• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.167-173
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• 1997

The embryogenic callus (EC), from which somatic embryos could be induced, was compared with nonembryogenic callus(NE) to study the origin and features of totipotent cell in water dropwort (Oenanthe stolonifera DC). To induce and maintain of EC and the NE, meristematic stem and immature floret were inoculated in MS media supplemented with 1 mg/L 2,4-D, and with 2.5 mg/L NAA and 5mg/L BA, respectively, The EC was not induced from the NE even after subculturing in MS medium supplemented with 1 mg/L 2,4-D. Plantlets were not regenerated from the NE in hormone-free medium. In histochemical comparison of the EC with the NE by light microscopy, the EC had smaller cells in size, dense cytoplasm, and more starch granules of cells compared to the NE cells. The cell from the EC, as observed by transmission electron microscopy, had smaller vaculoes, well developed ribosomes, mitochondria, and endoplasmic reticulum, whereas the cells from the NE had larger vacuoles and underdeveloped organelles. In protein pattern from NE, EC and Somatic embryo (SE), as analyzed by SDS polyacrylamide gel electrophoresis, different proteins specific for tissue were observed: 17 and 28 KD for NE, 50, 52, 57, 66, 68 KD for EC and 20 KD for SE. DNA polymorphism was also observed between EC and NE as analyzed by RAPD (randomly amplified polymorphic DNA) method. The origin of totipotent stem cell and the relationship between irreversible genomic change arose in differentiation and the loss of totipotency in plant were discussed.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.383-390
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• 2013

Several yeasts were isolated from flowers found in Gyonggi-do Province and Jeju island in Korea. They were then identified by a comparison of their PCR-amplified D1/D2 regions of 26S rDNA, internal transcribed spacer 1 and 2 inclusive of 5.8S rDNA, using the BLAST database. A total of fifty four yeast strains were isolated from wild flowers in Gyonggi-do and the genus Pseudozyma was noted as being dominant. A total of thirty two strains were isolated from Songaksan and Seongsan-ilchulbong in Jeju island and Sporobolomyces ruberrimus was seen to be dominant. The anti-gout xanthine oxidase inhibitory activities of the culture broths and cell-free extracts from eighty six yeast strains were then determined. The cell-free extracts of Pseudozyma hubeiensis 228-S-1 exhibited the highest xanthine oxidase inhibitory activity of 19.6%. The XOD inhibitor was also maximally produced when Pseudozyma hubeiensis 228-S-1 was cultured at $30^{\circ}C$ for 36h in YEPD medium.

• Journal of Life Science
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• v.23 no.12
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• pp.1428-1435
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• 2013

The aim of this study is to investigate the melanogenic effect of Oenanthe javanica ethanolic extracts (OJE) containing quercetin and kaempferol in melanoma cells (B16F1). In order to determine whether OJE inhibits melanin synthesis at the cellular level, the melanoma cells were cultured in the presence of different concentrations of OJE. In the present study, the antioxidant effects of OJE on DPPH radical scavenging, power reduction, lipid peroxidation, and DNA oxidation were evaluated in a cell free system. Furthermore, the effect of OJE on the production of melanin was determined by dopaquinone (DOPA) assay and tyrosinase activity. In addition, the protein expression of tyrosinase, as well as antioxidant enzymes such as superoxide dismutase (SOD)-1, SOD-2 and glutathione reductase (GSH), were examined using Western blot analysis. In this study, it was observed that OJE exhibited an inhibitory effect on lipid peroxidation and blocked the DNA oxidation induced by the hydroxyl radical produced by Fenton's reagent. OJE increased melanin synthesis above 50 ${\mu}g/ml$ and tyrosinase activity was detected above 50 ${\mu}g/ml$. In Western blot analysis, OJE increased the expression levels of tyrosinase, SOD-1, SOD-2, and GSH in a dose-dependent manner. These findings indicate that OJE with antioxidant activity can regulate the tyrosinase activity and melanin production in melanocyte, suggesting that it could promote the development of black hair as well as protect skin from oxidative stress.

• Design & Manufacturing
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• v.17 no.1
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• pp.20-26
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• 2023

Lab-on-a-disc is a circular disc shape of cartridge that can be used for blood-based liquid biopsy to diagnose an early stage of cancer. Currently, liquid biopsies are regarded as a time-consuming process, and require sophisticated skills to precisely separate cell-free DNA (cfDNA) and circulating tumor cells (CTCs) floating in the bloodstream for accurate diagnosis. However, by applying the lab-on-a-disc to liquid biopsy, the entire process can be operated automatically. To do so, the lab-on-a-disc should be designed to prevent blood leakage during the centrifugation, transport, and dilution of blood inside the lab-on-a-disc in the process of liquid biopsy. In this study, the main components of lab-on-a-disc for liquid biopsy are fabricated by injection molding for mass production, and ultrasonic welding is employed to ensure the bonding strength between the components. To guarantee accurate ultrasonic welding, the flatness of the components is optimized numerically by using the response surface methodology with four main injection molding processing parameters, including the mold & resin temperatures, the injection speed, and the packing pressure. The 27 times finite element analyses using Moldflow® reveal that the injection time and the packing pressure are the critical factors affecting the flatness of the components with an optimal set of values for all four processing parameters. To further improve the flatness of the lab-on-a-disc components for stable mass production, a quarter-disc shape of lab-on-a-disc with a radius of 75 mm is used instead of a full circular shape of the disc, and this significantly decreases the standard deviation of flatness to 30% due to the reduced overall length of the injection molded components by one-half. Moreover, it is also beneficial to use a quarter disc shape to manage the deviation of flatness under 3 sigma limits.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.1
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• pp.1-9
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• 2012

The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and $[Ca^{2+}]i$ may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels.

• Journal of Genetic Medicine
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• v.11 no.2
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• pp.43-48
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• 2014

Chorionic villus sampling has gained importance as a tool for early cytogenetic diagnosis with a shift toward first trimester screening. First trimester screening using nuchal translucency and biomarkers is effective for screening. Chorionic villus sampling generally is performed at 10-12 weeks by either the transcervical or transabdominal approach. There are two methods of analysis; the direct method and the culture method. While the direct method may prevent maternal cell contamination, the culture method may be more representative of the true fetal karyotype. There is a concern for mosaicism which occurs in approximately 1% of cases, and mosaic results require genetic counseling and follow-up amniocentesis or fetal blood sampling. In terms of complications, procedure-related pregnancy loss rates may be the same as those for amniocentesis when undertaken in experienced centers. When the procedure is performed after 9 weeks gestation, the risk of limb reduction is not greater than the risk in the general population. At present, chorionic villus sampling is the gold standard method for early fetal karyotyping; however, we anticipate that improvements in noninvasive prenatal testing methods, such as cell free fetal DNA testing, will reduce the need for invasive procedures in the near future.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.2
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• pp.75-78
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• 2014

Green tea and tea polyphenols have been studied extensively as cancer chemopreventive agents in recent years. Epigallocatechin-3-gallate (EGCG) is widely recognized as a powerful antioxidant and a free radical scavenger. The purpose of this study was to evaluate the protective effects of green tea catechins (GTC) on the Bleomycin- and Cyclophosphamide-induced cytotoxicity. Cell viability was measured by MTT assay. In the protective effect of GTC, the cell viability was significantly increased by the treatment of GTC. Furthermore, GTC showed the higher protective effect than EGCG and vitamin E. These results suggest that GTC has the protective effect which is related to the prevention of cancer. Our studies show that the continuous presence of EGCG can reduce radical-induced DNA damage in Chinese hamster lung fibroblast cells (CHL cells).

• Journal of Nutrition and Health
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• v.39 no.8
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• pp.773-785
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• 2006

Vitamin E in the body system plays an important role in preventing chronic diseases by decreasing the oxidative stress by free-radicals. However, there are not enough researches on analyzing the primary factors affecting vitamin E levels in the blood in Korean adults. Therefore, the purpose of this research was to examine blood tocopherol levels and the primary factors affecting the status. A complete lifestyle survey was performed on 314 Korean adult men and surveyed their smoking, drinking and exercising habits. The average plasma level of ${\alpha}-\;and\;{\gamma}-tocopherol$ showed similar mutual relations with plasma total cholesterol (TC), triglyceride (TG), or low density lipoprotein cholesterol (LDL-C) levels (p<0.001). Plasma ${\alpha}-tocopherol$ level of the subjects did not show any difference as smoking, drinking and exercising habits changed. However, ${\gamma}-tocopherol$ per TG showed much lower figure in smokers than non smokers (p < 0.05). Amongst diet factors, plasma ${\alpha}-tocopherol$ level showed negative correlations with Vitamin E intake, while ${\gamma}-tocopherol$ level showed positive correlations with Vitamin E intake. Erythrocyte superoxide dismutase (SOD) activity and plasma tocopherol showed negative correlations, and catalase activity and plasma ${\alpha}-tocopherol$ showed positive correlationship. The level of cell DNA damage of Iymphocyte and plasma ${\alpha}-\;or\;{\gamma}-tocopherol$ showed negative correlations. As a result of this research, the factors that affect Korean adult men's plasma ${\alpha}-tocopherol$ level are plasma TG, LDL-C and cell DNA damage in Iymphocyte, while the factors that affect ${\gamma}-tocopherol$ level are plasma TG, LDL-C and vitamin E intake based on multiple regression analysis. These findings implies that the level of different types of tocopherol depends on slightly different factors. A further research is needed on the factors involved in the differentiation of the types of tocopherol.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.304-310
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• 2012

The present study showed that Transforming growth factor beta 1 (TGF-${\beta}_1$) can induce apoptosis of bovine mammary epithelial cells. This apoptosis was also observed with phosphorylation of Smad2/3 within 0.5-2 h. Afterwards the signal transferred into the nucleus. Moreover, intracellular free $Ca^{2+}$ concentration was significantly elevated as well as Caspase-3 activated and DNA lysised, thereby inducing the programmed cell death. This signaling pathway of TGF-${\beta}_1$ was blocked by SB-431542 ($10^{-2}{\mu}M$) via inhibiting ALK-5 kinase activity, which thus reversed the anti-proliferation and apoptosis effect of TGF-${\beta}_1$ in mammary epithelial cells. These results indicated that TGF-${\beta}_1$ induced apoptosis of bovine mammary epithelial cells through the ALK-5-Smad2/3 pathway, which plays an important role in inhibiting survival of mammary epithelial cells. Moreover, intracellular $Ca^{2+}$ also played a critical role in TGF-${\beta}_1$-induced cell apoptosis.

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.402-407
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• 1996

Effects of oxidative stress on the induction of apoptosis and the activity of antioxidant enzymes were investigated in HL-60 cells using $H_2O$$_2$and cisplatin which generate oxygen species in the cell. Various concentrations of oxidants were treated to cells and at different incubation time, cells were harvested for assays. Cell viability, morphology by propidium iodide staining and DNA fragmentation by agarose gel electrophoresis were observed to determine whether they induce apoptosis. The activity of antioxidant enzymes such as superoxide dismutase and catalase was also measured to evaluate the cellular response to the oxidative damage. The results are as follows: $H_2O$$_2$ induced apoptosis at 10 $\mu$M after 6h incubation, while it took 12h for cisplatin. Both oxidants induced the superoxide dismutase activity at a tolerable low concentration. However, at a concentration which causes apoptotic cell death, the enzyme level was dropped markedly at first and then recovered to the normal level after which it declined again, probably due to cell death. On the other hand, changes in the activity of catalase were not significant at most concentrations except the statistically significant decrease at 24h after 10 $\mu$M-$H_2O$$_2$treatment. In this study, $H_2O$$_2$- and cisplatintreated cells showed similar results in apoptotic response and enzyme activities, suggesting that anticancer activity of cisplatin may be related, at least in part, to the production of oxygen free radicals.