Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
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Volume 80, Issue 9
Displaying 1-7 of 7 articles from this issue
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Review
  • Vitamin D and bone
    - How does vitamin D regulate bone formation and resorption? -
    Tatsuo SUDA
    2004 Volume 80 Issue 9 Pages 407-421
    Published: 2004
    Released on J-STAGE: January 14, 2005
    DOIhttps://doi.org/10.2183/pjab.80.407
    JOURNAL FREE ACCESS
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    Vitamin D was discovered as an anti-rachitic agent, but even at present, there is no direct evidence to support the concept that vitamin D directly stimulates osteoblastic bone formation and mineralization. It appears to be paradoxical, but vitamin D functions in the process of osteoclastic bone resorption. Osteoclasts, the only cells responsible for bone resorption, develop from hematopoietic cells of the monocyte-macrophage lineage. In 1992, we hypothesized that a membrane-bound factor, designated as "osteoclast differentiation factor (ODF)", is expressed on the plasma membrane of osteoblasts/stromal cells in response to osteotropic factors including the active form of vitamin D3, 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3]. Recently, four research groups including ours independently identified three key molecules (RANKL, RANK, and OPG) responsible for osteoclastogenesis. A long-sought-after ligand, ODF, was identical to RANKL. RANKL was a member of the membrane-associated TNF ligand family, which induced differentiation of spleen cells (osteoclast progenitors) into osteoclasts in the presence of M-CSF. RANK, a member of the TNF receptor family, was a signaling receptor essential for the RANKL-mediated osteoclastogenesis. OPG, a secreted member of the TNF receptor family, was a decoy receptor for RANKL. The discovery of RANKL, RANK and OPG opens a new era in the study of bone biology and the therapy of several metabolic bone diseases such as osteoporosis, rheumatoid arthritis, and periodontal diseases.


    (Communicated by Tadamitsu KISHIMOTO, M.J.A.)
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Original Papers
  • The oldest mid-oceanic carbonate buildup complex: Setting and lithofacies of the Vendian (Late Neoproterozoic) Baratal limestone in the Gorny Altai Mountains, Siberia
    Yuko UCHIO, Yukio ISOZAKI, Tsutomu OTA, Atsushi UTSUNOMIYA, Mikhail M. ...
    2004 Volume 80 Issue 9 Pages 422-428
    Published: 2004
    Released on J-STAGE: January 14, 2005
    DOIhttps://doi.org/10.2183/pjab.80.422
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    The Baratal limestone in the Gorny Altai Mountains, southern Siberia, occurs as large allochthonous blocks within a Cambrian accretionary complex that developed around the Siberia craton. Before the final accretion to Siberia in the Cambrian, the terrigenous clastic-free Baratal limestone was deposited directly upon a basaltic basement with a geochemical signature identical to that of modern oceanic plateau. The Baratal limestone with 598±25 Ma (Early Vendian) Pb-Pb isochron age consists of three distinct facies; 1) massive lime mudstone with ooids and stromatolites, 2) bedded lime mudstone, and 3) limestone conglomerate/breccia dominated by ooid-bearing lime mudstone clasts. The first represents a shallow marine environment on top of an ancient oceanic plateau, while the latter two represent the deeper slope to bottom-of-slope facies of a plateau. The Vendian Baratal limestone provides the oldest example of a reconstructed shallow marine carbonate buildup complex developed on a plateau/seamount in a mid-ocean.


    (Communicated by Tatsuro MATSUMOTO, M.J.A.)
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  • A plausible explanation of the b-value in the Gutenberg-Richter law from first Principles
    Panayiotis A. VAROTSOS, Nicholas V. SARLIS, Efthimios S. SKORDAS, Haru ...
    2004 Volume 80 Issue 9 Pages 429-434
    Published: 2004
    Released on J-STAGE: January 14, 2005
    DOIhttps://doi.org/10.2183/pjab.80.429
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    It is explained, from first Principles, why in the Gutenberg-Richter law (stating that the cumulative number of earthquakes N(>M) with magnitude greater than M is given by N(>M) ~ 10-bM) the so called b-value is usually found to be around unity varying only slightly from region to region. The explanation is achieved just by applying the analysis in the natural time domain, without using any adjustable parameter.


    (Communicated by Seiya UYEDA, M.J.A.)
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  • The three-dimensional structure of aspergilloglutamic peptidase from Aspergillus niger
    Hiroshi SASAKI, Atsushi NAKAGAWA, Tomonari MURAMATSU, Megumi SUGANUMA, ...
    2004 Volume 80 Issue 9 Pages 435-438
    Published: 2004
    Released on J-STAGE: January 14, 2005
    DOIhttps://doi.org/10.2183/pjab.80.435
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    Aspergilloglutamic peptidase from Aspergillus niger is a novel pepstatin-insensitive acid endopeptidase distinct from the well-studied aspartic peptidases, and thus is an interesting target for protein structure/function studies. In the present study, we have determined the three-dimensional structure of the enzyme by X-ray crystallography to a 1.4-Å resolution. The results revealed that the enzyme has a unique structure, composed of two seven-stranded anti-parallel β-sheets which form a β-sandwich structure and appear to have a partial two-fold symmetry, suggesting its possible evolution by gene duplication and that the glutamic acid-110 and glutamine-24 in the heavy chain form a catalytic dyad, consistent with our results obtained by site-directed mutagenesis.


    (Communicated by Masanori OTSUKA, M.J.A.)
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  • Crystal structure of acylphosphatase from hyperthermophilic archaeon Pyrococcus horikoshii OT3
    Ken-ichi MIYAZONO, Yoriko SAWANO, Masaru TANOKURA
    2004 Volume 80 Issue 9 Pages 439-442
    Published: 2004
    Released on J-STAGE: January 14, 2005
    DOIhttps://doi.org/10.2183/pjab.80.439
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    Analysis of the hyperthermophilic archaeon Pyrococcus horikoshii OT3 genome database led to the discovery and cloning of acylphosphatase (ORF PH0305a). To elucidate the first structure of archaeal acylphosphatase, we determined the crystal structure of P. horikoshii acylphosphatase at 1.72 Å resolution. The space group of the crystals was P3221, with unit-cell parameters a = b = 86.6 Å and c = 75.4 Å. The overall fold of P. horikoshii acylphosphatase was very similar to the structures of the eukaryotic enzymes. The conformation of putative active site was highly conserved.


    (Communicated by Masanori OTSUKA, M.J.A.)
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Errata
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