• 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 Microbiology
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• v.46 no.1
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• pp.15-20
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• 2010

Xenotransplantation of pig organs is complicated by the existence of polytropic replication-competent porcine endogenous retroviruses (PERV) capable of infecting human cells. Two classes of infectious human-tropic replication-competent PERVs (PERV-A and PERV-B) and one class of ecotropic PERV-C are known. The potential for recombination between ecotropic PERV-C and human-tropic PERVs adds another level of infectious risk. A recombinant PERV-A/C (PERV-A14/220) virus is 500-fold more infectious than PERV-A. Two determinants of this high infectivity was identified; one was isoleucine-to-valine substitution at position 140 in RBD (receptor binding domain), and the other lies within the PRR (proline rich region) of the envelope protein. To examine whether the effects of the cytoplasmic tail of the PERV-C Env on fusogenesity also influences infectivity, we constructed a pseudotype retroviral vectors containing MoMLV core protein and PERV envelopes. Pseudotyping experiments with the PERV envelope glycoproteins indicated that recombinant PERV-A/C virus is 10-fold more infectious than PERV-A by lacZ staining. This result supports the suggestion that viral transduction of PERV-A/C is enhanced by a membrane-proximal cytoplasmic amphiphilic ${\alpha}$-helix in PERV-C Env tail.

• Journal of Plant Biotechnology
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• v.45 no.2
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• pp.110-116
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• 2018

This study was conducted to develop a simple, rapid, and reliable method for in vitro propagation of disease-free and true-to-type clones from sucker explants of thornless blackberry (Rubus fruticosus L. ${\times}$ R. parvifolius L.). To induce multiple shoots, the sucker explants were sterilized in 1% NaOCl solution, and then were aseptically cultured on the full and 1/2 MS solid medium supplemented with BAP (0.1, 0.5, 1.0, 2.0 mg/L). After six weeks of culture, the highest frequency (85.4%) of shoot formation from sucker explants was obtained on the full-strength MS medium with 1.0 mg/L BAP. Node explants obtained from multiple shoots were cultured on the various media of full- or half-strength of AD, B5, MS, SH, QL, WPM media, respectively. After 30 days of culture, plant growth was good on the half-AD, half-QL medium. After 90 days of culture, plant growth was good on the full MS and full SH medium. The survival rate of the plantlets after transfer to plastic pots containing soil mixture (sand: soil: vermiculite was 1:1:1, vol.) in the greenhouse was 98%. The results indicate that a multiple-shoot procedure can be applied for an efficient mass propagation of Rubus fruticosus L. ${\times}$ R. parvifolius L.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.347-354
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• 1999

This experiment was carried out to determine the effect of maturity at harvest and inoculants on the quality of round baled rye(Secale cereale L.) silage at the experimental field of Grassland and Forage Crops Division, National Livestock Research Institute, RDA, Suwon in 1998. The experiment was consist of split-plot design with 3 replications. The main plots were 3 harvesting stages such as boot(20 April), heading(29 April), and flowering stages(14 May). The subplots wered inoculant treatments : control (untreated), inoculant A, and inoculant B. Acid detergent fiber(ADF), neutral detergent fiber(NDF), and in vitro dry matter digestibility (IVDMD) of rye silage were significantly increased with delayed harvesting date, but there was not significant difference between inoculants. Mean silage pH at flowering stage was the lowest(4.35), but the highest at early harvest(4.91). Inoculants significantly reduced acidity of silage compared with control. Dry matter(DM) content of the control was higher than that of inoculants. Ammonia-N as proportion of total N was below 10% which was maximum level of high quality silage. The addition of inoculants reduced ammonia-N. There were significant difference in organic acid contents between harvesting stages and inoculants. Lactic acid was increased with inoculants, but acetic and butyric acids were decreased. Various treatments increased colony forming unit(CFU) of lactic acid bacteria by 2 or 3 times compared with the control and the highest at flowering stage with inoculant B treatment. Results of this study indicate that use of microbial inoculant and harvesting after heading stage will improve the silage fermentation and quality of round baled rye silage.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.145-156
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• 1988

This study was conducted to investigate the effect of embryo stage on bisection rates of embryos, on development of separated demi-embryos and on subsequent development to full term following transfer of demi-embryos to recipients. The results obtained in this study are summarized as follows. The 2-, 4-, 8-cell and morula embryos were mostly obtained at 36-42, 48-54, 62-66 and 72-78 hours after injection of hCG, respectively, and the average number of embryos recovered per head was 17.0. The bisection rate of 8-cell embryos was 83.6%, which was significantly higher than that of morula embryos, 65.5%. But the development of morula demi-embryos to blastocyst after in-vitro culture was better than that of 8-cell demi-embryos and the rate was 76.5% and 60.9%, respectively. When the 2, 10 and 15 cultured demi-embryos or intact embryos were transferred to each recipient mouse, respectively. the highest pregnancy rate was obtained when 15 embryos were transferred. And the overall offspring production rate of intact embryos was higher than that of demi-embryos.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1073-1078
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• 2006

Purpose : This study was performed to assess how a fetal diagnosis of congenital heart disease affects parents, as regards pregnancy management and care of infants after birth. Methods : Database search to find out abnormal fetal echocardiography performed at Seoul National University Children's Hospital from July 1988 to June 2003 revealed 370 examinations. After excluding both arrhythmias without structural cardiac disease and multiple pregnancies, 299 pregnancies remained and this data formed the basis of this analysis. We retrospectively reviewed the medical records with special attention to pregnancy outcomes and also tried to find out factors influencing parental decisions on whether to continue or terminate pregnancy. Results : In this study, the mean gestation age at diagnosis was $28{\pm}6.0weeks$. The mean age of mothers was $30{\pm}3.9$ years old. Younger gestational ages at diagnosis(P=0.000), more severe grades of fetal heart disease(P=0.002) and younger mothers(P=0.014) correlated with terminations of pregnanies. But the grades of fetal status, the grades of associated anomaly, whether in-vitro-fertilization was carried out or not and numbers of previous children were not significant. Conclusion : This study found that the earlier gestational ages at diagnosis, younger maternal age and higher grades of fetal heart disease tended to lead parent to select abortions. Fetal echocardiographies were performed too late. Moreover Koreans have a biased view that malformation is a something incurable and a tragedy not only to oneself, but also to a family. So parents select terminations of pregnancy, even in curable cases. This is very unethical.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.483-490
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• 1999

Interdental enamel stripping is an usual method for correction of abnormal tooth shape and tooth size discrepancy which is one of the etiologic factors of malocclusion. Clinically it Is useful to correct the minor crowding in anterior teeth and posterior occlusion during finishing stage of orthodontic treatment. But this procedure has risks such as irreversible tooth reduction and remaining roughness of enamel surface can accumulate plaque which can evoke periodontal problem. Even if various methods were introduced to minimize the enamel surface roughness, their evaluation was limited in morphologic differences by scanning electronic microscope(SEM). The purpose of this study was to compare the various interdental enamel stripping method by SEM and to quantify the difference of surface roughness by use of Surfcorder SEF-30D(Kosaka Lab. Ltd.) which can measure the roughness of surface. The stripping methods were divided into mechanical and mechanical-chemical method. Air-rotor stripping and separating strip were used for mechanical stripping and $37\%$ phosphoric acid was used for chemical stripping. The enamel surface roughness after mechanical or mechanical-chemical stripping of interproximal surfaces of premolars which were extracted for orthodontic purpose were measured and compared by means of SEM and $Surfcorder^{\circledR}$, the results were as follows. 1. Enamel surface of primary treated by coarse diamond bur and separating strip groups showed highest value of roughness. 2. To compare the primary treated groups between mechanical and mechanical-chemical method, the latter group showed lower value of roughness remarkably. 3. Mechanical stripping groups which were treated both coarse and fine instrument showed lower value of roughness as much as non treated group. 4. The use of Pumice for final polishing did not show significantly smoothening the stripped enamel surface any more.

• The korean journal of orthodontics
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• v.32 no.2 s.91
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• pp.129-142
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• 2002

The purpose of this study was to evaluate the effects of caffeine and calcium on the activities of the osteoblastic cell from mouse calvaria. The author cultured osteoblastic cells obtained from the mouse calvaria and were divided into three groups : the caffeine-treated, the calcium-treated and the combine-treated group. In caffeine-treated group, the cell toxicity was measured by MTT assay at 1, 2 and 4 days after treatment of caffeine. In all groups, the densities of the mineralized bone nodules were measured by imaging analyzer after Von Kossa staining. The alkaline phosphotase (ALP) activities were measured at 2, 7, 14, 21 and 28 days and the interleukin-1 ${\beta}$ activities at 48 hours after treatment of caffeine and calcium. The measurements were statistically executed with ANOVA test and the results were as follows. 1. The cellular toxicity of the caffeine increased with the concentration of caffeine during the incubation period. 2. The maximum densities of mineralization were observed at 0.2 mM caffeine-treated group, 1.2 mM calcium-treated group, 0.1 mM caffeine and 1.8 mM calcium-treated group. 3. The activities of ALP were peaked at 14 days at calcium-treated group as no-treated. But, the activities of ALP increased with concentrations of caffeine at caffeine-treated group. At combine-treated group, the act of ALP were peaked at 24 days at 1.2 mM, 1.8 mM calcium-treated group, But decreased at 2.5 mM calcium-treated group. 4. The activites of the IL-1 ${\beta}$ were increased significantly at 0.2 mM caffeine-treated group, 1.8 mM calcium-treated group and 0.1 mM caffeine and 1.8 mM calcium-treated group. But, they were decreased at all groups of high concentration.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.381-390
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• 2004

The purpose of this in vitro study was to investigate the effects of Nd:YAG laser irradiation and fluorides on acid drink demineralized enamel. The materials were 30 freshly extracted permanent premolars with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12hours and then irradiated by Nd:YAG laser with 6W power, $50mJ/cm^2$ energy density, and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides; (1)0.05% NaF fluoride solution (2)1.23% APF gel and (3)0.1%F fluoride varnish, microhardness(VHN) and Diagnodent scores were measured and the surfaces of each treated specimens were also observed with SEM under 1500 magnification. The results were as follows: 1. In the change of microhardness(VHN), it decreased to 34.68% from the initial micrhardness, increased to 78.37% after laser irradiation and increased to 82.62% after fluoride treatment, there were significant differences except when it was irradiated and treated with fluoride(P<0.05). 2. In the change of Diagnodent scores, it was decreased to 28.08% from the initial scores after demineralization, and then increased to 59.81% after laser irradiation, and increased to 82.17% after fluoride treatment. Scores were different significantly between the scores of initial, demineralization, laser irradiation and fluoride treatment(P<0.05). All the scores were not different significantly between fluoride types. 3. SEM observation showed that the lased enamel surfaces after demineralization were thermally degenerated and showed molten lava-like appearance and crater with cracks and many microholes.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.474-480
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• 2004

The purpose of this in vitro study was to compare the remineralizing effects of three glass ionomer cements (high filled glass ionomer cement, compomer, resin modified glass ionomer cement) with resin composite (control group) on incipient interproximal caries, and to assess long-term change of remineralization effect, in each material, evaluated by microtomography. Proximal restoration was simulated with tooth specimen and Glass Ionomer Cements. And each of these groups was placed into a closed container with artificial saliva at $37^{\circ}C$ and pH 7.0 for a time period of thirty days with constant circulation. At the end of thirty and sixty days, tomographic images were taken from these specimens with micro CT scanner. Materials used in this study were as follows. Group 1: Fuji IX GP (GC Corp., Tokyo, Japan) Group 2: Vitremer (3M ESPE, St. Paul, Minn., USA) Group 3: F2000 (3M ESPE, St. Paul, Minn., USA) Group 4: Z250 (3M ESPE, St. Paul, Minn., USA) Using density-measuring program, the micro-density of carious lesions on the specimens were measured. The mean density changes of each group were compared to the other groups to evaluate the effect of remineralization. The results were as follows: 1. The lesion density of all groups increased. 2. The mean density increase of Group 1, 2, 3 were higher than that of Group 4 every month(p<0.05). 3. There were significant differences of density increase among glass ionomer group(Group 1, 2, 3).