Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 80 , Issue 6
Showing 1-9 articles out of 9 articles from the selected issue
Reviews
  • Kazuro SHIOMI, Satoshi OMURA
    2004 Volume 80 Issue 6 Pages 245-258
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    Microorganisms produce many useful antiparasitic agents. Antiparasitic activities and biochemical targets of antiprotozoal and anthelmintic antibiotics are reviewed. Antimalarial apicidin, thiolactomycin, fosmidomycin, and borrelidin, antitrypanosomal ascofuranone, and nematocidal emodepside, 2-deoxoparaherquamide A, and nafuredin are recently discovered antibiotics, and they have potential as useful drugs.


    (Contributed by Satoshi OMURA, M.J.A.)
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  • Kazumasa KUROSUMI, [in Japanese]
    2004 Volume 80 Issue 6 Pages 259-268
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    The cell types in the rat anterior pituitary were classified according to the function of hormone produced by each type cells. Depending upon the age and sex of the rat studied, the fine structure of the cell remarkably differs from each other. The name of cell type indicates the name (abbreviation) of hormone produced by each type cell, which is also divided into two or three subtypes according to the ultrastructure or developing stage viz. immature, intermediate and mature types. The immunocytochemistry is a useful method both for light and electron microscopy in order to study the activity of every cell organelles, because it is easy to indicate the localization of hormones in the cell. The anterior pituitary hormones are all proteins or polypeptides fragmented from the former, and making antibodies of these hormones is rather easy. Significance of every cell organelles in the endocrine function was clarified.


    (Communicated by Kiyoshi HAMA, M.J.A.)
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Original Papers
  • Akiko GOTO, Hirokazu FUJIMAKI, Toshiro MORIKIYO, Jianming LIU
    2004 Volume 80 Issue 6 Pages 269-275
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    We found a highly dolomitic lamprophyre diatreme at Badou, Shandong province, China for the first time. Although a number of silicate-rich carbonatite and glimmerite dikes and sheets were found around Badou, no alkaline rock–carbonatite plutonic complex exists nearby. Dolomitic lamprophyre diatreme that is not related with plutonic complex is not known yet either, and this is the first report of such an unusual occurrence. We report the whole-rock major and trace element chemistries of the lamprophyric rocks. The rocks consist of dominant dolomite with associated phlogopite, clinopyroxene, olivine, apatite and carry a number of xenoliths. Judging from all the geochemical and mineralogical data, the rock from Badou pipe should belong to the group of ultramafic lamprophyre and, more strictly, it should be called melnoite defined by Mitchell (1994).1) This finding should contribute to the understanding of the origin of carbonatite magma and the relationships between carbonatite and silicate magmas.


    (Communicated by Ikuo KUSHIRO, M.J.A.)
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  • Panayiotis A. VAROTSOS, Nicholas V. SARLIS, Efthimios S. SKORDAS
    2004 Volume 80 Issue 6 Pages 276-282
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    The study of low frequency signal transmission in conductive media, reveals that the electric and magnetic fields follow diffusion type equations. In a previous paper (Varotsos et al.1)) experimental evidence was forwarded that for epicentral distances of the order of 100 km, the SES electric field variations precede those of the magnetic ones by a time of the order of 1sec. In the present paper, we present evidence that this peculiarity still pertains (but to a smaller extent), when studying the differences in the components of the electric field. This cannot be probably observed in the scale of laboratory measurements, lying usually within the error bars of the current experimental facilities. A tentative theoretical justification, termed as τ-approximation, is presented which accounts for the measurements of electric field components. The present findings can provide a unique tool for the discrimination between remote and nearby sources by using data from electric measurements alone.


    (Communicated by Seiya UYEDA, M.J.A.)
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  • Haruo TANAKA, Panayiotis A. VAROTSOS, Nicholas V. SARLIS, Efthimios S. ...
    2004 Volume 80 Issue 6 Pages 283-289
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    In previous papers, we showed that in the new time-domain, called natural time: 1) the power spectrum of an SES-activity exhibits properties of critical phenomena and the power spectra of the local seismicity subsequent to an SES-activity become the same as that of the latter just before the main shock, 2) the power spectra of regional and long-term seismicity in both Greece and San Andreas fault system also exhibits features of critical phenomena. Here we show that the same can be found for the earthquakes in Japan. The "power spectra" in natural time of the seismicities in all the three areas fall on a universal curve.


    (Communicated by Seiya UYEDA, M.J.A.)
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  • Hideki OGINO, Akemi GUNJI, Nobuo KAMADA, Hitoshi NAKAGAMA, Takashi SUG ...
    2004 Volume 80 Issue 6 Pages 290-294
    Published: 2004
    Released: October 13, 2004
    JOURNALS FREE ACCESS
    Poly(ADP-ribose) polymerase-1 (Parp-1) localizes mainly in the nucleus and functions in DNA repair, genome stability and cell death regulation. Meanwhile, it also localizes in centrosomes and is involved in the regulation of centrosome duplication. An abnormal increase in centrosome numbers is frequently observed in Parp-1-deficient (Parp-1-/-) mouse embryonic fibroblasts (MEFs) (Kanai et al. (2003) Mol. Cell. Biol. 23, 2451-2462). However, there are no studies on whether the centrosome abnormality occurs also in other cell types under Parp-1 deficiency. In this study, we report that Parp-1-/- mouse embryonic stem (ES) cell lines did not show an abnormally increased number of centrosomes compared to wild-type ES cells. Recently, poly(ADP-ribose) glycohydrolase (Parg) has also been shown to localize in centrosomes (Ohashi et al. (2003) Biochem. Biophys. Res. Commun. 307, 915-921). The number of centrosomes of Parg-deficient (Parg-/-) ES cells was also analyzed in this study and was found to be stable under Parg deficiency. We also examined centrosome numbers in wild-type, Parp-1-/- and Parg-/- ES cell lines after treatment with methylmethanesulfonate (MMS) or γ-irradiation. Although a slight increase in the number of centrosomes is observed in each genotype twenty-four hours after treatment with MMS at 50 μM or with γ-irradiation at 1.4 Gy, there was no difference among the genotypes. These results suggest that loss of Parp-1 and Parg is insufficient to induce abnormality in centrosome numbers in ES cells and that ES cells possibly possess a strict mechanism for the maintenance of a normal number of centrosomes.


    (Contributed by Takashi SUGIMURA, M.J.A.)
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