• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.69-75
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• 2002

Sterols play two major roles in plants: a bulk component in biological membranes and precursors of plant steroid hormones. Physiological effects of plant steroids, brassinosteroids (BRs), include cell elongation, cell division, stress tolerance, and senescence acceleration. Arabidopsis mutants that carry genetic defects in BR biosynthesis or its signaling display characteristic phenotypes, such as short robust inflorescences, dark-green round leaves, and sterility. Currently there are more than 100 dwarf mutants representing 7 genetic loci in Arabidopsis. Mutants of 6 loci, dwf1/dim1/cbb1, cpd/dwf3, dwf4, dwf5, det2/dwf6, dwf7 are rescued by exogenous application of BRs, whereas bri1/dwf2 shares phenotypes with the above 6 loci but are resistant to BRs. These suggest that the 6 loci are defective in BR biosynthesis, and the one locus is in BR signaling. Biochemical analyses, such as intermediate feeding tests, examining the levels of endogenous BR, and molecular cloning of the genes revealed that dwf7, dwf5, and dwf1 are defective in the three consecutive steps of sterol biosynthesis, from episterol to campesterol via 5-dehydroepisterol. Similarly, det2/dwf6, dwf4, and cpd/dwf3 were shown to be blocked in $D^4$ reduction, 22a-hydroxylation, and 23 a-hydroxylation, respectively. A signaling mutant bri1/dwf2 carries mutations in a Leucine-rich repeat receptor kinase. Interestingly, the bri1 mutant was shown to accumulate significant amount of BRs, suggesting that signaling and biosynthesis are dynamically coupled in Arabidopsis. Thus It is likely that transgenic plants over-expressing the rate-limiting step enzyme DWF4 as well as blocking its use by BRI1 could dramatically increase the biosynthetic yield of BRs. When applied industrially, BRs will boost new sector of plant biotechnology because of its potential use as a precursor of human steroid hormones, a novel lead compound for cholesterol-lowering effects, and a various application in plant protection.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.88-95
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• 1992

The genetically engineered microorganisms (GEMS) could be released accidentally or ii)rexperimental purposes, as the genetic engineering, technique ha:. become very popular inany laboratories of biological sciences. But there have been littlt: informations on transkrbehavior of the genetically ~nodified genes in the natural en\ironmentx. In this stutly.antibiotic resistant bacteria were isolated from nat.ural waters. and then GEM strains wereconstructed i'rom the natural isolate (NI) by ~noclification oi' the Km' plasmitl. Thetransferability of the plasmids in the GEM and NI strains were examinetl by con-jugationin Luria-Bertani broth :it 30$^{\circ}$C. Also the cff'ccts 01' mating strain and pH on their transferfrequency and rearrangement of the plasmids in tl-~ec o~ijugantsM ere comp:irati\ely stuclictl.I'hc transkr frequency of Km' plasmid in donor of GEM and N1 strains wah similar a.;about 10 ' when co~ljugation was conducted wit11 M'I'I strain is recipient at pH 7. butthat of 1)KCOOI was lowered to 1.2X 10 '. And when the lab. stlain was uhccl as recipient.the transfer tendency of the plasmid was about same in both (;EM and NI strains usedas donor. All thc tionor 5trains. except for I)KC601. showecl the Ilighcs~ frequency of about10 ' at pH 7 and the frequcncics were lowered at both pH 5 and 9. Hut the mocliliedKm' plasmid in the cloned strain of DKC601 was transferred hy very low frequency of10 "at pH 5 ant1 7 comparing to other GEM strains. especiall! any co~~.jugantws ere notobtained at pH 4 and 9 even after conjugation for 6 hours. Rearrangement of the plasmidstranskrred into the lab. strain was not found in the conjugants. I\ulcornerut a lot of rearrangclncntwas ohservecl nlhen they were transferred into the NI strain. Such a rearrangement wasmore severe when donor was GEM strain rather then NI strain Hut such ;r phenomenonwas less affected by p!-l values.r phenomenon was less affected by p!-l values.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.551-558
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• 2016

Malignant glioma cells invading surrounding normal brain are inoperable and resistant to radio- and chemotherapy, and eventually lead to tumor regrowth. Identification of genes related to motility is important for understanding the molecular biological behavior of invasive gliomas. According to our previous studies, Metallothionein 1E (MT1E) was identified to enhance migration of human malignant glioma cells. The purpose of this study was to confirm that MT1E could modulate glioma invasion in vivo. Firstly we established 2 cell lines; MTS23, overexpressed by MT1E complementary DNA construct and pV12 as control. The expression of matrix metalloproteinases (MMP)-2, -9 and a disintegrin and metalloproteinase 17 were increased in MTS23 compared with pV12. Furthermore it was confirmed that MT1E could modulate MMPs secretion and translocation of NFkB p50 and B-cell lymphoma-3 through small interfering ribonucleic acid knocked U87MG cells. Then MTS23 and pV12 were injected into intracranial region of 5 week old male nude mouse. After 4 weeks, for brain tissues of these two groups, histological analysis, and immunohistochemical stain of MMP-2, 9 and Nestin were performed. As results, the group injected with MTS23 showed irregular margin and tumor cells infiltrating the surrounding normal brain, while that of pV12 (control) had round and clear margin. And regrowth of tumor cells in MTS23 group was observed in another site apart from tumor cell inoculation. MT1E could enhance tumor proliferation and invasion of malignant glioma through regulation of activation and expression of MMPs.

• Nutrition Research and Practice
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• v.11 no.3
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• pp.190-197
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• 2017

BACKGROUND/OBJECTIVES: Gallus gallus domesticus (GD) is a natural mutant breed of chicken in Korea with an atypical characterization of melanin in its tissue. This study investigated the effects of melanin extracts of GD on osteoblast differentiation and inhibition of osteoclast formation. MATERIALS/METHODS: The effects of the melanin extract of GD on human osteoblast MG-63 cell differentiation were examined by evaluating cell viability, osteoblast differentiation, and expression of osteoblast-specific transcription factors such as bone morphogenetic protein 2 (BMP-2), small mothers against decapentaplegic homologs 5 (SMAD5), runt-related transcription factor 2 (RUNX2), osteocalcin and type 1 collagen (COL-1) by reverse transcription-polymerase chain reaction and western blotting analysis. We investigated the inhibitory effect of melanin on the osteoclasts formation through tartrate-resistant acid phosphatase (TRAP) activity and TRAP stains in Raw 264.7 cell. RESULTS: The melanin extract of GD was not cytotoxic to MG-63 cells at concentrations of $50-250{\mu}g/mL$. Alkaline phosphatase (ALP) activity and bone mineralization of melanin extract-treated cells increased in a dose-dependent manner from 50 to $250{\mu}g/mL$ and were 149% and 129% at $250{\mu}g/mL$ concentration, respectively (P < 0.05). The levels of BMP-2, osteocalcin, and COL-1 gene expression were significantly upregulated by 1.72-, 4.44-, and 2.12-fold in melanin-treated cells than in the control cells (P < 0.05). The levels of RUNX2 and SMAD5 proteins were higher in melanin-treated cells than in control vehicle-treated cells. The melanin extract attenuated the formation of receptor activator of nuclear factor kappa-B ligand-induced TRAP-positive multinucleated RAW 264.7 cells by 22%, and was 77% cytotoxic to RAW 264.7 macrophages at a concentration of $500{\mu}g/mL$. CONCLUSIONS: This study provides evidence that the melanin extract promoted osteoblast differentiation by activating BMP/SMADs/RUNX2 signaling and regulating transcription of osteogenic genes such as ALP, type I collagen, and osteocalcin. These results suggest that the effective osteoblastic differentiation induced by melanin extract from GD makes it potentially useful in maintaining bone health.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.387-393
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• 1992

The fate of inoculum strain of Bradyrhizobium japonicum was studied by using genetically marked strain. RJB6 $str^rnal^rneo^r$. A spontaneous mutant of B. japonicum isolated from nodules was made to have antibiotic resistance against streptomycin and nalidixic acid. In order to make genetically marked strain, neomycine resistant gene(Tn5) was introduced into this spontaneous mutant by conjugation with E. coli containing pSUP2021. The southern hybridization was carried out to confirm the plasmid insertion. Hybridization of chromosome DNA using pSUP2021(Tn5) as a probe showed that Tn5 was located on the 4.9kb fragment of chromosome. Soybean seeds were planted into a soil previously cultivated with soybean and inoculated with different cell densities of marked strain. Fourty days after planting, the inoculation effects on nodule number, nodule fresh weight, plant height and nitrogen content in the plot inoculated with heavy cell suspension was a little better than those in the plot with low inoculation. The recovery percentage of the marked strains was about 12% in the plot inoculated with heavy density cell suspension, while 5% in the plot inoculated with low cell suspension.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.339-344
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• 2005

Rice blast, which is caused by the fungus Magnaporthe grisea, is one of the most destructive diseases of rice. To identify genes involving in the signal transduction pathways that mediate rice blast resistance, we screened over 2,000 mutant lines of a highly resistant variety RIL260 that were generated by using a DEB (1, 3-Butadiene diepoxide) treatment method. In the mutant population, the frequency of albino plants was 6.7%, indicating that this population has a high frequency of mutations in the genome. The primary screening identified 29 mutant plants that exhibit a complete or partial loss of the resistance to rice blast. Among them, M5465, the most susceptible line, was subsequently examined by DNA gel-blot experiments using DNA molecular markers of Pi5(t) that has been previously identified as a durable resistance locus in RIL260. The result revealed that a large deletion and rearrangement of genomic DNA occurred in the Pi5(t) locus. The results suggest that DEB can be used as an efficient mutagen to induce large scale mutations in the rice genome. The isolated mutants should be useful for elucidating the Pi5(t)-mediated signaling pathways of rice blast resistance.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.148-154
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• 2013

BACKGROUND: Genetically modified(GM) trigonal cactus(Hylocereus trigonus Saff.) contained a coat protein gene of cactus virus X (CVX), which conferred resistance to the virus, phosphinothricin acetyltransferase (bar) gene, which conferred herbicide resistance, and a cauliflower mosaic virus 35S promoter (CaMV 35S). This study was conducted to evaluate the possible impact of GM trigonal cactus cultivation on the soil microbial community. METHODS AND RESULTS: Microorganisms were isolated from the rhizosphere of GM and non-GM trigonal cactus cultivation soils. The total numbers of bacteria, and actinomycete in the rhizosphere soils cultivated GM and non-GM trigonal cactus were similar to each other, and there was no significant difference. Dominant bacterial phyla in the rhizosphere soils cultivated with GM and non-GM trigonal cactus were Proteobacteria, Uncultured archaeon, and Uncultured bacterium. The denaturing gradient gel electrophoresis (DGGE) profiles show a similar patterns, significant difference was not observed in each other. DNA was isolated from soil cultivated GM and non-GM trigonal cactus, we analyzed the persistence of the inserted gene by PCR. Amplification of the inserted genes was not observed in the soil DNA, which was collected after harvest. CONCLUSION(S): This result suggests that the GM trigonal cactus cultivation does not change significantly the microbial community.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.182-190
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• 2008

A survey on consumer's awareness and perception toward genetically-modified(GM) foods was conducted on 2110 random samples of Korean consumers. More than 65% of the respondents were exposed to some information related to GM foods. The respondents answered that the greatest benefit of the development of GM foods is remedy of potential food shortages in the future. More than 90% of Korean consumers wanted GM foods to be labeled as such. More than 50% of the respondents would not buy until they know more about GM foods. Only 35.8% of Korean consumers were found to know that food items originating from plants contained genes. More consumers responded that they would not buy herbicide-resistant GM soybean but buy vitamin-enriched GM soybean. Many Korean consumers' decision of acceptance or rejection of GM foods depend not on the basis of biotechnology, but on the basis of the degree of benefit to the consumers. Only 6.4% of Korean consumers responded that GM foods were the greatest threat to the safety of Korean foods. The perception of Korean consumers on GM foods has not changed significantly during the past 5 years.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.26-32
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• 2011

To improve genetic transformation of Brassica napus winter cultivar 'Youngsan', factors influencing shoot regeneration and transformation from cotyledonary petioles were investigated. Shoot induction was enhanced in the combination of 0.5 mg/L NAA and 2~4 mg/L kinetin. Silver nitrate was essential for successful shoot regeneration, ranging from 5 to 9 mg/L. The addition of $GA_3$ promoted plant regeneration. Among the tested Agrobacterium strains, co-cultivation times, and antibiotic selection regimes, choice of appropriate Agrobacterium strain was the most critical factor for efficient transformation of B. napus cv. 'Youngsan'. The EHA105 succinamopine strain was the most efficient and the maximum transformation efficiency was 26.8%. Transgenic shoots were selected on 10 mg/L phosphinothricin (PPT) containing media. The transgenic plants expressing bar and gus genes were resistant for commercial herbicide "Basta" and stained with X-Gluc. Southern blot hybridization indicated that the presence of one to three gus gene copies per genome and inheritance of the gus gene into the $T_1$ generation.

• Korean journal of applied entomology
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• v.17 no.2 s.35
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• pp.75-80
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• 1978

The study was conducted to determine the inherited properties of the MEB resistance to natural population of the small brown plant-hopper(Laodelphax striatelluss). The plant-hoppers were collected from the natural population of Naju area where the highest insecticide resistance of MEF to the green rice leaf hopper (Nephotettix cincticeps) have been examined in 1976. And Naju collections were crossed to the susceptible Lab stock to examine the MEP resistance in the $F_1,\;BC_1F_1\;and\;F_2$ and $F_2$ populations. Ail the data were analyzed by the probit method. There was a difference in MEP resistance between Naju collection and susceptible Lab stock, showing $LD_{50}$ value of the former was 0.0029ug/insect compared to 0.0008ug/insect for the later. The $LD_{50}$ values and dosage-mortality lines of the $F_1$ and $BC_1F_1$ tended to close their resistant parent. and it was considered that the character of the MEP resistance in the Naju collection of the small brown plant hopper was controlled by the genetic traits. However, $LD_{50}$ value and dosasage-mortality lines of the $F_2$ populations were intermediate to their parents, it would be conclusive that the trait will be governed by a interaction of the genes or factors rather than the single genic control.