The Journal of Antibiotics
Online ISSN : 1881-1469
Print ISSN : 0021-8820
ISSN-L : 0021-8820
Volume 54 , Issue 4
Showing 1-9 articles out of 9 articles from the selected issue
  • TOMOKAZU NAGAO, KYOKO ADACHI, MIHO SAKAI, MIYUKI NISHIJIMA, HIROSHI SA ...
    2001 Volume 54 Issue 4 Pages 333-339
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
    Seven new macrolactins (named G-M) and known macrolactins A and F were isolated from a culture broth of Bacillus sp. PP19-H3. The strain had been isolated from the macroalga, Schizymenia dubyi. Macrolactin A, which was 24-membered lactone, had previously been reported to show antibacterial, cytotoxic and antiviral activities. The new macrolactins include 22-membered ring or dicyclic lactone in addition to geometric isomers of known macrolactins A and F. The antibacterial activities of all the macrolactins examined in this study were relatively weak.
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  • YIDING HU, HEINZ G. FLOSS
    2001 Volume 54 Issue 4 Pages 340-348
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
    Five new type II manumycins, containing the hydroxyquinol mC7N unit, asukamycins A-II, B-II, C-II, D-II, E-II, were discovered in cultures of Streptomyces nodosus ssp. asukaensis. The biosynthetic origin of the type II manumycins from the type I compounds, containing an epoxyquinol mC7N unit, was deduced from the time course of production and proven by preparing [7'-13C] asukamycin A and demonstrating its incorporation into asukamycin A-II.
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  • MASAFUMI HAMADA, SHIGERU YAMAMOTO, SATORU MORIOUCHI, YASUO KISHINO
    2001 Volume 54 Issue 4 Pages 349-353
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
    Phagocytic functions of rat alveolar macrophages (AM) following intraperitoneal injection of conagenin (CNG) and of AM sub-populations fractionated by Percoll discontinuous gradient centrifugation were investigated. Phagocytosis of opsonized-sheep red blood cells (SRBC) following in vitro incubation with CNG showed a significant increase in a higher density of AM (fraction IV). In addition, phagocytosis was also increased in lower density ones (fractions I and II) by macrophage-activating factor (MAP) co-cultivation. CNG-injected rats for 5 consecutive days showed a dose-dependent increase in phagocytosis of AM compared to the control rats. Although the distribution of AM sub-population in rats injected CNG was not significantly different compared to the control rats, phagocytosis was significantly increased in AM of a lower density fraction (fraction II). These results suggest that CNG directly increases phagocytosis of AM in a higher density fraction, and indirectly enhances phagocytosis in AM of a lower density fraction via increasing MAF-like material production.
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  • LÁSZLÓ VÉRTESY, MICHAEL KURZ, ERICH F. PAULUS, DI ...
    2001 Volume 54 Issue 4 Pages 354-363
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
    The characterization of the structure of mumbaistatin (1), an effective inhibitor of the glucose-6-phosphatase system (EC 3.1.3.9), is reported. Isolation of mumbaistatin from cultures of Streptomyces sp. DSM 11641 was achieved by anion-exchange and reversed-phase chromatography. The acid-labile inhibitor was methylated for the structure determination. Single-crystal X-ray structure analysis of a triply methylated dehydration product, C31H24O11, revealed the structure of an aromatic dispirodiketal (2), a compound containing a previously undescribed ring system. Extensive 2D-NMR experiments with mumbaistatin and with the methylation products showed that mumbaistatin itself possesses the hydroxydiketodicarboxylic acid structure 1, C28H20O12, which, in the presence of acid or upon activation through methyl ester formation, undergoes self-condensation with loss of water to the dispirodiketal form (2). Mumbaistatin is an anthraquinone derivative, whose open-chain diketo form acts as a specific and powerful inhibitor of glucose-6-phosphate translocase: IC50=5nM. The activity towards the same enzyme of the cyclized dispirodiketal derivatives is roughly one thousand times lower.
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  • TOMOYASU ISHIKAWA, YUTAKA NAKAYAMA, MITSUMI TOMIMOTO, SHIN-ICHI NIWA, ...
    2001 Volume 54 Issue 4 Pages 364-374
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
    A systematic approach for improving the water-solubility of anti-MRSA (methicillin-resistant Staphylococcus aureus) cephalosporin derivatives is described. We first tried to improve the water-solubility of 7β-[2-(5-amino-1, 2, 4-thiadiazol-3-yl)-2(Z)-fluoromethoxyimino-acetamido]-3-[(E)-2-(1-methylimidazo[1, 2-b)]pyridazinium-6-yl)thiovinyl]-3-cephem-4-carboxylate (1a) by substitution of the C-3' pharmacophore. Replacement of the C-3' pharmacophore with a 1-methyl-4-pyridinio group improved the water-solubility without decreasing the anti-MRSA activity. Furthermore, we applied the N-modified prodrug strategy to the C-7 acyl group in order to enhance the water-solubility drastically. Among the compounds prepared, the N-phosphono type prodrugs 2a (1-methylimidazo[1, 2-b]pyridazinium derivative) and 2b (1-methyl-4-pyridinio derivative) showed water-solubility appropriate for a product intended for intravenous injection and in vivo anti-MRSA activity comparable to that of vancomycin.
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  • BONG-SIK YUN, TOMOMI HIDAKA, TOMOHISA KUZUYAMA, HARUO SETO
    2001 Volume 54 Issue 4 Pages 375-378
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
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  • TAIJIRO TOMIKAWA, KAZUO SHIN-YA, TAISEI KINOSHITA, ATSUSHI MIYAJIMA, H ...
    2001 Volume 54 Issue 4 Pages 379-381
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
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  • MASAKI HANDA, TOSHIAKI SUNAZUKA, KENICHIRO NAGAI, RYOUKO KIMURA, TATSU ...
    2001 Volume 54 Issue 4 Pages 382-385
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
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  • MASAKI HANDA, TOSHIAKI SUNAZUKA, KENICHIRO NAGAI, RYOUKO KIMURA, KAZUH ...
    2001 Volume 54 Issue 4 Pages 386-391
    Published: April 25, 2001
    Released: September 19, 2008
    JOURNALS FREE ACCESS
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