• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.105-110
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• 2002

The sequence of 3,221 nucleotides immediately adjacent to rpsA gene encoding 30S ribosomal protein S1 of Brevibacterium ammoniagenes was determined. A putative open reading frame (ORF) of 2,670 nucleotides for a polypeptide of 889 amino acid residues and a TAG stop codon was found, which is located at a distance of 723 nucleotides upstream from rpsA gene with same translational direction. The deduced amino acid sequence of the ORF was found to be highly homologous to the DNA polymerase I of Streptomyces griseus (75.48％), Rhodococcus sp. ATCC 15963 (56.69％), Mycobacterium tuberculosis (55.46％) and Mycobacterium leprae (53.99％). It was suggested that the predicted product of the ORF is a DNA polymerase I with three functional domains. Two domains of 5 → 3 exonuclease and DNA polymerase are highly conserved with other DNA polymerase I, but 3 → 5 exonuclease domain is less conserved.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.561-565
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• 2018

The late-stage doxorubicin biosynthesis pathway acting enzyme (DoxA) from Streptomyces peucetius CYP129A2 exhibited substrate promiscuity towards the stilbene group of compounds such as resveratrol. DoxA along with two accessory enzymes ferrdoxin reductase and ferredoxin from spinach hydroxylated resveratrol at the 3'-position in vitro to produce piceatannol. The product was identified by HPLC-PDA and high-resolution HR-qTOF-ESI/MS analyses in positive mode. The ESI/MS fragments resembled the hydroxylated product of resveratrol.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1876-1882
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• 2018

A series of pentacyclic triterpenoids similar to glycyrrhetinic acid were designed and synthesized via the combination of chemical modification and microbial catalysis. All products were screened for the glycogen phosphorylases inhibitory activities in vitro. Within this series of derivatives, compound 5 displayed good inhibitory activities with $IC_{50}$ value of $27.7{\mu}M$, which is better than that of the other derivatives and glycyrrhetinic acid. Structure-activity relationship (SAR) analysis of these inhibitors was also discussed.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.209-213
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR-93 which was capable of producing high level of an inhibitor was selected from plant leaf. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp.. The active compound (MR-93D) was purified from the culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatography and HPLC. The inhibitor was identified as 4-hydroxy-8-isocyano-l-oxaspiro[4-4]cyclonon-8-en-2- one by spectroscopic methods of UV, $^{1}$H-NMR, ESIMS and IR. MR-93D showed a strong tyrosinase inhibitory activity with 0.03 $\mu$g/m of IC$_{50}$ value. It also inhibited melanin biosynthesis with 35 mm inhibition zone at 30 $\mu$g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work.

• Microbiology and Biotechnology Letters
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• v.27 no.4
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• pp.339-343
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• 1999

Pasteurella haemolytica is well known to cause severe pneumonia, consolidation and oedema of the lung, and fibrinous pleurisy under the stress and infection of virus in the cattle. In the course of our screening for antimicrobial agents against P.haemloytica, compound 51086 has been isolated from the fermentation broth of Streptimyces sp. 51086. The compound 51086 was purified by SiO2, Sephadex LH-20 and ODS column chromatographies and HPLC, subsequently. The structure of compound 51086 was determined as hygromycin A by combination of 1H NMR, 13C NMR, HMBC, and ESI-MS. This compound showed significant antibacterial activity against P.haemolytica and P.multocida.

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.26-26
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• 1998

Superoxide dismutases are metalloenzymes catalyzing the dimutation of superoxide anion radical to hydrogen peroxide and molecular oxygen. Examples of enzymes containing Cu, Mn and Fe as the redox-active metal have been characterized. Recently, an SOD containing one Ni atom per subunit was reported.(omitted)

• Korean Journal of Microbiology
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• v.18 no.2
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• pp.59-66
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• 1980

Two strains S-P and S-P-2, both Streptomyces sp., have been isolated and were found to have relatively high specific enzyme activity compared to other organisms reported. The specific activity of the enzyme produced from these two strains were 0.25 and 0.2 international units respectively. The productivity of the enzyme achieved was about 50 IU/l/hr. Glucose isomerase form these strains was found to be stable under the temperature of heat treatment (at $65^{\circ}C$) for fixation of enzyme inside the dell. This organism has an advantage in that it did not require toxic metalic ion for enzyme activity and could utilize xylan in leu of xylose as an inducer. The optimal temperature and pH of enzymatic reaction purpose of using these data for the optimal operation and designing of enzyme reactor system. The reaction mechanism was found to follow the single substrate reversible reaction kinetics. The kinetic constants determined experimentally are : $K_{mf}=0.33M,\;K_{mb}=1.0M,\;V_{mf}=0.88{\mu}mole\;per\;min.,\;V_{mb}= 2.96{\mu}mole\;per\;min.\;and\;K_{eq}=0.74.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.116-116
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• 2003

In 1998, Osada and co-workers isolated 140 mg of a novel cytokine modulator from 18 L of the culture broth of Streptomyces RK95- 31 isolated from a soil sample in Hiroshima Prefecture. This new immunosuppressant was named (-)-cytoxazone and its absolute configuration was determined on the basis of its NMR, CD and X -ray analysis. It interferes with cytokine IL4, IL10 and IgG production by selective inhibition of the signaling pathway of Th2 cells, but not Thl cells. Inhibitors of Th2-dependent cytokine production have potential as potent chemotherapeutic agents in the field of immunotherapy. The (-)-cytoxazone is different from known immunomodulators such as FK 506 and rapamycin in respect of structure and biological activity. As such cytoxazone should be a useful tool for understanding signaling pathways in Th2 cells, the synthesis of (-)-cytoxazone is of interest for the development of new cytokine modulators.

• Journal of Life Science
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• v.12 no.5
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• pp.632-648
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• 2002

The term polyketide defines a class of natural products synthesized through the successive condensation of small arboxylic acids, which results in products containing multiple carbonyl or hydroxyl groups, each separated by one arbon atom, as in the structural element CH$_2$C(=0)CH$_2$CH(OE)CH$_2$C(=0)-. Plant flavonoids, fungal aflatoxins, as well as undreds of compounds of different structures that can inhibit the growth of bacteria, viruses, fungi, parasites or human umor cells are included in this diverse group. Some of antifungal polyketides also have immunosuppresive activity. olyketides can vary widely in structure, and the diversity of polyketide structures reflects the wide variety of their iological properties. This review focuses on the biosynthesis of polyketides and recent progress in combinatorial iosynthesis of new hybrid polyketide compounds.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.35-40
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• 1992

S. fradiae showed the highest acetanilide p-hydroxylation activity in the tested strains. And S. fradiae was well characterized genetically, especially with respect to tylosin production. Two mutants, which lost hydroxylation, were isolated in 140 regenerated colonies from protoplasts. In restriction enzyme digesion of total DNAs, isolation of giant linear plasmid DNA and determination of antibiotic resistances to chloramphenicol, tylosin, hygromycin B and mitomycin C, any differences among mutants and a wild type strain were not detected. These facts suggest that lesion on 6, 000 Kb chromosomal DNA was responsible for the lack of p-hydroxylation activity induced by protoplast formation and regeneration.