• Natural Product Sciences
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• v.2 no.2
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• pp.123-129
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• 1996

Chemical carcinogenesis is associated with the increase of intracellular polyamine levels, and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse epidermal ODC activity are essential to skin tumor promotion by TPA. Therefore, for the discovery of new cancer chemopreventive agents, we have evaluated about 73 kinds of natural products to study inhibitory effects against ODC activity induced by TPA in T24 cell culture system. The total methanol extracts of plants fractionated into three layers (hexane, ethyl acetate and water layer) were tested and the hexane fraction of Angelica gigas $(root\;bark,\;IC_{50}:\;7.4\;{\mu}g/ml)$ and the ethyl acetate fraction of Corydalis ternata $(root,\;IC_{50}:\;7.5\;{\mu}g/ml)$ were the most effective on the inhibition of TPA-induced ODC activity, These active fractions are under investigation with further sequential fractionation using column chromatography.

• The Journal of the Korean Society for Microbiology
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• v.22 no.4
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• pp.435-443
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• 1987

A total of 30 strains of Candida albicans were examined for susceptibility to amphotericin B and ketoconazole using Sabouraud's dextrose broth, Kimmig broth and Supplemented yeast nitrogen base broth media. Furthermore, the growth curve and colony forming units were checked for use of stationary-phase cells and 2-hour incubation cells in the absence of atifungal agents. The viable counts were determined periodically during incubation by standard plate count techniques. The minimum inhibitory concentrations of amphotericin B for use of stationary phase cells were as follows: SDB, $0.09{\sim}0.97mcg/ml$(0.39mcg/ml); Kimmig broth, $0.19{\sim}0.39mcg/ml$(0.42 mcg/ml) and SYNB, $0.19{\sim}0.39mcg/ml$mcg/ml(0.23mcg/ml). In ketoconazole, MICs were value SDB, $3.12{\sim}25.0mcg/ml$(12.5mcg/ml); Kimmig broth, $12.5{\sim}25.0mcg/ml$ (22.5mcg/ml) and SYNB, $3.12{\sim}12.5mcg/ml$(6.71mcg/ml). The MICs of amphotericin B(0.2mcg/ml cone.) for use of 2-hour incubation cells in absence of AMB were, SDB, $0.04{\sim}0.39mcg/ml$(0.11mcg/ml); Kimmig broth, $0.09{\sim}0.39mcg/ml$(0.18mcg/ml) and SYNB, $0.09{\sim}0.19mcg/ml$(0.14mcg/ml) and in KTZ, the value of MICs were SDB, $3.12{\sim}25.0mcg/ml$(12.22mcg/ml); Kimmig broth, $0.78{\sim}25.0mcg/ml$(11.01mcg/ml) and SYNB, $1.56{\sim}12.5mcg/ml$(3.90mcg/ml). The two-log reductions in CFU per milliliter observed when 2 hour preincubation cells were treated with 0.2mcg/concentrations of AMB and 25.0mcg/ml of KTZ. However, AMB treated cells were restored to growth activity, it suggested that the AMB has no active antifungal activity.

• YAKHAK HOEJI
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• v.16 no.2
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• pp.97-107
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• 1972

Thirty-three Mannich bases of 2,2'-methylene bis(3,4,6-trichlorophenoxyacetic acid) were synthesized as potential antimicrobial agents and tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Trichophyton rubrum, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger and Aspergillus oryzae in vitro. It was found that: 1) Compounds 24 and 22 were active against Staphylococcus aureus and Bacillus subtilis at the concn. of 1 $\mu$g/ml respectively; 2) Compounds 9 and 29 were active against Trichophyton rubrum at the concn. of 2 $\mu$g/ml respectively; 3) Compouns 9 and 30 were active against Microsporum gypseum at the concn. of 2 $\mu$g/ml respectively; 4) Compounds 6,9,13,15,21,28,29,31,33 and 34 were active against Epidermophyton floccosum at the concn. of 1 $\mu$g/ml respectively; 5) Compounds 6,9,18 and 28 were active against Aspergillus niger and Aspergillus oryzae at the concn. of 1 $\mu$g/ml respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.4
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• pp.575-580
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• 2019

In biological warfare, it is important to identify biological agents for proper treatment. We focused on developing a real-time RT-PCR kit that can detect multiple species of biological agents. AccuPower(R) Biothreat Real-Time RT-PCR Kit(v3.0) could detect Bacillus anthracis, Yersinia pestis, Vibrio cholerae, Francisella tularensis, Salmonella typhi, Rickettsia prowazekii, Variola virus, Hantaan virus, Yellow fever virus, Brucella spp., Shigella dysenteriae in a single reaction. The results showed that the kit was verified to be able to detect at least 0.005 ng of nucleotide and 10,000 CFU/ml of bacteria. Therefore, the kit is expected to be used as a rapid and sensitive detection kit for 11 species of biological agents within 2 hours.

• Animal cells and systems
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• v.2 no.3
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• pp.383-388
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• 1998

A RecA-like protein (RecAps) was identified from fluorescent Pseudomonas sp. and the inducible nature of the protein was characterized in detail. It was shown by dose-response and time-course experiments using two DNA damaging agents, nalidixic acid and mitomycin-C, that the cellular level of RecAps protein was increased 3-8 fold compared to that of the control. The most effective doses of nalidixic acid and mitomycin-C for the protein induction were $30{\mu}g/ml$ and $0.3{\mu}g/ml$ at the treatment time point of 150 min, respectively. The enhanced level of RecAps protein was gradually decreased to the control level after 10 hr in normal medium. Interestingly, the cellular level of RecAps protein was increased by the same DNA damaging agents even when cell growth was completely inhibited by treatment with $170{\mu}g/ml$ of chloramphenicol, an inhibitor of protein synthesis, suggesting that new protein synthesis is not required for the induction of RecAps. All these results suggest that a typical S0S repair function driven by RecA-like protein is conserved in Pseudomonas sp. cells as in E, coli.

• YAKHAK HOEJI
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• v.42 no.1
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• pp.82-88
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• 1998

The effect of hepatoprotective agents and bile acids on tumor necrosis factor-alpha, (TNF-${\alpha}$) production in murine and human macrophage cell line (RAW264.7 and U937) was inve stigated. The hepatoprotective agents including silymarin and its major component, silybin, significantly inhibited TNF-alpha production in a concentration dependent manner ($IC_50$ of silybin=67.7${\mu}g$/ml (140.3${\mu}g$M)). In differentiated U937 cells, especially, silybin showed more effective inbitory activity ($IC_50$=35.1${\mu}g$g/ml (72.7${\mu}g$M)). These results suggest that silymarin and silybin may inhibit TNF-alpha production in the process of hepatic diseases in human. However, biphenyldimethyl dicarboxylate (DDB) was not effective. In the case of bile acids, chenodeoxycholic acid (CDCA) showed a concentration dependent inhibitory effect on TNF-alpha production ($IC_50$ of CDCA= 71.5${\mu}g$g/ml (182.1${\mu}g$M)). In contrast, glycine or taurine conjugated form (G-CDCA or T-CDCA) restored to the control level or significantly increased TNF-${\alpha}$ production. And also ursodeoxycholic acid (UDCA) and its conjugated forms (G-UDCA and T-UDCA) showed a variety of patterns on TNF-${\alpha}$ production by changes of functional groups and concentration. These results also indicate that bile acids may regulate TNF-${\alpha}$ production in normal hepatic function or disease conditions.

• Journal of the Korea Society of Computer and Information
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• v.29 no.2
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• pp.61-66
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• 2024

This paper aims to design a simulation for path-finding of objects in a simulation or game environment using reinforcement learning techniques. The main feature of this study is that the objects in the simulation are trained to avoid obstacles at random locations generated on a given track and to automatically explore path to get items. To implement the simulation, ML Agents provided by Unity Game Engine were used, and a learning policy based on PPO (Proximal Policy Optimization) was established to form a reinforcement learning environment. Through the reinforcement learning-based simulation designed in this study, we were able to confirm that the object moves on the track by avoiding obstacles and exploring path to acquire items as it learns, by analyzing the simulation results and learning result graph.

• Natural Product Sciences
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• v.2 no.2
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• pp.130-136
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• 1996

Evaluation of plant extracts that might inhibit hepatitis B virus (HBV) replication was performed to find potent anti-HBV agents. Eighty-five species of plants from forty-three families were tested for their anti-HBV activities using HBV-producing HepG2-derived 2.2.15 cells. The anti-HBV activity of plant extracts was measured by slot blot hybridization technique and cytotoxicity was determined by crystal violet staining procedure. All plants were extracted with methanol and the extracts were partitioned into n-hexane, ethyl acetate and aqueous layer. The ethyl acetate fractions of Rhus verniciflua $(stem:\;EC_{50},\;8.2{\mu}g/ml;\;CC_{50},\;9.4{\mu}g/ml)$, Gastrodia elata $(root:\;EC_{50},\;17.7{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, Raphanus sativus $(seeds:\;EC_{50},\;17.3{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, and Angelica gigas $(root:\;EC_{50},\;8.3{\mu}g/ml;\;CC_{50},\;15.6{\mu}g/ml)$ revealed the anti-HBV activity in 2.2.15 cell culture system and these fractions are under the process of further sequential fractionation by column chromatography to find the active principles against HBV.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.493-501
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• 1989

A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens. Minimal inhibitory concentration(MIC) ranges of antimicrobial agents to C jejuni isolates were $${\leq_-}1.56$$ to $${\geq_-}100{\mu}g/ml$$ for erythromycin, rifampin, streptomycin and tetracycline, 50 to $${\geq_-}100{\mu}g$$ for cephalothin, $${\leq_-}1.56$$ to $50{\mu}g$ for ampicillin, $${\leq_-}1.56$$ to $25{\mu}g$ for kanamycin and nalidixic acid, $${\leq_-}1.56$$ to $12.5{\mu}g$ for chloramphenicol and gentamicin. Resistance rates of C jejuni were showed to in order of rifampin(84.7%), tetracycline(56.2 %), erythromycin(17.1%) and ampicillin(3.8%), all of the strains were sensitive to chloramphenicol, gentamicin and kanamycin, and the incidence rates of resistant C jejuni were highly frequent in pig isolates than chicken isolates. The drug resistance patterns of 87 chicken isolates C jejuni to 9 antimicrobial drugs were showed 12 patterns, and Sm Ra Tc(24.1%), Sm Ra(21.8%) and Ra Tc(14.9%) were relatively common, and also 21 pig isolates were showed 6 patterns and Em Sm Ra Tc(57.1%) were most frequent. The majority of the isolates showed multiple drug resistance. Bactericidal activity of 10% normal sera from healthy animals were examined for 60min at $37^{\circ}C$. C jejuni were decreased from 0.4 to 1.0 ${\log}_{10}$(p<0.01), and serum susceptibility were high in order of guinea pig, sheep, chicken and cattle sera. Serum sensitivity of C jejuni Ch-39 strain in increased serum concentation up to 10, 20, 40 and 80% were highly significant. In the normal animal serum, the number of Ch-39 strain were decreased from $1.8{\times}10^4/ml$ to $2.7{\times}10^3/ml$ after 60 min incubation(p<0.01), but the numbers were decreased to $6.6{\times}10^3/ml$ in the heat inactivated normal serum for 30 min at $56^{\circ}C$. Bactericidal activity was restored in the heat inactivated normal serum after the serum of complement source was added.

• YAKHAK HOEJI
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• v.15 no.3_4
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• pp.93-97
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• 1971

Seventeen novel compounds of thiosemicarbazone derivatives were synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H$_{37}$Rv and antibacterial activity against Staphylococcus aureus, Escherichia coli. It was found that 4-($\alpha$-naphthyl)-1-(2-furfuraldehyde)-3-thiosemicarbazone was active at 0.01$\mu$g/ml and 1, 1'-(p-phenylene)-4, 4'-bis(phenyl)-2, 2'-dithiosemicarbazide, at 0.01$\mu$g/ml against E. coli, respectively.