• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.44-55
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• 1989

Out of 826 isolates of Streptomyces isolated from different soils, 65 isolates were selected and identified according to their morphological and physiological characters. A total of 46 species of Streptomyces were identified, and the following 38 species were newly recorded in Korea. 1) Melanoid pigments producing group; S. lavendulae, S. purpurascens, S. violarus, S. lateritius, S. olivochromogenes, S. purpeofuscus, S. fulvoviolaceus, S. gallilaeus, S. naganishii, S. hygroscopicus subsp. ossamyceticus, S. nevagawaensis, S. anandii, S. phaeopurpureus, S. mirabilis, S. arenae, S. massasporeus, S. eurythermus, S. tuirus. 2) Melanoid pigments non-producing group; S. fellus, S. flavidovirens, S. exfoliatus, S. fumanus, S. termitum, S. glomeroaurantiacus, S. luteofluorescens, S. prunicolor, S. fradiae, S. tauricus, S. griseolus, S. misakiensis, S. poonensis, S. antimycoticus, S. diastaticus subsp. ardesiacus, S. nigrifaciens, S. tendae, S. narbonensis subsp. josamvceticus, S. atroolivaceus, S. chrysomallus subsp. fumigatus.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1741-1746
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• 2008

This study was conducted to select endophytic actinomycetes as biocontrol agents against Chinese cabbage clubroot caused by Plasmodiophora brassicae. A total of 81 endophytic actinomycetes were isolated from surface-sterilized roots of Chinese cabbage that was grown on paddy field and upland soils collected from various locations in Korea. By using 16S ribosomal DNA (rDNA) gene sequencing, they were classified to 8 actinobacterial genera. The genus Microbispora (67%) was most frequently isolated, followed by Streptomyces (12%) and Micromonospora (11%). Three of the 81 isolates, when inoculated in germinated Chinese cabbage seeds and then transplanted to pots, effectively suppressed the occurrence of a post-inoculated strain of P. brassicae in the pots. They showed control values of 58% for strain A004, 33% for strain A011, and 42% for strain A018. Based on cell wall components, morphological characteristics, and phylogenetic analyses, the three antagonistic isolates were identified as Microbispora rosea subsp. rosea (A004 and A011) and Streptomyces olivochromogenes (A018). Further researches on the field efficacy and action modes of the three actinomycetes are in progress.

• Journal of Microbiology
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• v.43 no.1
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• pp.34-37
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• 2005

In the present study, the xylA gene encoding a thermostable xylose (glucose) isomerase was cloned from Streptomyces chibaensis J-59. The open reading frame of xylA (1167 bp) encoded a protein of 388 amino acids with a calculated molecular mass of about 43 kDa. The XylA showed high sequence homology (92% identity) with that of S. olivochromogenes. The xylose (glucose) isomerase was expressed in Escherichia coli and purified. The purified recombinant XylA had an apparent molecular mass of 45 kDa, which corresponds to the molecular mass calculated from the deduced amino acid and that of the purified wild-type enzyme. The N-terminal sequences (14 amino acid residues) of the purified protein revealed that the sequences were identical to that deduced from the DNA sequence of the xylA gene. The optimum temperature of the purified enzyme was $85^{\circ}C$ and the enzyme exhibited a high level of heat stability.