Online ISSN : 1881-6371
Print ISSN : 0914-5818
ISSN-L : 0914-5818
Volume 7 , Issue 2
Showing 1-12 articles out of 12 articles from the selected issue
Review Article
Original Article
  • Chen-Lin Jiang, Li-Hua Xu, Yu-Rong Yang, Lai-Fu Wang, Zhong-Wen Shi, G ...
    1993 Volume 7 Issue 2 Pages 58-64
    Published: December 25, 1993
    Released: March 01, 2008
    A Lot of alkalophilic actinomycetes were isolated from alkaline soil samples collected at Yunnan, China using a number of different media adjusted to pH 10. Forty nine isolates and 10 type strains of the genus Streptomyces were selected for studying their physiological, biochemical, morphological and chemotaxonomic characteristics, and a cluster analysis based on their 82 unit characters was carried out. DNA-DNA homology among 9 strains selected from each cluster was determined. Characteristics of the alkalophilic actinomycetes and relationship between the alkalophilic and non-alkalophilic actinomycetes were discussed.
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SAJ Award Lectures
  • Sueharu Horinouchi
    1993 Volume 7 Issue 2 Pages 68-87
    Published: December 25, 1993
    Released: March 01, 2008
    A microbial hormone, A-factor, controls streptomycin production, streptomycin resistance, and aerial mycelium formation in Streptomyces griseus. A-factor exerts its regulatory role by binding to a specific receptor protein which, in the absence of A-factor, acts as a repressor-type regulator for these morphological and physiological differentiation. In the signal relay leading to streptomycin production, the A-factor signal is transmitted from the A-factor receptor to the upstream activation sequence of a regulatory gene, strR, in the streptomycin biosynthetic gene cluster via an A-factor-dependent protein that acts as a transcription factor for strR. The signal relay leading to aerial mycelium formation includes proteins similar to response regulators of the procaryotic two-component regulatory systems and to a family of membrane translocators engaged in ATP-dependent secretion mechanisms. Accumulating data show that a large family of γ-butyrolactones act as autoregulators in a wide variety of Streptomyces spp. In addition to the hormonal control by the autoregulators, secondary metabolism and morphogenesis are controlled by signal transduction systems via both procaryotic and eucaryotic protein kinases. A pair of the AfsQ1 and AfsQ2 proteins constituting a procaryotic-type histidine-aspartate phosphotransfer system globally controls secondary metabolite formation in Streptomyces coelicolor A3(2). Another pair of proteins, AfsK and AfsR, which also serves as a global regulator for secondary metabolism in S. coelicolor, constitutes an eucaryotic-type phosphotransfer system in which a protein serine/threonine/tyrosine kinase AfsK phosphorylates serine and threonine residues of AfsR. A wide distribution of DNA sequences homologous with the afsQ1/afsQ2 and afsK/afsR genes suggests that both procaryotic and eucaryotic protein kinases control secondary metabolism in general in Streptomyces. Inhibition by K-252a and staurosporine, known as eucaryotic protein kinase inhibitors, of antibiotic production and aerial mycelium formation of S. griseus and S. coelicolor supports this idea.
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  • Takashi Shomura
    1993 Volume 7 Issue 2 Pages 88-98
    Published: December 25, 1993
    Released: March 01, 2008
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Proceedings of the SAJ Symposium '93 New Basis for the Discovery of Novel Bioactive Substances July 2, 1993 in Tokyo