• 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.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.383-388
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• 2009

A strain YB914 was isolated from soil as a producer of the extracellular xylanase, which catalyzes the hydrolysis of oat spelt xylan. The strain YB914 was identified as Streptomyces sp. on the basis of its morphological, cultural and biochemical properties. The xylanase of culture filtrate was the most active at $55^{\circ}C$ and pH 5.5, and retained 80% of its maximum activity at the range of pH 4.5~7.0. In order to optimize the culture medium for xylanase production, ingredients of G.S.S medium were replaced by several carbohydrates. The carbohydrates such as oat spelt xylan, corn cob xylan, wheat bran and lactose increased the xylanase productivity of Streptomyces sp. YB914. However, xylanase production was greatly repressed by galactose or arabinose. The maximum xylanase productivity was reached to 48 U/mL in the modified medium containing 1% oat spelt xylan and 1.5% lactose.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1599-1605
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• 2015

The development of rapid and efficient genome sequencing methods has enabled us to study the evolutionary background of bacterial genetic information. Here, we present comparative genomic analysis of 17 Streptomyces species, for which the genome has been completely sequenced, using the pan-genome approach. The analysis revealed that 34,592 ortholog clusters constituted the pan-genome of these Streptomyces species, including 2,018 in the core genome, 11,743 in the dispensable genome, and 20,831 in the unique genome. The core genome was converged to a smaller number of genes than reported previously, with 3,096 gene families. Functional enrichment analysis showed that genes involved in transcription were most abundant in the Streptomyces pan-genome. Finally, we investigated core genes for the sigma factors, mycothiol biosynthesis pathway, and secondary metabolism pathways; our data showed that many genes involved in stress response and morphological differentiation were commonly expressed in Streptomyces species. Elucidation of the core genome offers a basis for understanding the functional evolution of Streptomyces species and provides insights into target selection for the construction of industrial strains.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.622-627
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• 2011

This study was designed to investigate the possible role of 10 green manure crop extracts in antimicrobial activity against potato common scab (Streptomyces scabiei). Ten green manure crops were extracted with hexane, ether, ethylacetate, methanol and water. The DPPH radical scavenging activity of ether, methanol and water was higher than those of hexane and ethylacetate fractions. The fractions of methanol, ethylacetate, ether and water showed antimicrobial activity against Streptomyces scabiei from the concentration of 0.25 mg/mL. Methanol fraction of Sorghum showed the highest antimicrobial activity against this microorganism. This result suggests the sorghum extract was the best as good green manure crop with antimicrobial activity against Streptomyces scabiei.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.83-88
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• 2003

We cloned a gene encoding acetyl xylan esterase(axeA) of Streptomyces coelicolor A3(2) and studied its expression pattern in Escherichia coli. The full sequence of axeA was amplified by PCR. Sequence analysis of the PCR product revealed an open reading frame of 1,008 nucleotides encoding a protein consisted of 335 amino acid residues, with a calculated molecular mass of about 38 kDa. The base sequence showed 98% homology to the same gene of Streptomyces lividans. Two different kinds of acetyl xylan esterases were produced in Escherichia coli(pLacI) by IPTG induction; their molecular weights were 38 kDa and 34 kDa, respectively. Of these, 38 kDa protein seemed to be a total protein holding N-terminal signal peptide region, whereas 34 kDa protein seemed to be a matured protein without signal peptide which was produced by peptide bond cleavage between two amino acid residues of alanine 41 and alanine 42.

• BMB Reports
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• v.32 no.1
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• pp.86-91
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• 1999

The sprT gene encoding Streptomyces griseus trypsin (SGT) was introduced into Streptomyces lividans TK24 and Streptomyces lividans 1326 to study which strain would be better to overexpress the extracellular proteinase. Various media with different compositions were also used to maximize the productivity of SGT in heterologous hosts. The SGT productivity was best when the transformants of S. lividans TK24 and 1326 were cultivated in R2YE medium, and their relative trypsin activity of the culture broth measured with an artificial chromogenic substrate, N-${\alpha}$-benzoyl-DL-arginine-${\rho}$-nitroanilide, were 382 units/ml and 221 units/ml, respectively. They produced high levels of SGT in GYE medium but relatively lower than those in R2YE medium, and negligible amount of SGT was produced in Ferm, RASF, LIVID, and NDSK media. Considering non-SGT associated activity in Pronase powder, it was estimated that the transformant of S. lividans TK24 can produce SGT in R2YE 3.5 times more than the amount by S. griseus 10137 from which the sprT gene had been originated. The growth of S. lividans reached the maximum level of cell mass at 5 d of culture, but SGT production started in the stationary phase of cell growth and kept increasing until the ninth day of culture in R2YE medium, but in GYE media the productivity reached at the maximum level at 7 d of cultivation.

• Research in Plant Disease
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• v.13 no.2
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• pp.93-97
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• 2007

The microorganisms with the antifungal activity against Phytophthora capsici and Colletotrichum acutatum and the plant growth promotion activity were screened from forest soils of Moon-gyeong (Juheul Mountain), Gyeongsangbuk-do. One of the isolates, strain MG 121 showed antifungal activity against P. capsici and C. acutatum and possessed phosphate solubilization activity was selected to development biocontrol agent. The strain MG 121 was identified as Streptomyces sp. by analysis of 16S rDNA. On the test with pepper fruits, the strain inhibited disease incidences of late blight and anthracnose over 80%. In greenhouse test, plant height, the number of leaf, fresh weight and roots length of pepper plants upon treatment of culture suspension of Streptomyces sp. MG 121 were significantly higher than those without the bacterial cells. In addition, strain MG 121 was capable to solublize rock-phosphate after incubation for 144 hours in potato dextrose broth. The concentration of soluble phosphate in PDB amended with 0.5% rock-phosphate was increased up to $765{\mu}g/ml$.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.196-201
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• 1995

Chemo- and numerical taxonomic studies on the isolate SL-387 producing novel aminopeptidase M inhibitors MR-387A and B were carried out The genus of the isolate was determined as Streptomyces by cultural and morphological data and chemical indices. Forty one taxonomic unit characters were tested for determining the species of the isolate, and the data were analyzed numerically using a computer program as called TAXON. The isolate was best matched to Streptomyces neyagawaensis in the major cluster 18 of Streptomyces with $S_{SM}$ value of 75.67%. On the base of chemotaxonomic data and TAXON analysis, the isolate SL-387 was identified to be a member of Streptomyces neyagawaensis.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.237-241
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• 1997

Lipase (EC 3.1.1.3) in the culture filtrate of Streptomyces coelicolor A3(2) was active on ${\alpha}$-naphthyl-butyrate as well as on various triacylglycerols with different lengths of acyl chains. The extracellular lipase was purified 15-fold by ammonium sulfate fractionation, Sephadex G-100, DEAE-Cellulose and Phenyl-Sepharose CL4B column chromatography with overall yield of 16%. It showed an molecular weight of 34.7 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme activity with tributyrin as substrate was optimal at pH 8.0~9.0 and at $37^{\circ}C$. The enzyme activity decreased when the chain length of acyl group of triacyglycerol increased. A-factor, a hormone-like regulator of Streptomyces differentiation inhibited the lipase activity, which might corelate with the low enzyme activity in early exponential growth phase.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.65-71
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• 1992

The two isolates of Streptomyces antagonistic to Phytophthora nicotianae var. parasitica and Fusarium oxysporum f. sp. vasinfectum were identified as based on the morphological, cultural and physiological characteristics on various culture media. Spore chains of St-11 isolate was rectus-flexibilis(RF), whereas the other isolate, St-20, was shown rectinaculum-apertum(RA). Spore surface of St-11 isolate was smooth, while St-20 was spiny. Aerial mycelia of the two isolates were all gray color and growing conditions on media were good as a whole. Any soluble pigment was not shown in cultivation of the two isolates. Stoll isolate showed negative response on starch hydrolysis and gelation liquefaction, whereas St-20 isolate was positive on starch hydrolysis and a negative on gelatin reaction. Stoll isolate was identified as Streptomyces bikiniensis and St-20 Streptomyces echinoruber, respectively.