• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.347-351
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• 2007

Potato scab is prevalent in all potato-growing areas of Jeju Island and causes economically significant losses. Streptomyces species are known as pathogens of potato scab. In this study, we analyzed the 16S rRNA sequences of Streptomyces spp, which are isolated from potato scab lesions in Jeju Island, and constructed 16S rRNA phylogenetic tree. All isolates were clearly differentiated into the genus Streptomyces, and the tree also showed that new scab-causing Streptomyces spp or not yet named species of Streptomyces are existed in Jeju Island, Korea.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.383-386
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• 2012

Streptomyces spp. were isolated from rhizosphere in fallow lands. The Streptomyces spp. were identified as Streptomyces griseus (MSS181), Streptomyces griseoaurantiacus (MSS269), Streptomyces microflavus (MSS275), Streptomyces herbaricolor (MSS276) based on 16S rRNA gene sequences. Afterwards, cucumber, pepper, tobacco and tomato were drenched with the isolates at early growth stages and plant growth such as height and dry weight of plants was measured. By treatment of Streptomyce spp., plant height of cucumber was increased by 16-29% compared to the control, But there were no statistically significant differences in dry weight. When the same isolates were treated on chili-pepper, plant height and dry weight of chili-pepper were increased respectively by 10-19% and 19-25% compared to the control. The dry weight of tobacco and tomato were increased by 44-73% and 65-165%, respectively compared to the control. When antifungal activities of the isolates were tested against plant pathogenic fungi, Streptomyces microflavus (MSS275) effectively inhibited the mycelial growth of Phytophthora capsici, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.420-422
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• 2005

TMC (Tautomycetin) is a liner polyketide immunosuppressive antifungal compound produced by Streptomyces spp. Inhibition of T cell proliferation with TMC was observed highly efficient at 100-fold lower than those needed to achieve maximal inhibition with cyclosporin A. To elucidate the biosynthetic pathway of TMC, a genomic DNA library was constructed using a E. coil-Streptomyces shuttle cosmid vector, pOJ446. The DNA libraries were screened by colony blot hybridization using several polyketide ${\beta}-ketosynthase$ (KS) probes amplified from TMC-producing Streptomyces genomic DNA using polymerase chain reaction (PCR), of which the degenerate primers were designed based on the highly conserved sequences present in KS domains of various type I polyketide synthase genes in Streptomyces species. This library construction and screening approach led to the isolation of several positive cosmid clones representing type I polyketide biosynthetic gene clusters. In addition, a Streptomyces regulatory gene called afsR2 (a global regulatory gene stimulating antibiotic production in both S. coelicolor and S. lividans) was successfully integrated into the TMC-producing Streptomyces chromosome via E. coil-Streptomyces heterologous conjugation mehtod. The more detailed results of production improvement and genetic characterization of TMC-producing Streptomyces spp. will be discussed.

• Microbiology and Biotechnology Letters
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• v.4 no.4
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• pp.138-144
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• 1976

five strains of Streptomyces spp. with high Productivity of glucose isomerase (15-30 units/ml) were obtained among 280 microbial strains isolated from 150 soil samples. These strains produced glucose isomerase with xylose as an inducer. These 5 strains were also identified to be different strains of Streptomyces spp.：streptomyces sp. K-14, K-53, K-71, K-77 and K-733. It was found that Streptomyces sp. K-14 produced the highest enzyme activity. The spore chains of these strains were rectiflexible and spore surface was smooth except Steptomyces sp. K-77 and K-733, with spiny surface.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.217-225
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• 1998

영국 Hertfordshire의 두지역에서 사육되고 있는 건강한 조랑말의 결막낭내 상존하고 있는 진균총의 분포도를 조사 비교하고자 36두 조랑말의 양안(총72안)의 상 하 결막낭에서 시료를 채취하여 진균을 분리 동정하였다. 총 76.4%의 안구에서 진균이 발견되었으며, 13종이 분리되었다. 전체적으로 가장 많이 분리된 진균은 Aspergillus spp(27.8%), Nocardia spp(25.0%), Cladosporium spp(19.4%), Penicillium spp(9.7%) 및 Penicillium spp(9.7%)순이었다. 1지역에서는 Nocardia spp와 Cladosporium spp가 가장 많이 분리된 반면, 2지역에서는 Aspergillus spp가 가장 많이 분리되었다. 상 하결막낭내 진균분리율의 차이는 상결막낭에서보다는 하결막낭내에서 진균이 유의성 있게 많이 분리되었다(p<0.05). 시료채취시에 사용된 swab의 상태에 따른 비교에서 건조된 swab과 젖은 swab간에는 통계적 유의성이 없었다.

• Research in Plant Disease
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• v.30 no.1
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• pp.66-77
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• 2024

Black wood ear mushroom (Auricularia auricula-judae) is one of the most economically important mushrooms in China, Japan, and Korea. The cultivation of wood ear mushrooms on artificial substrates is more efficient in terms of time and cost compared with their natural growth on trees. However, if the substrate cultivation is infected by fast-growing fungi, the relatively slow-growing ear mushroom will be outcompeted, leading to economic losses. In this study, we investigated the competitive fungal isolates from substrates infected with fast-growing fungi for the cultivation of ear mushrooms in Jangheung and Sunchon, Korea. We collected 54 isolates and identified them by sequencing their internal transcribed spacer region with morphological identification. Among the isolates, the dominant isolates were Trichoderma spp. (92.6%), Penicillium spp. (5.6%), and Talaromyces sp. (1.8%). To find an appropriate eco-friendly biocontrol agent, we used five Streptomyces spp. and Benomyl, as controls against Trichoderma spp. and Penicillium spp. Among the six Streptomyces spp., Streptomyces sp. JC203-3 effectively controlled the fungi Trichoderma spp. and Penicillium spp., which pose a significant problem for the substrates of black wood ear mushrooms. This result indicated that this Streptomyces sp. JC203-3 can be used as biocontrol agents to protect against Trichoderma and Penicillium spp.

• The Korean Journal of Mycology
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• v.19 no.3
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• pp.231-237
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• 1991

This study was conducted in order to find out biological control of sesame wilt and blight caused by Fusarium of oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica by using Streptomyces spp. Two sesame pathogens, Fusarium oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica were purely isolated from diseased sesame plants of the field. Streptomyces species were isolated from 72 soil samples collected from red pepper and sesame uplands in Chungbuk and selected as antagonists according to the results of dual culture. The selected Streptomyces isolates such as St-11 and St-20 were confirmed their antagonistic effect through mycelial inhibition zone and inhibitory effects on the mycelial growth of the pathogens by culture filterate of the antagonists. Inhibitory effects on the conidial germination of Fusarium oxysporum vasinfectum and Phytophthora nicotianae parasitica by the antagonists were also tested in addition to mycelial Iysis. The antagonists St-11 and St-20 showed inhibitory effect on growth of sesame seedlings after seeds soaked in the suspension. Effect of soil inoculation with antagonist St-11 showed 40 to 78 percent of control effect for two diseases in comparison with control under greenhouse.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.134.2-135
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• 2003

The plant-pathogenic species S. scabies, S. acidiscabies, and S. turgidiscabies cause the scab disease of potato and produce the phytotoxins, thaxtomins. necl, a gene conferring a necrogenic phenotype, is involved in pathogenicity and physically linked to the thaxtomin A biosynthetic genes. Identification of the pathogenic strains of Streptomyces from soil was performed through the polymerase chain reaction by using specific pathogenicity primer sets derived from the necl gene sequences of Streptomyces smbies. The DNA was extracted from soil using a bead-beating machine and modifications of the FastPrep system. The DNA was suitable for direct use in the PCR. The PCR products showed the bands of approximately 460 bp. This methods can be very usuful in identifying species responsible for scab diseases and studying on the ecology of plant-pathogenic Streptomyces spp.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.47-51
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• 1986

A study was undertaken to investigate the distribution of Streptomyces spp. in soil in Korea. Among the different types of soil surveyed, the highest population of Streptomyces spp. recording $5.6{\times}10^5\;CFU/g$ was observed in upland soil. With reference to the soil depth, most of their population was distributed from soil surface to 5cm depth and the highest value was found in $0{\sim}2cm$ soil depth. Comparing the population of Streptomyces spp. with different soil color (by Munsell soil color chart), the highest value of $9.2{\times}10^\;CFU/g$ was showed in Oliver yellow soil (2.5Y, 6/4). On the basis of the acidity of soil samples subjected to Streptomyces spp. isolation, it is considered that the optimum pH range for Streptomyces spp. in soil lies between 6.0 to 7.5, showing the highest value of $1.05{\times}10^6CFU/g$ at pH 7.5. Among the colors of isolated colonies, gray and white colonies occupied 60% and 26% of the total isolates respectively.

• Korean Journal of Microbiology
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• v.15 no.2
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• pp.93-99
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• 1977

Among the Streptomyces isolated from soil, two strains which have antibacterial activity aginst various pathogenic bacteria are identified as Streptomyces globosus and Streptomyces albus subsp. according to I.S.P. methods and Bergy's Manual of Determinative Bacteriology. Morphological and physiological characteristics of them on several media were observed. Antibiotics from S. albus subsp. or S. globosus was identified asw tetracycline or streptomycin-like substances respectively by the paper chromatographic behavior in eight solvent systems of V. Betina. And it was revealed that these antibiotic substances are stable to temperature and weak acid.