• KSBB Journal
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• v.14 no.5
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• pp.593-599
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• 1999

In this study, optimal conditions to infect CD34 positive cells containing hematopoietic stem cells obtained from cord blood and bone marrow were found using two different retroviral vectors expressing human growth hormone (hGH) and $\beta$-galactosidase. CD34 positive cells were successfully infected with recombinant retroviruses only when the CD34 positive cells were co-cultured with packaging cells secreting recombinant retroviruses. To find the highest infection efficiency for the gene transfer, CD34 positive cells from cord blood were co-cultured with packaging cells secreting recombinant retroviruses encoding E. coli lacZ gene. The highest infection efficiency was obtained when CD34 positive cells were cultured for 3 days, and then co-culturing was done for another 2 days. When CD34 positive cells from bone marrow were co-cultured with packaging cells secreting recombinant retroviruses encoding hGH gene, the maximum amount of hGH was also secreted at the same conditions found above, i.e. 3 days of culture and 2 days of co-culture. These results show that there are optimal conditions for the gene transfer into hematopoietic stem cells regardless of sources of target cells or retroviral vectors used to infect.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.162-176
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• 1991

For the purpose of contributing to wild birds protection and propagation, distribution characteristics and ecological breeding habitats were surveyed in Mt. Chiri from September, 1986 to December, 1989 by the use of the nestboxes installed in four study sites by the altitude. The results were as follows ; 1. During the study period, observed birds were 2,403 individuals belong to 59 species, especially, at the 1,400m above altitude the rare species, Falco tinnunculus and the protecting bird species such as Ninox scutulata, Strix aluco and Prunella collaris were observed. 2. In the inhabitation structure of birds by the altitude, Fringilla montfringilla was the highest dominance (41.33%) among the inhabitated birds in the surveyed area. 3. Phasianus colchicus and Streptopelia orientalis which were mainly inhabited in hilly area were observed until the altitude of 900m. 4. The 92.5% of nest boxes was mainly used by the small birds, Parus spp. and Sitta europaea. These species preferred the nest boxes installed at the edge or along the mountaineering path, because they could get food and water easily from those places. 5. The utilization rate of the nest boxes was showed 86% at 500m, 96% at 900m, 98% at 1,400m and 90% at 1,700m above the altitude, respectively. 6. The breeding rate of birds in the nest boxes was showed from 6% to 46% by altitude. Parus varius was the highest breeding species in the surveyed area. These birds inhabited above 500m laid eggs from 15th, April to 22th, May(n=22), but those above 1,700m laid eggs from 28th, April to 27th, May(n=13), that 13 days were delayed at high altitude. 7. Food items of the chicks of the 5 species collected by the collar method were animal matters ; 91.3% of the food was forest insects such as Phalera asiimilis and Pleuroptya batteata except 8.7% of spiders.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.796-804
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• 2010

This study was conducted to compare and analyze the qualitative property of MLT (mulberry leaf tea) and FMLT (fermented mulberry leaf tea) based on the antioxidant, anticancer activities of various extracts. When the antioxidant activity of MLT and FMLT extracts was evaluated, the electron donating activity was found to increase proportionally as the concentration of each extract increased. In addition, the extract of FMLT showed a higher electron donating activity than that of MLT. Furthermore, the ethanol extracts showed the highest electron donating ability. When the SOD activity was evaluated, it was also found to increase proportionally with the concentration of each extract. Furthermore, the SOD activity of the ethanol extract group was the highest, whereas the SOD like activities of both MLT and FMLT were similar. When nitrite decomposition was evaluated for each pH, the highest value was observed at pH 1.2. Finally, the nitrite deleting ability was the highest for the ethanol extracts. When each extract of MLT and FMLT was analyzed in vitro for anticancer effects, they were found to decrease the number of cancer cells proportionally as the concentration of extract increased for both HeLa cells and MCF-7 cells. Furthermore, FMLT was found to exert a greater inhibition of cancer cells than MLT. Among the extract groups, the ethanol extract induced the greatest inhibition of the development of cancer cells, and these effects were greater against MCF-7 cells than HeLa cells.

• Development and Reproduction
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• v.6 no.2
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• pp.97-104
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• 2002

In most mammals, mature oocyte-cumulus complexer(OCCs) ovulate into the oviduct where fertilization by sperm takes place. However, the complex that fail to fertilize eventually undergoes degeneration while they reside in the oviduct. Yet there is no blown mechanism how both oocyte and cumulus cells degenerate. Using human follicular fluid (hFF), bovine oviductal tissue extract (BOX) and mouse OCC, the present study aimed to find how the oviduct influence the viability of the oocyte and cumulus cells in vitro. There was no difference of oocyte maturation rate between the control and BOX-treated groups. However, there was a significant difference in the survival of cumulus cells between two groups. Cumulus cells cultured in the presence of hFF alone underwent initially expansion and then they formed monolayer in the culture dish. Even after 72 hr, they proliferated well and showed fibroblast-like morphology. Cumulus cells cultured in the presence of both hFF and BOX also expanded after 24 hr, however, after 72 hr culture, they eventually detached and degenerated. Cumulus cells cultured in the BOX alone gave a similar drastic result. When the cumulus cells cultured in the presence of BOX were stained with DAPI, their nuclei showed partial condensation and fragmentation. After detailed analysis of these cells by TUNEL assay, many nuclei of them exhibited well stained spots indicating the signs of apoptosis. Based upon these observations, it is suggested that BOX might possess a factor that leads mouse cumulus cells to undergo apoptosis in vitro.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.177-186
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• 2009

It is well-known that unregulated over-expression of foreign gene may have unwanted physiological or toxic effects in transgenic animals. To circumvent these problems, we constructed retrovirus vector designed to express the foreign gene under the control of the tetracycline-inducible promoter. However, gene expressions in the tetracycline-inducible expression system (Tet system) are not completely regulated but a little leaky due to the inherent defects in conventional Tet-based systems. A more tightly controllable regulatory system can be achieved when the advanced versions ($rtTA2^SM2$) of rtTA and a minimal promoter in responsive components (pTRE-tight) are used in combination therein. In this study, we tried to produce human thrombopoietin (hTPO) from various target cells and transgenic chickens using the retrovirus vector combined with Tet system. hTPO is the primary regulator of platelet production and has an important role in the survival and expansion of hematopoietic stem cells. In a preliminary experiment in vitro, higher hTPO expression and tighter expression control were observed in chicken embryonic fibroblast (CEF) cells. We also measured the biological activity of the hTPO using Mo7e cells whose proliferation is dependant on hTPO. The biological activity of the recombinant hTPO from CEF was higher than both its commercial counterpart and hTPO from other target cells. The recombinant retrovirus was injected beneath the blastoderm of non-incubated chicken embryos (stage X). Out of 138 injected eggs, 15 chicks hatched after 21 days of incubation. Among them, 8 hatched chicks were hTPO positive. When the Go transgenic chicken was fed doxycycline (0.5 mg per 1 gram of feed), a tetracycline derivative, hTPO concentration of the transgenic chicken blood was 200 ng/mL. Germline transmission of the transgene was confirmed in sperm of the Go transgenic roosters. These results are informative to establish transgenic chickens as bioreactors for the mass production of commercially valuable and biological active human cytokine proteins.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.401-408
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• 2017

Herein, we report the meristem-tip culture from dormant buds of grape 'Kyoho' single-infected with Grapevine fleck virus (GFkV), which is phloem-limited and transmitted by graft inoculation. We produced GFkV-free shoots without thermo- or chemotherapy using meristem-tip explants approximately 0.3 mm (73 explants) and 0.8 mm long (five explants) including shoot apical meristem, 2-5 leaf primordia, and 1-4 uncommitted primordia from dormant buds of the infected woody cuttings (stored at $4^{\circ}C$). Explants were cultured on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA). After 16 weeks of culture, shoot (10-mm long) regeneration frequency achieved from 0.3-mm explants was 4.1% and that obtained from 0.8-mm explants was 40.0%. Virus-free efficiency (expressed as the percentage of RT-PCR negative shoots regenerated) from 0.3- and 0.8-mm explants was 100% and 50%, respectively. Following in vitro multiplication, RT-PCR assays revealed identical results to assays of the first regenerated shoots. Our new methodological approach could be applied for eliminating other viruses in grapevines, as well as for producing virus-free plants in many other deciduous tree species, including fruit trees.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.157-165
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• 2011

Enterobacteria were isolated in the gut of the predacious multicolored Asian ladybird beetle, Harmonia axyridis, and their effects to the development of H. axyridis were examined. Populations of H. axyridis in this experiment were collected from Kimjae at Cheonbuk province (JK population), Geumsan at Chungnam province (CK population) and laboratory population at Laboratory of Insect Physiology in Chungnam National University, Daejeon. Thirty-four enterobacteria isolates were purified and isolated from the digestive tract of H. axyridis, and a total of 4 strains were classified into group by analysis of 16S rRNA gene sequences. About 70% of total isolates were phylogenetic groups of Bacillus genus and Staphylococcus genus, and they were commonly separated from the digestive tract of H. axyridis. After investigating their susceptibility against antibiotics with 18 representative enterobacteria isolates, ofloxacin and penicillin were selected for examination in this study of their ability to inhibit the growth of all of isolates. In order to remove the enterobacteria from the aphids, ofloxacin and penicillin were given to the green peach aphid, Myzus persicae, and the turnip aphid, Lipaphis erysimi. These aphids were provided to H. axyridis as prey. The weight of pupa, developmental periods of each larval instar, the number of eggs and their hatching ratio of H. axyridis with treatment aphids were lower compared with non-treatment aphids. Staphylococcus saprophyticus is a representative enterobacteria and commonly isolated from the digestive tract of H. axyridis. In the absence of S. saprophyticus, the developmental periods of each larval instar increased; however, the weights of pupa, the number of eggs, and their hatching ratio decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1353-1360
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• 2011

This study was performed to investigate the antimicrobial effects against food-borne pathogens and antioxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The $IC_{50}$ of the extract for DPPH radical scavenging activity was about half that of ${\alpha}$-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

• Tuberculosis and Respiratory Diseases
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• v.47 no.1
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• pp.77-89
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• 1999

Background: High-dose chemotherapy is increasingly employed in many refractory malignant diseases. This therapy has been reported to increase response rate and survival benefits but it is also associated with higher treatment-related morbidity and mortality. We evaluated clinical characteristics and course of the pulmonary toxicity following high-dose chemotherapy with peripheral blood stem cell transplantation. Methods: Ninety-seven patients who had received high-dose chemotherapy with peripheral blood stem cell transplantation were evaluated. Five patients who developed lung lesions which were not related to infection nor primary malignant disease underwent transbronchial lung biopsy. The patients' clinical characteristics, treatments, and prognosis were reviewed retrospectively. Results: Five patients(5.1%) developed idiopathic pneumonia syndrome. The high dose chemotherapy regimens employed were cyclophosphamide, BCNU, and cisplatin in 3 cases, one case of BCNU, etoposide, Ara-C, and cyclophosphamide combination, and a regimen consisting of BCNU, etoposide, Ara-C, and melphalan. The total dose of BCNU used was 300-400 mg/$m^2$ and that of cyclophosphsmide was 6,000 mg/$m^2$. All of 5 patients received radiation therapy before this treatment. After an average duration of 14 weeks (4-26 weeks) of high-dose chemotherapy, patients developed cough, dyspnea and fever. The chest X-rays showed bilateral diffuse infiltration in 3 cases and the focal infiltration in the other 2 cases. All the patients received corticosteroid therapy as a treatment for the lung lesions. Two of them progressed to acute respiratory distress syndrome and died. Three patients recovered without residual lung lesion but one of them died of dilated cardiomyopathy. Conclusion: High-dose chemotherapy with peripheral blood stem cell transplantation especially which containing BCNU regimen may develop idiopathic pneumonia syndrome related to pulmonary toxicity and corticosteroid therapy may be bel1eficial in some cases.

• Korean Journal of Poultry Science
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• v.18 no.3
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• pp.183-196
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• 1991

In order to establish ELISA method to detect antibody against IBV various factors involved were examined. Antigen was prepared from Massachusetts type IBV which is known to be one of serotypes distributed most widely. The virus was grown in embryonated SPF chicken eggs. Allantoic fluid harvested was processed to ultracentrifugation and sucrose density gradient centrifugation to produce a purified antigen The antisera selected from the field samples based on hemagglutination inhibition test were used as the standard positive and negative sera for this study and the results obtained were summarized as follows. 1 , It was found that ELISA test was satisfactory when the purified antigen was coated on the plate in the amount of about 40ng protein per well. In case of the phospholipase treated hemagglutinating antigen it gave satisfactory results when the each well wns coated with 1.2 to 2.5 hemagglutinating unit which was equivalent to 40 to 90ng of protein. 2. There was no significant difference in the ratio of optical density of positive to that of negative serum whether the coated antigen was held for 1 hour at 37$^{\circ}C$ or it was held overnight at 4$^{\circ}C$. The coated antigen could be kept in dried state without change of antigenecity for at least one month of experimental period at 4$^{\circ}C$. 3. There was a big variation in the optical density and P/N values depending on the maker of the plates and on the plate of the same maker. 4. It was found that background optical density was negligible when serum was diluted more than 1：50 and serum dilution of 1：100 appeared to be appropriate as a routine test dilution to screen the antibody. 5. Optical density was fairly constant 15 minutes afterward from the time substrate was treated and during the 4 hours after stopper was treated. 6. There was a low correlation(r＝0.42) between ELISA and HI test. However, when 74serum samples were tested for the IBV antibody, 98.7% were found to be positive by both tests in which titers of 2$^{6}$ or more by HI test and P/N values of 1.4 or more by ELISA were considered to be positive, 7 Day-old IBV vaccinated chickens shows a similar antibody decay and rising pattern until 8 weeks of age by the two tests, ELISA and HI.