• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.288-292
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• 1991

The aim of the current study is to evaluate the effects of medium compositions on the production of protease inhibitor in Streptomyces sp. SMF13. The production of protease inhibitor was counter-currently linked to extra-cellular protease, which were regulated by the culture conditions. Nitrogen source was the most critical ingredient affecting the production of protease inhibitor and protease. Carbon source was an important factor to determine the culture pH which affected very clearly the formation of protease and protease inhibitor. Inorganic phosphate inhibited the protease inhibitor production which was linked to the cell growth rate, although the optimal conditions for the production of protease inhibitor were not favouring to the cell growth.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.422-425
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• 2004

To discover a potent strain against wheat leaf rust, soil samples collected from Ilgamho, Seoul, Korea were tested in vivo and a strain belonging to Streptomyces sp. was found to show good antifungal activity when fermented in a broth. The identification of the strain was carried out based on 16S rDNA analysis, and the active compound was separated from the fermented broth. Even though its structure was not determined completely, the authors report the results obtained so far indicate that the fermented broth of the strain showed activity against wheat leaf rust. Therefore, we propose that this may be a potential novel strain showing antifangal activity against Puccinia recondita.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.439-443
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• 1991

A strain of Streptomyces sp. isolated from soil was found to produce extra-cellular $\beta$-lactamase associated partially to the cell growth. The $\beta$-lactamase was purified from the culture supernatant through anmonium sulfate fractionation, ion-exchange chromatographies and gel filtration. The final purification fold and recovery yield were 57 and 6.2%, respectively. Molecular weight of the $\beta$-lactamase was estimated to be about 67, 000 by SDS-polyacrylamide gel electrophoresis. The optimal reaction condition was at pH 7-8 and at 35-$45^{\circ}C$. The $K_m$ and $V_{max}$ values of the enzyme for penicillin G were estimated to he 3 mM and $3\times 10^3$ $\mu\textrm{M}$/min/mg protein, respectively. The purified $\beta$-lactamase was classified to the class A enzyme hydrolyzing only penicillin.

• Biomedical Science Letters
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• v.18 no.1
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• pp.29-34
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• 2012

Streptomycetes are gram-positive filamentous bacteria that are well-known for producing a vast array of bioactive compounds, including more than 70 % of commercially important antibiotics. For the research about Streptomyces sp., the protoplast and electroporation transformation method have been the general techniques for the construction of transformants. However, these techniques have low efficiency and are time-consuming. Another option is intergenic conjugation, which is used for DNA transfer using methylation-deficient E. coli as a DNA donor to avoid the methylated-DNA-dependent restriction systems of actinomycetes. This conjugation method has been widely improved and applied to many other actinomycetes. In this research, an effective transformation procedure for the construction of expression vector by using gateway system was established to avoid limit of restriction enzyme site for cloning of target gene based on transconjugation by Escherichia coli ET12567/pUZ8002 with a pSET152 integration vector.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.446-448
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• 2003

Cystocin belongs to the class of nucleoside antibiotics from Streptomyces sp. GCA0001. Cystocin showed good activity against Gram-positive bacteria, but showed less activity against the Gram-negative bacteria. Cystocin exhibited about two to four folds higher activity than puromycin. Especially, cystocin shows relatively strong activity against Streptococcus strains. Cystocin shows quite potent antitumor activity against all of the cells tested showing $IC_{50}$ values of 0.10 to 0.14 $\mu$ g/mL. This in vitro result indicates that the cytotoxocity of cystocin is two ten folds more active than puromycin s.

• Molecules and Cells
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• v.26 no.4
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• pp.362-367
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• 2008

We identified a 1,134-bp putative type III polyketide synthase from the sequence analysis of Streptomyces peucetius ATCC 27952, named Sp-RppA, which is characterized as 1,3,6,8-tetrahydroxynaphthalene synthase and shares 33% identity with SCO1206 from S. coelicolor A3(2) and 32% identity with RppA from S. griseus. The 1,3,6,8-tetrahydroxynaphthalene synthase is known to catalyze the sequential decarboxylative condensation, intramolecular cyclization, and aromatization of an oligoketide derived from five units of malonyl-CoA to give 1,3,6,8-tetrahydroxynaphthalene, which spontaneously oxidizes to form 2,5,7-trihydroxy-1,4-naphthoquinone (flaviolin). In this study, we report the in vivo expression and in vitro synthesis of flaviolin from purified gene product (Sp-RppA).

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1603-1606
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• 2019

Sortase A (SrtA), a type of transpeptidase responsible for anchoring surface proteins to the peptidoglycan cell wall, is important in the virulence of gram-positive bacteria. Three compounds were isolated from marine-derived Streptomyces sp. MBTH32 using various chromatography techniques. The structures of these compounds were determined based on spectroscopic data and comparisons with previously reported data. Among the metabolites tested, lumichrome showed strong inhibitory activity against Staphylococcus aureus SrtA without affecting cell viability. The results of cell clumping activity assessment suggest the potential for using this compound to treat S. aureus infection by inhibiting SrtA activity.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.322-328
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• 2024

Soybean (Glycine max), a crucial global crop, experiences yearly yield reduction due to diseases such as anthracnose (Colletotrichum truncatum) and root rot (Fusarium spp.). The use of fungicides, which have traditionally been employed to control these phytopathogens, is now facing challenges due to the emergence of fungicide-resistant strains. Streptomyces bacillaris S8 strain S8 is previously known to produce valinomycin t through a nonribosomal peptide synthetase (NRPS) pathway. The objective of this study was to evaluate the antifungal activity of S. bacillaris S8 against C. truncatum and Fusarium sp., assessing its efficacy against soybean pathogens. The results indicate that strain S8 effectively controlled both above-ground and underground soybean diseases, using the NRPS and NRPS-related compound, suggesting its potential as a biological control in plant-microbe interactions. These findings underscore the pivotal role of the stain S8 in fostering healthy soybean microbial communities and emphasize the significance of microbiota structure studies in unveiling potent biocontrol agents.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.373-381
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• 1994

An actinomycete strain, HSL-613 was isolated -from soil and identified by International Streptomyces Project (ISP) and chemotaxonomic methods. The spore chain of the strain HSL-613 appears in a spiral shape, and its spores are spherical shape with smooth surface. The cell wall contains LL-diaminopimelic acid (DAP). Menaquinone MK-9 (H$_{6}$, H$_{8}$) and iso- and anteiso-branched fatty acids were detected from whole cell extract. Sugars identified from whole cell extract include galactose, glucose, mannose and ribose, which are distinct from general sugar patterns of Streptomyces. Average G+C content in the chromosome is 59%. 5S rRNA of HSL-613 consists of 120 nucleotides as determined by comparing with that of a type strain Streptomyces griseus subsp. KCTC 9080. Through morphological, physiological, and chemical characterization, HSL-613 was identified and named as Streptomyces sp. HSL-613.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.126-133
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• 1994

Numerical identification was aplied for Streptomyces sp.264, an isolate producing a new restriction endonuclease Sdi I. The restriction enzyme would appear to be an isoschisomer of Xho I. Fifty taxonomic unit characters were tested and the data obtained were analyzed numerically by using the TAXON program. The isolate was identified to be the major cluster 19 of Streptomyces and best matched to S. diastatochromogenes. It was, therefore, concluded that the isolate was identified to be a member of Streptomyces diastatochromogenes.