• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.142-148
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• 2005

This paper proposes a cell age model for Penicillium chrysogenum fed-batch cultivation to supply a qualitative insight into morphology-associated dynamics. The average ages of the segregated cell populations, such as growing cells, non-growing cells and intact productive cells, were estimated by this model. A combined model was obtained by incorporating the aver-age ages of the cell sub-populations into a known but modified segregated kinetic model from literature. For simulations, no additional effort was needed for parameter identification since the cell age model has no internal parameters. Validation of the combined model was per-formed by 20 charges of industrial-scale penicillin cultivation. Meanwhile, only two charge-dependent parameters were required in the combined model among approximately 20 parameters in total. The model is thus easily transformed into an adaptive model for a further application in on-line state variables prediction and optimal scheduling.

• KSBB Journal
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• v.15 no.5
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• pp.423-427
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• 2000

Intense research on biosensors has been performed in a number of different institution over the past 15 years, but relatively few commercial products have resultingly, the blood glucose sensor is a good example of a product which penetrated the market. However recently, the development of electrochemical and optical technologies has accelerated the turnover of the research as is illustrated by a rapid increase in the number of point-of-care diagnostic systems and analytical devices. Examples of such biosensors used in the fields of medical diagnostics, bioprocess control, and environmental monitoring are described, and summarized in an introduction to their characteristics, structures, and functions, given.

• Food Industry And Nutrition
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• v.10 no.2
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• pp.32-39
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• 2005

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.172-177
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• 2000

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.103-104
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• 2000

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.192-197
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• 2005

The effects of macronutrients $(NO_3^-,\; NH_4^+\;and\;PO_4^{3-})$ on cell growth and triterpenoids production in Centella asiatica cell suspension cultures were analyzed using the Box­Behnken response surface model experimental design. In screening and optimization experiments, $PO_4^{3-}$ as a single factor significantly influenced cell growth where increasing the phosphate level from 0.1 to 2.4 or 2.6 mM, elevated cell growth from 3.9 to $14\~16g/L$. The optimum values predicted from the response surface model are 5.05mM $NH_4^+$, 15.0mM $NO_3^-$ and 2.6mM $PO_4^{3-}$, yielding 16.0g/L cell dry weight with $99\%$ fitness to the experimental data. While the $NH_4^+-NO_3^-$ interaction influenced cell growth positively in the optimization experiment, $NH_4^+$ and $NO_3^-$ as single factors; and interactions of $NO_3^--PO_4^{3-},\;NH_4^+-PO_4^{3-}$ and $NH_4^+-NO_3^-$ were all negative in the screening experiment. Cell growth and the final pH level were positively affected by $PO_4^{3-}$, but negatively affected by $NH_4^+\;and\;NH_4^+-PO_4^{3-}$ interactions. The different effects of factors and their interactions on cell growth and final pH are influenced by a broad or narrow range of macronutrient concentrations. The productions of triterpenoids however were lower than 4mg/g cell dry weight.

• Journal of Pharmaceutical Investigation
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• v.23 no.2
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• pp.111-118
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• 1993

The hemolytic characteristics of amphotericin B-containing liposomes have been investigated in vitro. From the hemolysis of human erythrocytes against free and liposomal amphotericin B, the marked reduction in the toxicity of amphotericin B was observed by incorporating the drug in egg PC liposomes. For 45 min, free amphotericin B at $9.6\;{\mu}g/ml$ could completely lyse 2 wt% human erythrocytes. However, liposomal amphotericin B had essentially no lytic effect even in the range over $9.6\;{\mu}g/ml$. In the 66 hr-hemolysis experiment, liposomal amphotericin B showed the slowly hemolysing chracteristics during the experimental period regardless of the concentration of amphotericin B but rapid hemolysis only for 12 hr was observed in the case of free amphotericin B and the degree of hemolysis for 12 hr was maintained after that time. Also the hemolysing ability of liposomal amphotericin B at $4\;{\mu}g/ml$ was lower than that of free amphotericin B at the same concentration for 66 hr. On the other hand, the dependence of hemolysis on amphotericin B contents in egg PC liposomes was significant between 1.64 mole% amphotericin B-containing liposomes and 15.79 or 27.27 mole% amphotericin B-containing liposomes. But no marked difference in hemolysis was observed between 15.79 and 27.27 mole% amphotericin B-containing liposomes. Especially, cholesterol as an excipient in amphotericin B-containing liposomes significantly reduced the hemolysis of human erythrocyte. The degree of hemolysis in 5 mole% amphotericin B-containing liposomes was reduced to approximately 50% of value in the cholesterol-free liposomes by adding 50% cholesterol.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6319-6325
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• 2012

We previously found cytotoxic effects of tomato leaf extract (TLE) on the MCF-7 breast cancer cell line. The aim of this study was to ascertain the molecular mechanisms associated with the usage of TLE as an anticancer agent by microarray analysis using mRNA from MCF-7 breast cancer cells after treatment with TLE for 1 hr and 48 hrs. Approximately 991 genes out of the 30,000 genes in the human genome were significantly (p<0.05) changed after the treatment. Within this gene set, 88 were significantly changed between the TLE treated cells and the untreated MCF-7 cells (control cells) with a cut-off fold change >2.00. In order to focus on genes that were involved in cancer cell growth, only twenty-nine genes were selected, either down-regulated or up-regulated after treatment with TLE. Microarray assay results were confirmed by analyzing 10 of the most up and down regulated genes related to cancer cells progression using real-time PCR. Treatment with TLE induced significant up-regulation in the expression of the CRYAB, PIM1, BTG1, CYR61, HIF1-${\alpha}$ and CEBP-${\beta}$ genes after 1 hr and 48 hrs, whereas the TXNIP and THBS1 genes were up-regulated after 1 hr of treatment but down-regulated after 48 hrs. In addition both the HMG1L1 and HIST2H3D genes were down-regulated after 1 hr and 48 hrs of treatment. These results demonstrate the potent activity of TLE as an anticancer agent.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6709-6714
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• 2013

Background: Breast cancer is a leading cause of death in women. The available chemotherapy drugs have been associated with many side effects. Bromelain has novel medicinal qualities including anti-inflammatory, anti-thrombotic, fibrinolytic and anti-cancer functions. Commercially available bromelain is obtained through tedious methods; therefore, recombinant bromelain may provide a cheaper and simpler choice with similar quality. Materials and Methods: This study aimed to assess the effects of commercial and recombinant bromelain on the cytokinetic behavior of MCF-7 breast cancer cells and their potential as therapeutic alternatives in cancer treatment. Cytotoxic activities of commercial and recombinant bromelain were determined using (sulforhodamine) SRB assay. Next, cell viability assays were conducted to determine effects of commercial and recombinant bromelain on MCF-7 cell cytokinetic behavior. Finally, the established growth kinetic data were used to modify a model that predicts the effects of commercial and recombinant bromelain on MCF-7 cells. Results: Commercial and recombinant bromelain exerted strong effects towards decreasing the cell viability of MCF-7 cells with $IC_{50}$ values of 5.13 ${\mu}g/mL$ and 6.25 ${\mu}g/mL$, respectively, compared to taxol with an $IC_{50}$ value of 0.063 ${\mu}g/mL$. The present results indicate that commercial and recombinant bromelain both have anti-proliferative activity, reduced the number of cell generations from 3.92 to 2.81 for commercial bromelain and to 2.86 for recombinant bromelain, while with taxol reduction was to 3.12. Microscopic observation of bromelain-treated MCF-7 cells demonstrated detachment. Inhibition activity was verified with growth rates decreased dynamically from 0.009 $h^{-1}$ to 0.0059 $h^{-1}$ for commercial bromelain and to 0.0063 $h^{-1}$ for recombinant bromelain. Conclusions: Commercial and recombinant bromelain both affect cytokinetics of MCF-7 cells by decreasing cell viability, demonstrating similar strength to taxol.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.136-141
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• 1991

Optimum culture conditions for the formation of nitrile hydratase by Brevibacterium sp. CH2 were investigated. Addition of ferric and ferrous ions greatly increased the nitrile hydratase formation. The effects of nitriles, amides, and acids as an inducer on the formation of nitrile hydratase were investigated. Isobutyramide was the best inducer among the tested compounds. When Brevibacterium sp. CH2 was cultivated for 23 h at $30^{\circ}C$ in a optimized medium containing 15 g of glucose, 5 g of bacto peptone, 3 g of yeast extract, 3 g of malt extract, 1 g of $KH_2$$PO_4$, 1 g of $K_2$$HPO_4$, 1 g of NaCl, 0.5 g of isobutyramide, 0.2 g of MgSO$_4$ㆍ7$H_2O$, and 0.02g of $FeSO_4$ㆍ$7H_2$O per liter of distilled water with pH controlled at 7.1, the maximum total activity was 665 units/ml of the culture broth and the specific activity was 70 units/mg of the dry cells. The medium optimization increased the specific activity of Brevibacterium sp. CH2 2.2 times.