• Korean Journal of Microbiology
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• v.52 no.3
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• pp.327-335
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• 2016

A novel Amycolatopsis strain KCTC 29142 was isolated and characterized based on the polyphasic taxonomic analysis including morphological observation, phylogenetic analysis, physiological and chemotaxonomic characteristics. The ethyl acetate extract of strain KCTC 29142 culture broth showed strong antibacterial activity and the active compound was identified as siderochelin A, a ferrous-ion chelating compound. In this study, siderochelin A showed good activity against multi-drug resistant pathogens, including Acinetobacter baumanii, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and Escherichia coli (E. coli). The minimum inhibitory activity against clinical isolates was also determined.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.221-230
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• 2015

Ground bed cultivation method for shiitake mushroom (Phogo; Lentinula edodes) has been advanced to use the oak-sawdust composted by microorganisms. This method has some advantages in saving the labors and improving productivity. The aim of this study is to analyze microbial community in oak sawdust and to provide the information for efficient cultivation of shiitake mushroom. In process of composting, the proportions of thermophiles increased from 10% to 80%. This results show the microbial community succession from mesophilic bacteria to thermophilic bacteria. T-RFLP analysis and nucleotide sequencing of 16S rRNA gene demonstrated that the change of dominant bacteria coupled with shifts in each stages. The family of Enterobacteriaceae as a mesophilic bacteria were dominant (100%) in oak sawdust sample, but Amycolatopsis (49.0%) and Saccharopolyspora (26.5%) as a thermophilic Actinomycetes were dominant in the last day of composting. In hyphal growth stage, Leuconostoc (psychrophilic bacteria) was dominant (75.0%). The composting process of sawdust is very important for growth of mushroom mycelium. Therefore, there is need for the further study for the Amycolatopsis as thermophilic Actinomycetes.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.356-365
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• 2004

In analyzing the region of the Amycolatopsis mediterranei S699 chromosome responsible for the biosynthesis of the ansamycin antibiotic rifamycin, we identified a gene, designated orj0, which is located immediately upstream of the rifamycin polyketide synthase (PKS). Orj0 encodes a protein, on the basis of sequence-comparative analysis, that is similar to several cytochrome P450 monooxygenases from different sources. The rifamycin producer, A. mediterranei, predominantly produces rifamycin B from its macrocyclic intermediate, proansamycin X, through dehydrogenation and hydroxylation steps. However, an A. mediterranei strain, deleted in orj0 by gene replacement, no longer produced rifamycin B. Furthermore, a versatile replicative vector in A. mediterranei was constructed and rifamycin B production was restored in a complementation experiment of orj0 using this novel vector. These consecutive results verified that the arf0 protein, which is a P450 hydroxylase, is required for the production of rifamycin B in A. mediterranei.

• Natural Product Sciences
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• v.19 no.1
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• pp.71-75
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• 2013

Actinofuranone C (1), a new 3-furanone-bearing polyketide, was isolated from an actinobacterium (Amycolatopsis sp.) associated with a female of the dung beetle, Copris tripartitus Waterhouse. The structure of actinofuranone C was elucidated by the spectroscopic interpretation of NMR, mass, UV, and IR data. The discovery of actinofuranone C indicates that chemical investigation of insect-associated microorganisms would be an effective strategy to explore natural chemical diversity.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.200-208
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• 2017

Actinobacteria are prolific producers of a large number of natural products with diverse biological activities. In the present study, an actinobacterium isolated from sunflower rhizosphere soil sample collected from Medak, Andhra Pradesh, South India was identified as Amycolatopsis thermoflava strain SFMA-103. A pigmented secondary metabolite in culture broth was extracted by using methanol and it was further purified by silica gel column chromatography with methanol-chloroform solvent system. Structural elucidation studies based on UV-visible, 1D and 2D-NMR, FT-IR, and mass spectroscopic analyses confirmed the structure as 1-methoxy-3-methyl-8-hydroxy-anthraquinone. It showed significant in vitro anticancer activity against lung cancer and lymphoblastic leukemia cells with $IC_{50}$ values of 10.3 and $16.98{\mu}M$, respectively. In addition, 1-methoxy-3-methyl-8-hydroxy-anthraquinone showed good free radical scavenging activity by DPPH method with an $EC_{50}$ of $18.2{\mu}g/ml$. It also showed other promising superoxide radical scavenging, nitric oxide radical scavenging and inhibition of lipid peroxidation activities. This is a first report of anti-proliferative and antioxidant activities of 1-methoxy-3-methyl-8-hydroxy-anthraquinone isolated from A. thermoflava strain SFMA-103 which may find potential application in biotechnological and pharmaceutical fields.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.613-619
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• 2003

The polyketide backbone of rifamycin B is assembled by the type I rifamycin polyketide synthase (PKS) encoded by the rifA-rifE genes. In order to produce novel analogs of rifamycin via engineering of the PKS genes, inactivation of the ${\beta}-ketoacyl:acyl$ carrier protein reductase (KR) domain in module 8 of rifD, by site-specific mutagenesis of the NADPH binding site, was attempted. Module 8 contains a nonfunctional dehydratase (DH) domain and a functional KR domain that is involved in the reduction of the ${\beta}-carbonyl$ group, resulting in the C-21 hydroxyl of rifamycin B. This mutant strain produced linear polyketides, from tetraketide to octaketide, which were also produced by a rifD-disruption mutant as a consequence of premature termination of the polyketide assembly. Another attempt to replace the DH domain of module 7, which has been considered nonfunctional, with a functional homolog derived from module 7 of rapamycin-producing PKS also resulted in the production of linear polyketides, including the heptaketide intermediate and its precursors. Premature release of the carbon chain assembly intermediates is an unusual property of the rifamycin PKS. that is not seen in other PKSs such as the erythromycin PKS.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.623-624
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• 2005

• Journal of Korean society of Dental Hygiene
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• v.1 no.2
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• pp.193-200
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• 2001

An appropriate amount of samples, collected from three each paddy forest, field and riverside soil near Taegu city, was suspended in sterile water and then diluted in order to isolation of antagonistic to oral cancer. The diluted samples were inoculated on separating medium in the routing spreading method. So, seven hundred and eighteen strains were isolated on HV agar and 220 strains were on methanol medium from soil samples. So, during the screening of anti-oral cancer activity from soil, we isolated microorganisms showing powerful antagonistic activity. Among them, No. 78 strain exhibited the most strongly anti-oral cancer activity. Microbiological properties were investigated by the methods described in the Bergey's Manual of Systematic Bacteriology and experimental methods of identification of actinomycetes by Hamada et al. As a result, a methylotrophic actinomycetes strain No. 79 was estimated as Amycolatopsis sp. based on taxonomic studies.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.391-398
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• 1999

A methylotrophic actinomycetes strain MO-16, which produce the antimicrobial compound, was isolated from soil and supposed as Amycolatopsis sp. based on taxonomic studies. The cell-free extract of methanol-grown strain MO-16 showed dehydrogenase activity for methanol and formaldehyde when various electron acceptors were added for oxidation. On the other hand, methanol did not affect the production of antimicrobial compounds, and organic nitrogen sources such as corn steep liquor and peptone were better than inorganic nitrogen sources. These compounds showed broad antimicrobial spectrum to the tested strains such as bacteria and yeast. The antimicrobial comounds were very stable under heat(121$^{\circ}C$), acid(pH2.0), alkali(pH11.0) treatments. These compounds were isolated by ethylacetate extract, silica gel column chromatography and reverse phase HPLC. Two compounds(peak 1 and 2) were detected as antimicrobial compounds through the HPLC analysis. The peak 2 was purified as a single compound and revealed a 98% purity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.378-384
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• 2005

Vanillin is one of the world's principal flavoring compounds, and is used extensively in the food industry. The potential vanillin production of the bacteria was compared to select and clone genes which were appropriate for highly productive vanillin production by E. coli. The fcs (feruloyl-CoA synthetase) and ech (enoyl-CoA hydratase/aldolase) genes cloned from Amycolatopsis sp. strain HR104 and Delftia acidovorans were introduced to pBAD24 vector with $P_{BAD}$ promoter and were named pDAHEF and pDDAEF, respectively. We observed 160 mg/L vanillin production with E. coli harboring pDAHEF, whereas 10 mg/L of vanillin was observed with pDAHEF. Vanillin production was optimized with E. coli harboring pDAHEF. Induction of the fcs and ech genes from pDAHEF was optimized with the addition of 13.3 mM arabinose at 18 h of culture, from which 450 mg/L of vanillin was produced. The feeding time and concentration of ferulic acid were also optimized by the supplementation of $0.2\%$ ferulic acid at 18 h of culture, from which 500 mg/L of vanillin was obtained. Under the above optimized condition of arabinose induction and ferulic acid supplementation, vanillin production was carried out with four different types of media, M9, LB, 2YT, and TB. The highest vanillin production, 580 mg/L, was obtained with LB medium, a 3.6 fold increase in comparison to the 160 mg/L obtained before the optimization of vanillin production.