing species adsorbed on electrodes of pure Pt and a Pt skin layer formed on a Pt−Fe alloy surface in N2- and O2-saturated 0.1 M HF solution by X-ray photoelectron spectroscopy combined with an electrochemical cell (EC−XPS). Three types of species were distinguished with binding energies at 529.6, 530.5, 531.1, and 532.4 eV, the first two of which were assigned to atomic oxygen (Oad), hydroxyl (OHad), and the others were water molecules (H2Oad), respectively. We found distinctive potential dependences of their coverage in the solution with/without O2 between both catalysts. The Pt skin layer exhibited a higher affinity to Oad but less to H2O compared to pure Pt, particularly in the O2-saturated solution. The higher coverage of Oad was ascribed to the higher ORR activity at Pt skin/Pt−Fe alloy electrode than that at pure Pt. It was also found that the coverage of H2Oad was considerably lowered at the Pt skin layer in both N2- and O2-saturated solution, which can be correlated to preferential adsorption of O2 and the increased coverage of Oad at the Pt skin layer.