• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.20-24
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• 2006

Plasmid DNA (pDNA) is a product of interest for many biopharmaceutical companies and research laboratories, because of increase in the number of gene therapy protocols that use nonviral vectors. This work was undertaken to study the effect of antibiotic and dissolved oxygen concentration (DOC) on the production of a ColE 1-type plasmid (pVAX1-LacZ) hosted in Escherichia coli $DH5\alpha$ and cultured in a batch fermentor with 0.751 of Terrific Broth. A decrease in the DOC from $60\%\;to\;5\%$ was shown to increase the specific pDNA concentration approximately 1.5-fold, due to the downregulation of growth. Additionally, this increase in the pDNA concentration led to a 2.2-fold increase in the purity of cell lysates obtained after cell lysis. However, the use of higher DOC led to 2.8-fold higher volumetric productivity as a consequence of a faster growth rate, reducing the fermentation time from 24 to 8 h. Interestingly, the specific pDNA concentration, and pDNA productivity and purity were always higher $(10-15\%)$ in the absence of antibiotic. Overall, the data indicate that nonselective conditions can be used without compromising yield, productivity, and purity of pDNA.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.203-209
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• 2015

The purpose of this study is to estimate the applicability of a stable anaerobic digester using a separator membrane to the preprocessing thickening process. The results of the experiments showed about a 47.16% weight loss rate for the sludge under anaerobic condition, and about 41.17% under intermittent aeration condition. The concentrations of rejection water were $SCOD_{Cr}$ 25 mg/L, T-N 16.6 mg/L, and T-P 1.4 mg/L on the average under the intermittent aeration condition, which were lower than the concentrations of rejection water under an anaerobic condition. As for the factors affecting the reduction of the flux, correlation analyses of TTF, MLSS, $SCOD_{Cr}$, and $EPS_{Protein}$, $EPS_{Polysacchride}$ resulted in -0.97, -0.95, -0.84 and -0.86, -0.95, respectively, which showed that TTF had the highest correlation to the reduction of the flux. In addition, it was concluded that MLSS, $SCOD_{Cr}$ and $EPS_{Protein}$, $EPS_{Polysacchride}$ also have close correlations. The results are considered to show that, in the case of the process using a tubular membrane in the preprocessing process of an anaerobic digester, an intermittent aeration condition of the thickener considering the contamination of the membrane and load of rejection water is appropriate for the stable preprocessing process.

• Journal of Ginseng Research
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• v.29 no.4
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• pp.176-181
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• 2005

Our previous reports demonstrated that ip. administration of Korean red ginseng acidic polysaccharide (RGAP) exerts antitumor activity In mice. The present study was carried out to compare the effects of ip. and p.o. routes of administration of RGAP on either normal or tumor-bearing BALB/c mice. RGAP was administered either ip. or p.o. at doses of 100, 300, 500, 1000 mg/kg for 1 or 5 weeks. Peritoneal macrophages from mice treated with RGAP p.o. at a dose of 300 mg/kg either for 1 or 5 weeks did not exhibit growth inhibition activity toward WEHI-I64 tumor cells. However, administration of RGAP at a dose of 600 mg/kg for both 1 and 5 weeks increased the antitumor activity of macrophages. Oral administration of RGAP (600 mg/kg) for 5 weeks and ip. administration of RGAP (300 mg/kg) for 1 week resulted in antitumor activities of $40\%$ and $45\%$, respectively, indicating that the effect of i.p. injection is more potent 2 and 5 times than that of p.o. one in terms of dose and duration, respectively. Tumor inhibition rates of RGAP at doses of 300, 500, 1000 mg/kg in mice transplanted with B16-F10 melanoma were 4.4, 12.0, and $45.4\%$, respectively, meaning that p.o. dose higher than 500 mg/kg possess marked antitumor activity. The results above suggests that p.o. administration of RGAP also show antitumor activity in vivo depending on the dose.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.7-14
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• 2019

The microencapsulation of nifedipine (NF) with 4 wt% of poly(${\varepsilon}-caprolactone$) (PCL)/polyvinylpyrollidone (PVP) or PCL/polyethylene glycol (PEG) was carried out by solvent evaporation method in oil in water emulsion system to investigate the effect of PVP and PEG addition on drug release behavior of the microcapsules. The PVA (emulsifier) concentration of 1.0 wt% was chosen for the formation of PCL capsule having an average size of $154{\pm}25{\mu}m$ due to nearly spherical shape with a narrow size distribution. As PCL/PVP and PCL/PEG ratios were raised from 10/0 to 6/4, the capsule size increased gradually from $154{\pm}25{\mu}m$ to $236{\pm}32{\mu}m$ and $248{\pm}56{\mu}m$, respectively. The drug release rate of PCL/PVP and PCL/PEG capsules increased dramatically from 0 to 4 h at the beginning and then reached the plateau region from 20 h. As the concentration of PVP or PEG increased, the amount of drug release increased, suggesting that the larger capsule size was attributed to the higher drug content. However, the drug release behavior remained almost constant. The PCL capsules exhibited no evidence of causing cell lysis or toxicity regardless of NF loading, implying that the microcapsules are clinically suitable for use as drug delivery systems.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.397-402
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• 1985

The fermentation of various sugars by C. thermosaccharolyticum was examined under pH controlled, anaerobic condition. The kinetic model for Product formation at various sugars was the combination of growth and non-growth associated mode. In the utilization of a single sugar, glucose was the best carbon source for growth. The specific growth rate of glucose, xylose and cellobiose were 0.363 h$^{-1}$, 0.242 h$^{-1}$ and 0.144 h$^{-1}$ respectively. The production of ethanol from glucose showed a negatively growth associated mode, so the higher growth rate decreased the productivity of ethanol. The maximum concentrations of the produced ethanol were 2.42 g/l, 3.76 g/l, and 3.4 g/l on glucose, xylose, and cellobiose. No glucose was detected during cellobiose fermentation. Sequential utilization of sugars was observed in the mixtures of glucose, xylose and cellobiose. It preferred glucose, followed by xylose and then cellobiose. The presence of other sugars had little or no effect on the rate of another sugar utilization. Cell lysis at the end of fermentation occured more slowly in the mixtures of sugars than a single sugar.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.172-178
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• 2010

The bloom of the genus Stephanodiscus was gradually extinguished after 18 April. Counts of bacterial population were increased as the diatom bloom was disappeared. Numbers of the heterotrophic nanoflagellates and ciliates were also increased during the disappearance of the bloom. The densities of the mesozooplankton, the major predator of the diatoms, started to increase in April. However, their growth was suppressed during the bloom period of the diatoms (from January to March). During the bloom period of the diatoms, the monthly average value of the basic productivity amounted up to 11,765.7 mgC $m^{-2}day^{-1}$, which is relatively high value considering the low temperature and light during that period. The growth rate of phytoplankton in March, when the bloom was beginning to be supressed was 0.007. The growth rate of phytoplankton was negative value in April when the decreasing of the algal density was started.

• Food Science and Preservation
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• v.13 no.5
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• pp.629-633
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• 2006

Pinus rigida Miller leaf extract (PRLE) showed antimicrobial activity remarkably against food pathogenic and spoilage bacteria at concentrations of $100{\sim}250{\mu}g/mL$. Alcohol-soluble PRLE had higher antimicrobial activity against Staphylococcus aureus and E-coli than any other-soluble PRLE such as butanol, ethyl acetate, ether and water. As PRLE concentration increased alcohol-soluble PRLE increased the remarkable inhibitory zone of microbial growth on the microbial media. PRLE showed good stability against temperature and pH in the range of $40{\sim}150^{\circ}C$ and $4{\sim}11$, respectively. This may indicate that PRLE can be a potential anti-microbial agent for industrial application. In addition, SEM of Listeria monocytogenes suggested that it antimicrobial component would perturb the functions of microbial cell membranes synergistically. In the feeding experiment the formaldehyde content in the serum of formalin-fed and PRLE-treated me decreased remarkably due to the lysis of formaldehyde and the rate of hemoglobin biosynthesis was recovered to the orignal state within a short breeding time.