• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.198-200
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• 2001

Grager-Induced colony formation was examined using strains of green alga Scenedemus dimorphus (Turpin) Kutzing. Alga was cultured in a medium with or without filtered water in which Daphnia magna or Moina macrocopa had been reared. Colony formation was obviously promoted in S. dimorphus by exposure to zooplankton filtered water (ZFW), showing in proportion to the volume of zooplankton filtered water in cultured media. The particle volume as well as the number of cells per one colony of S. dimorphus increased between 24 and 48 hours after exposure to ZFW, which were caused by an infochemical released from from Daphnia or Moina probably as a part of defense mechanism against zooplankton grazing.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.13-23
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• 2010

Objective: The present study was carried out to induce differentiation of human embryonic stem cells (hESCs) into germ cells and to establish a culture condition for single hESCs dissociated by enzyme. Methods: Embryonic body (EB) was formed by hanging drop culture for 3 days from hESCs colony. The EBs were cultured in the medium supplemented with retionic acid (RA) or/and bone morphogenetic protein-4 (BMP4) for 14 days to differentiate into germ cells. Germ cell specific markers, c-kit and VASA were used for immunohistochemistry of EB. Human ESCs colonies were dissociated into single cells by Collagenase, Tryple and Accutase, and then colony formation rate of the single cells was examined. Rho-associated kinase inhibitor (ROCK inhibitor, Y27632) was added into the culture medium of single cells to reduce the apoptotic damage during the dissociation. Results: Single cells dissociated with Tryple or Accutase showed higher colony formation rates compared to the cells dissociated with Collagenase. Seeding of $5{\times}10^3$ cells/well (4 well dish) was efficient to obtain high colony formation rate compared to other concentrations of seeding cell. Addition of Y27632 significantly increased the colony formation rate of the single cells dissociated by Tryple. Immunohistochemistry of EB with c-kit and VASA markers showed a weak fluorescence signals compared to the signals from the testicular tissue. Conclusion: Dissociation with Tryple was useful to obtain healthy single cells and addition of Y27632 was beneficial for survival and colony formation of the single cells. Unlike other studies, we just observed a dim fluorescence staining of the germ cell markers, probably caused by the short-term culture for the differentiation of EB compared to other studies.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.397-406
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• 2014

Maize is a socioeconomically important crop in many countries. Recently, a high incidence of stalk rot disease has been reported in several maize fields in Gangwon province. In this report, we show that maize stalk rot is associated with the fungal pathogens Fusarium subglutinans and F. temperatum. Since no fungicides are available to control these pathogens on maize plants, we selected six fungicides (tebuconazole, difenoconazole, fluquinconazole, azoxystrobin, prochloraz and kresoxim-methyl) and examined their effectiveness against the two pathogens. The in vitro antifungal effects of the six fungicides on mycelial growth and colony formation were investigated. Based on the inhibition of mycelial growth, the most toxic fungicide was tebuconazole with 50% effective concentrations ($EC_{50}$) of < $0.1{\mu}g/ml$ and $EC_{90}$ values of $0.9{\mu}g/ml$ for both pathogens, while the least toxic fungicide was azoxystrobin with $EC_{50}$ values of 0.7 and $0.5{\mu}g/ml$ for F. subglutinans and F. temperatum, respectively, and $EC_{90}$ values of > $3,000{\mu}g/ml$ for both pathogens. Based on the inhibition of colony formation by the two pathogens, kresoxim-methyl was the most toxic fungicide with complete inhibition of colony formation at concentrations of 0.1 and $0.01{\mu}g/ml$ for F. subglutinans and F. temperatum, respectively, whereas azoxystrobin was the least toxic fungicide with complete inhibition of colony formation at concentrations > $3,000{\mu}g/ml$ for both pathogens.

• Mycobiology
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• v.38 no.2
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• pp.118-121
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• 2010

Single ascospore isolates of Cordyceps bassiana were observed for their colony pigmentation on Sabouraud Dextrose agar plus Yeast Extract (SDAY) plates and were inoculated in a brown rice medium for production of fruiting bodies. Colony pigmentation did not show any relationship with perithecial stromata formation. The isolates were also grown on opposite sides of SDAY agar plates and were observed for vegetative compatibility. Neither vegetative compatibility nor perithecial stromata could be found to be related to each other. It was concluded that fertile fruiting body production was independent of colony pigmentation and vegetative compatibility. Synnemata formation was found to be more common than perithecial stromata formation. This might be due to its highly conidiogenous anamorphic stage, i.e., Beauveria bassiana.

• Journal of Ginseng Research
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• v.25 no.2
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• pp.68-73
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• 2001

Studies were performed to determine the effect of red ginseng and white ginseng on jejunal crypt survival, endogenous spleen colony formation, and apoptosis of jejunal crypt cells in irradiated mice. The radioprotective effect of ginseng was compared with the effect of diethyldithocarbamate(D). Jejunal crypts were protected from irradiation by pretreatment of red ginseng (50 mg/kg B.W., I.P. at 36 and 12 hours before irradiation) and white ginseng (50 mg/kg B.W., I.P. at 36 and 12 hours before irradiation). Red ginseng administration before irradiation and both pretreatment and posttreatment (50 mg/kg B.W., I.P. at 30 minutes after irradiation) of white ginseng resulted in an increase of the formation of endogenous spleen colony. the frequency of radiation-induced apoptosis in intestinal crypt cells was also reduced by both pretreatment and posttreatment of red ginseng, and pretreatment of white ginseng. The radioprotective effect of DDC (1000 mg/kg B.W., I.P. at 30 minutes before irradiation) on jejunal crypt survival and apoptosis was similar to those of ginseng treatment. Treatment with DDC showed no significant modifying effects on formation of endogenous spleen colony. These results indicated that ginseng might be a useful radioprotector. Further studies are needed to characterize effective radioprotective components and mechanism of ginseng.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.4
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• pp.265-272
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• 2006

Objective: This study was carried out to evaluate the effect of the isolation methods of inner cell mass from mouse blastocyst, types of feeder cells and treatment time of mitomycin C on the formation rate of ICM colony. Methods: The inner cells were isolated by conventional immunosurgery, partial trophoblast dissection with syringe needles and whole blastocyst co-culture method. Commercially available STO and primary cultured mouse embryonic fibroblast (pMEF) feeder cells were used, and mitomycin C was treated for 1, 2 or 3 hours, respectively. The formation rate of ICM colony was observed after isolation of ICM and culture of ICM on the feeder cells for 7 days. Result: The ICM colony formation rate on STO were significantly higher in partial trophoblast dissection group (58%) than that in immunosurgery (12%) or whole blastocyst culture (16%) group (p<0.05). The formation rate on pMEF feeder layer was higher in partial trophoblast dissection (88%) and whole blastocyst culture (82%) group than that in immunosurgery (16%) group (p<0.05). When mitomycin C treated to pMEF for 2 hours, the formation rate of 88% was significantly higher than those of other conditions. Conclusion: Above results showed that the efficient isolation method of ICM from blastocyst was the partial trophoblast dissection and the appropriate treatment time of mitomycin C was 2 hours. However, the subculture of ICM colony and characterization of stem cells should be carried out to confirm the efficacy of the partial trophoblast dissection method.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.6
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• pp.705-712
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• 2018

The tube formation assay is a widely used in vitro experiment model to evaluate angiogenic properties by measuring the formation of tubular structures from vascular endothelial cells (ECs). In vitro experimental results are crucial when considered the advisability of moving forward to in vivo studies. Thus, the additional attentions to the in vitro assay is necessary to improve the quality of the pre-clinical data, leading to better decision-making for successful drug discovery. In this study, we improved the tube formation assay system in three aspects. First, we used human endothelial colony forming cells (ECFCs), which are endothelial precursors that have a robust proliferative capacity and more defined angiogenic characteristics compared to mature ECs. Second, we utilized a real-time cell recorder to track the progression of tube formation for 48 hours. Third, to minimize analysis error due to the limited observation area, we used image-stitching software to increase the microscope field of view to a $2{\times}2$ stitched area from the $4{\times}$ object lens. Our advanced tube formation assay system successfully demonstrated the time-dependent dynamic progression of tube formation in the presence and absence of VEGF and FGF-2. Vatalanib, VEGF inhibitor, was tested by our assay system. Of note, $IC_{50}$ values of vatalanib was different at each observation time point. Collectively, these results indicate that our advanced tube formation assay system replicates the dynamic progression of tube formation in response to angiogenic modulators. Therefore, this new system provides a sensitive and versatile assay model for evaluating pro- or anti-angiogenic drugs.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.227-232
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• 1982

The methods determining the growth rate of mold on beans were investigated in order to compare the growth of Aspergillus oryzae on lupinseed to that on soybean. The growth of A. oryzae on cooked whole or paste form of bean substrates was evaluated by the measurements of colony diameter and hyphae length of the mold. The mold showed characteristic lag times to form the colony on different types of substrate. The growth of colony diameter was coincided with the increase in $\alpha$-amino nitrogen content of the substrate when the moisture level of the substrates was similar each other. The colony diameter and the cultivation time after the lag period showed a straight line relationship, from which the growth rate was estimated. in general, lupinseed paste allowed faster growth of A. oryzae than soybean paste at the initial growth phase. The lag time to form the colony was 24.0 hrs on lupinseed paste and 44.4 hrs on soybean paste. The growth rate after colony formation was, however, 7.05 mm/day for lupinseed paste and 8.83mm/day for soybean paste, which indicated that the growth rate after the lag period was faster on soybean compared to lupinseed. The sporulation time of the mold was related to the lag time for the colony formation. The measurement of hyphae length on whole beans could be used as a simple and rapid method of estimating the growth property of mold on different substrates.11 showed that the growth of A. oryzae was partly hindered by the thick hull of the lupinseed.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.420-428
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• 2005

Effects of three biological control agents such as Xanthobacter autotrophycus, Tanichthys albonubes and Oryzias latipes on the morphology and growth of cyanobacterium Microcystis aeruginosa were studied. The experiments were consisted of six treatments of living organism (LO) and culture filtered water of three organisms (CFW). Three LOs effectively decreased the density of M. aeruginosa, and then cyanobacteria hardy showed in the microscopic field after 5 days of cultivation. All LO and CFW agents induced the colonial formation of cyanobacterium M. aeruginosa, although there were little differences in colony formation according to the kinds, density and type of treatment. In particular, the higher density treatment of fish CFW induced effectively the colony formation of cyanobacteria, compared to the bacterial LO and CFW. Thus, the application of bio agents to control the cyanobacterial bloom is needed to the further study to diminish the adverse effects such as the enhancement of colony formation towards on the new bloom against the aquatic ecosystem.

• Korean Journal of Plant Resources
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• v.19 no.3
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• pp.422-426
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• 2006

This research was conducted to get the basic materials necessary to obtain the somatic hybrid plant between Solanum sisymbriifolium and other Solanum species (S. integrifolium and S. toxicarium). Regarding the formation of colony from the protoplast in S. sisymbriifolium, S. integrifolium and the fused protoplast mixture; for the S. sisymbriifolium, a colony was observed in F medium(Kao medium containing $5.0mg{\cdot}L^{-1}\;NAA,\;1.0mg{\cdot}L^{-1}$ 2,4-D and $1.0mg{\cdot}L^{-1}$ BA); and for the S. integrifolium, in G medium (a half strength MS medium containing 0.03 M sucrose, 0.4 M mannitol, $1.0mg{\cdot}L^{-1}\;NAA,\;1.0mg{\cdot}L^{-1}$ kinetin) respectively. In mixed cultured protoplast after electriofusion treatment, the cell division and colony formation were observed in both media F and G. For the shoot and root formation rate, there was no difference between the parent of each breed and mixed protoplast regardless of the medium. In the fused protoplast mixture of S. sisymbriifolium and S. toxicarium, a colony formation was also observed in both media F and H(a half strength MS medium containing 0.03 M sucrose, 0.4 M mannitol, $1.0mg{\cdot}L^{-1}\;NAA,\;1.0mg{\cdot}L^{-1}$ kinetin); and there was no difference in the shoot and root formation rate between the parent and the mixed protoplast.