• Korean Journal of Veterinary Research
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• v.29 no.1
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• pp.69-73
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• 1989

In vitro antifungal susceptibility test was carried out on 53 strains of Candida spp isolated from milk of dairy cows with subclinical mastitis and teat cups of milking machines, Nystatin, clotrimazole, miconazole, econazole, 5-fluorocytosine, cycloheximide, haloprogin and griseofulvin were tested by the agar dilution method. The 84.8% to 98.2% of Candida strains were inhibited by clotrimazole, econazole and miconazole at $${\leq_-}25{\mu}g/ml$$, and clotrimazole was most active. Interspecies differences of antifungal susceptibility were recognized and these were as follows. C albicans was most sensitive to clotrimazole (GM-MIC, $5.49{\mu}g/ml$) followed by 5-fluorocytosine, econazole and miconazole. C pseudotropicalis and C guilliermondii were notably sensitive to haloprogin, clotrimazole, miconazole, cconazole, 5-fluorocytosine, and haloprogin (GM-MIC, $0.17{\sim}0.19{\mu}g/ml$) was most active. C krusei was most sensitive to cycloheximide (GM-MIC, $0.54{\mu}g/ml$) followed by clotrimazole, haloprogin, miconazole and econazole. C parapsilosis was somewhat sensitive to econazole, cycloheximide, clotrimazole, and econazole (GM-MIC, $7.26{\mu}g/ml$) was most active. C tropicalis showed very low sensitivity to all tested drugs (GM-MIC, $${\geq_-}20.32{\mu}g/ml$$).

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.173-178
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• 1999

The extracellular cytosine deaminase (EC 3.5.4.1) from Chromobacterium violaceum YK 391 was purified 264.7-fold with an overall yield of 14.3%. The enzyme was for the first time homogeneous by the criteria of polyacrylamide gel electrophoresis performed in the absence and in the presence of sodium dodecyl sulfate. The molecular weight of the purified enzyme was estimated to be about 156 kDa. The enzyme consisted of two identical subunits of approximate molecular weight 78 kDa. The isoelectric point of the enzyme was pH 5.55. The enzyme had a pH optimum of 7.5 and a temperature optimum of around 40 to $45^{\circ}C$. Besides cytosine, the enzyme deaminated 5-fluorocytosine, cytidine, 5-methylcytosine, and 6-azacytosine, but not 5-azacytosine. The extracellular cytosine deaminase is believed to be unique because it was active not only on cytosine but also on cytidine. The apparent $K_m$ values for cytosine, 5-fluorocytosine, cytidine, and 5-methylcytosine were determined to be 1.55 mM, 5.52 mM, 10.4 mM, and 67.2 mM, respectively. The enzyme activity was strongly inhibited by heavy metal ions such as $Fe^{2+},Pb^{2+},Cd^{2+},Zn^{2+}, Hg^{2+}, and Cu^{2+}$ at 1 mM, and completely by $\alpha,\alpha$'-dipyridyl, and $\rho$-chloromercuribenzoate at 1 mM, and weakly inhibited by 1mM ο-phenanthroline. The enzyme activity was not affected by various nucleosides and nucleotides.

• YAKHAK HOEJI
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• v.43 no.2
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• pp.228-232
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• 1999

The combination effect of anethole with amphotericin B, fluconazole, miconazole, or 5-fluorocytosine was investigated against Saccharomyces cerevisiae. When combined with $\frac{1}{2}$ minimum inhibitory concentration (MIC) or $\frac{1}{2}$ minimum fungicidal concentration (MFC) of anethole, the antifungal activities of fluconazole and 5-fluorocytosine were not changed, but the fungistatic and the fungicidal activities of miconazole were increased 64-fold, respectively. In the case of amphotericin B, the fungistatic activity was increased 2-fold, while the fungicidal activity was decreased 2-fold. The combination effect of anethole with miconazole or amphotericin B was also investigated at the various concentrations using the macrobroth dilution checkerboard method. The fractional inhibitory concentration (FIC) and the fractional fungicidal concentration (FFC) index between B exhibited the FIC index of 8.25 and the FFC of 32.06, respectively. Thus, it is analyzed that the combination of anethole with miconazole or amphotericin B on the antifungal action shows synergism and antagonism, respectively.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.9-14
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• 1997

A bacterium, strain YK 391 producing extracellular cytosine deaminase, has been isolated from soil sample collected near Taegu City and identified. The strain YK 391 was observed to be a motile Gram-negative rod, and did not produced capsule nor spore. The bacterium produced acid from glucose and trehalose, not from arabinose. Esculine was nto hydrolyzed. The isolate could grow anaerobically at 37$\circ $C, but not at 4$\circ $C. Palmitoleic and palmitic acids comprised over 80% of the fatty acid composition of the strain. The strain. The strain YK 391 was identified as Chromobacterium violaceum YK 391 based on its morphological and physiolohical characteristics, and on the fatty acid composition. The extracellular cytosine deaminase produced by Chromobacterium violaceum YK 391 is believed to be unique because it was active not only on cytosine and 5-fluorocytosine but also on cytidine.

• Korean Journal of Microbiology
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• v.22 no.4
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• pp.257-263
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• 1984

A strain producing an extracellular cytosine deaminase was isolated from soil samples. The enzyme obtained from the strain possessed the substrate specificity to both cytosine and 5-fluorocytosine. From the results of its morphological, cultural, physiological, and biochemical properties, the strain was thought to be the genus Arthrobacter. Therefore, it was named as Arthrobacter sp. JH-13. The composition of optimum medium for the enzyme formation was 0.5% of peptone, 0.5% of meat extract, 0.5% of soluble starch, and 0.1% of KCl. The optimum pH for the enzyme formation was 8.0. When the microoganism was cultured aerobically in the above medium, enzyme production reached at maximum in 54 hours at $30^{\circ}C$.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.368-374
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• 1988

Enzymological proprties of an extracellular cytosine deaminase from Bacellus polymyxa YL 38-3 were investigated. The extracellular enzyme was very stable, and optimum pH and temperature for the enzyme activity were found to be near pH 6.0 in 0.2M potassium phosphate buffer and at $30^{\circ}C$, respectively. 5-Fluorocytosine was converyed to 5-fluorouracil by the enzyme, but 5-methylcytosine was not to thymine by it. The enzyme activity was completely inhibited by some heavy metal ion such as 1mM of $Cd^{2-}$ and $Hg^{2+}$, and by 1mM of p-chloromercuribenzoate, respectively. The enzyme activity was inactivated about 75% by 1mM of o-phenanthroline and monoiodoacetate. But the enzyme activity was stimulated up to 200% by 1mM of 2-mercaptoethanol.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.305-309
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• 1992

Cytosine deaminase (EC 3.5.4.1) from BaciNus stc~urorhermophilus was partially purified 7.2-fold with an overall yield of 52.7%. The partially purified enzyme deiiminated cytosine only.but not 5-methylcytosine and 5-fluorocytosine. The apparent Michaclis constant. Km valuefor cytosine was 5.9 mM. The enzyme was relatively stable in the range of pH 4.0 to 7.0.furthermore extremely thermo-stable : more than 75'X) of the activity was remained afterheating at 80$^{\circ}$C for I0 min at pH 6.5. The enzyme had a pH optimum at around pH7.0 to 7.5. and temperature optimum at 35 to 31$^{\circ}$C. And the activation energ (En value)determined from an Arrhenius plot was 26 Kcal/mol. The enzyme activity was stronglyinhibited by heavy metal ions such as Cd", Hg". Cut' at 1 mM, anJ by o-phenanthroline,and p-chloromcrcuribcnzoate at I mM. But the enrymc activity was activatetl increased byGMP, and CMP at 1 mM.ased by GMP, and CMP at 1 mM.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.169-174
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• 1986

Cytosine deaminase was partialy purified about 10 fold from the ceil-free extract of Aspergillus fumigatus. The partialy purified enzyme was relatively stable in a pH 5.5 to 8.0, but thermo-unstable. The enzyme activity was found in a pH optimum of 7.0 and temperature optimum of 30 to 35$^{\circ}C$. The activation energy calculated to be 13,240 cal/mol. The apparent Michaelis constants Km for cytosine was found to be 1.53 mM and the molecular weight was determined to be approximately 32,000. The enzyme was strongly inhibited by 0.1 mM of Hg$^^{2+}$, Pb$^{2+}$, Cd$^{2+}$ and Fe$^{2+}$, furthermore inhibited by 1mM of ATP, UTP, o-phenanthroline and p-chloromercuribenzoate.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.53-59
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• 1997

In this study investigated the effect of cytosine deaminase activity from Aspergillus fumigatus IFO 5840 by cytosine analogues. The results were as follows. The enzyme was strongly inibited by 2-thiouracil, 2-thiocytosine, 6-azacytosine and 2-mercaptopyrimidine. The half inhibitory concentration(HIC) of 2-thiocytosine and 6-azacytosine on cytosine deaminase was 0.80mM and 1.15mM, respectively. The enzyme was inhibited at a certain level by addition of 2-thiocytosine immediately, but was maintained to some extend under the inhibited state by 6-azacytosine in proportion to reaction time. Regardless of kinds of substrate such as cytosine and 5-fluorocytosine, 2-thiocytosine and 6-azacytosine showed action as inhibitors, 2-thiocytosine inhibited cytosine deaminase activity about twice as strong as 6-azacytosine. The enzyme, when cytosine was used as a substrate, was revealed the pattern of competitive inhibition by 2-thiocytosine and 6-azacytosine, The ki value for these compounds was 4.5$\times$10-4M and 1.756$\times$10-3M, respectively. At this point, the Hill coefficient for cytosine, 2-thiocytosine and 6-azacytosine was 1.80, 1.81 and 2.45, respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.477-483
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• 2005

Corynebacterium ammoniagenes ATCC 6872, which does not accumulate pyrimidine nucleoside or nucleotide, was metabolically engineered to secrete a large amount of thymidine. Characteristics of 5-fluorouracil resistance ($FU^r$), hydroxyurea resistance ($HU^r$), trimethoprim resistance ($TM^r$), thymidylate phosphorylase deficiency ($deoA^-$), inosine auxotrophy ($ino^-$), 5-fluorocytosine resistance ($FC^r$), thymidine kinase deficiency, and thymidine resistance ($thym^r$) were successively introduced into mutant strains KR3 and DY5T9-5, and shake-flask cultures were able to accumulate 408.1 mg/l and 428.2 mg/l of thymidine, respectively, as a major product. The mutant strains did not accumulate thymine at all and accumulated less than 10 mg/l of other pyrimidine nucleosides, such as cytosine, cytidine, and deoxycytidine, as byproducts.