• KSBB Journal
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• v.13 no.6
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• pp.700-705
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• 1998

Studies were made to investigate effects of the scale-up of stirred tank bioreactors on cell growth and alkaloids production for suspension cultures of Eschscholtzia californica. In the 1.5 L STR, cell lysis was observed at 110 rpm or higher agitation speed. The agitation speed of 30 L STR was 43.7 rpm to maintain the same shear stress developed in 1.5 L STR of 100 rpm. As a result of scale-up from 1.5 L to 30 L STR, the specific growth rate was decreased from 0.12 to 0.07 day-1. The alkaloids productivity was also decreased from 0.24 to 0.14 mg/L-day. Changes of mixing performance and oxygen transfer were studied to explain the decrease of cell growth and alkaloids production. Decreased oxygen transfer rate coefficient(KLa) and increased mixing time by the scale-up was observed at various aeration rates.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.53-65
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• 1995

The growth and synthetic activities of fibroblasts are regulated by cytokines and growth factors derived from activated inflammatory cells. Stimulatory effect of low level laser (LLL) radiation on wound healing seems to be in part due to direct stimulatory action on cell proliferation and synthetic activities of fibroblasts. Also indirect stimulatory effect on the fibroblast function through inflammatory or immune cells is another possible mechanism of biostimulatory action of LLL. This study was performed to determine the growth rate of human gingival fibroblasts obtained biopsy and culture, fibroblast cell line, and immune cell line by using $[^3H]-$ thymidine incorporation test. And gene expression pattern was also analyzed by using the DNA probe such as Hsp70, IL-1$\beta$, MIP-1$\alpha$ and actin cDNA. Proliferation rate of gingival fibroblast was increased by LLL irradiation, but no more effect was added by LPS or IL-1$\beta$ pretreatment Enhanced Hsp70 gene expression was found from gingival fibroblasts and fibroblast cell line COS by LLL irradiation., which was not more increased by LPS or IL-1$\beta$ pretreatment. LLL-irradiated promyelcytic cell line HL-60 and macrophage cell line RAW264.7 showed significant stimulatory effect of proliferation rate when compared with respective control. However there were no changes in growth rate of other immune cell tested in this study, such as B cell line WR19n.l and 230, helper T cell line Jurkat and Hut78, cytolytic T cell line CTLL-r8. By LLL-irradiation Hsp70 gene expression was increased in RAW246.7 and HL-60, not in CTLL-R8. And IL-1$\beta$ and MIP-1$\alpha$ gene expression were induced only from LLL-irradiated RAW264.7. These results led us to presume that LLL radiation may affect to the immune cells, especially to macrophage, through which it might promote wound healing process.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.435-441
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• 1998

Optimal conditions for the production of natural color, betacyanin were investigated by varying light intensity, C/N ratio, concentrations of phosphate and kinds of elicitors. Batch cultivation was employed to characterize cell growth and betacyanin production of 32 days. The maximum specific growth rate, ${\mu}$$\sub$max/, was 0.3 (1/day) for batch cultivation. The maximum specific production rate, q$\^$max/$\sub$p/, was enhanced 0.11 (mg/g-cell/day) at 3 klux. A light intensity of 3 klux was shown to the best for both cell growth and betacyanin production. The maximum specific production rate was 0.125 (mg/g-cell/day) at 0.242 (1/day), the maximum specific growth rate. The dependence of specific growth rate on the light lintensity is fit to the photoinhibition model. The correlation between ${\mu}$ and q$\sub$p/ showed that the product formation parameters, ${\alpha}$ and ${\beta}$$\sub$p/ were 0.3756 (mg/cell) and 0.001 (mg/g-cell/day), respectively. The betacyanin production was partially cell growth related process, which is different from the production of a typical product in plant cell cultures. In C/N ratio experiment, high carbon concentration, 42.1 (w/w) improved cell growth rate while lower concentration, 31.6 (w/w) increased the betacyanin production rate. The ${\mu}$$\sub$max/ and q$\^$max/$\sub$p/ were 0.26 (1/day) and 0.075 (mg/g-cell/day), respectively. Beta vulgaris L. cells under 1.25 mM phosphate concentration produced 10.15 mg/L betacyanin with 13.46 (g-dry wt./L) of maximum cell density. The production of betacyanin was elongated by adding 0.1 ${\mu}$M of kinetin. This also increased the cell growth. Optimum culture conditions of light intensity, C/N, phosphate concentration were obtained as 5.5 klux, 27 (w/w), 1.25 mM, respectively by the response surface methodology. The maximum cell density, X$\sub$max/, and maximum production, P$\sub$max/, in optimized conditions were 16 (g-dry wt./L), 12.5 (mg/L) which were higher than 8 (g-dry wt./L), 4.48 (mg/L) in normal conditions. The ${\mu}$$\sub$max/ and q$\^$max/$\sub$p/ were 0.376 (1/day) and 0.134 (mg/g-cell/day) at the optimal condition. The overall results may be useful in scaling up hairy root cell culture system for commercial production of betacyanin.

• KSBB Journal
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• v.13 no.6
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• pp.675-680
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• 1998

In both 7L and 20L fermentor experiments the level of dissolved oxygen (D.O) strongly affected growth and PHBV production of Azotobacter vinelandii UWD. A higher D.O. increased carbon substrate consumption rate and cell growth rate with a similar residual biomass production. However, a lower D.O. was a much better condition for PHBV production. In a 20L fermentor experiments controlled at 5% D.O. cell growth rate was about twice faster(0.555 hr-1 and 0.260 hr-1 at the acid and the glucose phase, respectively) with an equal amount(4.5 g/L) of residual biomass production. However, PHBV content in the cell(62.3 wt%) increased 17.3 times at 1% D.O.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.17-30
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• 1995

The growth of Scenedesmus quadricauda (Trup.) Breb. is enhanced by methylyoxal (MG), a general inhibitor of cell division, at threshold concentration in conjunction with reatment timing relative to growth stage. The stimulatory effect of MG on algal cell growth was most significant with 2.27-fold of untreated algal culture in cell number when 0.5 mM of MG was added to the algal culture at the beginning of logarithmic phase with an initial MG concentration of 0.535 mg $MG/10^6cell$. A Specific growth rates (SGRs) of MG-treated cultures were rapidly increased at the beginning of logarithmic phase with 1.89-fold of untreated algal culture. Cultures inoculated with high cell numbers of 2.4 to 4.8 X $10^4$ cells/ml were less sensitive to 0.5 mM of MG treatment. The algal cell division was ranged from 0.392 to 0.924 mg MG/106 cell. If the cell number of an algal culture at the time of inoculation was low (0.6 X $10^4$ cells/ml) and MG was added before logarithmic phase, the cell number of 0.5 mM of MG-treated cultures were lower than those of controls. In algal cultures treated with high concentrations of MG (1.0 mM and 2.0 mM), the algal growth was inhibited. Photosynthetic rate of growth-enhanced algal by 0.5 mM of MG was significantly higher than that of untreated or 1.0 mM of MG-treated algal cell, while there was no significant difference among those groups in respiratory rate. Pyruvate concentration in 0.5 mM of MG-treated culture was incrcased agter methylglyoxal trcatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.121-125
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• 2004

In plants, nitrogen is the major component for growth and development. Leaf growth is based on the division, elongation and maturation of cells, which are used for making of epidermis, mesophyll, bundle sheath, xylem, phloem and so on. Dynamics of these tissues with respect to nitrogen are required for better understanding. This experiment was conducted to evaluate effect of nitrogen on the elongation of epidermal and guard cell of two rice (Oryza sativa L.) varieties, Seoanbyeo and Dasanbyeo on May 2000 at Chungbuk national university in Cheongju. After transplaning the 20-day-old seedlings into a/5000 pots, the main characteristics related with cell elongation were investigated and evaluated. A maximum. leaf length reached at 7 or 8 days after emerging from the collar, and also the leaf elongation rates were greatly affected by the increase of N application rate. The initial and final cell length were about $17\mu\textrm{m}$ and $130\mu\textrm{m}$, respectively. Cell divisions occurred within 1.0mm from leaf base. With die higher nitrogen application rate of 22 kg-N $10\textrm{a}^{-1}$, cell division per hour was greater 1.5 to 1.9 and 1.2 to 1.3 fold as compared to the N application rate of 0 and 11 kg-N $10\textrm{a}^{-1}$, respectively. Cell enlargement of epidermal and guard cell under higher N application rate (22kg-N $10\textrm{a}^{-1}$) was finished within about 20 (Seoanbyeo) and 15 hours (Dasanbyeo), while it took much time, about 30 hours.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.308-309
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• 2012

One of the critical issues in the growth of multijunction solar cell is the formation of a highly doped Esaki interband tunnel diode which interconnects unit cells of different energy band gap. Small electrical and optical losses are the requirements of such tunnel diodes [1]. To satisfy these requirements, tens of nanometer thick gallium arsenide (GaAs) can be a proper candidate due to its high carrier concentration in low energy band gap. To obtain highly doped GaAs in molecular beam epitaxy, the temperatures of Si Knudsen cell (K-cell) for n-type GaAs and Be K-cell for p-type GaAs were controlled during GaAs epitaxial growth, and the growth rate is set to 1.75 A/s. As a result, the doping concentration of p-type and n-type GaAs increased up to $4.7{\times}10^{19}cm^{-3}$ and $6.2{\times}10^{18}cm^{-3}$, respectively. However, the obtained n-type doping concentration is not sufficient to form a properly operating tunnel diode which requires a doping concentration close to $1.0{\times}10^{19}cm^{-3}$ [2]. To enhance the n-type doping concentration, n-doped GaAs samples were grown with a lower growth rate ranging from 0.318 to 1.123 A/s at a Si K-cell temperature of $1,180^{\circ}C$. As shown in Fig. 1, the n-type doping concentration was increased to $7.7{\times}10^{18}cm^{-3}$ when the growth rate was decreased to 0.318 A/s. The p-type doping concentration also increased to $4.1{\times}10^{19}cm^{-3}$ with the decrease of growth rate to 0.318 A/s. Additionally, bulk resistance was also decreased in both the grown samples. However, a transmission line measurement performed on the n-type GaAs sample grown at the rate of 0.318 A/s showed an increased specific contact resistance of $6.62{\times}10^{-4}{\Omega}{\cdot}cm^{-2}$. This high value of contact resistance is not suitable for forming contacts and interfaces. The increased resistance is attributed to the excessively incorporated dopant during low growth rate. Further studies need to be carried out to evaluate the effect of excess dopants on the operation of tunnel diode.

• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.409-411
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• 1998

The effects of iron and EDTA on the growth of Chlorella sp. KR-1, a highly$CO_2$tolerant fresh water micro alga, have been determined. The algal growth was significantly affected not only by iron concentrations in the medium but by the ratio of iron to EDTA. The linear growth rate and the final cell concentration are increased with the supplementation of EDTA. Enhanced growth of Chlorella sp. KR-1 by the supplementation of EDTA was mainly due to the fact that the supply of iron to the algal culture had been possible for a longer time. When Chlorella sp. KR-1 is cultured in the medium of iron-15H-EDTA, the linear growth rate and the final cell concentration are at their maximum, 0.88 g/l${\cdot}$day and 9.1 g/l, respectively. The results show that Chlorella sp. KR-1 may be used for mass cultivation to fix$CO_2$from stack gases.

• Environmental Analysis Health and Toxicology
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• v.13 no.3_4
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• pp.133-142
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• 1998

Effects of phosphorous (P) and methylglyoxal (MG) on the cell number, dry weight, chlorophyll content, photosynthetic and respiratory rate, phosphate uptake and protein content of green algae (Scenedesrnus obliquus) were studied. The algal cell number from the medium treated with 0.5-1.0 mM of MG at 1/2 P or 1/4 P concentration was significantly lower than those of algae treated :with full strength of phosphrous in medium. The inhibitory effect of MG on algal cell division was enhenced at low concentration of phosphorous in medium. At the beginning of logrithmic phase of algal growth, the mean dry weight of algae from the medium without MG-treatment in 1/2 P media was significantly higher than that of algae treated with MG. After logrithmic phase of growth cycle, the mean dry weight of algae from the medium with 1.0 mM of MG-treatment in 1/4 P media was significantly lower than that of algae treated with or without MG. At logrithmic phase of algal growth, there were significant differences in the chlorophyll content among all groups of tested algae with various concentrations of P and MG. At 15 days after inoculation, the mean chlorophyll content per algal cell from the media without MG-treatment in 1/2P was significantly higher than that of other cells from MG-treated media. The adverse effect of MG at concentration of 0.5-1.0mM in 1/2 and 1/4 P media on photosynthetic rate was observed. The mean photosynthetic rate of algal cell without P and MG treatment at 15 days after inoculation was significantly higher than that of MGtreated algae. After logarithmic phase, the algal cell treated with 0.5mM of MG with full strength of phosphorous showed significantly high respiratory rate than that of other cell groups. There were significant differences in mean phosphate uptake rate among all groups of Scenedesmus obliquus at logarithmic phase. At 12 days after inoculation, phosphate uptake rate per each algal cell from the basic media without MG and P treatment was rapidly reduced which shows early introduction to stationary phase.

• KSBB Journal
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• v.9 no.4
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• pp.412-417
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• 1994

The biodegradable characteristics of starch-filled polyethylene film by fungi were investigated. Aspergillus niger showed the highest cell growth among five species of fungi used in the experiment. Higher starch content gave the higher growth rate of A. niger; however, the kind of film or cutting direction did not give any effects on the cell growth. The use of vinyl trimethoxysilane for the stronger binding of starch and polyethylene did not inhibit the cell growth. When the starch content was higher than 10%, the elongation of the film decreased significantly after the growth of microorganism in the case of transverse direction samples.