• 한국미생물·생명공학회지
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• 제23권4호
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• pp.384-389
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• 1995

Streptoalloteichus hindustanus ATCC 31219, a nebramycin complex producer, is similar to Streptomyeces tenebrarius in a viewpoint of resistance to a wide range of aminoglycoside antibiotics. S. tenebrarius has resistance mechanisms of 16s rRNA methylation and aminogycoside modification. However, it is not known whether resistance mechanisms of Stall. hindustanus are the same as in S. tenebrarius. Therefore, we have tried to isolate resistance determinants from Stall. hindustanus. Two different types of aminoglycoside resistance determinants were isolated from Stall. hindustanus and expressed in Streptomyces lividans TK24. The apramycin resistance gene (amr) and the tobramycin resistance gene (tmr) isolated from Stall. hindustanus showed broad resistance spectrum against a dozen of aminoglycoside antibiotics. The complete nucleotide sequences of apramycin resistance gene (amr) were determined. The deduced amino acid sequence of the amr gene of Stall hindustanus ATCC 31219 showed extensive sequence homology to the 16s rRNA methylase gene (kamB) of S. tenebrarius.

• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.263-266
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• 2011

Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an ${\alpha}$-glucosidase inhibitor with an $IC_{50}$ value of 10 ${\mu}M$. It showed mixed-type inhibition of ${\alpha}$-glucosidase with a $K_i$ value of 5.94 ${\mu}M$. In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells. Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.885-892
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• 2011

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and -independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culturedependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1332-1338
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• 2018

In the course of studies to discover natural products with anti-angiogenic properties, two cyclic octapeptides, octaminomycins A (1) and B (2), were isolated from the cultures of Streptomyces sp. RK85-270. Octaminomycins suppressed the vascular endothelial growth factor (VEGF)-induced proliferation, adhesion, tube formation, migration, and invasion of HUVECs. Anti-angiogenic activity was futher confirmed in vivo by the chicken chorioallantoic membrane assay. We also identified that 1 and 2 inhibited the phosphorylation of VEGF receptor 2, AKT, and ERK1/2 and the expression and activities of MMP-2 and MMP-9. These results suggest that 1 and 2 may serve as potential scaffolds for the development of therapeutic agents to angiogenesis-dependent diseases.

• 농업과학연구
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• 제37권2호
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• pp.255-260
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• 2010

Rusty root, the browning disease on ginseng, decreases quality and value. Recent studies indicated that endophytic bacteria could be a possible cause of rusty root. Actinomycetes antagonistic to the rusty-root-causing bacteria were isolated from soil. Twenty nine out of 932-isolates of Actinomycetes from soil showed antibacterial activity against Agrobacterium tumefaciens and Pseudomonas veronii an endophytic isolate in ginseng. The strongest antibacterial strain(ATO4O104) was classified based on 16S rDNA sequence. The Actinomycetes strain, ATO4O104, isolated in soil of USA volcano national park was identified as Streptomyces adephospholyticus. To test plant toxicity, radish seeds were sprouted with the culture of S. adephospholyticus and it did not show any harmful effect. The butanol partition out of n-hexane, ethyl acetate, butanol, and water partions showed the highest antibacterial activity.

• Journal of Microbiology
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• 제33권4호
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• pp.315-321
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• 1995

The relationship between morphological differentiation and production of trypsin-like protease (TLP_ in streptomycetes was studied. All the Streptomyces spp.In this study produced TLP just before the onset of aerial mycelium formation. Addition of TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP activity. Addition of 2% glucose to the Bennett agar medium repressed both the aerial mycelium formation and TLP production in S. abuvaviensis, S. coelicolor A3(2), S exfoliatus, S. microflavus, S. roseus, s. lavendulae, and S. rochei. However the addition of glucose did not affect S. limosus, S. felleus, S. griseus, S. phaechromogenes, and S. rimosus. The glucose repression on aerial mycelium formation and production of TLP was relieved by the addition of glucose anti-metabolite (methyl .alpha.-glucopyranoside). Therefore, it was concluded that TLP production is coordinately regulated with morphological differentiation and TLP activity is essential for morphological differentiation in streptomycetes. The proposed role of TLP is that TLP participates in the degradation of substrate mycelium protein for providing nutrient for aerial mycelial growth.

• Preventive Nutrition and Food Science
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• 제3권1호
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• pp.27-35
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• 1998

Starch-polyethylene films containing high molecular weight(NW) oxidized-polyethylene and prooxidant were prepared , and thermal -and bio-degradability of the films were determined. Increased levels of starch resulted in a corresponding reduction in mechanical strength of the films. However, the addition of high MW oxidized-polyethylene did not significantly reduce the percent elongation of the films. Thefilms containing high MW oxidized-polyethylene andproosicant were degreaded faster than those containing no aadditive during the heat treatment. The films lost their measureable mechanical properties when their weight-average MW(Mw) fell below 50,000. Biodegradability of the films was determined by a pure culture assay with either Streptomyces badius 252.S. setonii 75Vi2 or S. viridosporous T7A, and by an extracellulr enzyme assay using S. setonii 75vi2. The results from pure culture assay indicated that biomass accumulation on the film surface inhibited chemical and biological degradation of the films. The extracellular enzyme assay demonstrated decrease of percent elongation and increase of carbonyl index of the films. Therefore, extracellular enzyme assay could be used as a good method to evaluate biodegradability of the films.

• Journal of Microbiology and Biotechnology
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• 제7권6호
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• pp.417-422
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• 1997

Recombinant Bacillus subtilis LKS88[pASA240] containing the amylase gene from Streptomyces albus KSM-35 was exploited in fed-batch cultivation for mass production of maltotetraose-producing amylase. The effects of dissolved oxygen, additional organic nutrients (peptone and yeast extract) and mixed carbon sources (glucose plus soluble starch) on amylase production were examined in fed-batch operations in an effort to determine the optimum conditions for a maximum amylase productivity. Under the optimum conditions, maximum amylase activity was about 4.2 times higher than that obtained in batch cultivations, indicating that mass production of maltotetraose-producing amylase could be accomplished in fed-batch cultivation of the recombinant B. subtilis strain.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.295-299
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• 1998

Oligonucleotide primers were designed and successfully applied to amplify DNA fragments of P450 hydroxylase genes from actinomycetes which produce a large variety of medically important metabolites. Primers were designed based on several regions of strong similarities in amino acid sequence of P450 hydroxylases from a variety of actinomycetes, primarily in the regions of an oxygen binding site and a heme ligand pocket. These primers were used to amplify DNA fragments from seven different actinomycetes species producing a variety of different compounds. The deduced amino acid sequences of the isolated fragments revealed significant similarities to known P450 hydroxylase including the product of the suaC or subC genes from Streptomyces griseolus that is capable of metabolizing a number of sulfonylurea herbicides, and to the product of the $P450_{sca2}$ from S. carbophilus that produces a specific HMG-CoA reductase inhibitor. This method should help researchers in cloning the P450 hydroxylase genes involved in the biosynthesis of useful compounds.

• Journal of Microbiology and Biotechnology
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• 제18권5호
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• pp.874-879
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• 2008

Tyrosinase is a key enzyme for melanin biosynthesis, and hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, which can be reduced by treatment with depigmenting agents. The methanol extract of Lespedeza cyrtobotrya $M_{IQ}$ showed inhibitory activity against mushroom tyrosinase. The active compound was purified from the methanol extract of L. cyrtobotrya, followed by several chromatographic methods, and identified as dalbergioidin (DBG) by spectroscopic methods. The results showed that DBG exhibited tyrosinase inhibitory activity with an $IC_{50}$ of $20\;{\mu}M$. The kinetic analysis of tyrosinase inhibition revealed that DBG acted as a noncompetitive inhibitor. In addition, DBG showed a melanin biosynthesis inhibition zone in the culture plate of Streptomyces bikiniensis that has commonly been used as an indicator organism. Furthermore, $27\;{\mu}M$ DBG decreased more than 50% of melanin contents on the pigmentation using the immortalized mouse melanocyte, melan-a cell.