• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.81-86
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• 1995

A Streptomyces strain YS-943, which produced amino acid antimetabolite, was isolated from soil. During the course of screening for new amino acid antimetabolites from the culture broth of Actinomycetes, we found that the strain produced a substance active against Gram-positive bacteria and its activity was reversed by L-methionine and L-histidine on the synthetic minimal agar medium in the culture broth.The morphological and cultural characteristics serve to identify the producing organism strain YS-943 as the genus Streptomyces. Fermentation was carried out in the synthetic medium at 28$\CIRC$C for 48 hours. The fermentation yield reached about 12 mg per liter of the broth. The YS-943 substance was obtained as white powder, mp 194$\CIRC$C and has the molecular formular of C$_{4}$H$_{8}$N$_{2}$O$_{4}$. Its structure was determined to be o-carbamyl-D-serine by spectroscopic data. It is active against some Gram-positive bacteria and reversed by L-methionine and L-histidine.

• Journal of the Korean Chemical Society
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• v.27 no.4
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• pp.239-243
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• 1983

EHMO calculations were performed on several antitumor active as well as inactive purine antimetabolites. Results showed that the N atom (position 9) which corresponds to the position of sugar (position 10) linkage in DNA bases has a net negative charge for antitumor active whereas it has a positive charge for inactive purines. It was also found that overlap population was the smallest for bond between atoms 9 and 10, which agrees with the experimental findings that antitumor activity is effected after conversion to nucleotide level.

• The Journal of the Korean dental association
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• v.11 no.10
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• pp.655-661
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• 1973

• YAKHAK HOEJI
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• v.21 no.2
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• pp.70-80
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• 1977

본고에서는 핵산 생합성과 Salvage patheway (Preformed Purine Utilization), De novo Pyrimidine Biosynthesis, Slavage patheway (Preformed Pyrimidine Utilization), Purine Base 및 Purine Nucleoside와 비슷한 구조를 가진 핵산 대사 길항제에 대한 내용으로 구성되어 있다.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.335-343
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• 1992

A Streptomyces strain No. 182-27, which produced amino acid antimetabolite, was isolated from soil. During the course of screening for new amino acid antimetabolites from the culture broths of Actinomycetes, we found that the strain produced a substance active against Gram-positive bacteria and its activity was reversed by L-Ieucine on the synthetic minimal agar medium in the culture broth. The morphological and cultural characteristics serve to identify the producing organism strain 182-27 as the Streptomyces, although the species of this strain should be resolved in further studies. Fermentation was carried out in the synthetic medium at $28^{\circ}C$ for 78 hours. The fermentation yield reached about 2 mg per liter of the broth. Purification was done by ion exchange resin, active carbon, silica gel column chromatography and obtained 20 mg of pure active substance from the 20 $\ell$ culture broth. The 182-27 substance was obtained as white powder, mp 18SoC. From the physicochemical characteristics of the substance, it was amino acid like substance but unknown about its chemical structure. It is active against some Gram-positive bacteria and reversed by L-Ieucine.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.327-330
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• 1996

An amino acid antimetabolite named YS-460 was isolated from the culture filtrate of a newly isolated Actinomycetes identified as Streptomyces sp. Fermentation was carried out in the synthetic medium at 30$\circ$C for 5 days. Purification was done by ion exchange resin, active carbon, silica gel column chromatography and obtained 38 mg of pure active substance per liter of the broth. YS-460, an amino acid like substance, has the molecular formula of C$_{7}$H$_{11}$NO$_{3}$- Its structure determined to be furanomycin by spectral analysis. It is active against some bacteria on a chemically defined medium and reversed competitively by L-isoleucine and non-competitively by L-leucine and L-valine.

• Journal of Chest Surgery
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• v.11 no.1
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• pp.12-17
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• 1978

Rifampicin has been widely hailed as the most effective antituberculosis antibiotics since the clinical use of streptomycin, but its immunosuppressive side effect was still annoying problem to be excluded. These studies were carried out to determine the effect of Tuberein-3, tuberculous bacilli extraction with water, on Rifampicin induced T-lymphocytopenia in 5 cases of pulmonary tuberculosis who have never exposed to antimetabolites or steroid compounds. After 2 weeks treatment of Rifampicin, all cases showed T-lymphocytopenia, active $13.0{\pm}2.3$ % and total $43.1{\pm}4.4$%. Followed by another 2 weeks treatment with Rifampicin combined with Tuberein-3, T-lymphocytes in peripheral blood returned to the normal limit, active $21.6{\pm}3.3$% and total $56.3{\pm}1.7$%. Tubercin-3 revealed the restoring activity of suppression of T-lymphocyte rosettes by Rifampicin.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.281-289
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• 1991

Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.228-232
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• 2003

Lovastatin produced by Aspergillus terreus via polyketide pathway is a secondary metabolite with high anti-hypercholesterolemic activity. In this paper we are going to present effective strain development strategies for lovastatin production by comparing the productivity of the mutants obtained through traditional rational screening process and protoplast fusion method. Mutants resistant against various antibiotics and/or antimetabolites showed significantly higher lovastatin productivity than the corresponding mother strains, demonstrating that rational screening method was very efficient in selecting high yielding producers. Recombinant fusants obtained using protoplast fusion between high producers were observed to have very different morphology and physiology as represented by the production and secretion of lovastatin, as well as cell growth pattern. In parallel with the strain development, optimization process for the production medium was carried out in order to find optimal concentrations of the medium components using such a powerful statistical method as response surface method (RSM). It was concluded that not only the optimum production medium but also good morphological characteristics of the high-yielding producers led to higher lovastatin production.

• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.187-196
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• 1978

Antimetabolite N-2292 substance, an antagonist of L-aspartic acid and L-glutamic acid was isolated from the fermentation broth of Streptomyces. Taxonomical study on the producing strain made it a related species of Streptomyces albulus judged by cultural characteristics and carbon utilization. N-2292 substance was isolated as amorphous white powder with melting point at 185$^{\circ}C$. From the physicochemical characteristics of the substance, it was peptide like substance. It was active against Gram positive and Gram negative bacteria but negative against yeast and mold in its biological properties. It was reversed by L-Asp and L-Glu on the synthetic medium.