Online ISSN : 1881-6371
Print ISSN : 0914-5818
ISSN-L : 0914-5818
Volume 20 , Issue 1
Showing 1-3 articles out of 3 articles from the selected issue
Original Article
  • Akane Meguro, Yohko Ohmura, Sachiko Hasegawa, Masafumi Shimizu, Tomio ...
    2006 Volume 20 Issue 1 Pages 1-9
    Published: June 25, 2006
    Released: February 27, 2007
    More than 100 isolates of endophytic actinomycetes were obtained from field-grown rhododendron. By root-growth tests using cucumber germlings, one isolate, MBR-52, was selected as a final candidate to accelerate rooting of tissue-cultured rhododendron. Re-isolation test proved that when tissue-cultured seedlings of rhododendron were treated with MBR-52 in flasks, this isolate colonized in the seedlings and survived there even after their transplanting in soil. Another transplanting test revealed that emergence of adventitious roots was prominently accelerated in the MBR-52-treated tissue-cultured seedlings, suggesting that MBR-52 might release some type of rooting-promoting plant hormone(s). In addition to nucleotide sequence analysis of 16S rDNA, cultural, physiological, chemical and morphological characterizations showed that MBR-52 belongs to a strain of Streptomyces sp. MBR-52 certainly gives a great practical advantage to shorten the acclimatization period of tissue-cultured seedlings in warm and humid environment which very frequently increases the disease-infection risk of the seedlings.
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  • Suchada Jongrungruangchok, Somboon Tanasupawat, Prasat Kitakoop, Rapep ...
    2006 Volume 20 Issue 1 Pages 10-14
    Published: June 25, 2006
    Released: February 27, 2007
    Five strains of actinomycetes were isolated from soils in Thailand. PNK1–3, PNK1–5, TT2–9 and KN-6 were belonged to Streptomyces and FLM-2 was Kitasatospora based on their phenotypic and chemotaxonomic characteristics. Phylogenetic analysis using 16S rDNA sequences revealed that PNK1–3 and PNK1–5 were identified as S. hygroscopicus (99.7%), TT2–9 was closed to S. nogalater DSM 40546T (98.0%), KN-6 was S. purpurascens (99.8%); and FLM-2 showed highest similarity with K. kifunensis LMG 19957T (97.6%). The selected strain, PNK1–3 produced geldanamycin that showed inhibition on the growth of Gram-positive bacteria and strong cytotoxicity against KB and BC cells lines. Its taxonomic characterization has been described.
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