Online ISSN : 1881-6371
Print ISSN : 0914-5818
ISSN-L : 0914-5818
Volume 11 , Issue 2
Showing 1-6 articles out of 6 articles from the selected issue
Original Article
  • Ryu Kawachi, Takuya Nihira, Yasuhiro Yamada
    1997 Volume 11 Issue 2 Pages 46-53
    Published: December 25, 1997
    Released: March 01, 2008
    Streptomyces virginiae is one of the most difficult Streptomyces strains to transform because of its strong restriction barrier. We succeeded in transforming S. virginiae by combining heat treatment of protoplasts and in vitro methylation of plasmids. In order to avoid the host restriction barrier, plasmids were modified by methylase AluI, and S. virginiae protoplasts were treated at 42°C for 15 min prior to transformation. Under the optimal conditions, plasmids pIJ486, pKC1064 and pUWL-KS isolated from Streptomyces lividans were introduced into S. virginiae at a frequency of 1.4×103, 7.0×102 and 1.2×103 transformants per μg DNA, respectively. Plasmid pKC1064 and pUWL-KS isolated from Escherichia coli DH5α could not transform S. virginiae, but those isolated from E. coli JM110 (dam, dcm) could transform at a frequency of 1.0×102 and 2.4×102 transformants per μg DNA, indicating the presence of a methylation-specific restriction system in S. virginiae.
    Download PDF (1208K)
SAJ Award Lectures
  • Tamotsu Furumai
    1997 Volume 11 Issue 2 Pages 69-79
    Published: December 25, 1997
    Released: March 01, 2008
    Download PDF (1490K)
  • Osamu Nimi
    1997 Volume 11 Issue 2 Pages 80-85
    Published: December 25, 1997
    Released: March 01, 2008
    Main studies on Streptomyces, especially S. griseus, during about thirty years of the author’s career are outlined. 1. Studies on streptomycin biosynthesis using resting mycelium-suspension culture of S. griseus revealed the following; 1) Streptomycin 6-phosphate is the final precursor, which is converted to streptomycin by a specific alkaline phosphatase, 2) Streptomycin 6- phosphotransferase contributes to self-protection from a toxic effect of streptomycin, and 3) Suppression of the phospholipid cycle of cell wall synthesis results in the accumulation of glucosamine 6-phosphate in the resting mycelium and the enhancement of streptomycin production 2. Genetic studies provided the following; 1) S. griseus has two genes contributing to self-protection against streptomycin, 2) Pleiotropic mutants were obtained at a high frequency by incubating mycelium under stress condition for growth, and 3) Physical macrorestriction map of S. griseus 2247 strain was constructed.
    Download PDF (1108K)