• The Korean Journal of Food And Nutrition
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• v.12 no.3
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• pp.271-278
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• 1999

We isolated activnmycetes LAM-98-80 as strain producing an effective antibiotic for cephalosporin re-sistant pathogenic PSeudomonas sp. and identified as Streptomyces sp. LAM-98-80 from cultural and phyisological characteristics. We investigated the optimal culture conditions for producation of an anti-biotic becoming effective for cephalsporin-resistant pathogenic Pseudomonas sp. It was found that 1.5% soluble starch and 1.0% yeast extract were good as carbon and nitrogen source respectively. The pro-duction of antibiotic was also activated by 0.04% Mn2+ as 80% degree. The optimum initial pH on pro-ductio of antibiotic was pH 7.0. The culture condition for the maximal productivity of the antibiotic was at 3$0^{\circ}C$ for 5 days. The cephalosporin-resistant pathogenic Pseudomonas sp. as test bacteria was rev-ealed to resist antibiotic of cepha families but revealed to not resist those of $\beta$-lactam families ampicil-lin and amoxicillin. Parital purified antibiotic was stable for the pH from 3 to 9 and was also stable when treated at 70 $^{\circ}C$ for 1 hour, This antbiotic was effective against all gram positive and negative bac-teria but was not effective against molds and yeasts.

• Archives of Pharmacal Research
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• v.22 no.4
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• pp.391-397
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• 1999

The quaternary ammonium cephalosporin derivatives were prepared with various pyridines substituted at the 3 or/and 4 position. Their in vitro antibacterial activities were determined and substituent effect on pyridine nucleus was studied. Preparation of substituted pyridines are also described.

• YAKHAK HOEJI
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• v.44 no.4
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• pp.315-317
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• 2000

The in vitro activities of DA-074, a new cephalosporin against 34 various standard strains and its in vivo efficacies against 6 important strains were obtained. DA-074 showed two fold enhanced in vitro antibacterial activity against some Pseudomonas aeruginosa compared to Ceftazidime and more than 2 fold in vivo efficacy against Staphylococcus aureus Smith, Klebsiella pneumoniae 1 and Escherichia coli KC-14, compared to Cefpirome. DA-074 might be a good candidate for further evaluations.

• YAKHAK HOEJI
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• v.44 no.4
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• pp.318-324
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• 2000

9 New cephalosporin derivatives were synthesized and screened for antibacterial activities against various bacteria. (6R,7R) -7$\beta$-[(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(fluoromethoxyimino)acetamido]-3-[(2-hydroxycarbamoyl)-s-triazolo[1,5-a]-pyrimidin-7-yl]thiomethyl]-3-cephem-4-carboxylic acid sodium salt (compound 3) showed 2 fold enhanced in vitro activity against P. aerurginosa, compared to ceftazidime.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.674-678
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• 1991

Methanolysis of a ${\beta}$-lactam ring of a cephalosporin was simulated with AM1 semiempirical quantum mechanical calculation. The tetrahedral intermediate TD1 from an O-protonated cephalosporin and a methanol transfers the proton intramolecularly to the C-4 carboxylate to generate an oxyanion, i.e., second tetrahedral intermediate TD2, which undergoes the amide bond cleavage without further protonation on the N-5. For this cleavage a low-energy barrier TS2 was located. According to the energy diagram, tetrahedral intermediates easily undergo ring cleavage even without the protonation on the amide nitrogen.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.603-607
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• 1994

New cephalosporin antibiotics,7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-[(substituted pyrimidin-2-yl)thiomethyl]-3-cephem-4-carboxylic acid derivatives(2a∼2d) were synthesized. These new cephalosporin derivatives were prepared by the introduction of pyridinylthiomethyl moiety in 3-position and thiazine group in 7-position of 7-ACA. Antibacterial activities of these compounds were examined and the relationship between structure and activities were studied. As the result, these compounds showed low antibacterial activities compared to cefotaxim used as control.

• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.95-100
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• 1997

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.224-229
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• 2004

Several microorganisms (esterase-producing group) were isolated by the solid selective media containing-naphtylacetate. Among them, strain 366M-9 having a high activity of cephalosporin-C deacetylase (CAH; EC 3.1.1.41) was selected. The strain 366M-9 was identified as Bacillus sphaericus on the basis of morphological, physiological, and biochemical characteristics. The production of CAH reached at maximum value after 32 hrs, when cultivated in the optimal medium containing dextrin 2.5%, peptone 2.5%, sodium chloride 0.5%, dipotassium phosphate 0.25%, ferrous sulfate 0.02%, and 7-ACA 0.1% at $30^{\circ}C$ with initial pH 6.0. The CAH was purified by 3 steps with ammonium sulfate precipitation, adsorption chromatography on hydroxyapatite column, and Sephadex G-200 gel chromatography. The final enzyme preparation was homogeneous as judged by the analysis of SDS-PAGE and HPLC. Optimum temperature and pH for CAH activity were $50{\circ}C$ and around 7.0, respectively. And the enzyme was stable at pH 6.0～8.0, up to $50^{\circ}C$. The Michaelis-Menten constants ($K_{m}$ ), $V_{max}$ were 0.87 mM and 1.22 unit/ml, respectively.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.611-618
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• 1989

Effects of methionine on cephalosporin C(CPC) production in a fluidized-bed bioreactor were investigated using bioparticles of Cephalosporium acremonium. Since methionine was found to be an important metabolic regulator on the synthesis of cephalosporin C, the effects of its concentration in the cuture broth and feeding mode to the bioreactor were studied. It was observed that the presence of initial methionine was essential for higher cephalosporin C production and there existed an optimal content of methionine. Carbon consumption rate also increased significantly under the presence of methionine. Production of cephalosporin C was most active when methionine was exhausted in the broth; however its additional feeding did not enhance the antibiotic production in the fluidized-bed bioreactor as much as expected. It was therfore considered important to feed an optimal content of methionine at the early operating stage for a higher cephalosporin C production in a fluidized-bed bioreactor. An interesting thing to note was that titre of the antibiotic with reused bioparticles was about 2 times higher in the methionine containing medium than that without methionine. Therefore repeated use of bioparticles, with an optimal content of methionine, was believed to be very useful to enhance to process productivity.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.375-380
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• 1986

Thirty-one strains of Pseudomonas aeruginosa were submitted to the synergistic activity test of amikacin(AK) and gentamicin(GM) combined with moxalactam(MX), ceftizoxime(CTZ) or cefoperazone(CFZ). The minimal inhibitory concentrations(MICs) of each drug and drugs combined in various ratios were measured by checkerboard dilution method. The synergism was determined through analysing the MIC distribution curve on isobologram and calculating the fractional inhibitory concentration index(FICI). MICs of GM, AK, MX, CFZ and CTZ against the 31 tested strains were distributed from $12.5{\mu}g/ml$ to $800{\mu}g/ml$, from $0.8{\mu}g/ml$ to $25{\mu}g/ml$, from $3.1{\mu}g/ml$ to $50{\mu}g/ml$, from $3.1{\mu}g/ml$ to $400{\mu}g/ml$, and from $12.5{\mu}g/ml$ to $100{\mu}g/ml$, respectively. The rate synergism of each drug combination by means of FICl was 45.5% in GM-MX, 36.4% in GM-CFZ, 63.6% in GM-CTZ, 48.6% in AK-MX, 35.3% in AK-CFZ, and 35.7% in AK-CTZ combination. Thus, it is suggested that Pseudomonas aeruginosa may effectively be inhibited by various aminoglycoside and cephalosporin combinations.