• Journal of Periodontal and Implant Science
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• v.22 no.1
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• pp.196.1-196.1
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• 1992

• Applied Biological Chemistry
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• v.35 no.3
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• pp.173-178
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• 1992

A bacterium having CMCase activity was isolated form soil and identifed as a Pseudomonas sp YD-15. The optimum conditions for the production of CMCase were avicel 1.2%, yeast extract 0.5%, $KNO_3$ 0.06%, $K_2HPO_4$ 0.2%, $MgSO_4$ $7H_2O$ 0.15%, pH 8.0, $30^{\circ}C$ and 60 hours cultivation. The CMCase was purified 15.2 folds with 14ft yield through ammonium sulfate precipitation, DEAE-sepharose column chromatography and sephadex G-100 gel filtration chromatography. The optimum pH and temperature for the enzyme activity were 6.0 and $50^{\circ}C$, respectively. The enzyme was stable between pH 5.0 and 8.0, below $50^{\circ}C$. The molecular weight was calculated about 100,000 by SDS-polyacrylamide gel electrophoresis. $K_m$ value for CMC used as a substrate was 40 mg/ml.

• International Journal of Oral Biology
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• v.45 no.3
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• pp.115-125
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• 2020

Resveratrol has been reported to exert anticancer activity via modulation of multiple pathways and genes. In this study, we examined the effect of resveratrol on YD-10B human oral squamous cell carcinoma cells and its molecular mechanisms of action. We found that resveratrol inhibited the proliferation of YD-10B cells in a dose- and time-dependent manner. The suppressive effect of resveratrol was accompanied by a reduction in Bmi-1 gene expression. We observed that silencing the Bmi-1 gene by small interfering RNA effectively downregulated the levels of GLUT1 mRNA and protein, which were also repressed by resveratrol. Bmi-1 silencing increased the number of YD-10B cells in S-phase arrest by approximately 2.3-fold compared with the control. In conclusion, the results of the present study demonstrate, for the first time, that resveratrol suppresses Bmi-1-mediated GLUT1 expression in human oral squamous cell carcinoma cells and suggest that the specific molecular targeting of Bmi-1 and/or GLUT1 expression can be combined with a chemotherapeutic strategy to improve the response of oral cancer cells to resveratrol.

• Tuberculosis and Respiratory Diseases
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• v.80 no.3
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• pp.270-276
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• 2017

Background: A disputed rpoB mutation is a specific type of rpoB mutation that can cause low-level resistances to rifampin (RIF). Here, we aimed to assess the frequency and types of disputed rpoB mutations in Mycobacterium tuberculosis isolates from South Korea. Methods: Between August 2009 and December 2015, 130 patients exhibited RIF resistance on the MTBDRplus assay at Asan Medical Center. Among these cases, we identified the strains with disputed rpoB mutation by rpoB sequencing analysis, as well as among the M. tuberculosis strains from the International Tuberculosis Research Center (ITRC). Results: Among our cases, disputed rpoB mutations led to RIF resistance in at least 6.9% (9/130) of the strains that also exhibited RIF resistance on the MTBDRplus assay. Moreover, at the ITRC, sequencing of the rpoB gene of 170 strains with the rpoB mutation indicated that 23 strains (13.5%) had the disputed mutations. By combining the findings from the 32 strains from our center and the ITRC, we identified the type of disputed rpoB mutation as follows: CTG511CCG (L511P, n=8), GAC516TAC (D516Y, n=8), CTG533CCG (L533P, n=8), CAC526CTC (H526L, n=4), CAC526AAC (H526N, n=3), and ATG515GTG (M515V, n=1). Conclusion: Disputed rpoB mutations do not seem to be rare among the strains exhibiting RIF resistance in South Korea.

• Korean Journal of Ichthyology
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• v.20 no.3
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• pp.156-162
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• 2008

Five microsatellite DNA markers were used to investigate genetic diversity and population structure of olive flounder Paralichthys olivaceus collected from four locations (YD, SC, GJ, WD) where hatchery-based seeds of the flounder have been released. The average of observed (Ho) and expected heterozygosity (He) ranged from 0.833 to 0.871, and from 0.842 to 0.876, respectively. The average number of alleles per locus ranged from 12.4 to 17.8. The proportion of stocked flounder ranged from 20.0% to 95.8% for wild-caught populations with a decreasing tendency of alleles per locus following a higher proportion of stocked flounder. There is need to implement a more careful stock-enhancement program of hatchery-based seeds and to monitor its genetic effects on wild populations to ensure conservation of natural flounder resources.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.251-257
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• 2008

Four potential microcystin-producing cyanobacteria were isolated from large reservoirs which act as sources of drinking water supply in Korea. Strain DC-2, YD-l, and YD-6 were closely related to Microcystis aeruginosa based on the analysis of l6S rRNA gene and mcyA gene sequences. mcyA gene sequence of YDS2-3, isolated from Yongdam Reservoir, was closed to that of M. aeruginosa, whereas l6S rRNA gene sequence was not related to the known sequences of microcystin-producing cyanobacteria indicating this strain can be a novel cyanobacterium belonging to the genus Microcystis. When mcyA gene sequences of isolated cyanobacteria were compared with the mcyA gene sequence library of two reservoirs, the sequence of DC-2 matched with the dominant ones.

• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.185-190
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• 2019

Periodontitis is a chronic inflammatory disease and gums pull away from the teeth and form spaces. The main goal of treatment is to control the infection and anti-inflammation. Eucommia ulmoides Oliv. Bark (EU) is a traditional Korean herbal used for the treatment of arthritis and hypertension. In the present study, we investigated the anti-inflammatory properties of EU in Porphyromonas gingivalis-LPS (LPS-PG) induced YD-38 epithelial cells. We observed significant inhibition of nitric oxide (NO) production and the expression of interleukin-8 (IL-8), interleukin-6 (IL-6), tumor necrosis factor alpha ($TNF-{\alpha}$), cyclooxygenase-2 (COX-2) in LPS-PG-induced YD-38 cells. These results support that EU has an anti-inflammatory effects for the treatment of periodontitis.

• Composites Research
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• v.31 no.6
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• pp.293-298
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• 2018

In this paper, we have studied the physical properties of braided composites for use as aircraft stringers. Process variables such as drum winder speed, braid velocity, and mandrel diameter for $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$ braid preforms were quantified and different epoxy resin types were applied to the braided preform using TGDDM, YD-128. Physical properties such as tensile strength and flexural strength of braided composites were investigated. Thermal properties and decomposition temperature of epoxy resin were investigated by TGA analysis. As a result, the lower the angle of the braid composites, the higher the tensile strength and the Flexural strength. The physical properties of braided composites fabricated using TGDDM epoxy resin were superior to the physical properties of braided composites fabricated using YD-128 epoxy resin. This is because the molecular weight of TGDDM epoxy resin was higher than that of YD-128 epoxy resin.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.1033-1040
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• 2022

The current experiment was conducted to evaluate the effect of diallel crossbreeding on the body weight and laying performance of Korean native chicken from hatch to week 40. A total of 1,000 one-day-old chicks were allotted to 10 cages per crossbreeding treatment with 10 birds per cage on a random basis and then raised until 16 weeks and subsequently moved to layer battery cages and raised until 40 weeks. Ten crossbred treatments (YC, YD, YF, YK, CD, CF, CK, DF, DK, FK) that were obtained from the diallel crossbred of five pure lines were used in the current experiment. The body weight and mortality were measured biweekly from hatching to week 20 and every four weeks from week 20 to week 40. The number of eggs was measured daily. YC and YD crossbreeds showed a higher body weight (p < 0.05) and FK crossbreed showed a lower body weight (p < 0.05) during the whole xperimental period. The week 20 weight range was 1,501 to 1,729 g and the week 40 weight range was from 1,829 to 2,179 g. Earlier onset of egg-laying was noted in the YC and YD groups whereas late onset was observed for the DF and DK groups. YK reached its peak earliest at week 25 with 89.15% while the DK crossbreed attained its peak at week 36 with 89.69%. The YC and YD crossbreeds showed the improved body and egg-laying performance. Conclusively, there are variations in the body weight and laying performance of Korean native chickens with diallel crossing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.975-982
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• 2015

Piceatannol (trans-3,4,3',5'-trihydroxystilbene), a natural stilbene, is an analogue of resveratrol. In the present study, possible mechanisms by which piceatannol exerts its pro-apoptotic action in cultured human oral cancer YD-15 cells were investigated. To investigate whether or not piceatannol has effects on cancer cell viability, human oral YD-15 cells were treated with piceatannol (0, 50, and $100{\mu}M$). Piceatannol treatment ($100{\mu}M$) showed the strongest inhibition of cell proliferation and reduced cell viability in a dose-dependent manner. Chromatin condensation detected by DAPI staining significantly increased in a concentration-dependent manner, indicating apoptosis. Piceatannol treatment activated initiator Bax (pro-apoptotic) and cPARP in a concentration-dependent manner. Further, piceatannol induced down-regulation of Bcl-2 (anti-apoptotic). We also evaluated the activity of piceatannol against oral cavity cancer tumors in mice. Piceatannol-treated nude mice bearing YD-15 xenograft tumors exhibited significantly reduced tumor volume and weight due to the potent effect of piceatannol on tumor cell apoptosis, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Immunohistochemistry staining showed elevated expression of cleaved-caspase-3 as well as reduced expression of Ki-67 in the piceatannol-treated group. Therefore, piceatannol can be developed as a cancer preventive medicine due to its growth inhibitory effects and induction of apoptosis in human oral cancer cells.