• Journal of Plant Biotechnology
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• v.1 no.1
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• pp.1-7
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• 1999

Large-scale cultures of plant cell, tissue, and organ have been achieved by using BTBB. When different sized BTBBs (5 L, 20 L, 100 L, 300 L, and 500 L) were tested for the culture of yew cells (Taxus cuspidata Sieb. et Zucc.), cell growth increment reached to 94.5% in SCV after 24 days of culture with 30% of inoculation cell density. However, there were some variations in the production of taxol and its derivatives among the BTBBs of different size. Approximate 4 ㎎/l of taxol and 84 ㎎/l of total taxanes were obtained by using a 500L BTBB after 6 weeks of culture. With a 20L BTBB, about 20,000 cuttings of virus-free potatoes (cv. Dejima) could be obtained by inoculating 128 explants and maintaining 8 weeks under 16 hr light illumination. The frequency of ex vitro rooting of the cuttings revealed as more than 99% under 30% shade. By incorporating two-stage culture process consisting of multiple bulblet formation in solid medium and bulblet development in liquid medium, mass propagation of lily through bioreactor seemed to be possible. In the case of 'Marcopolo', the growth of mini-bulblets in BTBB was nearly 10 folds faster than that of the solid medium. Time course study revealed that maximum MAR yield of ginseng (Panax ginseng C. A. Meyer) in a 5 L and 20 L BTBB after 8 weeks of culture was 500 g and 2.2 ㎏, respectively. By cutting the MAR once and/or twice during the culture, the yield of root biomass could be increased more than 50% in fresh weight at the time of harvest. With initial inoculum of 500 g of sliced MAR in a 500 L BTBB, 74.8 ㎏ of adventitious root mass was obtained after 8 weeks of culture. The average content of total ginseng saponin obtained from small-scale and/or pilotscale BTBBs was approximately 1% per gram dry weight. Based on our results, we suggest that large-scale cultures of plant cell, tissue, and organ using BTBB system should be quite a feasible approach when compared with conventional method of tissue culture.

• Ecology and Resilient Infrastructure
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• v.1 no.1
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• pp.19-24
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• 2014

The research evaluates the possibility of generating electricity using pyrite containing mine tailings, which are the major cause of acid mine drainage (AMD), by applying iron oxidizing bacteria (in this case, Acidithiobacillus ferrooxidans) and chemical fuel cell technology. The changes in the aqueous $Fe^{2+}$ concentration, which can represent an ionized form of pyrite, with an initial concentration of 9,000 mg/L were investigated during the 20 d growth period. Both the $Fe^{2+}$ and total iron (i.e., total $Fe^{2+}$)concentrations with or without A. ferrooxidans were observed. The $Fe^{2+}$ concentration decreased to about 6,000 mg/L, in the abiotic condition, while it decreased to about 400 mg/L in the biotic condition. The results showed that the increased $Fe^{2+}$ oxidation in the presence of A. ferrooxidans (i.e., catalytic ability of A. ferrooxidans) can be applied to electricity generation using pyrite containing mine tailings. In the co-presence of A. ferrooxidans and pyrite containing mine tailings, $Fe^{2+}$ oxidation and hence electron production increases, which, in turn, improves current density. This study can be applied to utilize ecological functions of indigenous bacteria in mine areas to enhance electricity generation efficiency.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.412-419
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• 2023

Anion exchange membrane electrolysis is considered a promising next-generation hydrogen production technology that can produce low-cost, clean hydrogen. However, anion exchange membrane electrolysis technology is in its early stages of development and requires intensive research on electrodes, which are a key component of the catalyst-system interface. In this study, we optimized the pressure conditions of the hot-pressing process to manufacture cobalt oxide electrodes for the development of a high uniformity and high adhesion electrode production process for the oxygen evolution reaction. As the pressure increased, the reduction of pores within the electrode and increased densification of catalytic particles led to the formation of a uniform electrode surface. The cobalt oxide electrode optimized for pressure conditions exhibited improved catalytic activity and durability. The optimized electrode was used as the anode in an AEMWE single cell, exhibiting a current density of 1.53 A cm^-2 at a cell voltage of 1.85 V. In a durability test conducted for 100 h at a constant current density of 500 mA cm^-2, it demonstrated excellent durability with a low degradation rate of 15.9 mV kh^-1, maintaining 99% of its initial performance.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.89-102
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• 1996

The goal of periodontal therapy is to regenerate the loss of periodontal attachment appratus. Current theories suggest the cells of the periodontium have the capacity, when appropriately triggered, to actively participate in restoring connective tissues, including mineralized tissues. This study was performed to define the hard tissue regeneration effect of periodontal ligament(PDL) cells in vitro and the effect of rate of the composition in gingival fibroblasts(GF) on the hard tissue regeneration capacity of PDL cells. For this study, Cell growth rate, alkaline phosphatase(Al.Pase) levels and the ability to produce mineralized nodules in co-culture of PDL cells and GF were examined. The results were as follows : 1. At 7 and 15 days, Cell growth of co-culture of PDL and GF(50 : 50) was greater than that of PDL cells or GF alone(P>0.05). 2. Measurements of ALPase levels indicated that PDL cells had significantly higher activity when compared with that of co-culture groups and GF only(p<0.05). And, ALPase activity in 10 days was higher than that of 7 days(P>0.05) 3. The tendency of formation of the mineralized nodule were observed dose-depend pattern of PDL cells. There was statistically significant difference among group 1(PDL 100%), 2(PDL 70% : GF 30%), and 3(PDL 50% : GF 50%)(P<0.01). But, there was no difference among group 3, 4(PDL 30% GF 70%), and 5(GF 100%). 4. Also, the number of nodule was greater in co-culture of PDL 70% and GF 30% than in culture of PDL 70%(P<0.05) From the above results, it is assumed that the co-culture of PDL cells and GF stimulates the cell growth, which is not that of PDL cells but GF. And, the activity of ALPase depends on the ratio of PDL cells, and ALPase may relate to the initial phase of nodule formation. Also, it is thought that the calcified nodule formation principally depends on PDL cells, is inhibited by GF, and affected by cell density.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.997-1001
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• 2013

Background: Lymphangiogenesis, assessed as lymphovascular density (LVD), is the initial step of generalized tumor lymphovascular invasion (LVI). It also involves VEGF-C as the most important protein family. Lymphangiogenesis among breast cancer cases correlations with several clinicopathological factors are important to determine prognosis and treatment strategies, but results have been controversial and require clarification. Aim: To define correlations between VEGF-C expression, LVD and LVI with several clinicopathological parameters from Indonesian breast cancer patients. Materials and Methods: Using a cross-sectional study, a total of 48 paraffin-embedded tissues of breast cancer from Dr. Sardjito General Hospital Indonesia were assessed for VEGF-C expression, LVD and LVI by immunohistochemistry. Correlations of these markers with clinicopathological parameters like patient age, tumor size, lymph node status, grade, ER/PR and Her-2 status, cell proliferation and p-53 expression were investigated by linear analysis. Correlations of VEGF-C expression and LVI with several clinicopathological parameters were analyzed with Coefficient Contingency Chi-Square test. Results: The mean of patients age was 53.0 year, pre and post-menopausal patients accounting for 56.3% and 43.8%, respectively. Some 10.4% were well, 41.7% moderate and 47.9% poorly differentiated. ER positivity was evident in 50% while PR and Her-2 positivity was found in 31.3% and 33.3%, respectively. Breast cancer cells with over-expression of p-53 was 64.6% and with high cell proliferation was 56.3%. Lymph node metastasis was noted in 63.5%, and LVI in 72.9%. Significant correlations were found between LVD and tumor size (p:0.037), grade (p:0.000), lymphnode status (p:0.036), LVI (p:0.003), as well as with p-53 and cell proliferation. There were also significant correlation of VEGF-C (p:0.011) and LVI (p:0.001) with tumor grade. Only ER status was found to have a correlation with tumor size (p:0.027). Conclusions: This study suggested that in Indonesian breast cancer patients, lymphangiogenesis is correlated with tumor size, grade, lymph node status and tumor lymphovascular invasion, the latter also being related with p-53 over expression and high cell proliferation.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.949-965
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• 1996

The main goal of periodontal therapy is to restore the lost periodontal tissue and establish the attachment appratus. Current acceptable therapeutic techniques are included : removal of diseased soft tissue, demineralization of exposed root surface, using the barrier membrane for preventing the downgrowth of gingival epithelial cell, insertion of graft materials as a scaffolding action, and biological mediators for promoting the cell activity. The latest concept one among them has been studied which based on the knowledge of cellular biology of destructed tissue. Platelet-derived growth factor(PDGF) is one of the polypeptide growth factor which have been reported as a biological mediator to regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purposes of this study is to evaluate the influences of the PDGF as biological mediator to periodontal ligament and bone marrow cell. Both right and left maxillary first molar were extracted from rat which had treated with 0.4% ${\beta}-Aminopropionitril$ for 5 days, and feeded until designed date to sacrifice under anesthesisa. Periodontal ligament were removed from the extracted socket of the rat, and cultured with Dulbecco's Modified Essential Medium(DMEM) contained with 10% Fetal Bovine Serum, 100U/ml penicillin, $100{\mu}g/ml$ streptomycin, $0.5{\mu}g/ml$ amphotericin-B. Bone marrow cell were culture from bone marrow suspension with which washed out from femur with same medium. The study was performed to evaluate the effect of PDGF to periodontal ligament and bone cell, cell proliferation rate, total protein synthesis, and alkaline phosphatase activity of rat periodontal ligament(PDL) cell and bone stromal(RBS) cell in vitro. The effects of growth factors on both cells were measured at 3, 5th day after cell culture with (control group) or without growth factors(experimental group). The results were as follows: 1. The tendency of cell proliferation under the influence of PDGF showed more rapid proliferation pattern than control at 3 and 5 days after inoculation. 2. The activity of Alkaline phosphatase revealed 14, 80% increased respectively at 3, 5 days culture than control group. Measurements of ALPase levels indicated that PDL cells had significantly higher activity when compared with that of co-culture groups and GF only(P<0.05). And, ALPase activity in 10 days was higher than that of 7 days(P<0.05). 3. The tendency of formation of the mineralized nodule were observed dose-depend pattern of PDL cells. There was statistically significant difference among group l(PDL 100%), 2(PDL 70%:GF 30%), and 3(PDL 50%:GF 50%)(P<0.01). But, there was no difference among group 3, 4(PDL 30%:GF 70%), and 5(GF 100%). 4. Also, the number of nodule was greater in co-culture of PDL 70% and GF 30% than in culture of PDL 70%(P<0.05). From the above results, it is assumed that the PDGF on PDL cells and RMB cell culture. GF stimulates the cell growth, which is not that of PDL cells but GF. And, the activity of ALPase depends on the ratio of PDL cells, and ALPase may relate to the initial phase of nodule formation. Also, it is thought that the calcified nodule formation principally depends on PDL cells, is inhibited by GF, and affected by cell density. In conclusion, platelet-derived growth factor can promote rapid osteogenesis during early stage of periodontal tissue regeneration.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.311-316
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• 2008

In this study, biological PCE degradation by using a BTEX degrading bacterium, named BJ10, under aerobic conditions in the presence of toluene was examined. According to morphological, physiological characteristics, 16S rDNA sequencing and fatty acid analysis, BJ10 was classified as Pseudomonas putida. As a result of biological PCE degradation at low PCE concentrations (5 mg/L), PCE removal efficiency by P. putida BJ10 was 52.8% for 10 days, and PCE removal rate was 5.9 nmol/hr (toluene concentration 50 mg/L, initial cell density 1.0 g (wet weight)/L, temperature 30, pH 7 and DO $3.0{\sim}4.2\;mg/L$. At high PCE concentration (100 mg/L), PCE removal efficiency by P. putida BJ10 was 20.3% for 10 days, and PCE removal rate was 46.0 nmol/hr under the same conditions. The effects of various toluene concentration (5, 25, 50, 100, 200 mg/L) on PCE degradation were examined under the same incubation conditions. The highest PCE removal efficiency of PCE was 57.0% in the initial PCE concentration of 10 mg/L in the presence of 200 mg/L toluene for 10 days. Furthermore, the additional injection of 5.5 mg/L PCE (total 7.6 mg/L) made 63.0% degradation for 8 days in the presence of 50 mg/L toluene under the same conditions. Its removal rate was 13.5 nmol/hr, which was better than the initial removal rate (8.1 nmol/hr).

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.319-331
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• 2004

This study was conducted to evaluate the ecological impact of freshwater bivalve (Corbiculidae) on plankton communities in experimental enclosure systems (2 m ${\times}$ 2 m ${\times}$ 2 m). During the acclamation period of one month, cyanobacteria, including Microcystis viridis and Microcystis aeruginosa, dominated in both control and treatment enclosures with no noticeable density difference. After the addition of 100 mussels, dominant species of phytoplankton shifted from Microcystis to Scenedesmus in concert with slight decrease in the cell density and the increase of N/P ratio. However, cell density in the control quickly increased, accompanied with changes of dominant species to Oscillatoria spp. With the introduction of additional 500 musseles in the treatment enclosure, dominant phytoplankton species in both enclosures were replaced with Selenastrum spp. and Cryptomonas sp. In the initial stage, the total zooplankton abundance in the control was higher than that of treatment, but it was reversed after the addition 100 mussels. After mussel density increased up to 600 indivisuals, zooplankton density in the treatment decreased with dominance of small taxa, such as rotifers and nauplius. However, abundance and carbon biomass of large zooplankton, such as Bosmina longirostris and Diacyclops thomasi were maintained in a high level compared with those of control. During the study period, Chl. a concentration in mussel treatment and control increased with DIP and $NH_3-N$, respectively. Due to the increase of $NH_3-N$, especially after the introduction of additional 500 mussels, nitrogen limitation did not occur in the treatment enclosure in contrast with strong nutrient limitation occurred in the control. These results indicate that filter-feeding Corbicula could exert important impact on nutrient recycling and plankton community structure in a freshwater ecosystem, through direct feeding and competition for the same food resource as zooplankton on one hand, and through alteration of nutrient availability on the other.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.268-272
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• 2003

Experiments were carried out to investigate the selection of industrial medium and optimization of fermentation process for the production of erythritol by Candida magnoliae SR101. In the batch fermentation, light steep water(LSW) was the best nitrogen source for the industrial production of erythritol. For the optimization of culture condition, the batch culture was performed. When the concentration of LSW was 65 mL/L in the defined medium containing 250 g/L of glucose, 44% of erythritol yield with 110 g/L of erythritol concentration and 0.66 g/L-hr of productivity, respectively were obtained. Two-stage fed-batch culture was performed to improve the volumetric productivity of erythritol. High density cell culture in the growth stage was performed by batch type with 100 g/L glucose and 500 mL/L LSW concentration, respectively. The cell yield was 0.72 g-cell/g-glucose. Productivity of erythritol was increased and concentration of organic acids such as gluconic acid and acetic acid were decreased when initial pH of 6.5 controlled by 28% ammonia water For increasing yield of erythritol, glucose concentration in the production stage was tested. 37% of total erythritol yield with 186 g/L of erythritol concentration and 1.66 g/L-hr of erythritol productivity were obtained when 820 g of glucose powder was directly added for making up 450 g/L of glucose at production stage.

• KSBB Journal
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• v.10 no.5
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• pp.475-481
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• 1995

The effect of metallothionein expression on the metal resistance and removal by recombinant Saccharomyces cerevisiae containing the plasmid pJW9 was investigated. The recombinant strain S. cerevisiae BZ-pJ was constructed by transforming the host strain S. cerevisiae BZ3l-1-7Ba with the gene coding for a metal-binding protein, metallothionein. Introduction of the MT gene yielded an increase in the minimum inhibitory concentration (MIC) of copper more than three times compared with the host strain. The minimum inhibitory concentrations of $Cr^{2+}, Znr^{2+} and Pb^{2+}, $ were not different for the two strains. The recombinant yeast grown in a medium containing 8mM CuSO4 was able to remove copper with a capacity of 18.9mg $Cu^{2+}$/g dry cell. In a mixture of copper and zinc, the presence of copper relieved the toxic effects caused by zinc, resulting in an enhancement of the final cell density and the specific growth rate of the recombinant yeast. The capability to remove copper by the recombinant yeast was linearly proportional to the copper concentrations in the medium. The efficiency of copper removal was rather constant regardless of the initial copper concentrations. The specific removal of zinc was dependent on the zinc concentrations in media, though, and such dependence was not so pronounced as the concentration of copper.