• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.110-110
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• 2017

Stomata are the main gateways for water and air transport between leaves and the environment. Inward-rectifying potassium channels regulate photo-induced stomatal opening. Rice contains three inward rectifying shaker-like potassium channel proteins, OsKAT1, OsKAT2 and OsKAT3. Among these, only OsKAT2 is specifically expressed in guard cells. Here, we investigated the functions of OsKAT2 in stomatal regulation using three dominant negative mutant proteins, OsKAT2(T235R), OsKAT2(T285A) and OsKAT2(T285D), which are altered in amino acids in the channel pore and at a phosphorylation site. Yeast complementation and patch clamp assays showed that all three mutant proteins lost channel activity. However, among plants overexpressing these mutant proteins, only plants overexpressing OsKAT2(T235R) showed significantly less water loss than the control. Moreover, overexpression of this mutant protein led to delayed photo-induced stomatal opening and increased drought tolerance. Our results indicate that OsKAT2 is an inward-rectifying shaker-like potassium channel that mainly functions in stomatal opening. Interestingly, overexpression of OsKAT2(T235R) did not cause serious defects in growth or yield in rice, suggesting that OsKAT2 is a potential target for engineering plants with improved drought tolerance without yield penalty.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.106-110
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• 2001

In an effort to evaluate the economic value and durability of the expanded rice hull as substrates, changes in the physical and chemical properties of material and plant growth in that substrate were studied. Using and electron microscope, the structure of used and new expanded rice hull substrate was examined. Considerable decomposition was found in the substrate which had been used one to three times. Compactness and lowered porosity in the used substrates were probably caused by decomposition. The results of cation analysis showed the possible destruction of cell wall of rice hulls. Abundant $Ca^{2+}$ in the substrates used for two to three times also indicated the possibility of decomposition. In tomato yield comparison, 15.2% more yield of tomato fruit in a new substrates indicated the negative effects of decomposition of one-time used substrates. Yield decreased in the substrates used for three times. if perlite substrates is used for three years before renewal and the cost of the perlite renewal is counted. 65.3% saving in the cost will be realized with the use of an expanded rice hull substrate. Another positive effect of the expanded rice hull substrate is the decrease of environmental contamination.n.

• Korean Journal of Medicinal Crop Science
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• v.17 no.4
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• pp.280-285
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• 2009

Both fresh Codonopsis lanceolata and lactic acid bacteria fermented Codonopsis lanceolata were extracted with water at $100^{\circ}C$, and tested for anticancer activity using several human cancer cell lines. The fermented extracts inhibited the growth of hepatocellular carcinoma cells up to 90%, compared to 75% for fresh Codonopsis lanceolata. The extracts of cytotoxicity on human normal lung cells (HEK293) were as low as 15%. Especially, human hepatocellular carcinoma cell were more efficiently inhibited than other cells. This extract also inhibited $\alpha$-glucosidase activity up to 60% at 1.0mg/$m{\ell}$. This fermented extracts showed the inhibition potency on tyrosinase by 25% at 1.0mg/$m{\ell}$. From the results, the fermented Codonopsis lanceolata enhanced several biological activities up to $20{\sim}30%$, compared to those from fresh Codonopsis lanceolata. It implies that fermentation process could be one of useful methods of utilizing low quality Codonopsis lanceolata. Because this process could yield high amounts of biologically active compounds by the help of microbial growth.

• KSBB Journal
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• v.11 no.3
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• pp.340-346
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• 1996

Variations of rheological properties of culture broth during the production of biopolymer by an alkali tolerant Bacillus sp. were investigated. Correlations among the rheological characteristics of culture broth, cell growth and biopolymer production were examined. Rheology of the culture broth changed in the course of fermentation. The culture broth showed a non-Newtonian flow behavior, as the viscosity and pseudoplasticsity increased during the cultivation. The rheological parameters such as flow index, consistency index, yield stress and apparent viscosity during the cultivation were not influenced by the cell growth, but significantly related to the biopolymer synthesis. Changes in the rheological parameters of the broth were affected not only by the biopolymer concentration, but also by the progress of fermentation. Some rheological parameters showed maximum values just before the completion of biopolymer production and substrate consumption. Hence, it was shown that the rheological characteristics of the culture broth could be used as a good indicator for the detection of the progress or completion of fermentation.

• 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.

• Microbiology and Biotechnology Letters
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• v.8 no.1
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• pp.9-18
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• 1980

During an extensive screening tests of yeasts for their RNA formation, it was found that Cryptococcus laurentii had especially high RNA content and high dry cell weight, when hydrolyzate of sliced and dried sweet potatoes was used as a carbon source. Growth conditions of this strain were examined, and the most desirable results were obtained at 48 hours of cultivation on a reciprocal shaker at 3$0^{\circ}C$ with initial pH 6.0. Under the above conditions, the RNA content and yield of dry cells were investigated using various media compositions. Ammonium sulfate 0.40%, peptone 0.6 ％, and yeast extract 0.4% were appeared to be favorable as a nitrogen sources. The optimum concentrations of K $H_2$P $O_4$, M $n^{++}$, C $O^{++}$ were 0.05 ％, 0.1 ％, and 0.001 ％, respectively. Ca-pantothenate, 400$\mu\textrm{g}$/$m\ell$, showed relatively favorable effects as a growth factor. The maximum RNA content obtained in this study was 16.8 ％ of the total dry cell weight.t.t.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.88-92
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• 1986

Determination of bacterial adenosine triphosphate (ATP) based on luciferin-luciferase bioluminescene reaction was applied to the measurement of bacteria on the surface of chicken as an alternative rapid method. The light yield was proportional to the concentration of ATP giving a straight line within a range of $10^{-10}\;to\;10^{-6}M$. The bacteria isolated from the surface of chicken were identified as Escherichia coli, Hafnia alvei, Pseudomonas putida and Aeromonas hydrophila. When the ATP contents of each bacteria were determined by bioluminescence reaction and compared, there was no significant difference (r = 0.95). The Patterns of growth curves for E. coli look very similar, when the bacterial growth was monitored by ATP content and viable cell count. When bacterial ATP of each samples collected every 2 days during storage for 14 days at $4^{\circ}C$was determined and compared with viable cell count, it gave a good correlation (r = 0.95, n = 32).

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.756-761
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• 1996

Influence of acetic acid on xylitol production from xylose using Candida parapsilosis KFCC 10875 was investigated at the different concentrations of acetic acid. Acetic acid was totally consumed below 1.0 g/l of its concentration, whereas partially consumed above 3.0 g/l and remained in the medium during xylitol fermentation. Cell growth, xylose consumption, and xylitol production decreased when acetic acid concentration was increased. Specific growth rate of cell and specific consumption rate of xylose also decreased with increasing the concentration of acetic acid. However, the xylitol yield from xylose and specific production rate of xylitol were maximum at 1.0 g/l of acetic acid. The inhibitory effect of acetic acid on xylitol fermentation increased when pH was decreased.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.317-321
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• 2006

This study was performed to compare effect of anticancer activities on Rhodiola sachalinensis by ultrasonifi-cation process and solvent. Compared the yield to the water extracts (WE), wafer extracts with ultrasonification (WEU) at60, loot and ethyl alcohol extracts (EE), ethyl alcohol extracts with ultrasonification (EEU) at 60 ${\circ}$C from Rhodiola sachalinensis. Experimental studies were progressed through the anticancer activities such as cell cytotoxicity, inhibition activities of cell growth. The cell cytotoxicity using human embryonic kidney cell (HEK293) was showed cytotoxicity of below 26.26%by extracts of Rhodiola sachalinensis in 1.0 mg/ml concentration, The anticancer activities were increased in over 70% by extracts of Rhodiola sachalinensis in A549, AGS, Hep3B and MCF-7 cells. From the results, the extract Rhodiola sachalinensis were showed useful anticancer activities.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.257-262
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• 1989

The induction of calli from tissues of a grape, Vitis hybrid, and their suspension cultures were performed and various factors were investigated on cell growth and anthocyanin production. It was shown that light intensity and inorganic nitrogen concentration played an important role on anthocyanin production.1:he contents of anthocyanin produced under 10,000 Iux light irradiation were about twice as much as under the dark. The reduction of inorganic nitrogen concentration of MS medium to one to twenty brought about the increase of approximately five to six-fold in total anthocyanin or sixteenfold in anthocyanin content per dry cell weight and addition of nitrate only as inorganic nitrogen source was shown to be the best for anthocyanin production. Miller medium and Gamborg medium were suitable for the anthocyanin production, as well as high concentrations of Co$^{2+}$ and Fe$^{2+}$. And high yield of 40mg anthocyanins per 200m1 flask was obtained by two stage culture using MS medium for the first stage and the modified MS medium for the second stage.